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+--- Thread: A Gen 1 Stutter saga! (/showthread.php?tid=65006)
A Gen 1 Stutter saga! - nick crisp - 14-08-13
Well, I hope it won't turn out to be that!
So, the symptoms have been that approximately between 3-4k rpm, if I came off throttle very slightly, for instance when regulating throttle to match traffic speed, the bike gets a jerky stutter. It did it at exactly the same revs in every gear. As soon as I got clear of that rev band, it cleared so that above those revs it pulled cleanly and strongly just as it should. Below 3k it's a little glitchy, but no more so than I expect on these bikes (it hasn't been Ivanised yet). I have covered a little over 3000 miles in 2 months with these symptoms, and during that mileage the problem hadn't altered at all in any way. It doesn't do it if I accelerate through that rev band, only coming off throttle. And if I come off throttle slightly anywhere else in the rev range, it doesn't do it. If I come completely off throttle at any revs, the revs drop normally, there is no sticking that would suggest an air leak of noticeable proportion.
Today I had it looked at by a mechanic who was recommended to me. He cleaned the carbs, and noted that they were perfectly set up. Then I test rode it. It then only showed the symptoms at just about bang on 3k, instead of through a band of about 1000 revs. Still only when coming slightly off throttle, but every bit as bad at that point. He changed the plugs. I test rode it again, absolutely no further change. The old plugs came out a perfect light brown colour on all 4. (I've kept them as spares).
There was no time to investigate further today, but he said his next moves would be:
Ultrasonically clean carbs.
Check O rings at carb rubber-to-cylinder head face, as he said these can flatten down a bit and if even one was letting in just a little air it could cause the symptoms I'm experiencing.
We were both in agreement that it is not likely to be an electrical fault as a) it hasn't worsened with further use. b) it would likely be worse at higher revs if it was something electrical breaking down, ie, under heavier load. c) cleaning the carbs has improved things, although not eradicating the problem entirely. d) changing the plugs has made no difference. HT leads and plug caps are all in excellent condition.
There is some cracking in the carb rubbers, but it does not appear to have gone all the way through. The air filter appears to be in new condition.
We have decided for now that as Mike will be Ivanising it in September anyway (I hope - unless he disagrees), it might be an idea to see if this makes any difference to the problem.
Thoughts anyone?
Re: A Gen 1 Stutter saga! - ogri48 - 14-08-13
hope you get it sorted nick, nuffin worse than a daft niggling problem like that. had it on a gpz thou rx once, tried everything including swapping coils leads etc had the carbs off umpteen times and never did completely cure it.
atb mate
paul
Re: A Gen 1 Stutter saga! - nick crisp - 14-08-13
Cheers Paul. I have a feeling it'll be one of those things I'll have to live with for a long while then one day some little servicing job or other that seems totally unconnected will clear it up! :rolleyes
Re: A Gen 1 Stutter saga! - red98 - 14-08-13
hi nick....this sounds a lot like "the stuttering one" :o .....very interested in how things go....good luck and keep us updated
Re: A Gen 1 Stutter saga! - Simon.Pieman - 14-08-13
This sounds like a normal/standard Fazer thou to me. The 'stutter' is addressed by the Ivanising mods, there are a couple of holes in the inlet side of the carbs feeding the pilot jets -that need to be enlarged, this is so that the transition from pilot to main jet is smoother.
Mine was like this before it was Ivanised, it stuttered and hunted at about 3,000rpm making filtering a bit more effort than it should be.
Re: A Gen 1 Stutter saga! - nick crisp - 14-08-13
Thanks Paul (Red 98), I have a feeling that this one won't fill many pages cos I'll be paying for others to do the work, and the pot sure isn't limitless :'(
Simon, I think if you rode mine you'd find that it's worse than the normal glitches of a standard bike. This is my 4th gen 1 thou, and none of them were like this. Maybe some of them have more exaggerated symptoms than others, but I can't help but think that this one is just a bit too extreme. But yes, I am kinda hoping that Ivanising will sort it now!
Re: A Gen 1 Stutter saga! - ChristoT - 14-08-13
Parp.
Re: A Gen 1 Stutter saga! - nick crisp - 14-08-13
Parp indeed.
Re: A Gen 1 Stutter saga! - unfazed - 14-08-13
Out of balance carbs and a TPs showing 0 instead of 5 or 10 will exacerbate the problem.
Synch the carbs and set the TPS to the 10000 side of 5000 on the rev counter. You will understand what I mean when you do the adjustment.
With the engine hot after synching the carbs set the idle to 1100 rpm.
Turn off the ignition and turn it on again (don't start it)
Disconnect the TPS and reconnect it.(the connector is under the tank) this puts the system into adjustment mode
It should read 5000 on the Rev counter. 0 or 10000 means it is out of adjustment.
Now loosen the security torx bolts just enough to allow you to turn the TPS left and right. Turn the TPS slowly until it just goes to ten and bring it back slowlt until it just goes to 5000. Retighten the bolts, but be carefull not to overtighten them.
Turn the ignition off and on to take it out of adjustment mode.
That should improve it low down.