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is motorcycling awesome
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alr
May 14, 2009

Steakandchips posted:

Gonna change the oil on my bike.

Where do I get a spare oil drain bolt and sealing washer in case the existing ones are no good once they are taken off the bike to drain the oil?

Pretty much anywhere. Grab a pack of the correct size crush washers since you'll be replacing them every change, and if you buy one of those aluminium magnetic drain bolts make sure it's one where there's enough metal around the magnet. This is just a random google search so I have no idea about these brands, but I'd personally avoid the first one. Don't over-tighten it.





Also have a plan to get rid of the oil soonish, because it's real easy to be lazy and have something like 8 litres in random containers in the back of the shed

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Gorson
Aug 29, 2014

Most places like Autozone or O'Reilly's will take your old oil. It's an odd process where they walk you into the back of the store through all the inventory so you can dump it yourself into a giant dumpster.

Shelvocke
Aug 6, 2013

Microwave Engraver

alr posted:

make sure it's one where there's enough metal around the magnet.

HenryJLittlefinger
Jan 31, 2010

stomp clap


Steakandchips posted:

Gonna change the oil on my bike.

Where do I get a spare oil drain bolt and sealing washer in case the existing ones are no good once they are taken off the bike to drain the oil?

The drain bolt should be fine, unless idiots have gotten their hands on it. It's not a "replace every service" item. That said, a magnetic one isn't terrible to have. In the US, our general auto parts stores have assortments of copper washers pretty cheap. I buy one every couple years for oil changes on all our vehicles and the odd fluid line (brake lines, oil lines) changes on the bike. They're cheap.

So if you're set on getting a new oil pan bolt, get that first, then go to the auto parts store and find some washers that fit around it snug but easily. Then get 10 of em and you're good for years.

alr posted:

Also have a plan to get rid of the oil soonish, because it's real easy to be lazy and have something like 8 litres in random containers in the back of the shed
:ughh: I've got like 15 gallons of used fry oil and at least a couple of motor oil and probably a quart of brake fluid that's accumulated in my garage over the last couple years.

MomJeans420
Mar 19, 2007



I always put the used oil in the bottles the new oil came in once I'm done changing the oil, but my last change I ran out of time and now I've had dirty oil in the drain pan for two months. I keep on having to work weekends though so I haven't really had time for anything.

Elector_Nerdlingen
Sep 27, 2004



Big stupid day.

Washed the bike, had a look around the bike to see if anything's broken or changed which I usually do when I wash the car too. The rear (of two) screws that holds the chain guard on is gone, the front one's loose, and the chain's visibly loose, it's got maybe 70-80mm play and it's supposed to have 20-30, and I swear that's what it had when I last looked a month ago.

Read the service manual. Realised that last time I checked the chain, I did it with the bike in gear, not in neutral. Confirmed that this makes a difference.

Went to adjust chain. Went to the hardware store for the right size wrench for the axle. Adjusted chain which was actually fairly easy. Checked for tight or kinked sections, didn't find any. Borrowed my cool neighbour's torque wrench and did everything back up. Went to the hardware store again because I forgot to get a replacement for the missing chain guard bolt and I don't have any spares the right size. Put the bike back together. Rode around town for 15 minutes, checked everything, looks like I've done a good job.

Rode to the next big town to buy a torque wrench and some chain lube and cleaner and stuff. Bike feels smoother and nicer.

Ran out of fuel 5km out of that town. Less kms than when I usually fuel up, so either I didn't fill it up full last time or I've been riding harder, or probably both. Tried to switch to the reserve tank but the bike wouldn't start. Pushed it, which was fuckin miserable, for about 1km. None of the loving arseholes driving past even stopped to see if I was ok. Tried to start it again, it started, and I got fuel then got all my poo poo done and had an actually really nice and chill ride back home with nice sunny weather just barely cool enough to be comfortable at speed.

