Mac, former owner informed me that last time he rode the sled the spark plug on the mag cylinder worked its way out and striped the threads,must of not been tightened, so it must of been sucking air in that cylinder for a while before he installed another plug which was cross threaded and not in all the way still sucking air till he got back, also the exhaust pipe was sitting right on the head bolts looks like he hit something by the exhaust outlet which moved the pipe down on the cylinder so a combo of sucking air and the heat from the pipe burned it down , makes a lot more sense now.
staggs65
Moderator
I don't know what aaen calls for jetting with their pipes but with all those holes in the airbox and a stripped plug thread that jetting isn't much more than stock. One possible explanation of the excess wash is it was run on the stand with already very low compression. So it was washing that piston clean every second it ran. Just a thought.
toydoc
Member
IMO, you cant wash carbon cake off the top of a piston or the dome of the head with gas, not after it's baked on.
It never made heat in the first place to start to bake it.
If you look past the damage, and your jetting this sled by piston wash (the way we should be, not plug color). In no way does that the piston or head look lean to me.
You can run all season with loose spark plugs. Not one will pop out. It will make a mess and spit black gunk all over under the hood.
By all means check everything everyone has told you. Everyone have given good advice on what to check. I'm just giving my .02 on where you may end up
It never made heat in the first place to start to bake it.
If you look past the damage, and your jetting this sled by piston wash (the way we should be, not plug color). In no way does that the piston or head look lean to me.
You can run all season with loose spark plugs. Not one will pop out. It will make a mess and spit black gunk all over under the hood.
By all means check everything everyone has told you. Everyone have given good advice on what to check. I'm just giving my .02 on where you may end up
staggs65
Moderator
Not disagreeing with you just throwing it out there for discussion
Jetting PTO carb @152.5 , Ctr Carb @ 152.5 Mag Carb @ 153.8, don't understand why mag main jet is larger is it because of the Heat from the pipes run close to the mag side head? I thought the PTO carb jet is richer because the heat of the clutch ? maybe i am wrong ?? possible the tuner put the larger jet in the wrong carb?
toydoc
Member
I know your not. All good things to question. Made me ask myself if it could do just as you said, and i posted my thoughts.
Im also just bouncing ideas off you and Mac. I really don't know what is causing the issue.
Sure it didnt have the wrong heat range plug at one time?
Check the outlet end of the pipe under the sled for the mag cyl, see if it's bent over?
toydoc , Yes there was a wrong spark plug cross-threaded into the head it was not a br9ecs, thats for sure, lot adding up know, wrong heat range plug & the pipe sitting on top of the head caused the heat issue on the top of that piston, i think the jetting should be good, makes scents having the 153.8 main on the mag cylinder due to the excessive heat from the pipes rite over that head?? I think I will get all the parts together and builder back up, then check it from there.
Thank you all for your input!! Very helpful!!
Thank you all for your input!! Very helpful!!