Petcock problem?

[Chris Daniel]

I have been through all the previous posts on petcocks and THINK that is the problem I am having, I just wanted to make sure before I buy one.

At highway speeds 70-80 MPH the bike (1983 GS650GD) surges pretty badly, if I accelerate then it will quit for a few seconds and start doing it again.

Also, I ran the bike up to 120-125 MPH and held it there for roughly a minute, I let off the gas and coasted back down to around 80 and had absolutly no throttle response, it acted like it was completely out of gas for about 15 seconds. Then it suddenly jumped right back up and had perfect throttle response and ran fine (other than the surging at highway speeds).

Around town the bike runs great, but it seems when I get into 5th gear cruising it begins surging.

From the previous posts I have read it indicates possibly a bad petcock, but I just wanted some expert opinions on this.

Thanks in advance for any help.

[Rock]

I just had mine out to test after some tuning and it is doing the same thing at high speeds. I turned the petcock to prime and the problem goes away. It may be time to try the Pingel for me, I would hate to rebuild this stock one and have the problem again in the future.

[Anonymous]

Have you been riding my bike?

I will be interested in seeing the response to your question my 82 GS850L does the same thing.

[scarr]

Try the same experiment with the petcock set at "prime". This setting does not rely on engine vacuum for gas flow.

[Rock]

To be more specific, I swiched back and forth between run and prime and it would cut out again on run and take right off again on prime each time I switched it. But it will run fine around town at lower rpm. I would think it would have to vacuum related and not enough gas flow.

[Anonymous]

Be sure to check the vacuum hose, a small vacuum leak can cause the valve to not open completely. If no vacuum leaks, a petcock rebuild kit & a good cleaning should fix you right up

[KGB]

All of the above and.........


Does it have an inline fuel filter?
I ran into the same problem and it turned out the filter was restricting flow.

[Chris Daniel]

Thanks.

Once I am able to ride the bike on the highway again (when the crappy weather stops) I will try running it on PRIME and seeing if that solves it. I will check vacuum leaks from there.

Now, what are the drawbacks to running a pingle (I am assuming this uses NO vacuum just like a dirt bike)?

Other than having to turn it off every time is there any other problems with it? I have the habit of turning the one on my dirt bike off every time I get off of it....so it wouldnt be a problem doing to same with my GS.

Also, it does not have an inline filter.........should I put one on?

Thanks again.

[Planecrazy]

One other thing, Chris ... make sure the gas cap is venting properly. If it's clogged it might cause a surging or fuel starvation situation. Some people have even reported having the bike die after riding awhile ... they wait several minutes (or more) and then the bike runs properly again ... for awhile. Turned out the gas cap vent was clogged.

Worth a look...

Good Luck!
Steve 8)

[KEITH KRAUSE]

Now, what are the drawbacks to running a pingle (I am assuming this uses NO vacuum just like a dirt bike)?

No drawbacks to me. I have a Pingel on my 1000. I recommend it. One less thing to go wrong.

[Rock]

Now, what are the drawbacks to running a pingle (I am assuming this uses NO vacuum just like a dirt bike)?

No drawbacks to me. I have a Pingel on my 1000. I recommend it. One less thing to go wrong.

Do you have the vacuum model? If not, have you heard if the are totally reliable. I think I'm getting older and more forgetful which would probably result in me not shutting it off half the time.

[KEITH KRAUSE]

Now, what are the drawbacks to running a pingle (I am assuming this uses NO vacuum just like a dirt bike)?

No drawbacks to me. I have a Pingel on my 1000. I recommend it. One less thing to go wrong.

Do you have the vacuum model? If not, have you heard if the are totally reliable. I think I'm getting older and more forgetful which would probably result in me not shutting it off half the time.

The whole idea of buying it was to get away from the vacuum design.
Mine works on gravity. I've had it about 2 1/2 years now. It operates smoothly and I've had no problems. About $90 w/adapter plate/shipped. If you want to see a close up of it on my '79 GS1000E, check out my photo section at my website.
Just click the WWW symbol at the bottom of my post here.