Questions:

1) Have I damaged anything riding around with a loose chain? What do I need to check?

2) Is it possible that the chain etc has worked loose that much in the ~2500km I've ridden, or was it always adjusted like poo poo? If the former, what do I do to stop that from happening?

3) Is there a trick to getting the petcock switched over? Or else what might I have been doing wrong that the bike wouldn't re-start after I switched to reserve but did re-start after the switch had been left there and the bike pushed? edit: It's "stand the bike up straight instead of leaving it on the kickstand", right?

4) It's just gonna be like this some days, isn't it?

Elector_Nerdlingen fucked around with this message at 05:19 on Dec 7, 2019

Slavvy
Dec 11, 2012

Elector_Nerdlingen posted:

Big stupid day.

Washed the bike, had a look around the bike to see if anything's broken or changed which I usually do when I wash the car too. The rear (of two) screws that holds the chain guard on is gone, the front one's loose, and the chain's visibly loose, it's got maybe 70-80mm play and it's supposed to have 20-30, and I swear that's what it had when I last looked a month ago.

Read the service manual. Realised that last time I checked the chain, I did it with the bike in gear, not in neutral. Confirmed that this makes a difference.

Went to adjust chain. Went to the hardware store for the right size wrench for the axle. Adjusted chain which was actually fairly easy. Checked for tight or kinked sections, didn't find any. Borrowed my cool neighbour's torque wrench and did everything back up. Went to the hardware store again because I forgot to get a replacement for the missing chain guard bolt and I don't have any spares the right size. Put the bike back together. Rode around town for 15 minutes, checked everything, looks like I've done a good job.

Rode to the next big town to buy a torque wrench and some chain lube and cleaner and stuff. Bike feels smoother and nicer.

Ran out of fuel 5km out of that town. Less kms than when I usually fuel up, so either I didn't fill it up full last time or I've been riding harder, or probably both. Tried to switch to the reserve tank but the bike wouldn't start. Pushed it, which was fuckin miserable, for about 1km. None of the loving arseholes driving past even stopped to see if I was ok. Tried to start it again, it started, and I got fuel then got all my poo poo done and had an actually really nice and chill ride back home with nice sunny weather just barely cool enough to be comfortable at speed.

Questions:

1) Have I damaged anything riding around with a loose chain? What do I need to check?

2) Is it possible that the chain etc has worked loose that much in the ~2500km I've ridden, or was it always adjusted like poo poo? If the former, what do I do to stop that from happening?

3) Is there a trick to getting the petcock switched over? Or else what might I have been doing wrong that the bike wouldn't re-start after I switched to reserve but did re-start after the switch had been left there and the bike pushed? edit: It's "stand the bike up straight instead of leaving it on the kickstand", right?

4) It's just gonna be like this some days, isn't it?

1. Probably not, just take a good side on look at the sprockets, make sure the teeth aren't hooked or scooped out.

2. It is not only possible but pretty much guaranteed if you aren't lubing your chain 3-4 times in that interval. It also depends on the chain itself, have a look on the plates to see if there's any writing - the reputable brands usually have size numbers as well as branding - and establish that it's at least an o-ring chain. If you've got red dust the chain is hosed, try again next time. You also wanna be adjusting it at the tightest spot, found by spinning the rear wheel slowly and jiggling the bottom run until you find the least jiggly bit.

3. Switch to reserve when you're still coughing out of full. Failing that your bike should have a vacuum petcock, ON and RES both need the engine turning to open so you may not have been cranking long enough, but anyway it should have a PRIME position which is what you want. Prime is mechanically open without the engine needing to turn over, if there's gas in there prime will get it out. Your bike also has a vacuum operated lift pump and if that empties then you have to crank the engine regardless.

