Higher RPM's not pulling

[Nobody]

I have GS850G 1985 or 85 the problem I'm having with my bike is something in the higher RPM's. I can start my bike up no problem and run it at idle and up to about 4 grand and have no issues at all. Yet when ever I go into my higher RPM's it will choke out and die if I go fast into it or it will start to pop and sound like it's back firing and sometimes if I just roll into it goes jerky like a rocking horse.

Also I took the plugs out and they are black and sooty from running rich as well.
I've cleaned the carbs, changed the plug leads and caps the new spark plugs only 3 seem to work now
Also checked out the coils with a multimeter, What could be the issue?

 

[Steve]

If you have an '85 850, you are either not in the USA or you have a European import.
Having a location would REALLY help.

Back to your problem:
- Stock airbox and exhaust or aftermarket stuff?
- How did you "clean" the carbs?
- What spark plugs?

.

 

[Nobody]

OK so the bike might be an 84 edition it has the CV carbs and me and the bike are located in Germany

- Stock airbox and exhaust or aftermarket stuff? it has a Marshell exhaust with a stock air-box the rest of the bike is stock
- How did you "clean" the carbs? the old fashioned way by dropping out the float bowels removing and blowing out the jets and replacing
- What spark plugs? NGK B8ES

 

[Nessism]

- How did you "clean" the carbs? the old fashioned way by dropping out the float bowels removing and blowing out the jets and replacing

This could be the problem. You might want to check the carb rebuild tutorial linked in my signature, and review the Newbie Mistakes thread as well.

 

[Steve]

Thanks for the info. :encouragement:

We, in the Western Hemisphere, did not get 850s past the '83 model year, but they all had CV-style carbs from '80 onward.

I have no experience with the Marshall exhaust system, but I think they are one of a few that suggest that no jetting changes are necessary.

I agree with Nessism, your carbs likely need to be cleaned properly. Simply cleaning the jets does absolutely nothing for the small passages between them inside the carb bodies. They really need to be stripped down to pretty much bare bodies (leave the throttle plates installed), soaked in chemical cleaner, then re-assembled with new o-rings. One of our members has o-ring kits available, I'm reasonably sure he will have no problem shipping to Germany. Contact him at cycleorings.com.

.

 

[mcquillr]

I was having a similar issue with my GS400 and it turned out to be that my advance timing was not properly set.

 

[Buffalo Bill]

I have GS850G 1985 or 85 the problem I'm having with my bike is something in the higher RPM's. I can start my bike up no problem and run it at idle and up to about 4 grand and have no issues at all. Yet when ever I go into my higher RPM's it will choke out and die if I go fast into it or it will start to pop and sound like it's back firing and sometimes if I just roll into it goes jerky like a rocking horse.

Also I took the plugs out and they are black and sooty from running rich as well.
I've cleaned the carbs, changed the plug leads and caps the new spark plugs only 3 seem to work now
Also checked out the coils with a multimeter, What could be the issue?

As your carbs move into using more of the main jet it's going lean, hence the back fire and loss of power.
Your main jets are filthy/clogged with residue. You need to do a total carb rebuild, DIY or pay a locale rebuilder.
Best 'O luck!!! Wise up.