Slow to warm up, high rpms

[Guest]

I'm not sure if this is in the correct forum, but here's my issue:
My '77 GS750 is slow to warm up. I'll start her up, let her idle with the choke on for 10-15 minutes while I get my gear on. Throttle response is quick when I start out, but when I get on the highway and start to go through the gears she hits about 6000 rpms and "spins". By that I mean the rpms shoot up after 6000 but nothing happens, no increase in speed, no pull, just more rpms. Then after about 10 minutes of riding this goes away and I have no problem reving her up to 8500-9000 rpms. Could this be a clutch adjustment?

Thanks for your help!

[Big T]

What maintenance have you done?

10 minutes is way too long to warm up

Yes, your clutch is slipping

[Nessism]

Your clutch is slipping.

Make sure you have some freeplay at the lever, but if that doesn't help, you need to pull down the clutch and measure the plates for wear and replace the clutch springs. Most of the time that's all that's needed, but in some cases, you need to buy new clutch plates too.

And YES on the maintenance. Most GS's don't wear out, they are maintenance deprived and run into the ground and killed prematurely. Please don't allow this to happen to your bike.

[Steve]

Sounds like you have multiple problems.

First of all, NO bike (or any other vehicle) should take 10-15 minutes to warm up.
When the carbs are cleaned and properly adjusted, you should be able to fire it up and ride away within 30 seconds or so.

Usually, when the engine speeds up and the rest of the bike doesn't, it's a clutch issue. Not sure why yours would change behavior after a while, though. The most-common cause of clutch slippage is lack of proper cable adjustment. That is sured easily by performing and adjustment of the cable and any associated linkages.

The next-most common cause of clutch slippage is tired springs. Replace the six springs in the clutch hub, along with the cover gasket, you might be back riding. However, while you have the hub apart, it would be well worth your while to inspect and measure the steel and fiber disks to make sure thaty are still good. New springs usually clear it up, but worn fibers or warped steels are not unheard of.

.

[blowerbike]

worm gear.....

[Steve]

worm gear.....

That would be for the clutch, not the slow warm-up.

.

[blowerbike]

That would be for the clutch, not the slow warm-up.

.

uhuh...
he also said 6k and bike won't go any faster...
plus i like saying "worm gear"

[Nessism]

worm gear.....

Thought you might show up...

[Chuck78]

sounds like your bike is probably running too rich at idle on the pilot circuit, as is mine. Mine also takes an excessive amount of time to warm up and I believe this is the cause of it. A lean mixture burns a lot hotter. fuel will condense on the cylinder walls on an engine that is not warmed up, causing poor running condition until it is warmed up properly.this would necessitate keeping the choke on for a lot longer. Also, vacuum leaks might start to seal up as the engine gets warmer. But I don't think that is my current problem.

please feel free to correct me if I'm wrong.