4. Oh yeah! Don't buy wrenches in ones and twos, in the long run it works out cheaper to get a set glhf!

Slavvy fucked around with this message at 06:02 on Dec 7, 2019

Elector_Nerdlingen
Sep 27, 2004



Thank you once again. PRIME, huh? Given that there's 3 positions I probably should have tried all 3 before I pushed :downs:

Yeah, I adjusted the chain at the tightest spot (not much difference between that and the loosest) and did the service manual recommended check to see if it'd stretched. It has not. It's an o-ring chain, too. I'll lube it more often. And maybe buy a driveshaft bike next time.

I have an adequate set of sockets and spanners, I had somehow lost my 19mm ring spanner, and I thought I had my dad's old torque wrench in a box, but it's not in that box and I have a terrible feeling I've lost it when I last moved.


Super late edit: That's "stretched too much", not "stretched at all".

Elector_Nerdlingen fucked around with this message at 10:07 on Dec 7, 2019

Supradog
Sep 1, 2004

A POOOST!?!??! YEEAAAAHHHH
I always think of this video when people talk about overly loose chains

https://www.youtube.com/watch?v=xBZWjwHgveY

Rolo
Nov 16, 2005

Hmm, what have we here?
Think I’ll go measure and lube my chain.

Elector_Nerdlingen
Sep 27, 2004



Ok, chain cleaned and lubed then I checked the alignment and the tightness again because now I'm paranoid. Took all morning and made a huge mess (but I put cardboard down!) and I'm gonna get a stand because gently caress doing this again without one.

So, lube every 500-800km, clean... what, every 2 or 3 lubes?

Coydog
Mar 5, 2007



Fallen Rib
You'll get a clean and lube down to 15 minutes soon, don't worry. A stand helps a ton. You've got it about right. Lube every 500 miles, clean every 1500 miles.

Or do it more often, the clean part isn't a huge deal after the first few times. It's just really important that you keep the chain properly lubed, as that also keeps debris out of the links.

builds character
Jan 16, 2008

Keep at it.
This popped up on my youtube feed https://www.youtube.com/watch?v=1es8ce2eJ9I and reminded me of the version of this that I'd actually done, cornerspin. Example video here https://www.youtube.com/watch?v=YiQDheIVCRc&t=134s. Anyway, I think it's well worth doing one of these classes as soon as you can if you're new. Even if you don't want to race. It'll give you a solid foundation in appropriate body position and a great amount of practice in a low-risk environment. Plus some experience dealing with limited traction so you don't panic when you hit gravel for the first time.

Elector_Nerdlingen
Sep 27, 2004



My fuel economy started off at 4.5 to 5 litres per 100km. It's now 5.5 to 6.5 litres per 100km which seems insane given that my VW van gets about 7.5. I mean, van's a diesel but still.

What do I need to think about doing maintenance to?

Also where do I buy the weird shaped air filters (yes plural, it's got one each side) that I need for this bike? (Intruder 250). Scratch that, they're foam and they're not hosed, I'll clean them and see if that helps for starters.

Elector_Nerdlingen fucked around with this message at 11:03 on Dec 12, 2019

Shelvocke
Aug 6, 2013

Microwave Engraver
Just posted about this, plugs/filter

Iridium plugs are better (I have no evidence to support this)

Slavvy
Dec 11, 2012

Elector_Nerdlingen posted:

My fuel economy started off at 4.5 to 5 litres per 100km. It's now 5.5 to 6.5 litres per 100km which seems insane given that my VW van gets about 7.5. I mean, van's a diesel but still.

What do I need to think about doing maintenance to?

Also where do I buy the weird shaped air filters (yes plural, it's got one each side) that I need for this bike? (Intruder 250). Scratch that, they're foam and they're not hosed, I'll clean them and see if that helps for starters.

Plugs, valve clearances, you haven't hit the oil change interval have you? Also the choke on those bikes really loves to stick on so check that.

Also a good chance you're just more confident now so you're riding faster.

