Page 1 of 2 12 LastLast
Results 1 to 10 of 12

Thread: Sputtering Chief

  1. #1
    Join Date
    Jun 2011
    Location
    Nebraska
    Posts
    28

    Default Sputtering Chief

    Here is my situation
    Two weeks ago I took my Chief on my chapter's dirt road run, it ran like a champ and made it home absolutely filthy.
    After a thorough cleaning, including the air filter, it starts ok but sputters under load at lower rpms; cannot take it down the road.
    I replaced the old foam air filter with a new one; no change.
    I discovered it runs pretty good if the choke is applied to the first or second click. While sitting still, it will puff a little black smoke when revving the engine with the choke on.
    Next I sprayed the manifold / head junction with starting fluid and the engine bogged down and stalled. I expected it to rev-up if there was a leak. The manifold nuts were / are still very tight.
    Other specifics to my machine is that it has a M51 Carburetor with a steel manifold. Compression feels about the same as before.
    I am not sure what to try next and would appreciate some input.
    Thanks
    Steve

  2. #2
    Join Date
    Jul 2010
    Location
    Vermont
    Posts
    753

    Default

    Steve, if it were me and I could get the bike started, then I’d warm it up for while and start fiddling with the carburetor adjustments. Low speed needle first, then high speed. Two weeks is a while up north of the Mason-Dixon line in Sept.-October.... and maybe all you’re experiencing is a need for cold weather tuning instead of something related to your wash job? Just guessing!
    Pisten Bulley is Harry Roberts in Vermont.

  3. #3
    Join Date
    Sep 2012
    Location
    Saltsburg PA
    Posts
    354

    Default

    If there is any engine speed change up or down when you spray the intake nuts, you have a leak. A routine check I do every 6 months or so is spray mine with Gumout while the bike is idling. If idle drops all, I snug the nuts just a bit and retest so there is no detectable change. If your bike actually stalled you have a BIG leak. Perhaps this may not be root problem of sputtering but any leak at the intake to head junction will lean out the mixture and negatively affect performance. I'd want to correct that first.
    I converted to intake seals made from Peak material several years ago and have been very happy with them. Depending on condition of your intake seal rings, yes the nuts can be very tight and still leak as you state. At this point it must be taken apart to see where the problem is and correct.

    Don't forget anytime you adjust the low and high speed needles write down where they were at the starting point by winding them in carefully counting number of turns until stop so worst case you can go back to where it was.
    Last edited by Skirted; 10-04-2019 at 07:13 AM.
    Jason Z
    AMCA #21594
    Near Pittsburgh PA (Farm Country)
    Allegheny Mountain Chapter http://amcaamc.com/

  4. #4
    Join Date
    Jun 2001
    Location
    Central Illinois, USA
    Posts
    4,338

    Default

    Quote Originally Posted by Skirted View Post
    If there is any engine speed change up or down when you spray the intake nuts, you have a leak....
    You mean a HUGE leak, Skirted!

    Bubble-testing finds leaks that spraying while running cannot.

    And pinpoints exactly where.

    No leak is an acceptable leak.

    ....Cotten
    PS: Its called PEEK.
    Attached Images Attached Images
    AMCA #776
    Dumpster Diver's Motto: Seek,... and Ye Shall Find!

  5. #5
    Join Date
    Jun 2011
    Location
    Nebraska
    Posts
    28

    Default

    Cotton
    I am not familiar with bubble testing for an intake manifold leak. Do do the test with the engine running? Does an intake leak push air out in addition to sucking air in?

    Or do I block the carburetor, position the crank so the valves are in my favor and pressurize the system through the spark plug thread with compressed air?
    Thanks
    Steve

  6. #6
    Join Date
    Jun 2001
    Location
    Central Illinois, USA
    Posts
    4,338

    Default

    It's a whole lot simpler than that, Steve!

    http://virtualindian.org/11techleaktest.html

    Fixing it is another thing, but believe me, Chiefs rarely, if ever, have all the problems HDs have...

    ....Cotten
    PS: One bad experience tells me to suggest using a 102628 Standard main nozzle instead of the original HD M51 issue.
    Could be an isolated incident, but it cured it.
    PPS: What the hell, I'd cut to the chase and put a 1 1/8" venturi in it with a Bonne nozzle. It doesn't look like you have a heavy load.
    Last edited by T. Cotten; 10-04-2019 at 03:14 PM.
    AMCA #776
    Dumpster Diver's Motto: Seek,... and Ye Shall Find!

  7. #7
    Join Date
    Jun 2011
    Location
    Nebraska
    Posts
    28

    Default

    I pressurized the intake manifold and and no leaks between the manifold and the heads as well as the carburetor. I will make make some adjustments to the carburetor tomorrow.

    Cotton - I see the venturi and nozzle you recommended on Greers website. What improvement am I shooting for with these components? Should a similar change be made on a 53 FL with a M51?

  8. #8
    Join Date
    Jun 2001
    Location
    Central Illinois, USA
    Posts
    4,338

    Default

    Quote Originally Posted by ssantelman View Post
    I pressurized the intake manifold and and no leaks between the manifold and the heads as well as the carburetor. I will make make some adjustments to the carburetor tomorrow.

    Cotton - I see the venturi and nozzle you recommended on Greers website. What improvement am I shooting for with these components? Should a similar change be made on a 53 FL with a M51?
    You cannot pressurize the carburetor, Steve!

    And beware Greer's venturi will be throat-vented;
    You want an HD model.

    ....Cottejn
    AMCA #776
    Dumpster Diver's Motto: Seek,... and Ye Shall Find!

  9. #9

    Default

    On other vehicles I’ve had small dirt particles completely throw off the carb. This could make sense since you were on a dirt road. You may want to drain the bowl, pull off the carb, and give it a good cleaning with carb cleaner and compressed air. It’s worked for me several times in the past.

  10. #10
    Join Date
    Jun 2011
    Location
    Nebraska
    Posts
    28

    Default

    I removed the carb, made a plate and discovered I do have two manifold to head leaks. I also determined there is a small head gasket leak, there was not sign of combustion leak in the area.

    Its kind of amazing it had been running real well...

    I checked my usual Indian parts sources and did not see and PEEK Manifold Cones; any suggestions?
    Thanks
    Steve

Posting Permissions

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