What did you do to your ride: forensic welding

The Something Awful Forums > Discussion > Automotive Insanity > Cycle Asylum > What did you do to your ride: forensic welding

«‹›2 »

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Geirskogul posted:

I won't clog this thread up with any responses re: sprockets/gearing/fuel economy, but thank you for your replies.

I will!

Geirskogul, you seem to be working under the assumption that an engine has a constant efficiency at a given power output. ie as long as you're putting 10hp down at the wheel, you're using pretty much the same amount of fuel.

There are several things that make this not true. Mechanical friction, volumetric efficiency variations over the rpm range, and most importantly throttling losses.

Brake specific fuel consumption is they key efficiency metric for any IC engine. It is a measure of the mass of fuel to work done by the engine.http://en.wikipedia.org/wiki/Brake_specific_fuel_consumption

You can see that for a given power output, the amount of fuel required to produce it increases with rpm. This is primarily due to throttling losses, the further closed the throttle is, the harder the engine is working just to pull air into the cylinder. The lowest bsfc, or highest efficiency, for this engine is between 2000 and 2500 rpm, at 35 to 55 kW.

Peak efficiency is at full* throttle and peak torque. The real world peak efficiency depends on the jetting/fuel map, most engines are going to be dumping extra fuel in at full throttle to avoid going lean, so peak efficiency is usually going to be at a slightly lower throttle opening.

In conclusion, it is more fun to gear a bike for acceleration, than fuel economy. You can't do a power wheelie while accelerating from 20 to 60 mpg.

# ¿ Sep 26, 2011 15:02

Adbot: ADBOT LOVES YOU

# ¿ May 21, 2024 16:22

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Detroit117 posted:

I have a V-rod muscle with a 1250cc engine, and it pulls really nice for a bike that weighs a metric ton. the clutch has a slipper function that comes in handy.

I need to test ride a V-rod so I can back it in to the Harley parking lot.

# ¿ Apr 21, 2012 02:49

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Spiffness posted:

I have a 74 125S

I'd challenge you to a race, but I'd clearly win

The S is for sayonara.

# ¿ Apr 30, 2012 16:35

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

I had a look at the piston on the RS125. The poor little guy has a pretty tough life. I guess that's why you're supposed to replace it every 300 miles.

# ¿ May 13, 2012 04:21

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

I took apart and reassembled (with lube) the front caliper on the SM450R, and the rear on the RS125. Hopefully neither will stick anymore. I put the new slicks on the RS, the sidewall was cracked after a track day on the old tires. Now to order $60 pads for both bikes, and measure the bore on the RS so I can order a new piston.

# ¿ May 14, 2012 03:50

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Tamir Lenk posted:

I used insulation foam board from the local hardware/home center.

I'm pretty sure that would be dissolved by styrene monomer, you'll want a barrier between it and the glass when you lay-up if you weren't already planning on it.

# ¿ Jun 1, 2012 23:05

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

I did all this over the last week, but I got it all back together today. I replaced the knackered aluminum sprockets on my 250SX-F with a steel set, changed the brake pads, removed a link from the chain, changed the tires (GeoMax), checked the valve lash, and put on frame protectors.

Oh, and I routed the throttle cables wrong.

# ¿ Jan 26, 2013 05:09

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

the walkin dude posted:

Worth it just to keep my four-fingered mechanical fist of fury relatively pristine.

Do you not count the thumb, or are you short a digit?

# ¿ Feb 1, 2013 05:14

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

I nearly destroyed my 250SX-F when I didn't set the ratchet correctly. The cam chain slipped on the second kick, had it started... Manual tensioner is on the way

# ¿ Feb 5, 2013 15:04

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Slavvy posted:

Sounds like a piston's picked up if it's proportionate to temperature. Condolances.

Maybe this is just a regional dialect issue, but... what did the piston pick up?

# ¿ Feb 18, 2013 16:17

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

the walkin dude posted:

So this kind of thing happens because of low oil levels?

Low oil pressure, which can be caused by low oil level. That's not the only possible cause, plane bearings work by keeping a thin film of oil (which comes through a hole in the bearing) between the crank and the bearing. If the oil doesn't have enough pressure, or there is too much play between the crank and bearing, they will rub. Then they weld.

# ¿ Feb 19, 2013 20:59

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

theperminator posted:

What kind of oil were you running in that anyway?

I'm jealous of your ability to buy an engine/parts in general so easily.

Auctions are another good place to get one too, I found a 675 here with a current bid of $200

Rapeseed.

# ¿ Feb 22, 2013 02:39

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

BlackMK4 posted:

Ordered an 09+ 675 exhaust header off eBay for $100 shipped and three header-to-head gaskets off BikeBandit. I'm doing the 09 swap. Wee...

What changes?

# ¿ Feb 28, 2013 15:37

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Spiffness posted:

- Fork emulators & re-spring from local race shop

You're getting the terminology wrong, emulators are a modification to damping rod forks (SV560 stock) to make them perform a bit more like a cartridge fork (GSXR600 stock). You got new 25mm cartridges. Did they set everything at a recommended starting point?

Did you tell Barry to finish my forks?

# ¿ Mar 1, 2013 15:08

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

clutchpuck posted:

Based on my experience with my vstar exploding a gearbox bearing, it's less "disposable" income, more "oh gently caress me come on" income.

You sold your body for a Vstar gearbox?

# ¿ Mar 11, 2013 23:46

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

I finally got the suspension for my R6 back from the shop, it ended up taking a few months because they had to design new fork caps to fit the cartridge kit on right side up forks. Penske rear, gp suspension cartridges up front. Can't wait to throw it on and get to the track.