Shelvocke
Aug 6, 2013

Microwave Engraver

Slavvy posted:

fuel economy is for nerds

Elector_Nerdlingen
Sep 27, 2004



Slavvy posted:

Plugs, valve clearances, you haven't hit the oil change interval have you? Also the choke on those bikes really loves to stick on so check that.

Also a good chance you're just more confident now so you're riding faster.

Changed the oil and filter first thing, not up to it again yet.

I can do plugs. Valve clearances look like a bitch but I'll try.

How do I tell if the choke's stuck on? I've needed to put it on twice on the coldest of cold mornings but I usually ride afternoons and it's been warm through hot here mostly. Also my area is warm on average even when the places I ride to are cold - so like yesterday I was sweating when I left, then after an hour I got cold as I went south and up.

Also I'm riding a little faster, yeah.

HenryJLittlefinger
Jan 31, 2010

stomp clap


Elector_Nerdlingen posted:


How do I tell if the choke's stuck on?

If it don't idle right. Could manifest in different ways. On my 96 Yamaha 600cc inline four it meant idling moderately high, like 2500 rpm. On my 99 Suzuki 650 single, it bogs and lopes and tries to kill itself. On my 91 Suzuki 350 single it would progressively climb higher and higher in idle till it was screaming.

Or you could just make sure to turn the choke off with the choke lever, wherever it is and know for sure it's not stuck on.

Elector_Nerdlingen
Sep 27, 2004



Seems to idle fine.

I usually don't need the choke to start the bike, but if the bike's on and I turn the choke lever to on, the bike dies. That indicates it's not stuck, right?

E' If that means "tuned wrong", then what do I do about that?

Elector_Nerdlingen fucked around with this message at 00:41 on Dec 13, 2019

Slavvy
Dec 11, 2012

Elector_Nerdlingen posted:

Changed the oil and filter first thing, not up to it again yet.

I can do plugs. Valve clearances look like a bitch but I'll try.

How do I tell if the choke's stuck on? I've needed to put it on twice on the coldest of cold mornings but I usually ride afternoons and it's been warm through hot here mostly. Also my area is warm on average even when the places I ride to are cold - so like yesterday I was sweating when I left, then after an hour I got cold as I went south and up.

Also I'm riding a little faster, yeah.

If it starts without the choke from dead cold on a normal day it is probably tuned wrong or the choke is stuck. 90% of bikes with CV carbs shouldn't start well with no choke; if you think about it, the carb is jetted for the bike being at operating temperature and the choke is just there to richen the mixture so it'll start when cold, so if it starts without the choke something is wrong.

Your bike has a few extra twists: it has a vacuum operated lift pump and vacuum petcock, both of which fail regularly and can cause it to sip fuel through the vacuum line. It also has an accelerator pump that can make judging rich/lean idle tricky.

HenryJLittlefinger posted:

Or you could just make sure to turn the choke off with the choke lever, wherever it is and know for sure it's not stuck on.

Typically on these you can tell because someone has cranked up the idle and shut the pilot screw so it'll idle semi ok.

Also the lever being forward means nothing on these, the choke plunger itself seizes open and pushing the lever forward just bunches up the cable and does nothing. I've had to drill out several, my theory is that the elbow shaped choke cable directs rain water straight down the hole.

Elector_Nerdlingen
Sep 27, 2004



Just finished up doing some reading and video watching. Can I please get a sanity check, I'm tired and this is still all new to me.

Because moving the choke lever to on kills the engine, I.m working on the assumption that the choke is not stuck (if there's a way to physically check it, can you let me know, I can't figure it out from the manual). Because it usually starts without the choke, it's likely that the bike is running too rich (poor fuel economy, choke not needed from cold start, smell petrol while idling). One of the ways I could confirm this is by checking the spark plugs and seeing if they're black/sooty, which I'll do tomorrow. I'll also check the gaps while they're out. Another problem could be a dirty air filter, so I'll remove and clean those too.

