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Doublepostin because I've had enough of this poo poo. This is the third time on as many completely different bikes that I've seen this issue and I still have no loving idea what causes it. Symptoms as follows: bike is always fuel injected (this time it's an SV1000, last time it was a CBR1000) and the issue is not affected by temperature or anything else I'm able to change. What happens is the bike will (only at idle) backfire out of one intake port every once in a while. It's always the same cylinder irrespective of what you do with coils/injectors/blahblah and with the airbox removed you can physically see the flash behind the throttle plate so I'm not being misled or misjudging where it's coming from. Eventually it will do it badly enough that the bike stalls. No fault codes, it's plugged into the wall and I've tried restarting windows. What in the gently caress causes this on a perfectly healthy efi engine? I would genuinely prefer carbs at this point.
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Aug 31, 2017 04:09
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I remember you dealing with that before. Had it all apart and everything. What was the resolution last time? Resolution- only have one cylinder and one carb
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Aug 31, 2017 05:09
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The resolution last time was telling the guy to go away with his piece of poo poo 100kkm rolled bowled and assholed fireblade, I sent him in the direction of a honda dealer and haven't heard back since. This time it's different because the bike is worth money and the owner has some to spend.
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Aug 31, 2017 05:59
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Are you fighting valve issues rather than FI? Or is this something that only shows up when you mess with FI?
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Aug 31, 2017 16:45
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The only psi reference I see on my pirelli sport demon tires is "max load at 42 psi (cold)". Is that what I should fill them to?
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Aug 31, 2017 17:12
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Jack B Nimble posted:The only psi reference I see on my pirelli sport demon tires is "max load at 42 psi (cold)". Is that what I should fill them to? i think ~32 psi is probably a good rule of thumb for most street bikes
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Aug 31, 2017 17:23
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I'd been told something similar when I started riding but wanted to double check my bro science. Thanks!
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Aug 31, 2017 17:24
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Go with the pressures on your swingarm/mfr label. And yeah, ~32 is pretty standard.
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Aug 31, 2017 17:30
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Jim Silly-Balls posted:Are you fighting valve issues rather than FI? Or is this something that only shows up when you mess with FI? I don't know what causes it, it's just always been on FI bikes.
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Aug 31, 2017 20:25
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Slavvy posted:Doublepostin because I've had enough of this poo poo. Isn't this basically either timing being off or running too rich? Like there just aren't any other options for what could be causing those two root causes? On running too rich, could the TPS sensor be off a little and the air intake (which I'm not familiar with) is more on one side than the other?
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Aug 31, 2017 22:55
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HenryJLittlefinger posted:Go with the pressures on your swingarm/mfr label. Yep. The numbers on the tire are just "don't go above this or the tires might blow up" figures; the correct ones for your bike are going to be written on it somewhere. Go up from there a few psi if you're riding two-up or are a big fatty.
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Sep 1, 2017 01:29
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32 is effectively track pressures. I run 28/28 on my sumo (260 pounds), 34/34 on anything in the 300 pound range, 36/38 on the 400 pound range and 38/40 on 500+ / high HP bikes. Running low pressures will just burn out your tires faster and make the bike slower steering. Doesn't really add a significant amount of traction for street use.
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Sep 1, 2017 05:05
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Yeah, I weigh 175 and the bike needs to be at 29 psi, so I adjusted it. It never occurred to me that the data would be on the bike instead of the tire. And sure enough I opened my car door and saw the same thing there; whaddya know.
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Sep 1, 2017 05:21
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builds character posted:Isn't this basically either timing being off or running too rich? Like there just aren't any other options for what could be causing those two root causes? I can't speak for the other bikes but in this instance it's because someone pulled the intake boot of the head and forgot to put the gasket in. It passed the engine start misting test so hosed if I know, but runs ok now.
