I was riding in the trails the other day and noticed my blaster would make a ping\knock sound at WOT. I am running 93 octane with pre-mix I have a FMF fatty pipe, Vforce 3 reeds, WIseco piston, vitos high comp head gasket. open air box lid. I am running a stock carb with stock settings except 270 main jet and spark plug is a br8es. I tried a plug chop and when I took the plug out it was covered in heavy black carbon. Is this a sign of being lean or rich and has anyone else ever experienced this problem? I also wanted to note that when ridding in the dunes my bike seems to overheat. After riding in loose sand for about 30-45 mins the bike died and wouldnt start until a 20 min. cooldown then it ran perfectly fine ......
Blaster Pinging Under load ?
- Thread starter luxuriespremier
- Start date
sounds like you have an airleak. you need to buy a leakdown tester from holeshotman. he has them forsale on the forsale tread. 30 bucks. this should solve your problem after you fix the airleak. looks like you are jetted a little lean just by the numbers not the plug. the plug won't tell the truth with an airleak
A rattle sounds like detonation... The black color spark plug is way to rich
Maybe your best bet is to pull the head off and take a snap shot of the top of the piston for us.... You could try running a fuel such as 110 to see if the noise goes away or pulling ignition timing out of it
Maybe your best bet is to pull the head off and take a snap shot of the top of the piston for us.... You could try running a fuel such as 110 to see if the noise goes away or pulling ignition timing out of it
Lay off, Dude.
luxuriespremier, what's your altitude you're running at? That could explain the 270 main. I'm running a 290 with close to the same modifications but I'm at about 300ft elevation.
The sound you're hearing could also be piston slap not necessarily detonation.
Detonation will go away with higher octane fuel, as Kennedy suggested. Piston slap will not. Also, heavy dune riding causing an overheat is a quick way to kill a topend. You may want to check the top end open and roll it over to see if there is any piston damage.
luxuriespremier, what's your altitude you're running at? That could explain the 270 main. I'm running a 290 with close to the same modifications but I'm at about 300ft elevation.
The sound you're hearing could also be piston slap not necessarily detonation.
Detonation will go away with higher octane fuel, as Kennedy suggested. Piston slap will not. Also, heavy dune riding causing an overheat is a quick way to kill a topend. You may want to check the top end open and roll it over to see if there is any piston damage.
Thanks for all the input so far! I pulled the head and there doesnt seem to be any piston damage but it does have the same black carbon buildup that my plug has. I ride anywhere from 300 -600 ft above sea level. I replaced the head gasket and torqued the head and also the base gasket while i was there. I also checked the intake and exhaust gaskets they all seem fine but replaced anyway. Is it possible I am running lean with the mods that I have ? I Have a 280 jet in my garage that I think I will throw in. Is it possible i need to adjust my needle or pilot? Thanks
and id like to add that even if you replaced the gasket dosent mean you dont have a air leak id try puting that 280 in and go up a size on the pilot it couldnt hurt
The 270 main at 300-600 ft seems a little low but every carb/engine setup is different. Black carbon on a piston is normal, black carbon on a spark plug isn't. The spark plug should get burnt fairly clean each stroke because it's not protected from the heat of the fire like the piston is.
It sounds like you might be having a timing issue. Way over advanced timing would lead to overheating, black carbon deposits even with slightly lean conditions and pinging at WOT. You wouldn't necessarily notice a power difference because it's still able to run like that but not as well as it would without an over advanced timing. I'd run through the checks in the service manual for the ignition system to make sure you don't have a failing component and then pull the flywheel off to check everything under there. Pay extra close attention to the condition of the flywheel key.
It sounds like you might be having a timing issue. Way over advanced timing would lead to overheating, black carbon deposits even with slightly lean conditions and pinging at WOT. You wouldn't necessarily notice a power difference because it's still able to run like that but not as well as it would without an over advanced timing. I'd run through the checks in the service manual for the ignition system to make sure you don't have a failing component and then pull the flywheel off to check everything under there. Pay extra close attention to the condition of the flywheel key.
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