can't get revs up over @ 5,000 rpm

[81 GS650L]

Hi everyone.

I am new on this site and from what I have seen so far this is a great site with lots of info and helpful people.

I just bought back my 81 GS650L. I bought this bike new and then sold it to a co-worker after 10 years when the kids came along (egads I bought a minvan!!) Now I have the chance to ride my first new bike again.

The problem I am having is the engine won't rev past @ 5000rpm, sometimes higher if I full choke it. It does appear to idle OK @ 1000rpm once warmed. It does pop and backfire once it gets to the 5000rpm level.

Anyways I have cleaned it, painted and polished it and now have been trying to get it to run properly. The prior owner unfortunately left gas in the tank and carbs for a few years without riding it so of course the carbs where dirty and some of the lifters where seized.

The problem I am having sounds so much like other people are having.

I know the battery isn't holding it's charge but would that cause this kind of problem? Also I don't have the air filter on, only the airbox. Also am using a temp gas holder so I am running clean gas thru the carbs and not from the tank.
I have tried adjusting the air flow screw on the carb and that helped it idle better but again still cutting out at 5000 rpm. If I back off the thortle it seems to be ok again but as soon as I try to rev up again it starts to make noise and cut out.

Very frustrating as I really would like to ride my old bike again.

Also I noticed there was a write up on the VM carbs that looked good but wrong carbs, is there a write about the cv carbs besides the pdf images on this site?

Thanks in advance for your replys.

Ready to ride but stuck in the workshop.

[Nessism]

http://www.thegsresources.com/gs_carbrebuild.htm

http://cycleorings.com/

http://cycleorings.com/intake.html

[waterman]

First, welcome to forum. As anxious as you are to get back on your original bike, I think you will need to spend some workshop time to get it back to good running shape. As Nessism links, a carb cleanup and rebuild is a must.
From there, you will need to get air filter back in airbox. Without a filter, the bike will be too lean and thus pop and backfire upon acceleration. Don't waste time messing with air flow screws until carbs are cleaned and air filter in place.

Replace battery. You will need a good one to start it reliably anyway. May effect running.

May want to purchase a manual, this link has a downloadable manual along with a lot of other great stuff.

http://www.dslextreme.com/users/bikecliff

He is a member here and will give you a grand welcome shortly.

Post some pics, we all like pics.:-D

[Nessism]

Direct link to factory service manual for free http://www.mellowmoodz.com/GS650GManual.pdf