Missing/backfiring 4500-6500rpm ???Ignitor box??

[Hayduden]

I thought I had an electrical problem on my 1985 GS1150E leading to my ignitor box but replaced wiring and symptoms continued. It's a bad loss of power between 4500-6500 rpm however below and above those rpm's the bike run hard and clean on acceleration. It seemed initially to be wiring at the ignitor box as I moved the wiring the missing seem to come and go at iddle running on 2 then 4 cylinders. Now, at the lower rpm's it runs fine, on acceleration pulls hard after 6500rpm but if I level it off some miss firing occurs but not too bad. I do notice my tach is affectted every time it missfires in that the the tach seems to loose power and drop drastically when the bike is running bad (from 4500-6500 rpm).
Any thoughts? Nothing has been change or modified recently.

[BassCliff]

Greetings and Salutations!!

Hi Mr. Hayduden,

Your issue sounds carb related. Maybe shim the needles and raise them just a bit?

Anyway, I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[Danjal]

I had the same symptoms. My problem is rust in the tank.