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Sep 1, 2017 06:52
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I was trail riding on my WR250R today and dropped it at low speed cause im short as hell and wasn't expecting a stopped line of utvs right around a blind corner. Didn't think anything was wrong and rode it about a mile back to the trailhead to call it a day, but when we got back to where we're staying I noticed a small oil spot on the trailer deck. turns out the shifter was a little bit loose and must have landed right on a rock or something cause it tapped the crankcase cover just hard enough to cause a little L-shaped hairline crack that's leaking a very small amount of oil. I've never dealt with damage specifically like this before, so what should I do about the fact that we were hoping to get a couple more hours riding in tomorrow before we packed up and headed home? In my personal experience I've either been lucky enough to escape with scratches in the case of my bikes up to this point, or I've seen holes big enough to peer into the transmission and safely call it a day in the case of some of my friends, but I'm not sure what to think about a small crack and leak like this. It's a slow drip and I've got plenty of spare oil to keep any losses topped off, but I'm kind of worried about chips that may have broken off the inside as I've heard some people mention when it comes to aluminum parts. I'm also concerned that the crack may enlarge due to thermal expansion and start leaking more than I expect or even worse, maybe take a minor hit in the same spot and go from a crack to a hole. Think I should risk it, or stay behind to stick it back on the trailer and let it be until after I replace the cover and do an oil change at home? I eats my spinach fucked around with this message at 04:54 on Sep 3, 2017 |
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Sep 3, 2017 04:38
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I'd take the risk. Low impact force like that won't lead to any chips or anything on the inside, it's just a crack. Just stop frequently to check the oil.
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Sep 3, 2017 04:56
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JB weld. That's my serious answer, not my "lol, watch this guy on the internet blow up his SXV 5.5" answer. You could also just ride and bring some oil, but jewels will fix you right up. I bring some quick setting jb weld with me when I'm riding without folks for this reason.
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Sep 3, 2017 13:17
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Cool, thanks. No JB weld on hand and we're kind of in the middle of nowhere with no stores nearby so I'm just gonna keep it topped off until we get back home and I can get it welded by one of my friends once we're there. Sounds like I should pack some in my toolkit though cause I'm not always just gonna be a mile from my spare oil, how do you prep it for surface adhesion in this case? I'm guessing lay the bike on its side with the crack up to keep oil from leaking out, but will it stick well enough without proper solvent cleaning and roughing up the smooth surface finish first? I work with epoxies a lot in aerospace but we always sand the surface to a specific measurable roughness and clean the hell out of with MEK prior to application. Would a little bit of gas work to clean the surface or would that leave residue that would make it worse?
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Sep 3, 2017 15:45
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I eats my spinach posted:Cool, thanks. No JB weld on hand and we're kind of in the middle of nowhere with no stores nearby so I'm just gonna keep it topped off until we get back home and I can get it welded by one of my friends once we're there. The bigger the glob, the better the job. You're out in the sticks. Use whatever you have to clean it and it's going to be better than nothing. Gas is better than nothing, but probably not as good as acetone or alcohol or MEK. Camping fuel is really pure kerosene, and would be better than about anything else you're likely to have in the backwoods. The standards of brake cleaner, carb cleaner, and starting fluid are also pretty great.
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Sep 3, 2017 17:25
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I eats my spinach posted:Cool, thanks. No JB weld on hand and we're kind of in the middle of nowhere with no stores nearby so I'm just gonna keep it topped off until we get back home and I can get it welded by one of my friends once we're there. So here's what I'd really do if I was going to replace the side when I got home: Bike on side Mix JB weld Wipe off oil with glove (I keep a spare set of nitrile gloves too because they pack down and you can put them under your gloves if you're cold and because, honestly, I saw other folks doing it). Put a big glob of JB weld on That's it. I'm sure that's not very good in terms of prep but it's not like you need it to stick forever. It'll dry and stick on just fine for the rest of your ride. Note: I've only done this once, but it was fine. I prefer to break clutch levers and bend bars when dropping my bike on rocks.
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Sep 4, 2017 00:27
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Quiksteel is what you want.
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Sep 4, 2017 05:25
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To add to everything said, I would pop the cover off when I got home just to inspect it / put more goop on the backside of the crack. I've seen JB weld on case covers last thousands of miles, I would have no problem using it on a trail side fix. The better you can clean the area with whatever cleaning solvent you have and maybe some sand paper/scotch brite the better.
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Sep 5, 2017 03:23
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Hello stupid bike questions thread. My dumb friend bought himself a bike from a random guy and we're going to be trying to get it running. The biggest problem we're expecting to run into is where to go for parts because he couldn't buy a Honda, Yamaha or even a Harley like a normal red blooded american. No, he had to go and buy himself a god damned Chinese bike. It is a 2009 American Lifan 250-b. Now as we understand it, the motor in this bike is a licensed copy of or made with the molds from a different bike motor, but we're not sure which one. The motor is supposedly a honda 250cc vtwin, but the specs also match a yamaha 250xv. Specs: 250cc vtwin motor, air cooled 4stroke 10:1 compression 18.5kw\8000 rpms 49x66mm bore x stroke Any idea what bike takes a similar enough motor that I can use it to track down plugs, filters, etc for him so we can get this thing rideable again so I can prove that I'm right and owning a bike around florida old people drivers is a horrible idea?
