let me explain this

[dogboystoy]

OK, I need some fine tuning advise. This is my issue.

Banshee starts within the first or second kick. I usually pull out the choke for a second, start her, then I will push it in. I need to rev her a little to get her to warm up, once she is warm she idles fine. But I cannot leave the choke out for more than a few seconds during the warm up process or she will die, when I push it in she also wants to die, so that is why I need to rev the engine a little (I dont rev it hard, I keep the R's as low as possible).She will hesitate when I go to rev her. This is all in the warming up procedure.

Now once she is warm and I am driving her, I do have a little hesitation on the low end, then she "snaps into it" and has a crisp throttle response. On occasion I will get a backfire, which occurs on the low end of a gear. Some backfires are loud and some are just a putt. I believe it is comming out of my right pipe.

 

Could it possibly be that I need to repack my silencers?

Could it be my reeds? ( looked at them through the hole when I had the carbs removed, and from what I saw they looked fine.)

Carbs are synced.

I have cleaned my carbs twice in the past month, I have also cleaned out my gas tank and put in an inline fuel filter.

I am running 32:1 yamalube, Thinking about going to 40:1 yamalube. My plugs look a little rich, but they are not quite black.

This issue has come up since this summer. For the 4 years I have had her since new, I have run the 32:1 and have minimal mods. (k&N, twist throttle (put in 3 years ago)). She has run great, until now I have this little issue.

Compression

LT-117psi

RT-117-118psi

Thanks

[sredish]

Could it possibly be that I need to repack my silencers?

Could it be my reeds? ( looked at them through the hole when I had the carbs removed, and from what I saw they looked fine.)

Carbs are synced.

I have cleaned my carbs twice in the past month, I have also cleaned out my gas tank and put in an inline fuel filter.

I am running 32:1 yamalube, Thinking about going to 40:1 yamalube. My plugs look a little rich, but they are not quite black.

This issue has come up since this summer. For the 4 years I have had her since new, I have run the 32:1 and have minimal mods. (k&N, twist throttle (put in 3 years ago)). She has run great, until now I have this little issue.

Compression

LT-117psi

RT-117-118psi

Thanks

How does it run when warm? You said slight hesitation and sometimes a backfire, but otherwise great? That makes me want to say your pilot jet is maybe a size too lean. Using the throttle to "keep the R's up" will pull additional fuel from the needle and that keeps it running, so this makes me think the pilot is just not getting all the fuel there during warm up.

 

Could possibly be reeds, but i'm thinking not since it runs fine after warm up. You have brought up a lot of valid places to look but it might simply need one size bigger on the pilot. I'd try that before I got any more serious on searching out a problem.

 

Later.

[hamuel]

I would say lean.... or no air from the air screw. That can do it to...... try playing with the air screw a little. if it runs better under 1 turn go up a pilot or better 2.5+ down on pilot

[dogboystoy]

Well, she runs great when she is warmed up, hits the power band strong, idles great. But does have a little hesitation at the bottom of a gear (which may be normal, but I feel that it may be a little out of wack). I will mess with my air screws, I was messing with them before I sync'd my carbs, so maybe that is the key. My airscrews were turned either 1.5 turns or 2 turns out. But I will twaek it and see what happens. Do you think that the airscrews could be the cause of the backfiring? Top end she runs like a bat out of hell.

 

Note: I had more backfiring issues before I sync'd the carbs, since I have sync'd them The backfiring has definitely gone down. Maybe I should check sync again and reassure myself that they are truely in sync

 

I also would like to discount changing the pilot jet because I did not have this problem since she was new, And I have done very little in mods (k&N, twist throttle about 3 years ago).

Also what do you think about running 40:1 with yamalube? Been running 32:1 but I know she is a tad rich, plugs are a little darker than chocolate.

Thansk for the input

[sredish]

Going to 40:1 is richer in the air/fuel mixture than 32:1 because it will be more fuel than there was before, but the difference is so little, it will not be noticeably by any means.

 

If you believe your pilot is fine, then follow your instinct. You know your machine better than any of us. If your carbs weren't synced properly and then the backfire ceased some after you adjusted, maybe it is correct to think you might check them once more to assure proper adjustments.

 

I would say the hesitation is not really something that should be there. Is it possoible that some dirt may have gotten in there and is causing the pilot to clog a little and leaning your idle circuit a little bit? Just a thought, I'm trying to think of some possibilities. The reeds are a possibility also, but I would think the problem would continue up through the powerband some.

 

It's late and my brain isn't all here so instead of continuing to ramble on, I'll save you from it and get back to you tomorrow.

[dogboystoy]

Thanks, Didnt have a chance to work on her today, hopefully tomarrow, or if im lucky later tonight. Iwill check the sync and then mess with the airscrews.

Also, If I mix 40:1 that will lean out the oil mixture... But I see what you are saying about having more fuel.

Thanks again guys.

Edited July 19, 2004 by dogboystoy

[sredish]

If I mix 40:1 that will lean out the oil mixture... But I see what you are saying about having more fuel.

If you lean the oil from the gas/oil mixture, then you will have more fuel in the air/fuel mixture, therefore richening the air/fuel mixture by increasing the amount of combustible fuel in it.

 

make sense?

[dogboystoy]

yep. Thanks

[Banchetta]

Changing the oil ratio doesn't fix the problem....You should be able to run it 32:1 w/ no problems...I'd say you have a clogged pilot....How did you clean them? I'd use a air compressor and blow all the little ports out...Backfiring is a lean condition, I'd be careful and take this seriously, you might have an air leak or just a clogged jet, either way, find the problem...could save you a top end.