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Yet another question...

Took my bike out today with 5% toluene in my tank the response is great and the pull is great.
About 2 rides ago I had a new top end and I got the head modded. First ride out I experience this gung gung gung as the revs dropped. But the bike was running great so I ignored it.

Anyway today as the day went on and the temp of the air and the bike increased I think my response got not as good and it began to smoke more and the gung gung gung seemed to get worse it was doing it all the time (accept accelerating) even at idle.

What causes this uneven drop in revs and what is it? I believe it has got worse since running the toluene.

My jetting is a 155 main CGK needle #2 clip, 42 pilot with air screw out 0.75 turns.

I experimented with my air screw and found that the problem got a little better if I put the airscrew at 0.5 turns out but it made the response worse.

Please help im lost

What does your plug look like?

Ive done a plug chop with a 152 main jet and that is about right but I figured cause I ride alot of sand is better to be on the safe side with a 155 I know im rich but is that the problem or is it the needle or the pilot is it something else It doesnt return to idle very fast after blipping the throttle it does the uneven drop in revs and doesnt get back to idle to quickly. Ive heard this condition is from running to rich but if I turn the airscrew in even though it decreases response it mellows the problem and makes it slightly better. I do notice If I let the bike cool for 10 min still warmed up but just not as hot it doesnt do it as bad.

When you added the toluene, did you add it straight to your mix or did you figure it as a fuel & adjust from there. ie: 5 gal @40:1 + toluene or 5% toluene, plus gas equaling 5 gallons of fuel @ 40:1.. The sound you are describing sounds like a LEAN condition, is it a running out of gas sound or do I have the "gung gung gung" wrong.....

I worked the Toluene out at 5% of the Total Gasoline without oil then I worked the oil out. It could be running lean but with a CGK needle the richest pilot i've heard of people using is a 42 and my air screw fastest idle is around 1 turn out which I don't think is too bad. My needle clip is in the #2 clip which is also the richest clip i've heard anyone running a CGK needle uses. My main I know I am rich on but that is only about 1 size just to be safe for sand. How does toluene affect the jetting does it make it run richer or leaner? it seems the hotter the bike gets the worse it gets.

You don't think it could be something else (i.e the head mods or something engine related) do you.

It don't know what it really sounds like, but to me it sounds like it is actually having trouble to burn off excess fuel. But then that would not explain how turning in the air screw helps the problem but makes the response worse, or that its not spooging and that it's smoking alot. If I stop giving it throttle it tugs back and forward and makes a gung gung gung sound slowly dropping in revs. If I pull the clutch in it just makes the gung gung gung sound without the tugging.

I wondering if you've developed a small air leak somewhere . . . double-check all of your intake connections

Ill check for air leaks, but I actually think im 4 stroking.

Question for m0rie

Just wondering what position your air screw was in when you were running the CGK and what pilot you used to go with it thanks.

Im just wondering as ive got my needle in the #2 clip and the airscrew 0.75 turns out and excessive 4 stroking along with a slight bog just off idle. The problem is turning the air screw out to lean it makes the bog worse which I think is strange.

Im trying to solve the problem and im not sure whether to go left or right.
Your air screw position might gimme an idea.

Thanks m0rie

GhostRider wrote:I got the head modded.

From where did you get your head mods ?? RB Designs ?? If so, forget I asked.

Not from RB I would of liked to get it from RB but couldn't.

Wheres m0rie, please answer my question.

Do you know what was actually done to the head ?? I'm just thinking it may be the cause of your problems. Have you tested with fresh fuel to eliminate that from the equation ??

Good luck...

Me head was skimmed for more compression, im assuming the guy knew what he was doing as the last engine he did for me worked great, and he said he used to race an e series kdx so he knew how far to take it. I can only take his word for it.

The fuel was new as of last weekend when I rode it so it wasn't that.

So just to clarify it was 4-stroking/surging without ANY tolulene added ??

Yeah, It just felt like it got worse but I now think thats cause when I was going through trees at low speed. Ive heard it is normal that a bike should 4 stroke then, the only thing is mine was 4 stroking at idle quite badly.

I had it anywhere from 0.5 to 1.5 depending on the temp, altitude and weather conditions (foggy, clear, etc).

If you can post up some measurements of the head Ron might be able to roughly tell you if its been over done.

What measurements as in depth etc. If I do that I might do it next time my heads off for a service. In the mean time I might just play with my jetting. I could be wrong but I dont think its overdone or it would of been asking for some high octane fuel (pinging etc).