If I'm still getting the same symptoms, I need to adjust the mixture? Which involves pulling the carb apart? Or is the idle screw the thing I need to be loving with first?

Or do I need to think about changing the spark plugs from "Standard" CR7E to a CR6E?

Or if I'm on the wrong track entirely please let me know what the right track is and how I can get to it?

Slavvy posted:

Typically on these you can tell because someone has cranked up the idle and shut the pilot screw so it'll idle semi ok.

I get what the idle screw is and what it does, but I can't access the pilot screw without disassembling the carb, right?

Ulf
Jul 15, 2001

FOUR COLORS
ONE LOVE
Nap Ghost

Elector_Nerdlingen posted:

I get what the idle screw is and what it does, but I can't access the pilot screw without disassembling the carb, right?
The pilot screw is the idle screw that you're thinking of. It's the one that's externally adjustable, but in normal circumstances you shouldn't fiddle with it unless changing altitude.

HenryJLittlefinger
Jan 31, 2010

stomp clap


Ulf posted:

The pilot screw is the idle screw that you're thinking of. It's the one that's externally adjustable, but in normal circumstances you shouldn't fiddle with it unless changing altitude.
Unless a PO has fiddled with it before and he's trying to walk back some of that tinkering.

Slavvy will surely chime in soon, but generally you seem to understand how it's working. The choke forces the fuel/air mixture to richen by choking out the air component. On some bikes, it's an enrichment, which just opens up an extra fuel circuit, dumping more gas into the cylinders. So when a choke is killing the engine, it's likely because the fuel/air mixture is too rich, either because the air intake is restricted (dirty filter, pilot screw too rich) or because the fuel flow in the carb has been richened (bigger jets). Slavvy, correct me on that wherever.

BUT, you should only make one change at a time when you're dicking around with fuel/air mixture. Air filters should be clean anyway, so do that if it needs to be done. Also do the plug chop and see what the electrodes look like. Having fresh plugs is a good place to start from, but your symptoms are rarely plug-related.

If and when you get around to messing with the pilot screw, make sure you record exactly where it was when you started. To do that, screw it all the way in, counting the turns down to the 1/4, and write it down. Then go back to where it was and start from there. My general rule when I mess with pilot screws is to start with them at about 1-3/4 turns out and go from there, but I also try to avoid doing it if I can.

I keep this guide to tuning carbs bookmarked and open it every time I touch one.

Slavvy
Dec 11, 2012

Ulf posted:

The pilot screw is the idle screw that you're thinking of. It's the one that's externally adjustable, but in normal circumstances you shouldn't fiddle with it unless changing altitude.

No. If you don't know, please refrain from throwing erroneous poo poo around ITT, it'll just confuse things.

Idle screw sets the idle speed, it's just the moveable stop for the throttle plate. It has a little knurled knob, you turn it by hand and it's on the LH side of the bike.

Pilot screw is the fine mixture adjustment for idle and first crack of the throttle. This doesn't have a major effect on the way the bike rides or uses fuel, it's purely idle/low revs thing.

The carb has three ranges: pilot/idle, needle/part throttle, main jet/WOT. You establish rich or lean running by finding a straight stretch of road and riding for ~30 seconds while keeping the throttle still in the range you want to check, then hitting the kill switch and removing a plug to see how rich/lean you are. The plugs are basically a snapshot of what the engine was doing in the last thirty seconds.

Plug heat range you don't need to gently caress with, that's a whole different alleyway you'll almost certainly never have to go down in your life.

Practical advice:

The pilot screw is a small brass flathead screw recessed in a hole, you can access it from the RH side of the bike but may need to remove the air filter pod thingy to do so. Wind it in while counting the number of turns it takes to fully seat, do this while the bike is warned up and idling. It should be somewhere between 1.5-2.5 turns. Turning it out is richer, in is leaner, so when you shut the pilot screw the engine should die shortly thereafter; if it doesn't it's either getting fuel some other way or the idle speed is set really high to compensate for something. Try to avoid touching the throttle while doing this as the accelerator pump will spray fuel in every time you do and that can confuse the situation. Again this is the idle mixture when the engine is hot, never do this with a cold engine.

