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Jim Silly-Balls posted:The momentum of the exiting gasses helps scavenge the next cycle, so having those pulses arrive and exit at the wrong time hurts things. Precisely. MomJeans420 posted:Perfect timing as I have a bunch of exhaust questions. I need to replace the completely hosed up yoshi exhaust on my project bike. It's currently obnoxiously loud, but it also has the rivets drilled out and who knows what it looks like on the inside. I would like the replacement exhaust to be a reasonable volume so that my neighbors don't hate me and maybe one day it can visit Laguna Seca, which has a notoriously low sound limit. Do these exhausts usually come with a sound insert, or do I have to buy the TRS model exhaust then the TRS insert? And finally, carbon fiber or stainless? I usually avoid carbon fiber, but the stainless looks like a pain in the rear end to keep clean. No idea but stainless is more correct. They usually come with an insert, the trs insert is for the trs cans specifically which you will note are triangular.
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Jan 8, 2021 21:17
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MomJeans420 posted:Perfect timing as I have a bunch of exhaust questions. I need to replace the completely hosed up yoshi exhaust on my project bike. It's currently obnoxiously loud, but it also has the rivets drilled out and who knows what it looks like on the inside. I would like the replacement exhaust to be a reasonable volume so that my neighbors don't hate me and maybe one day it can visit Laguna Seca, which has a notoriously low sound limit. Do these exhausts usually come with a sound insert, or do I have to buy the TRS model exhaust then the TRS insert? And finally, carbon fiber or stainless? I usually avoid carbon fiber, but the stainless looks like a pain in the rear end to keep clean. I bought a dirt-cheap stock muffler for my gixxer bc the aftermarket one it came with was loud as literal balls, and also killed my battery. People buying aftermarket exhausts after 120 miles of riding makes the stockers cheap and easy to find on eBay. Also of note: I may be able to sell my stock plastics for about the same price as a set of armour bodies. It's free real estate 
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Jan 8, 2021 21:35
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captainOrbital posted:I bought a dirt-cheap stock muffler for my gixxer bc the aftermarket one it came with was loud as literal balls, and also killed my battery. Your muffler killed your battery? How's that?
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Jan 8, 2021 21:50
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When a muffler and an engine don't get along, sometimes they have to spend some time apart. It doesn't mean that they don't love each other, but I'm not 100% sure where I'm going with this. OP didn't bother to...do whatever you have to do with the ECU to adjust for the new muffler, so it would take a couple tries to start every time. Eventually the amount of starts caught up with the amount of time I was riding it between starts. It was annoying as hell. The noise was kind of fun, but it hurt my right ear and made me feel v. self-conscious. e: once I got the stock unit back on, the thing would start first try every time like a proper japanese bike.
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Jan 8, 2021 22:03
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MomJeans420 posted:the stainless looks like a pain in the rear end to keep clean. They get obviously dirty very quickly, but you can buff them back to like-new shine with surprisingly little effort.
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Jan 8, 2021 22:28
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Carbon fiber can also start to get really lovely after a few years in the sun, especially if whatever coating they're using to give it some uv resistance starts to wear away.
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Jan 8, 2021 22:44
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Stainless steel it is, and that saves me some money. The exhaust yoshi exhaust is CF and definitely did not age well in the sun.
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Jan 8, 2021 23:21
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So following on from the last page, am I understanding right that a muffler like this: will always be obnoxiously loud? Or is it just that it'll be louder than a larger can, but could still be relatively quiet if it has good baffles fitted?
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Jan 9, 2021 15:31
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You're asking practical questions but getting theoretical answers I think. What you're asking is if you can judge how loud something is based on a picture on the internet and the answer is no. The only piece of information you have is: nobody ever gets an aftermarket pipe because they want the bike to be quieter, if noise is a concern the factory have already sorted you out.
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Jan 9, 2021 20:03
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re. aftermarket quiet exhausts i think it would be kinda neat to do that as an experiment. just build a huge custom muffler that spirals around the whole rear of the bike and completely deadens the sound. kinda like the concept behind this guy, the YO-3:  the army wanted a silent observation plane so they took a couple of sailplanes and modified them with hand-carved wooden propellers, fiberglass batting around the engine compartment, and the giant muffler system that runs along the entire right side of the plane that you can sort of make out above. the engine was so quiet that the loudest sound the plane made was from misaligned control surfaces whistling in the wind. maintenance techs would stick a piece of tape onto the trailing edge of the wing and adjust the control surfaces and have the pilot fly over; when the only thing they could hear was the tape fluttering, they were done. supposedly it was so quiet that at night it could fly over convoys as low as 200 feet without alerting the enemy.
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Jan 9, 2021 20:17
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Yeah I remember reading about that one, iirc it used a couple of frame sections as expansion chambers too? Maybe this can be Buell's next thing (do not attempt to do fuel-in-frame at the same time). Slavvy posted:You're asking practical questions but getting theoretical answers I think. My actual practical concern is that my factory pipes are rotting away and while I could repaint them, I'd rather spring for a full stainless system (and restore the old pipes at my own pace), and I really like the appearance of those conical mufflers like you'd see on an old CB or something. The dilemma is that I also really like the noise level of the stock pipes, which are about as close to totally silent as you can reasonably get, and as you say almost everyone buying aftermarket wants the opposite.
