loss of power

[Anonymous]

I have had some posts on this subject already and am narrowing things down but could still use some help. just purchased 1980 gs1000 g , when I first got it it idled ok and revved up ok if you turned the throttle slowly, but if you open it up fast it bogs out so I took the carbs off had them cleaned up at the suzuki dealer put them back on , no change .then I rebuilt the petcock and took the bike in and had the carbs all synced . it runs much better now ,when sitting in my driveway I can rev it up and crank it open and the motor sounds veryt strong ,but when I start riding and the engine is under load it's a totally different story if I keep it under 4000rpms it's ok but if I try and open it up it starts to bog out again but will start to come around in the higher rpm's . the service mgr. at the suzuki shop said the clutch was slipping after he rode it . I don't think so ,when it bogs out it seems to get quite loud and throaty sounding and I am wondering about the air box it is stock with stockexhaust but it has a k&n filter in it and the box isn't sitting in the slots on the rubberboots so there are cracks there between the airbox and the rubberboots ,could this be letting too much air in . Also the top and bottom head gaskets are leaky could this be loss of compression from that ,I have had leaky head gaskets before and never had any power issues. p.s bike has 79,000 kilometeres shoul;dn't need top end work yet should it ...all help greatly appreciated......mark

[Dink]

A leaky head gasket etc will do it , but so will a leaking intake.
What colour are your plugs?
Dink

[saaz]

It sounds like air leaks in the intake manifolds, or perhaps problems with the CV carb diaphrams. The bogging under load sounds like a malfunctioning carb for a CV setup.

As Dink asked, knowing what the plugs look like will be a big help in people here helping.

[Anonymous]

My 1981 550L was like that until I got an airfilter installed. When I got a top to the airbox in place it ran even better. I'd look at those airleaks you describe and fix them.

[KGB]

Try pulling the air box out and run it.
Not far, just to get it under a load. It will be louderr without the airbox.
This will make it lean out. Does it feel the same?
If yes, the nit's the carb boots.

You may have 2 issues, the carb boots and a leaking headgasket.

Is it blowing any smoke?
I'll ask again, what color are the plugs?

Try one thing at a time, not multiple things.

[Anonymous]

the last few threads on the plugs are black but the plug itself is not the usual tan colour it's more whiteish which means lean right ? I did try running it shortly with the air box off before I took it into the shop and if anything it made the condition worse also before I took it to the shop the service mgr. had told me to turn the air screws on top of the carbs a half turn out because when I checked the plugs they were very white this seemed to help the colour of the plugs a bit but not the running condition should I try replacing the k&n filter with a stock one ?
I've already spent more money than I have at the shop trying to get this fixed so from now on I'm on my own so your continued help is invaluable to me ...thank you ....mark

[Anonymous]

sorry I forgot....no it does not blow any smoke

[Anonymous]

Had same problem with my GSX750es would work great upto 4500rpm then die. Replaced carbs coils plugs tried without air filter nothing worked, ended up replacind cdi unit now been working great for last 2 years. Might be worth looking at worked for me :?