Anyway if the screw was set really far out or nearly shut, set it to 1.5-2 turns out, adjust the idle speed until it's normal and see what that's like. Fine tune to taste a quarter turn at a time, you want to find the sweet spot where the engine idles the highest and smoothest, than adjust the idle speed down. Don't gently caress with this longer than 10-15 minutes cause the bike is air cooled and won't suffer standing still forever.

If you can shut the pilot completely and the bike keeps running fine:

Set your fuel tap to on or reserve, remove the hoses. If fuel gushes out despite it being set to on or reserve, replace the tap. If not, plug the fuel hose back in and suck on/use a vacuum pump on the petcock vacuum port. If fuel comes out through the vacuum port (it's supposed to come out the fuel hole which is why I told you to plug it back in!) it is hosed, replace.

If that's all fine, locate the vacuum line going to the fuel pump (it T-junctions with the tap vacuum and disappears into the rear bowels of the bike), pull it off and give it a suck. If fuel comes through, the vacuum diaphragm on the pump is hosed, replace.

If all that checks out, it's probably the choke plunger. For this you need to take off your tank and rh side pod, as well as the pair valve thingy blocking the view of the carb. The choke cable is the one that elbows into the bike-forwards facing wall of the carb. There is a hex fitting you can awkwardly turn with an open ended spanner, inside is the end of the cable, a spring and a brass plunger. Make sure the plunger is free to slide back and forth in the hole and the cable end moves freely when you operate the lever.

Slavvy fucked around with this message at 18:09 on Dec 13, 2019

HenryJLittlefinger
Jan 31, 2010

stomp clap


Slavvy posted:

No. If you don't know, please refrain from throwing erroneous poo poo around ITT, it'll just confuse things.


To be fair, the pilot screw is pretty commonly referred to as the idle air screw.

Slavvy
Dec 11, 2012

Yep and that's also wrong because an idle air screw gets leaner as you wind it out!

Oh and some older bikes have both a pilot screw AND an air bleed/bypass screw, x4 carbs that all need balancing :thumbsup:

Those can often be literally impossible to set up right if someone has disturbed the settings unless you've got an o2 sniffer machine handy.

Slavvy fucked around with this message at 23:17 on Dec 13, 2019

Carth Dookie
Jan 28, 2013

Hey Slavvy, your opinion:

My dad owns my old Honda 2001 VTR100F. Never had the carbs touched in the time I or he has owned it and almost certainly never maintained by any PO. Bike runs fine as is. Dad, while not a professional mechanic, is mechanically handy (has done full car rebuilds and does all his own bike maintenance).

So:

1. Do 2x carb rebuild and balance since it's 20 years old and would benefit from some preventative maintenance

2. Leave it alone until something happens and the carbs need it?

Thoughts?

Slavvy
Dec 11, 2012

Balance them and leave it. Those have the largest carbs ever factory fitted to a bike afaik, paradoxically this makes them super sensitive to the point where they have different needle profiles for the front and rear cylinders. Plus they're a oval office to remove. But basically they're so huge and sensitive that if something has gone wrong the bike will immediately run like a sack of poo poo.

Aside from that the carbs are very simple and straightforward. They're jetted a bit too lean down low and benefit enormously from a step or two bigger on the pilots if you have a pipe, with the stock exhaust just winding the pilots out to a good 3.5 turns is usually enough.

Check the valve clearances too, those make a big difference on big twins.

