Power and Noise questions

[DMPLATT]

After cleaning my carbs, changing the clutch disks and getting the right fuel line on - I still think I may have further "Issues".

A little history of my bike.
I just got this in June. She ran sweet until I had an idling issue which is why I took off the carbs and cleaned them. However, it was still lacking power in the upper RPM range. I assumed clutch slipping. I changed disks and springs.
During the first Hurricane that came thru here I was stuck in traffic in upper 90 deg day. The bike started getting hot and I started to hear a pretty loud ticking noise. I shut it off at the next light. After I started running again and it cooled down it went away. I've not heard it that loud again.

Alright, now to my question. I've always heard a slight ticking noise at idle. It's hard to hear with full face helmet on. The other day I was getting on it pretty good and it sounds like I have some engine noise "Rattle"?
I also think I might have an exhaust leak, would that cause any power loss?

So, any ideas of what I should check next?

Thanks
Dave

[Joe Nardy]

Dave,

A lot of these bikes tick at idle. Air cooled engines do not muffle engine noises as well as liquid cooled engines. It's all a question of how loud the tick is. If you have a hard time hearing it with a helmet on it probably isn't an issue. When you were 'Getting on it pretty good' were you lugging it hard from low rpm in a higher gear? Was the bike hot? If so you may have been hearing detonation or knocking. If this is the case try a higher octane fuel and see if it helps.

When you say 'lacking power in the upper RPM range' do you mean the bike struggles to rev to high RPMs? If you had clutch slippage the engine would rev freely but the bike would not accelerate proportionately. Does the bike rev freely when in neutral? Does it seem to rev easier in lower gears?

Is the bike stock or do you have a pipe and/or pods? My GS1100 had a similar issue where it ran strong in the low to midrange but seemed to lose steam at higher RPMs. At the time I had a pipe and pods and the bike was jetted by a local shop. I installed and tweaked a K&N (Dynojet) jet kit and the bike now runs stronger everywhere and revs freely to and past red line.

Joe

[Mr. Jiggles]

I've had some of the same issues on my bike. The noise abated somewhat after I changed over to a manual cam chain tensioner and set the valve lash. But Joe's right - these engines tend to be noisy even when set up perfectly. As for top-end power it could be due to a number of things. Mine improved after re-rejetting the carbs and fine-tuning the cam timing. Bad coils could also cause the top end to crap out so you might want to check those as well.

Good luck.

Jeff

[DMPLATT]

Thanks for the replies.

I guess the ticking would be considered normal then. It only got really loud the one time it got real hot in traffic. I just thought I heard some "Rattling" the other day when I was hitting it pretty hard. I've only heard it the one time though, so didn't give it much thought.

When you say 'lacking power in the upper RPM range' do you mean the bike struggles to rev to high RPMs? If you had clutch slippage the engine would rev freely but the bike would not accelerate proportionately. Does the bike rev freely when in neutral? Does it seem to rev easier in lower gears?

Yes it does pull better and Rev better in the lower gears. But even in the lower gears, once I get to say 7k or higher, she kinda hits a wall. Actually the bike seems to run very well up to the higher RPMs. Doesn't seem to matter what gear I'm in, though I usually don't reach the upper RPMs (say 7k or higher) until about 3rd gear. YES it appears that the engine is still revving up, just quits pulling. I might also mention that my Tach is one of the electronic ones. I tried the capacitor fix, but it still gets "Buggy" after about 6k. Anyway, once I get past the 6k mark it revs a bit higher and just seems to quit pulling. It's hard to tell as I'm usually up to about 80 or so and have to watch traffic, and my Tach kinda hangs, but it just sounds like that is all she has? When I first got the bike it just kept pulling, now it just kinda hits a limit? Does that make sense?
I posted a week or so ago about how badly my friend beat me on his '93 ZX6. It's like the GS just wouldn't go. Like it didn't have any Umph.
A few months ago on the way back from Scotty's place and he gave me some pointers, I was keeping up with a 1500 tricked out Kaw cruiser. That's the power that seems to have disappeared.
I'm getting a Carb Tune, so maybe that's all she needs?

I've had some of the same issues on my bike. The noise abated somewhat after I changed over to a manual cam chain tensioner and set the valve lash. But Joe's right - these engines tend to be noisy even when set up perfectly. As for top-end power it could be due to a number of things. Mine improved after re-rejetting the carbs and fine-tuning the cam timing. Bad coils could also cause the top end to crap out so you might want to check those as well.

Actually that was another question I've had. I trimmed about 1/2" of my plug wires and 1 cap had some corrosion on the screw. Of course the local shop doesn't stock any caps, so I just tried it (yes I cleaned the corrosion with a wire brush). Is there a good way to test the strength of the spark? Or should I just go thru the checks listed in other threads?

Is the bike stock or do you have a pipe and/or pods? My GS1100 had a similar issue where it ran strong in the low to midrange but seemed to lose steam at higher RPMs. At the time I had a pipe and pods and the bike was jetted by a local shop. I installed and tweaked a K&N (Dynojet) jet kit and the bike now runs stronger everywhere and revs freely to and past red line.

All stock that I know of. I know the jets are stock and the air box. I believe that the exaust is stock, but not 100%.

As long as you don't think it's valves, it could just be a matter of Carb Tune and Coils?

P.S. It was running the same way before I took the carbs off. I didn't change any settings on air mixture OR linkage.

Thanks for the help guys.

Dave
'83 GS750E

[DMPLATT]

Oh and ALL 4 plugs are identical in color. They are a TAD lean, but according the the color charts I looked at, they are in the Good Range.

Dave

[saaz]

Whats the bike again? All the GSs are relatively noisy. A real ticking sound when hot if it is from the cam cover is usually a loose valve that needs adjusting. Exhaust leak may also be a problem. Rattles..within reason they are normal, especially if they go away when you pull in the clutch.

[DMPLATT]

Whats the bike again? All the GSs are relatively noisy. A real ticking sound when hot if it is from the cam cover is usually a loose valve that needs adjusting. Exhaust leak may also be a problem. Rattles..within reason they are normal, especially if they go away when you pull in the clutch.

THanks, I can't feel any holes up near the manifold, but there may be. It seems a bit louder coming from that area. Would that cause a power loss?

I was concerned about the ticking, but now realize that may just be normal. I was afraid I might be doing more harm.

I just order a Carb Synch tool from Cycle Recycle. I will do a carb synch and see if that helps.

If not, then I may try a used set of coils. After that, I don't know?

Thanks
Dave
'83GS 750E

[Joe Nardy]

Dave,

If you're still having problems and suspect jetting may be an issue you can try a couple things. I'm not familiar with your airbox setup but try running with the air filter out and/or with the top off. This allows more air flow which leans out your fuel mixture. If it runs better you need to go to smaller jets. Then try taping over 1/2 of your air filter and using it in the stock airbox with the cover on. This restricts air flow which richens your fuel mixture. If it runs better now you need to install larger jets. Since your problem is mainly at full throttle you might start with larger main jets. Obviously, test under identical circumstances, I.E. hot engine, same gas, same weather, etc.

Good Luck,
Joe