Any gueses?

[johnmarchetta34]

It died on me suddenly while high in the rpm range. 701 with a ada head and B pipe

Any guesses before I dig into it?

 

[Baja 252]

My guess is you melted a piston, high speed, lean, fuel issue.

 

[503701]

Leak down test before you tear it down. Do you run open flame arrestors or the stock air box with the Wax adapter?

 

[johnmarchetta34]

Leak down test before you tear it down. Do you run open flame arrestors or the stock air box with the Wax adapter?

I run blowsion arrestors. Just pulled them off before doing the compression test

 

[johnmarchetta34]

My guess is you melted a piston, high speed, lean, fuel issue.

I think you're probably right. Will report back later lol. Im running 89 octane (ethanol free) gas with 36cc domes. Does this sound right?

 

[503701]

 

[mikesx]

I think you're probably right. Will report back later lol. Im running 89 octane (ethanol free) gas with 36cc domes. Does this sound right?

What ignition?

 

[johnmarchetta34]

What ignition?

OEM

 

[JC-SuperJet]

 

[Big Kahuna]

Well?

 

[johnmarchetta34]

No holes! The pistons actually look pretty good. Theres some mild scoring in the cylinder above the intake port but noting that I would think should cause that kind of compression loss. Must be be the reed?

 

[kevbo]

Look for stuck rings or a dome lost contact pressure. A broken reed wont change the compression seal.

 

[Roseand]

That's a lot of metal transfer. Bet you your rings are stuck.

 

[joeschuit]

my guess is the side of the piston will look like this. Some muriatic acid on the cylinder should clean up the smears.

 

[Roseand]

my guess is the side of the piston will look like this. Some muriatic acid on the cylinder should clean up the smears.

We all gotta learn somehow right?
Acid, hone, a fresh piston and rings and you'll be good as long as the tolerances are still within spec.

 

[fastgtfairlane]

I would expect to be boring thr cylinder after a full throttle seizure. Especially when it looks lean like the piston wash indicates. Which could also be not enough Octane for the compression. The only way to know is to have the piston and cylinder measured. Y0u might get lucky but plan on a rebuild

 

[DylanS]

I have a spare one if you want to borrow it
Don’t use metal spoons you need the tension from the plastic

 

[WFO Speedracer]

I have a spare one if you want to borrow it
Don’t use metal spoons you need the tension from the plastic View attachment 459069

Plastic is Fantastic !