3ma carb setup.

[Edd]

Hi Guys;

Right here we go again. Had my track bike at red star this weekend. Been doing a lot of jet changes and setteled on 210 mains. However I have a problem that jetting is not sorting. The bike doesnt want to go full throttle immediately I need to feed the power in slowly, this only happens after I have runned full throttle for about 20 sec. Usually at the end of a main straight. Or while I am acceleratig 1st 2nd 3rd 4th then nothing.The bike just dies as if it is not getting fuel or it is getting too much fuel. When you do a run and you open the choke the same type of symptom. Plugs are burning perfectly?

I do have bigger pilots my thinking is as I shut off the pilot system is flooding the cases. I need to clutch in on turns and go 1/8 throttle to get the engine going then clutch out and smooth power on the gas to get exit speed. If I dont clutch and I just play with the throttle to get it going, once it bites I need all my skill to keep the thing in check .

Also the bike is blowing a lot of fuel out the pipes.

Edd

[Paul]

Hi edd. Did you advance the timing like we spoke? It needs a lot right through from about 7000 onwards.
Also while you have come down on mains, my guess is your needle is allowing too much fuel through, adding to any possible timing issues. Avgas will be looking for a lot less fuel.
Put your curve up on here and I will check it out.
Remember I didn't get mine perfect at RSR but I did get rid of the hesitation.
For everyone else, mine and Edds 3ma track bikes are both Coker tuned with his unique pipes. Setup is designed for avgas fuel and pure race tuning.

[Louis]

Edd,

Does your bike have the EGT fitted?
If so what does it do when she dies on you. (temp goes down or up)

Don't know this phenomenon, perhaps the breather hole is to small in your tank cap.
Just a idea

[Edd]

Hi Guys;

You have me thinking now. I have spend a whole day on flow; I did have problems and I removed all filters fuel now straight into the carbs. I am running an advanced curve 27 and 29 degrees; which I will post soon no diffrence. So one of two things are happening. (A) I dont burn all the fuel whilst running full throttle and once I tap off I have too much unburnt fuel in the cases causing the bike to flood. OR (B) I am using the fuel in the carbs at full throttle dropping the float bowl height and I run out of fuel.

Scenario B seems the most logic for me; however I have removed all restrictions their is no way it can be an issue I run 4L of fuel through the system 10 TIMES and the stream didnt weaken at all.

Those flippin check valves is haunting me, we had this discussion a million times but my brain just wont let it go. Is it not possible that they are causing the flooding then A is possible.

Edd

[Crank]

Edd, the EGT on the bike, is it working as Louis asked?

[Edd]

Hi Guys

Sorry Louis didnt look at it was focusing on apex . Attached my zeel setup,

Edd

[Louis]

Those flippin check valves is haunting me, we had this discussion a million times but my brain just wont let it go. Is it not possible that they are causing the flooding then A is possible.

I don't think so Edd,
They have a tiny little metal boll inside, Its most unlikely that the close and open at high revs.
Think the mass of the boll is to high to let it close and open the valve at let say (10.000rpm)

From what I read (your description), think you just run out off fuel.
Especially when you say you have to use the throttle gently to start here going again.
(on the EGT you probably would see temp rising fast on the end off that straight)

Think you should run it again but remove the tank cap and temperately pot in a sponsh or something like that.
(just to make sure it can breath clearly now)

[Edd]

Hi Louis;

I will take her out on satutday without the cap. I have however ran 4 litres of fuel through the system 10 times no blockages so the feed into the carbs is fine. I have however not runned it through the carbs my problem may be there? Will test that as well.

My gut feeling says I am running out of fuel but I have tested the system so many times maybe I have missed something?

Edd

[Warwick]

The only time I've had similar-sounding symptoms was with clogged carb inlet filters, but if you don't have those fitted, that's out. Does sound like fuel though... Plenty of fuel in the tank? (try using reserve as the main feed maybe? - shorter stub less likely to run dry). Cap breather is a possibility of course, so certainly worth checking.

[Paul]

Edd
Get your son to plot your advance curve out and post it
It is flooding

[Edd]

Hi Paul;

I have attached the zeel maps will that not help?

Edd

[Paul]

Oops. My apologies bud. I missed a few posts back there.
On the right you have "Advance (*)"
You can safely set that to +3
Give it a go and see. Let me know
Also pay attention to where the lag is happening. For me it's was 8000-9500.

[Edd]

Hi Guys;

I have changed the pilot jets went from 22.5 to 20's bike is slightly better . I will now start with zeel to see if it clears it up totally. Running 210 main jets and still rich at 5 to 6 K range.

Edd

[Paul]

Howzit edd
I got my windows laptop out and I don't have the curves on there to check. I can dig them out of my backup hard drive. Once I have it I'll email it.
Is that rich spot wot or while twisting. What I noticed after the tune was by controlling the rate at which you open the throttle would also affect it. I think you must fit smaller nozzles. Might even have to drop the needle. Just remember to watch plugs when changing needle in 3ma
You also have the EGT
Hold it on 1/2 and 3/4 throttle and check temp

[Edd]

Hi Paul;

Found the reason I was struggeling with setup. LHS carb had a sticky float and overfilled the bowl. I am back on 240 mains bike is beter but still has the hesitation also advance the curve by 3 degrees will first do a run on old curve then on 3 degrees advance to find the effect it has. Left it there yesterday got tired of removing airbox

Edd