97 F650ST Carburetor? Problems

[k75s]

I have a 97 F650ST with only 3,000 miles. I took the carburetor apart to clean it. The previous owner never serviced the foam air filter and I discovered that it had mostly disintegrated.

The bike would randomly just die at idle. I wanted to make sure the carburetor did not have any pieces of foam in it.

It also had an electrical connector short which was causing some additional problems. That seems to be fixed.

I currently have the bike running fine at idle (never dies), it accelarates very well and smoothly, runs smooth at 5,000 RPM and above.

However, around 4,000 RPM and 40 MPH (I think that is in 3rd gear) the engine will cut out like it is not getting fuel. Basically, somewhere in the mid-range it does not run well.

Any ideas if this is a carburetor adjustment or something else? (I did not have this problem before I took the carburetors apart)

 

[redram]

I too have a '97 ST, and went thru the carbs, and replaced about all the parts that I could. I also experienced much the same problem you are describing afterward. I eventually found it to be the float level. It is critical that they be set exactly, or you will experience the bogging down when accelerating. Once they were set correctly, it ran perfectly, and has ever since, (about 2 years now, IIRC). Hope this helps some. Check out F650.com, too (The Chain Gang)

 

[k75s]

Thanks, I think I will give that a try. My Clymer manual explains how to adjust the floats.

I am getting pretty good at tearing down that part of my bike!

Did you read Paul Glaves article on F650 camshaft chain tensioners in the April BMW ON?

 

[redram]

Thanks, I think I will give that a try. My Clymer manual explains how to adjust the floats.

I am getting pretty good at tearing down that part of my bike!

Did you read Paul Glaves article on F650 camshaft chain tensioners in the April BMW ON?

No haven't seen that yet, but I will definitly look for it

 

[scotchale]

I am having pretty much the same issues as stated in the first posting of this topic in this forum. This is a 98 F 650 Funduro, with about 27,000 miles on it.

I won't go into the prior issues up to this point, but so far, I have removed the carbs, cleaned and replaced all the internal gaskets/o-rings then reinstalled. Then a new variety of problems cropped up. Overflow of fuel, which was an original problem prior to the carb cleaning. Then fuel not flowing after taking them back off and rechecking everything.

Replaced external fuel filter (something you should consider adding and remove the internal filter at the T-split into the carbs. Bike starts well, idled ok, but still rough at the 2000 RPM mark and doesn't really want to go beyond that. Then it started the same "quit" mode you just mentioned, runs and stops abruptly, wasn't do that previously.

Long story short, I still think the carb needs a full "soaking" and that will be done in the next couple of days, one carb at a time, then fully air it out, etc. Main concern is proper adjustment of the two idle screws, not sure if 3.5 or 1.5 to 2 turns? Its one or the other? Will look that up tomorrow.

Hopefully by the weekend, this thing will run well....then the next phase...rebuilding forks!

Scotchale