Piston Damange,, this still ridable?

[Motorheads5]

I would say it went out the exhaust port in a gray spray

 

[DAG]

Here are some pics wiith the cylender off. just trying to show how much is missing.

I was able to just lightly scrap the build up of melted allum that acclumated on the ring. It should be good to go. however the lower ring, i noticed it's gap seem pretty big. Whats the spec on ring gap?

maybe i'll be able to pick up some rings locally untill i send it off in a month. :tomato:

i know i'm dogging bullets here,, it seems to me the only thing that can go wrong is the ring catching... which i'm sure can then grenade the entire setup:crazy: Anyone have experience running something like this? :wall:


thanks for any help and advice.

 

[WDKfan]

David get it bored locally and some new pistons bro, you dont want to end up like I did last year...

 

[750SX]

I would not run that! That top ring will be exposed to a lot of heat with the crown being wore away like that. Order some new pistons and drop the pistons and jug off at a local machine show and you can be up and running in a week.

 

[yamahammer]

pistons are a wear item and you need 2 more--i wouldnt chance it on those-- that piston can break off in a chunk right there and hurt some stuff-- seen that too-- i wouldnt bore it just hone and new pistons, rings, con rod bearings, and rock out

 

[Big Kahuna]

grif, go to a hydrolic hose supply house, they will have the orings 043 Viton. you can get them locally most of the time.

 

[ATS_Scott]

#.0 called it. you already cooked that upper ring. Don't even think of re-using them. You'll just trash your domes and possibly the cylinder.

 

[Scorn800]

Piston is toast. Replace it.

 

[DAG]

Yeah, change of heart.

I drove down yesterday morning and talked to a machine shop my old bossman uses for his motorcycle.
Just ordered some 84.50 kits and hopefully it will be up and running by holiday weekend.
yes, i'm retarded to even think about running it.. i know,,, thanks for the advice.

 

[djkorn1]

Good call... It could take out your crank, cases, cyllinder and pistons.

 

[blaster4life]

what would couse that... i just ask cuz i have my bosses gpr800 in my back yard that has a pistion that looks identical to that... i had him order a cylender exchange kit and 2 new power valves from SBT.. i just don't want it put it back togeather and have the same thing happen

 

[Kennay]

heat... deto...

The older model v-4 Evinrude/Johnson outboards had the same problem. It was super common on them to have deto, and then the edges of the piston would start chipping off. It's either lean, too sketchy of timing or both. From looking at the pistons, I think anyone who can look at a piston wash chart would see something isn't quite right about them hone:

 

[DAG]

Whats why i was like WUT. Been running this setup for a light season. alsways used 40:1 benoil. however i did hold it WOT for ~20-30 seconds, and before i limited myself to 10seconds max. I'm using jetting recommended from my engine builder. but as anyone can see its uber lean. so i think a combo of lean and WOT =! good.

For those of you that have ported setups, how do you plug chop if you cant even WOT?

 

[blaster4life]

if i take the oil pump off what do you thik i should tell him to run 40:1?

 

[Scorn800]

Deto can also be caused by overloading the motor with too steep of prop