NO POWER

[Anonymous]

I have an '80 GS450S I had to put another engine in it b/c my other one bit the dust. I have no power with the newer engine. To get any type of power I have to keep the eninge at 6-7000 rpms. Takes forever to get from 0-20mph and the eninge has to be at high rpm to even get that accoplished. I have check for clutch slippage and the clutch seems to be catching and releasing just fine. Any ideas?

[earlfor]

Re: NO POWER

The first thing to check is compression. If that is low, nothing you tune will help.

Earl

I have an '80 GS450S I had to put another engine in it b/c my other one bit the dust. I have no power with the newer engine. To get any type of power I have to keep the eninge at 6-7000 rpms. Takes forever to get from 0-20mph and the eninge has to be at high rpm to even get that accoplished. I have check for clutch slippage and the clutch seems to be catching and releasing just fine. Any ideas?

[Anonymous]

engine

Was it the same year of engine with the same timing plate, to match your electronic ign. is it a type that can be timed ,also if it has an mech. type adv. unit is it working? go over the tune up, did you use your old carbs or ones with the engine, is the airbox on the bike and all the parts and the filter installed if not do so. do you know the mileage on the new engine

[nabrams]

I've restored two GS450 bikes that had been sitting for long periods (mine and a friend's) so I've encountered almost all the typical issues.
First: Have you verified that both plugs are firing?. My friend's bike had the same symptom as yours - he had only one plug firing (the other was fouled).
You might need to do a thorough carb cleaning (especially if the bike has been sitting for more than two months). The fact that it started up is deceptive. It will not produce smooth, full power till you get those carbs spotless.
Your air filter element, air box and all boots that connect to the carbs will have to be checked (any air leaks and all bets are off - see my other posts about this). The symptom you described could very well be air-leak related.
Also, you must be absolutely certain that there are NO leaks where the exhaust pipes join the header - this will make your bike run like crap and also could be the cause of the symptom you described. You put in a new engine, so this must be checked.
Your regulator/rectifier and stator should be checked (as described in the garage section of this site) as well, for good measure.

[AOD]

When I pulled a 550 out of a barn that had sat for a while the carbs were pretty gunked up. I rode it around and it would take FOREVER to accelerate. After about 20 minutes of riding it woke up like a giant bat out of hell!

You should really pop off the carbs and clean it up some. It can only help.

~Adam

[Anonymous]

I bought new plugs and I have TONS of power now. I also replaced the clutch cable. Thanks for the help. The compression is about 110psi for each cylinder, it is on the low side according to the service book. I have cleaned te carbs up real nice before I put them on the engine. I think I need to time it and sync the carbs now.

[Anonymous]

looking for an exhaust system that will give me better performance and a little rumble

[nabrams]

My advice: Don't go there. Changing your exhaust will require some re-jetting experimentation (possibly very frustrating), especially if you remove, replace or modify the stock airbox/air-filter.
See my other posts about the CB750 I had to do re-jetting for.
If you bike is running well, leave it as it is.