i just got a yamaha blaster not sure of year i think its around 95-2000 i was told it has a big bore kit but im not 100% sure but it sure seems like it here is my problem when it is cold it runs great and pulls hard for about 5 mins but once it gets hot as soon as it gets into the power band it starts misfiring and poping im not sure what the problem is could this be jetting? and it misfires regardless of throttle position if im half 3/4 or full as soon as the power starts coming on it starts poping any help would be appreciated?
big bore blaster misfire when hot
- Thread starter blaster888
- Start date
i just got this 4 wheeler it has an aftermarket silencer and stock head pipe that leaks bad where it goes in the cylinder and where it connects to the silencer no air filter or airbox lid (i ordered a filter) ill do research on how to do a leakdown test and have no idea what jets are in it im new to 2 strokes
but right off the top of your head do you have any ideas? i wanna try to seal the exhaust and rejet it think thats a good start?
A leaky header pipe will cause it to run lean.
No air box lid will make it run leaner.
No air filter will make it run very much leaner.
Combine all 3 problems and you have a melted piston and enough ingested dirt to make a brick.
Ride no more until you have checked the jetting suits the mods and there is an air filter fitted?
Another observation, if you are riding it cold you are asking to cold seize the piston in the bore.
An engine should never be put under riding stress until it is fully warmed up.
Clean the carby, fit the correct jets, set the float level, adjust the idle as per specs.
Warm up the engine and perform a plug chop to confirm jetting.
No air box lid will make it run leaner.
No air filter will make it run very much leaner.
Combine all 3 problems and you have a melted piston and enough ingested dirt to make a brick.
Ride no more until you have checked the jetting suits the mods and there is an air filter fitted?
Another observation, if you are riding it cold you are asking to cold seize the piston in the bore.
An engine should never be put under riding stress until it is fully warmed up.
Clean the carby, fit the correct jets, set the float level, adjust the idle as per specs.
Warm up the engine and perform a plug chop to confirm jetting.
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person before you either had a pod filter or they cut out the airbox to install a aftermarket airbox.The airbox is part of the rear fenders.No way you can run that without a filter,thats crazy...
Dunno who made the vid on carb cleaning, but it is about at useful as tits on a bull.
I am sure anyone who has taken the float bowl off knows what a needle looks like.
I am sure anyone who has taken the float bowl off knows what a needle looks like.
From my forced induction car days, popping meant one of two things: lean or weak ignition.
While you're ordering stuff, go ahead and get yourself a leak down tester. That's going to be a potential culprit as well. If you can, get your hands on a compression tester and see if that sand-hardened cylinder needs work.
Get filter oil, too.
While you're ordering stuff, go ahead and get yourself a leak down tester. That's going to be a potential culprit as well. If you can, get your hands on a compression tester and see if that sand-hardened cylinder needs work.
Get filter oil, too.
This is out of character for me, but running it without a filter (outside of for a quick start-up test) doesn't sit too well.
2 strokes are a very finicky species and mandate a level of dedication to detail that most are reluctant to deliver.
2 strokes are a very finicky species and mandate a level of dedication to detail that most are reluctant to deliver.
Tell it as it is! 2 strokes do demand a high level of maintenance that unfortunately many do not realise.
i tore my head off my piston is indeed melted i figured out the misfire before i did that tho it was a wire under the stator cover grounding out then a day or 2 after i figured that out a reed broke off so i ordered vitos 2 stage reeds and while i was waiting for them to come in i decided to take the head off and inspect the cylinder im gonna have the cylinder bored its at 67 mm right now im gonna get a new piston and an air filter and seal the exhaust and go from there it ran great with a melted piston wore out reeds and leaking exhaust i figure with a fresh bore and piston new reeds and sealed exhaust it will be alot healthier
Have the cylinder measured for size and have the new piston in the machinists hand before it is bored.
Before starting the engine make sure the jetting is correct for your mods.
Before starting the engine make sure the jetting is correct for your mods.
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