So my '97 ice bike, which I've abused horribly for a decade or more, has finally retaliated by not running right. Starts fine, but once the bike warms up it misfires in the upper revs, and will die if you don't keep blipping the throttle when you come into the pits. If it dies, it's an absolute PITA to get going again. Generally, no choke half throttle will get it going after about 15 kicks. Also feels down on power. Has new air filter and carb was rebuilt mid-season last year, so at first I thought it was carb related. But it's clearly heat related as well. Now I'm thinking either a coil issue, or exhaust valves have tightened up. Valves are way overdue for adjustment, but I don't have the shims, so hoping I can eliminate the other items.
What is this “kick” bullshit? First order of business is to get a bike you don’t have to kick start. Do that. Then if you eventually have problems with THAT bike, we will help you.
Yeahh....couldn't agree more. Matter of fact, I broke my foot and ankle when I caught the peg last season, but it was always a one kick bike. It's hard to justify spending serious $$ on a bike that you sometimes don't even get to use. Last season was a good one, with plenty of ice, but we've had years where the ice is junk and there's just no place but way north to ride. That said, I'm pulling the trigger on a 2012 KTM 350 EXC-F that's already set up for the ice, for $3k. I'll keep the KLX, as it's a great bike for newbies, but need to get it running right.
Plug and wires? Check all coil electrical connections. Ohm the coil? Check valves and see if they are tight?
Plug was new, but swapped it anyways. Connections all seem stable, no wear marks or corrosion. Agree about the coil, that's next, but I loaned my meter to someone so need to get a new one. Valves....I've got a sneaking suspicion that's going to be the end result, as I haven't adjusted them in.....forever, and a tight exhaust valve might act like that.
Yeah, I dumped the decompression for that reason. Which might have contributed to me breaking my foot! Had the carb apart twice, so I don't think it's there, as the pilot wouldn't act differently with heat. I don't think at least.
Water in the fuel? Valves would make it hard to start but wouldn’t notice it as much once it’s running. Unplug the kill switch. Close the plug gap up some, if that improves it may be a weak coil/high voltage leak. By tighten it up I mean close the gap from .028” to .018”or so. Checking valve clearance is also a good idea, TIGHT intake valves will make it overly rich and cause issues.
When I rebuilt the carb, I flushed the entire fuel system. But that was a good thought. Never really thought of the intake valve being tight, as it's usually the exhaust side that tightens up, and then you lose compression as it heats up. There's been some good ideas on checking the coil, so I'm going to try that first.
Are the valves really that difficult to check on that bike that you're going out of your way to not have to? Or is it because you don't have the shims?
Don't have shims, and my recollection of the last time I did valve shimming, it took way too long, and that was back when my hands still worked.
Stop being cheap and spend some of your millions. Take it to a shop and have them adjust the valves and do a leak down and compression check. Then you will know. Also, put a new and bigger carb on it.
It’s almost always the intakes tight when dirt cycle valves are out of adjustment, and normally only affects starting and idle/low RPM running. Normally if it will kick start at all once it comes off idle it runs fine.
Had a four-wheeler that I bought semi-running. Cleaned the fuel system. Still wasn't right. Chased my tail for way too long because I just knew the carb was clean. Finally circled back around to the carb. It had a partially obstructed pilot jet. No idea where that piece of debris came from. I'd still start with checking the valves in your case though. Checking them is free and easy at least.
Ken....my friend....I'm sure you forgot that I was born cheap. I ran my RZ with stock suspension all those years, and always ran my rubber way past a useful point. Plus my ex constantly kept me broke, so I'm just predisposed to chase my tail rather than spend money.
It starts perfectly when cold, and only starts to get rough after it warms up a bit. Not much, like maybe 3 laps on an oval. Then you have to keep revving it to like 4k rpm just to keep it running. I know that sounds like a pilot, but I've actually passed a wire through the hole on the pilot, and even all the small pickup holes. I guess why I always think the exhaust valves tighten first, is...well they're exhaust valves. But I suppose the intakes being tight would make it run richer once they heat up. I guess I'm being lazy in my old age. I keep 'wishing' it's something simpler so I don't have to fight with shimming. iagsxr says it's free and easy? Well I still gotta buy shims, and my hands don't have the dexterity for that crap anymore, so not easy. Maybe I should crowd fund a top end rebuild.... I've literally wrung that things neck for at least 10 seasons, with only oil changes. When ice conditions have me running the oval with more speed and not enough gear, I just rev it farther, as it doesn't have a limiter.
