Gas Petcock
Results 1 to 3 of 3

Thread: Gas Petcock

  1. #1
    Senior Member RockyTFS's Avatar
    Join Date
    Feb 2011
    Hailey, ID
    I just thought I'd relate what happened to me today. I changed my front sprocket back to the 14 tooth from 13, mostly as an experiment and because I'd been doing more pavement riding on 55 mph roads. I got it all back together and went for a spin.

    Hey! it goes 65 now! (doh!) But wait, what's this? It seems to be hunting and faltering a little at full throttle....uh oh, what'd I do wrong? Chain too tight? Screwed up the stator and rotor putting it back together? I'm figuring all these possibilities all the way into town and berating myself for my poor mechanical abilities.

    Well, guess what? After I stopped, I got off the bike and noticed the petcock was not exactly on the ON mark. Only a couple of degrees off, but I turned it to the stop and after I'd run my errands I ran the 8 miles back home and it held 65 with no problems.

    My guess is that I'd done this quite a few times before, but since I rarely hold full throttle in 5th for long I hadn't noticed it. The slight restriction caused by not having the valve turned all the way must have been just enough to partially starve the engine of fuel at max speed.

    So if your TW suddenly starts acting real lean for no reason at full throttle on the highway, it might be worth reaching down and making sure the petcock is all the way against the stop. I was surprised such a small amount off the stop could do that.

    Oh, and for anybody who's changing a front sprocket for the first time, I just took the seat and the gas tank off and leaned the bike over on a cooler at about 60 degrees and I only lost a 1/4 teaspoonful of oil. I didn't realize how powerful the rotor magnets are and thought something was hung up at first, but a careful straight pull got the case off. Be careful to keep the bolts in order because some of them are longer. I used only 36 inch/lbs. on the little M5 bolts for the sprocket locking collar and 60 inch/lbs for the case bolts as per the manual. The gasket was so new it separated perfectly so I just re-used it, although I had a new one handy.

    I'll probably change back to the 13 in July when I get onto the rougher higher trails...that is if we ever even have a summer this year!
    2018 TW200
    2014 BMW R1200GS LC

  2. #2
    Senior Member Rainman's Avatar
    Join Date
    Jul 2010
    Ephrata, WA
    Thanks for the heads up!
    If you can't find it, grind it

    1990 TW200

  3. #3
    Senior Member Gerry's Avatar
    Join Date
    Jul 2010
    Paradise, Calif.
    Good for you Rocky, interesting insight. Thanks, Gerry

    Take care my Friend.........

Sponosred Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts

Similar Threads

  1. petcock angle extension
    By danwray in forum Performance and Customization
    Replies: 35
    Last Post: 03-28-2014, 04:15 PM
  2. Petcock repair
    By Tirebiter in forum Technical Help
    Replies: 4
    Last Post: 04-15-2013, 07:23 PM
  3. 91 carb/petcock
    By FnMag in forum Technical Help
    Replies: 12
    Last Post: 08-27-2012, 09:03 AM
  4. Fuel petcock question
    By Boarder255 in forum Technical Help
    Replies: 12
    Last Post: 06-19-2011, 03:22 PM
  5. Pingel petcock
    By mtjoe in forum Technical Help
    Replies: 9
    Last Post: 03-13-2011, 07:00 PM