# ¿ Apr 17, 2013 18:43

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Z3n posted:

That thing is going to be the best sleeper.

I don't know if you can call a vehicle with such a gaudy paint job a sleeper. But its probably going to be one of the best suspended first gen R6s in existence. If only I sprung for the triple clicker.

# ¿ Apr 17, 2013 21:25

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

I got my R6 'ready' for the track on monday. It's still not idling too well. I'm hoping it just needs an italian tune up, but I'll be bringing the KTM as a backup. Fresh brake fluid, mounted the body work, checked just about every bolt on the bike, safety wired the calipers and drain plug, and waxed it up.

# ¿ Apr 28, 2013 04:56

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

I got the R6 running right, after cleaning and adjusting the float heights on the carbs for the forth time, I traced the problem to two bad ignition coils. I was not able to rule out the possibility that I'm an idiot.

# ¿ May 14, 2013 16:23

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

There's always something. I put the 'new' rear tire on the R6 today. It's a Dunlop GP-A, a 190-55, up from the current 180-55. Installed with the correct chain slack it clears the swing arm by just a hair. I'm going to have to lengthen the chain to keep it from rubbing at speed.

# ¿ May 15, 2013 05:32

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Z3n posted:

Cam holders are matched to heads, fyi, if you're talking about the bits that hold the cams down.

This, a machine shop can do an align bore and hone to make the new cam caps fit properly though.

# ¿ Jun 22, 2013 15:42

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

My RS125 died on me at the last track day, I finally got around to working on it this weekend. It looks like it burned through the head 'gasket' (o-ring), then burned all the coolant, then the piston and cylinder got to know each other real well. At least parts are cheap and easy to find.

# ¿ Jul 9, 2013 05:22

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

n8r posted:

Is that sarcasm? I want an RS125 - I remember when you bought that too, didn't you get a really good deal on it?

The parts being cheap and easy to find, yeah that was sarcasm. A top end kit was $330 when HRC was still producing them (10 years ago).

# ¿ Jul 13, 2013 02:50

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Nur_Neerg posted:

Dropped it >< And somehow can't find a set of replacement forks for an '04 SV650 now between ebay, craigslist, and svrider. Stupid bent forks. Otherwise only damage was a broken but still usable brake lever and a sad bar-end mirror. Thanks, frame sliders! Gonna try to do an oil change and fork swap this weekend if I can find parts quickly enough.

You sound like a previous owner, I dropped it in the driveway... bent the forks, destroyed the gauge cluster, put a hole in the headers, ripped off the subframe, and dented both wheels. But don't get replacement sv forks, now is the time for a gsxr front end.

# ¿ Jul 16, 2013 19:51

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Geirskogul posted:

40 minutes outside in the sun and every article of clothing was 100% drenched.

Get yourself an EZ-up so you can at least be in the 'cool' shade.

# ¿ Sep 20, 2013 21:04

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

I took apart my YZ125 to replace the piston... and I found that the Nikasil coating on the cyliner has worn through in a couple spots, and the head has so many pits it looks like the surface of the moon. I can pick up a new head for $50 on Ebay, and it looks like a cylinder core exchange is going to run about $200. All for a bike that I only have to let my friends ride.

# ¿ Sep 21, 2013 23:45

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Well I'm an idiot. I ordered a 2000 YZ125 head for my '01 thinking they're the same. They aren't, $50bux down the hole.

# ¿ Sep 26, 2013 03:11

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Terminus Est posted:

We use massive amounts of simple green when cleaning wind turbines and there is a ton of aluminum everywhere. Never had a problem with it doing damage, what exactly is it supposed to do to aluminum? Its one of the few cleaners approved by corporate since it doesn't strip gel coats or take off paint, and not deadly in confined spaces.

I think the issue is that it causes polished aluminum to form an oxide layer and lose it's shine.

# ¿ Sep 28, 2013 23:20

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

goddamnedtwisto posted:

Even with decompressors most modern engines would catapult you over the bars long before they'd actually start.

Dirt bikes are still a thing.

# ¿ Feb 14, 2014 18:41

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

NitroSpazzz posted:

That being said I never had any trouble starting CRF450R and never used the decomp lever.

That's interesting, I found a pre-autodecomp yz250f almost impossible to kick over without using the decomp lever. Maybe there's some design difference that... Oh I'm probably just a weakling.

# ¿ Feb 14, 2014 20:35

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

I pulled the forks with GP cartridges and penske shock off of the R6 to get setup for the 675. Turns out I lost a shaft that goes in the lower pivot on the stock shock, so the R6 is hanging from the rafters until its delivered.

I got the power commander in, and ordered some clip-ons. Its getting closer to being a nicely setup track bike... It still looks like its been stolen and crashed a few times though.

# ¿ Feb 20, 2014 17:21

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Z3n posted:

I give it all of 30 minutes before the ktm chews that up and blows it out.

But I think it's rad anyways.

Yours chewed up and spit out the Leo Vince insert... Followed by the rest of the muffler.

# ¿ Feb 21, 2014 20:30

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Had decent weather and rode in to work yesterday. Two people leaned out of their cars to ask me about

. This thing is going to be great for picking up dudes this summer.

Zool fucked around with this message at 15:07 on Feb 27, 2014

# ¿ Feb 27, 2014 15:02

Adbot: ADBOT LOVES YOU

# ¿ May 21, 2024 16:22

Zool: Mar 21, 2005; The motard rap
for all my riders
at the track
Dirt hardpacked
corner workers better
step back

Whatever that brown orb is made of, its highly polished.

# ¿ Mar 14, 2014 19:19

The Something Awful Forums > Discussion > Automotive Insanity > Cycle Asylum > What did you do to your ride: forensic welding

«‹›2 »