Piston Carbon Build Up Help

[jetskier79]

A couple weekends ago, my blaster started having problems towards the end of the ride, and when I pulled the plugs, they were covered in "junk" Not goopy gunk, but a dry gunk, that I'm guessing is carbon?

Anyhow, I had the same problem at the end of a ride today, and pulled the head. The clean piston is the front piston, the other is the rear. This motor is only a few months old, so it's not like I'd expect a massive carbon build up.

Also, when we pulled the head, the domes were COVERD in oil. Absolutely gooped on....the picture below is them after wiping them down quickly.

Any idea what the hell would cause something like this??

 

[DaUpJetSkier]

weird, never seen a head like that before. Something doesnt seem right. Does it run good cold and then starts the run like shiat?

 

[cambo au]

do you still have the oil pump set up or do you run pre mix

 

[Robert]

My bet is that you have a slight water leak in the front cylinder. The front cylinder looks like it has been steam cleaned. That happens when you have a bad head gasket. The goopy crap is water mixed with oil. I think you need new o-rings in that head.

 

[butti]

My bet is that you have a slight water leak in the front cylinder. The front cylinder looks like it has been steam cleaned. That happens when you have a bad head gasket. The goopy crap is water mixed with oil. I think you need new o-rings in that head.

i concour

 

[jetskier79]

weird, never seen a head like that before. Something doesnt seem right. Does it run good cold and then starts the run like shiat?

It runs fine cold, it runs fine hot. It eventually WILL start to run like sh*t. And the reason is that I'm getting what seems to be carbon build up on the plugs. A new set of plugs (or even knocking off the carbon) and it runs fine.

do you still have the oil pump set up or do you run pre mix

pre-mix. I suppose it's worth noting that this is a 760 motor running about 195lbs compression.

My bet is that you have a slight water leak in the front cylinder. The front cylinder looks like it has been steam cleaned. That happens when you have a bad head gasket. The goopy crap is water mixed with oil. I think you need new o-rings in that head.

I thought the same thing, but it's the back cylinder that's causing me problems with build up. I definitely think there was SOME water intrusion up front, but fixing that doesn't seem like it will fix my main problem.

 

[norcal ex]

what carb setup/ignition are you running?

 

[jetskier79]

46mm buckshot carb, modified stock CDI

 

[SUPERTUNE]

Put a dual 44/46's carb system on it for starters, Nothing worse than running a modified stock CDI and a single Buckshot... You can't tune it between the 2 cylinders, unless you run staggered compression ratio's. But make sure you have no water intrusion problems first!

P.S.
We had no choice to run them that way way back in '94 for limited racing, I'll never go back to tune any of that type of set-ups now! Like being hauled to jail as a tuner...Handcuffed!

 

[jetskier79]

Put a dual 44/46's carb system on it for starters, Nothing worse than running a modified stock CDI and a single Buckshot... You can't tune it between the 2 cylinders, unless you run staggered compression ratio's. But make sure you have no water intrusion problems first!

P.S.
We had no choice to run them that way way back in '94 for limited racing, I'll never go back to tune any of that type of set-ups now! Like being hauled to jail as a tuner...Handcuffed!

Fair enough.......definitely good info. I've got no problems ditching the buckshot, but I'm not going to go to duals....I haven't got the knowledge to keep them running right.

 

[Matt_E]

I don't understand what's more difficult in keeping "duals running" compared to singles. :dunno:

Granted, it takes quite a bit more time to dial in properly and maintain if needed. Two out of my three engines run singles, and I do like the simplicity.
But what's involved in "keeping it running"?

 

[SUPERTUNE]

All you have to do is GET A PROFESSIONAL, to set them up for you! Dual carbs are hardly never a problem once you get them set up correctly. (the only problems I've had once in a blue moon is stuck open needle valve and a loose coupler drive in hundreds of dual set-ups that I have done)

 

[douglee25]

All you have to do is GET A PROFESSIONAL, to set them up for you! Dual carbs are hardly never a problem once you get them set up correctly. (the only problems I've had once in a blue moon is stuck open needle valve and a loose coupler drive in hundreds of dual set-ups that I have done)

Chuck, what exactly is involved with the 'setup' from you? Is there a base charge? Do you ask what type of setup I'm running, then tweak accordingly, send it back, and I do the final water test/tune? Thanks again.

Doug

 

[Idok]

46mm buckshot carb, modified stock CDI

ported or non ported cyl?


do you have access to a mik 46?

 

[GDFL]

Sounds like you're running the wrong color powerband. Might want to try a red one. :biggthumpup:

 

[SUPERTUNE]

Doug, Shoot me a PM...

 

[jetskier79]

All you have to do is GET A PROFESSIONAL, to set them up for you! Dual carbs are hardly never a problem once you get them set up correctly. (the only problems I've had once in a blue moon is stuck open needle valve and a loose coupler drive in hundreds of dual set-ups that I have done)

Chuck, I won't dispute that for a second! I'll be the first to tell you, I don't know what the hell I'm doing when it comes to tuning.

ported or non ported cyl?


do you have access to a mik 46?

The ports have been cleaned up, but that's it. I might be able to track down a 46, and after this coversation, I'm more than ready to try something new.

 

[jetskier79]

FWIW, I replaced the O-Rings in the head, and changed to a stock 44mm carb. The ski ran noticeably better today, and burned through a tank and a half with no carbon fouling.

 

[jakew4]

Revive this thread

I am having problems just like Jerry had on his blaster. The only exception is that I have a goopy gunk on my plugs after I ride. I can feel the cylinder drop inconsistantly throughout my ride, and I know it's because of this.

My question is: Is my plug goopy because there is water mixing with the oil? (Leak) There's an even mixture of goop and carbon build up on the plugs. Thanks.

 

[D Slicker]

Jerry, glad to hear it is running better. I am running duals on sj with no tunning issue and will be on my blaster. I actually like it better because I can set each cyl is one is slightly off.