Rev. Dr. Moses P. Lester
Oct 3, 2000
That sounds awesome and I would love to find a beat up one to race against 80cc 2-strokes

Elector_Nerdlingen
Sep 27, 2004



OK, so I pulled the sparks and they're a bit black but no build-up. Wiped them off a little, checked the gap and it's about 0.1mm wide so I closed them to spec then started the bike to make sure I hadn't hosed up and it started as normal (from cold, no choke). Confirmed that using the choke killed the engine, it did.

Pulled and cleaned the air filters and while they were soaking I poked around and identified the idle and pilot screws. Don't need to remove the airbox, just undo it and rotate it slightly to get a screwdriver through.

Oiled and reinstalled the filters, put the covers back on aaaaaaand...

Bike doesn't start.

Choke on, and it nearly starts. Choke on, throttle on, and it starts and dies. Turn the idle up a little and it starts and idles, making a little white smoke that goes away in 30 seconds. Let it warm up for 2 minutes, turned the choke off, engine died but restarted with the choke on. Rode with the choke on for a couple minutes, turned the choke off, bike is now warm and starting fine (choke off) but idling real high, so I rode 15 mins around the town to warm it up and also to wave at the local kids who all seem to love waving at bikes.

Checked the pilot screw. It was about 4 turns out, so with the bike runing I slowly closed it all the way, and the engine died. hosed around with it like Slavvy said, and got it feeling right at about 1.75 turns.

Bike's now idling fine so I took it for a 30 minute ride. Feels smoother, feels like it's accellerating a bit harder on wide open throttle too.

Brought it home, lubed the chain because I did about 600km the other day, and put it away. Guess we'll see how it starts tomorrow or maybe tonight, but it's looking like the problem's solved in pretty much the easiest way it could have been.

This poo poo is turning out to not only be cheaper than paying someone to do it for me, but also quite a lot of fun, and thank you so so much,

Elector_Nerdlingen fucked around with this message at 02:49 on Dec 14, 2019

Skreemer
Jan 28, 2006
I like blue.

Slavvy posted:

Really good carb advice

Holy poo poo I understood what was being said... Though one caveat I need to throw in. Depending on where the bike was destined to live there might be a small plug of solder over the pilot screw. For some reason during the beginning of the smog era some bikes had this done to them so you couldn't make changes. I had to drill out a few of them when I was rebuilding a few early 80's Suzuki GS bikes.

HenryJLittlefinger
Jan 31, 2010

stomp clap


Skreemer posted:

Holy poo poo I understood what was being said... Though one caveat I need to throw in. Depending on where the bike was destined to live there might be a small plug of solder over the pilot screw. For some reason during the beginning of the smog era some bikes had this done to them so you couldn't make changes. I had to drill out a few of them when I was rebuilding a few early 80's Suzuki GS bikes.

Yeah, I thought about that but didn’t mention it since he’s in Australia. All US carbed bikes since 1972, right? Mine have all been accessible, but brass plugs are common too. Just drill em, screw in a sheet metal screw, yank it with a pair of pliers.

Thanks for all that, Slavvy.

Slavvy
Dec 11, 2012

Skreemer posted:

Holy poo poo I understood what was being said... Though one caveat I need to throw in. Depending on where the bike was destined to live there might be a small plug of solder over the pilot screw. For some reason during the beginning of the smog era some bikes had this done to them so you couldn't make changes. I had to drill out a few of them when I was rebuilding a few early 80's Suzuki GS bikes.

I do know about those but didn't want to add even more words! Every gs500 I've come across has had them, plus we get a lot of usdm Japanese bikes imported here, not to mention the millions of Harleys.

The worst are still those loving D shaped ones that demand a ridiculously fragile tool that gives up at the slightest seizing.

Slavvy
Dec 11, 2012

HenryJLittlefinger posted:

he’s in Australia
Thanks for all that, Slavvy.

Mixed messages here m8

Carth Dookie
Jan 28, 2013

Slavvy posted:

Balance them and leave it. Those have the largest carbs ever factory fitted to a bike afaik, paradoxically this makes them super sensitive to the point where they have different needle profiles for the front and rear cylinders. Plus they're a oval office to remove. But basically they're so huge and sensitive that if something has gone wrong the bike will immediately run like a sack of poo poo.