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Jan 9, 2021 20:46
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You live the in the man-in-shed capital of the universe, why look for a plebian off the shelf solution? I don't need google to know there are at least three custom exhaust builders who would happily repair/improve the stock pipes within a hundred miles of your location.
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Jan 9, 2021 20:58
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Sagebrush posted:maintenance techs would stick a piece of tape onto the trailing edge of the wing and adjust the control surfaces and have the pilot fly over; when the only thing they could hear was the tape fluttering, they were done. drat that's pretty cool
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Jan 9, 2021 21:35
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Sagebrush posted:Quiet plane stuff That's real neat, especially given the level of tech at the time. Back when I had the grom, I was obsessed with making it the quietest I could, with the highest flow. This included sound deadening in the airbox, and mating the stock airbox to the high flow intake pipe with a high flow snorkel. The degenerate grom peeps with their $500 custom straight pipes that lowered hp couldn't fathom why I would do that. Obviously the answer is "get an electric bike" but I'd really like super quiet aftermarket options. I thought about having a high flow exhaust but making a U shape to the other side of the bike with yet another exhaust. At that point you are adding weight to the bike, but that's negligible. One person put the DR650 favorite gsxr muffler on a WR250R and it was pretty quiet with high flow. Always wanted to try that.
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Jan 9, 2021 23:51
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The British and their presumably tiny, overly sensitive ear drums have taken that to a very high level:
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Jan 10, 2021 01:40
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i mean honestly i think that looks pretty rad. definitely better than a suitcase
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Jan 10, 2021 01:48
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Slavvy posted:The British and their presumably tiny, overly sensitive ear drums have taken that to a very high level: foul
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Jan 10, 2021 01:49
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Slavvy posted:You live the in the man-in-shed capital of the universe, why look for a plebian off the shelf solution? I don't need google to know there are at least three custom exhaust builders who would happily repair/improve the stock pipes within a hundred miles of your location. Good point! Looks like there's a well regarded builder 70 miles down the road from me, I'll give him a ring at some point, see what he can put together.
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Jan 10, 2021 02:00
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Slavvy posted:The British and their presumably tiny, overly sensitive ear drums have taken that to a very high level: lol I just realised that's a twin pipe. Put them both under the tail you cowards
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Jan 10, 2021 14:12
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Is there anything wrong with this spark plug? I've tried comparing it to one of those condition charts but honestly apart from the super oily or ash-covered ones they all look alike to me.
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Jan 10, 2021 15:39
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I’d run it
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Jan 10, 2021 16:43
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If that's a plug chop it's running perhaps a little bit lean but not dangerously so. If you're just asking about physical condition it's fine, I don't see any damage
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Jan 10, 2021 18:58
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Renaissance Robot posted:Is there anything wrong with this spark plug? I've tried comparing it to one of those condition charts but honestly apart from the super oily or ash-covered ones they all look alike to me. It's perfect. Sagebrush posted:If that's a plug chop You know it's not.
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Jan 10, 2021 19:22
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Thanks all. Just had it out while I was checking the valve clearances and thought I'd ask.
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Jan 10, 2021 19:34
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Isn't your bike a twin...?
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Jan 10, 2021 19:39
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gf rides a 125
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Jan 10, 2021 19:43
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Ooooh. Is this the one that wouldn't start without a lot of choke? Looks like we were right about it needing another quarter turn out on the pilot screw, if it was idling before it got switched off anyway.
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Jan 10, 2021 19:46
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The opposite, it won't start unless the choke is off, and runs really badly for a couple minutes until it gets warm (sounds like it's misfiring or something, occasionally dies suddenly while idling in those couple of minutes, attempting to add throttle also kills it) It runs okay once it's hot, but I'd like to hunt down this issue if I can. Earlier this evening I fished out the air filter to clean it out, on the idea that maybe it's running rich for lack of air; I'm doubtful that'll fix it but it definitely needed doing anyway. Renaissance Robot fucked around with this message at 19:59 on Jan 10, 2021 |
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Jan 10, 2021 19:57
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Slavvy posted:Ooooh. Is this the one that wouldn't start without a lot of choke? Looks like we were right about it needing another quarter turn out on the pilot screw, if it was idling before it got switched off anyway. This was my wife, she's figured it out now and it starts and works fine, both from cold, and when coming out of the shops. 
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Jan 10, 2021 19:58
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Wait so there are two GN-mounted spouses from the uk ITT? My mind is blown.Renaissance Robot posted:The opposite, it won't start unless the choke is off, and runs really badly for a couple minutes until it gets warm (sounds like it's misfiring or something, occasionally dies suddenly while idling in those couple of minutes, attempting to add throttle also kills it) Ok right. Wind your pilot screw in until it stops (it's made of brass don't be an idiot) and count the turns, it should be somewhere between 1.5-2.5 turns out from the stop. In = leaner, out = richer, only play with it when the bike is fully warmed up. What you've described sounds like conflicting symptoms but it could have one problem that has then been compensated for by a PO, leading to a more complicated situation.