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Sep 5, 2017 08:54
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all that "same as a honda" or "from the same factory" as a way of indicating quality or a good deal is basically bullshit. At best you are getting the parts that failed QC which is bad. With that Chinese stuff you can often buy a whole new engine on alibaba for cheaper than fixing it.
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Sep 5, 2017 09:33
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Cop Porn Popper posted:Hello stupid bike questions thread. My dumb friend bought himself a bike from a random guy and we're going to be trying to get it running. The biggest problem we're expecting to run into is where to go for parts because he couldn't buy a Honda, Yamaha or even a Harley like a normal red blooded american. No, he had to go and buy himself a god damned Chinese bike. It is a 2009 American Lifan 250-b. Now as we understand it, the motor in this bike is a licensed copy of or made with the molds from a different bike motor, but we're not sure which one. The motor is supposedly a honda 250cc vtwin, but the specs also match a yamaha 250xv. Those are 100% a Virago 250 copy engine-wise and a fake chrome colored scooter in every other way. However there are two Virago v-twins with minor yet fatally incompatible differences and I don't know which one it copies.
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Sep 5, 2017 10:42
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Yo Slavvy, What the gently caress do I buy to clean my chain? There's not really much choice here on this little backwards island. EDIT: Also please assume I am retarded and do not know how to clean a motorbike chain. Am happy to buy a front & rear stand if they make things easier.
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Sep 7, 2017 05:20
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All you need is a can of WD-40 and a brush or old rag. Use a proper chain lube afterwards -- don't just count on the WD-40 to provide any lubrication. If you can't find WD-40, use kerosene or paint thinner (mineral spirits).
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Sep 7, 2017 06:35
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Odette posted:Yo Slavvy, PM'd but I just realised you said clean and not lube so do as sage says, kero is the most effective but also the smelliest and messiest. Don't use brake cleaner spray or similar as they are not rubber safe and will annihilate the o-rings. WD40 is good but only if you're starting with a fairly clean chain already.
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Sep 7, 2017 07:07
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Kero works fantastically and smells great too IMO.
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Sep 7, 2017 12:07
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put your bike on the center stand and just let it idle in first and rub a brush on the chain
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Sep 7, 2017 12:56
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EX250 Type R posted:put your bike on the center stand and just let it idle in first and rub a brush on the chain *advice only applies to people who've bought a superduke and a GoPro. GoPro must be running.
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Sep 7, 2017 13:06
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Keep your hand close to the sprocket when you're doing this, the teeth pull more gunk out of the chain as they rotate out. Just make sure the GoPro is on and running.
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Sep 7, 2017 15:51
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I prefer to lick the sprocket when I run out of mineral spirits. May require a head mount for gopro.
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Sep 7, 2017 16:44
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If the chain is rotating too slowly, or not at all, kick it into first gear for a quick burst. Helps fling grime off, too.
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Sep 7, 2017 17:50
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tjones posted:I prefer to lick the sprocket when I run out of mineral spirits. May require a head mount for gopro. use your dick next time. <3 it.
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Sep 7, 2017 18:22
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EX250 Type R posted:put your bike on the center stand and just let it idle in first and rub a brush on the chain I watched a guy lose a couple fingers doing this, literally seconds after I told him not to.
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Sep 7, 2017 18:26
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GnarlyCharlie4u posted:I watched a guy lose a couple fingers doing this, literally seconds after I told him not to.
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Sep 7, 2017 18:42
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Fifty Three posted:I figured that's what everyone was referencing. Didn't you mention it here? Probably but I don't recall. It was sever-al years ago 
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Sep 7, 2017 19:17
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It's not a GnarlyCharlie-specific event. Tons and tons of people have lost fingers by trying to clean their chains with the engine running. I once got my thumb caught between the sprocket and the lower chain run just while slowly turning the rear wheel by hand, and the inertia of the wheel alone punched out a chunk of flesh and the nail instantly turned black. Under power, I'm sure the engine wouldn't even slow down.
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Sep 7, 2017 19:18
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A friend of mine started spraying his chain with the bike on the center stand and in first. I promptly yelled at him. Not nearly as dangerous as cleaning, but he did get chain lube all over his garage.
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Sep 7, 2017 20:16
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