Aside from that the carbs are very simple and straightforward. They're jetted a bit too lean down low and benefit enormously from a step or two bigger on the pilots if you have a pipe, with the stock exhaust just winding the pilots out to a good 3.5 turns is usually enough.

Check the valve clearances too, those make a big difference on big twins.

They do indeed have biggest factory carbs ever at the time. Interesting that they're so sensitive. It has stock exhaust so no fiddling required. Didn't know they had different needle profiles. Good to know. Valve clearances were done not that long ago, so should be good. Thanks for the input.

Rev. Dr. Moses P. Lester posted:

That sounds awesome and I would love to find a beat up one to race against 80cc 2-strokes

:bisonyes:

Slavvy posted:

Mixed messages here m8

Bushfires or volcanoes, either way we're hosed m8.

Ulf
Jul 15, 2001

FOUR COLORS
ONE LOVE
Nap Ghost

Slavvy posted:

No. If you don't know, please refrain from throwing erroneous poo poo around ITT, it'll just confuse things.

Idle screw sets the idle speed, it's just the moveable stop for the throttle plate. It has a little knurled knob, you turn it by hand and it's on the LH side of the bike.

Pilot screw is the fine mixture adjustment for idle and first crack of the throttle. This doesn't have a major effect on the way the bike rides or uses fuel, it's purely idle/low revs thing.
oh poo poo, that's right.

i have a 4-carb cb750 so i do know this, but I haven't thought about it in a while. I move my pilot screws all the time (i live at 6,000 ft but ride from 14k to 0k ft) but don't really think about the idle throttle screw hiding behind carb #2 much, I only set it the once when I got the bike and synced the carbs etc.

when I was a kid my dad always did the carbs (2-stroke yamahas mostly), then every car I had from '87 onward had EFI. this nighthawk I got a year ago is actually the first carb'd engine I've ever had to deal with. Luckily they're CVs so pretty forgiving to what I do with them.

Slavvy
Dec 11, 2012

Before I forget:

Elector_Nerdlingen posted:

This poo poo is turning out to not only be cheaper than paying someone to do it for me, but also quite a lot of fun, and thank you so so much,

I honestly should be thanking you, this thread helps keep me sane. But you're welcome :) keep doing what you're doing.

Ulf posted:

oh poo poo, that's right.

i have a 4-carb cb750 so i do know this, but I haven't thought about it in a while. I move my pilot screws all the time (i live at 6,000 ft but ride from 14k to 0k ft) but don't really think about the idle throttle screw hiding behind carb #2 much, I only set it the once when I got the bike and synced the carbs etc.

when I was a kid my dad always did the carbs (2-stroke yamahas mostly), then every car I had from '87 onward had EFI. this nighthawk I got a year ago is actually the first carb'd engine I've ever had to deal with. Luckily they're CVs so pretty forgiving to what I do with them.

That's a pretty big elevation change! Is there much of a difference in perceived performance?

Ulf
Jul 15, 2001

FOUR COLORS
ONE LOVE
Nap Ghost
My butt dyno is defective so I’ve never truly been able to tell. There’s something like 20% more air at sea level than home which should translate to more power down there, but when I’m traveling I’m riding conservatively anyway.

You definitely feel the lack at high altitude though, and if you forget to bring a tool to turn the screws you likely won’t have a working idle at all.

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HenryJLittlefinger
Jan 31, 2010

stomp clap


Slavvy posted:

Mixed messages here m8

My assumption being that blanked off pilot screws are more of a thing in the US because so much carb restriction followed the Environmental Protection Agency’s 1972 passage of the Clean Air Act. Access to the pilot screws was a casualty.


Also I thought “mate” was a really aggressive thing to call someone, oval office.

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