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Jan 10, 2021 21:07
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Slavvy posted:Wait so there are two GN-mounted spouses from the uk ITT? My mind is blown. This one's a Chinese YBR clone, but close enough. Dunce question, is the pilot screw the same thing as the idle screw?
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Jan 10, 2021 22:09
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Renaissance Robot posted:Dunce question, is the pilot screw the same thing as the idle screw? No, pilot screw adjusts air/fuel mix at idle, idle screw adjusts rpm at idle. Edit/Note: turning your pilot screw can/will also cause the rpm to change a bit, which helps you find the right spot (see “idle drop procedure”). In my experience it was helpful to temporarily lower the rpm (using the idle screw) to more easily hear changes in rpm while setting the mix (using the pilot screw). epswing fucked around with this message at 00:30 on Jan 11, 2021 |
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Jan 10, 2021 22:19
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The carb in question is, if not a genuine mikuni, at least very similar to this one: If I'm reading right, the pilot screw is the one to the right? And the idle screw is the one in the middle with a spring behind it?
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Jan 10, 2021 22:40
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Yup. If it's that type of carb, the pilot screw is actually an air bypass and works opposite - turning it in makes it richer, out leaner. The viable range on those is much narrower, a normal setting is usually between 0.5-1.5 turns. They are slightly trickier because they're a bit non-linear compared to the fuel type, and the effect on idle speed is greater, but it's still pretty much the same procedure.
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Jan 10, 2021 23:41
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In general on two strokes, the pilot adjusts fuel and on four strokes it adjusts air, so they do the opposite of each other.
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Jan 10, 2021 23:57
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Jim Silly-Balls posted:In general on two strokes, the pilot adjusts fuel and on four strokes it adjusts air, so they do the opposite of each other. I've seen both kinds on four strokes. On the ones that are out = richer, the little passage goes bellmouth - t-junction down to the fuel bowl - carb throat. So I figure that's a fuel screw. On the type in the picture above, the little passage doesn't t-junction to the bowl, the screw is just a big blunt thing that exposes an air bypass and doesn't directly act on the pilot circuit. So I figure that's an air screw. But for the most  thing, some gn250's seem to have both so you can get fully lost in the settings.
Slavvy fucked around with this message at 05:25 on Jan 11, 2021 |
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Jan 11, 2021 05:23
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Okay, slight setback, the carb actually looks like this: The one screw there is the idle screw, in this position it idles warm at 1.1krpm; the slightest turn out and it won't run at all for lack of fuel, the slightest turn in and it'll idle a little faster but die immediately as soon as you touch the throttle. This is the other side, top is no choke, bottom is full choke:   Looks like the choke lever is operating the air bypass maybe? Or maybe just a big fat butterfly valve, judging by the way the difference between off and on is a quarter turn. I don't see any other accessible screws on this thing (except on the bottom but I assume that's not the one I'm after) At what point do I shrug and walk away, accepting that this bike runs but is just irredeemably kind of poo poo? Renaissance Robot fucked around with this message at 12:08 on Jan 12, 2021 |
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Jan 12, 2021 12:06
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Two somewhat related questions. 1. My tyres have sticky weighted stickers to help with wheel balancing. On the rear tyre, one of the stickers is about 5 squares of weights long and 2 of the squares have peeled off and are dangling from the other 3 still stuck on. Should I stick the 2 dangling back on? If yes, what glue/substance should I use? If not, should I get similarly weighted squares and stick them in the same location that those 2 would be snipped off? 2. The rear tyre's valve is a pain in the rear end to reach. If I extend the stem using the below pictured extender, to make it easier to fill up/check pressure, can I leave it on the tyre all the time, or would that have a negative effect in any way? If I left the valve extender on, would I have to rebalance the wheel (I don't have the tools or space to take off the wheel, so I don't want to have to do rebalance the wheel)? 
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Jan 12, 2021 18:19
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Renaissance Robot posted:Okay, slight setback, the carb actually looks like this: Ok so that is nothing like an actual Suzuki, that carb would be at home on an xr100 from 1982. The pilot screw is probably underneath next to the bowl. Don't get preoccupied by the choke, it literally is just a flap on those. But also the bike is likely running as good as it ever will because it's a chinese turd. Steakandchips posted:Two somewhat related questions. Just stick them back on with double sided tape, that's what they come with. Just clean the rim super surgically or you'll ruin the glue, it only gives you one chance to get it stuck down. And yeah just leave the extender on there all the time it won't hurt anything. Slavvy fucked around with this message at 18:59 on Jan 12, 2021 |
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Jan 12, 2021 18:56
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Slavvy posted:Ok so that is nothing like an actual Suzuki, that carb would be at home on an xr100 from 1982. The pilot screw is probably underneath next to the bowl. Don't get preoccupied by the choke, it literally is just a flap on those. But also the bike is likely running as good as it ever will because it's a chinese turd. Sort of figured it might come to this, thanks for the clarification.
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Jan 12, 2021 19:44
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