Fuel issue, topend studder, getting annoyed

Hey Ibcnya, hopefully you have isolated the problem by now. One thing that you'd mentioned that caught my eye was you set the plug gap at only .022 and i would suggest trying a wider gap setting. Generally for wot bogg combined with an already weak plug you'll be pulling your hair out for days to come. I've resolved this by setting the gap to .035-.042 on a new NGK iridium plug. Note that .045 is the max that you should go.,..,.,,..,.good luck oh i'd use a min. 89 octane for premix.,.just a thought
 
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I think Pops has a very good point. It sounds to me like the float in your carb is letting in too much gas. I'd inspect and/or replace it, (along with the inlet needle valve, seat, etc. if these apply here) then make sure it's adjusted properly so the bowl doesn't overfill.

Something tells me this is not a serious mechanical problem ... just one of those little "forehead slappers" that drives you bonkers for awhile.

I once had a snowmobile motor that defied any and all attempts to make it run for more than a mile or two. After I sold it (too cheap) I found out that that particular model came from the factory with the "in" and "out" gas lines reversed.

Hope you get to the solution soon ...
.trk.
 
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JD-StukNchaoS said:
Hey Ibcnya, hopefully you have isolated the problem by now. One thing that you'd mentioned that caught my eye was you set the plug gap at only .22 and i would suggest trying a wider gap setting. Generally for wot bogg combined with an already weak plug you'll be pulling your hair out for days to come. I've resolved this by setting the gap to .35-.42 on a new NGK iridium plug. Note that .45 is the max that you should go.,..,.,,..,.good luck oh i'd use a min. 89 octane for premix.,.just a thought
Click to expand...

I am not at all sure where you guys are coming up with these gap measurements.

First of all it looks like you are one digit off. These engines do best at .020-.025". In fact some run pretty darn well at .015". They will do OK at .030", but larger gap buys nothing, and may even invite alternative pathways (read: fouling shorts).

Also higher AKI fuel won't help these engines either. Use FRESH 87 RON-MON/2, and a good oil mixed fresh.
 
You're right Pablo ... I mistakenly wrote a spark plug gap of .30 when I should have written it as .030 ... big difference! I guess I just got used to saying it as "thirty" and so wrote it that way.

Actually, I just went back and deleted my spark plug gap recommendations. I was offering some "general" information that, while it may have been relevant years ago, may not be accurate today on these particular engines. Just couldn't resist offering my (old) 2-cents worth to try and make the motor go.


Thanks for the correction and sorry for any bad info.
.trk.
 
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OOOOPS!!!.ya my bad as well. Only here to help, and it's true that you can't assume that common sense will prevail.,..,.

If it helps to bring a little clarity...,.as to why i had suggested gap size may be of some concern. Possibly even to enlighten some of the new builders that may benefit from this tech advise.
 
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In the power of an engine theres a trade off......

You can advance an engine at the flywheel or run a tighter gap to get a better bottom end take off advantage and better punch in the corners....

When you retard an engine it gives you a top end advantage by allowing a wider spark generated at higher rpm's to prevail in a bigger power increase by taking away the predetonation that occurs at top end speeds with a closer plug gap or advanced timed engine;-also retarding the flywheel gives leeway to fulltime nitrous usage without hurting the engine....

In my pick-up truck I run a MSD6 box with timing adjust knob on the dash.......I had one in my OLDs 442 also..It gives you on demand adjustability of the timing with the twist of a knob up to 15 degrees total and can be set to split the timing 7 1/2+ and 7 1/2-.The plug gap went from .035 to .o60;-{MSD recommendations}.......I use it set the knob a few degres advanced in stop and go traffic and when Im in 5th gear cruising I cut it back a few degrees and I save gas or use it to get the engine in places it would of never gone stock;-lol. I also run the MSD single cylinder CDI in my X-15 bike and it has flick of the switch capability to change from two timing advance or retard modes while on the fly.

The only thing it can hurt is the lower and midrange power and not a whole bunch that cant be made up with adding a stiffer clutch spring............................Peace
 
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Hi ibcnya, This may sound stupid but I would first check the muffler like pablo said, and if that's ok then here comes the part you'll think is stupid take off that deltoro & put the stock one back on to see if it still runs better.
 
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