Sunday, September 8, 2013

The Champ

Nothing is more depressing than to get your new-old Yamaha Champ LC50 scooter home only to find that there is not much info about it.  What I've tried to do with this blog is create a place for Champ owners to discuss and share information, gripe and generally have fun with these old bikes.

One of the most interesting and vexing aspects of these little bikes is over the top engineering, if you have ever taken those two top covers off you know what I'm talking about.  If you have never taken the cover off, be prepared for the shock and awe of what surely must have been the result of Japanese engineers at Yamaha in the late 70's totally baked on crack and steroids trying to out engineer the guys at Honda, Suzuki and Kawasaki!  I think they succeeded!  You be the judge.

This is only a 49cc 2 Stroke


I'm still in somewhat of a state of shock with all the pumps and vacuum hoses in this little 49cc engine.  While getting the carb dialed in can be a task it has a surprising amount of pep for such a little bike.

My Champ is just shy of 4000 miles as of the writing of this blog and gives no indication of slowing down, however one of the most common problems that can afflict the Champ is the bimetal valve (BMV) which sits on top of the cylinder head and acts as an automatic choke, it's a temperature actuated spring thermostat. These are not manufactured any more and when they go are problematic to deal with since you're Champs engine will run as if the choke is on. In later posts I'll go over a hack that should give you some options for running with BMV that's toast.

Otherwise here's a lamp shot of my Champ with my XR 250L in the background.  Love the look of that chrome and glass on the Champ!





33 comments:

  1. Hey folks not sure when a post was last put up here however I'm in a mess here my little dog and I :-) are trying to get this lc50 champ running but its so hard given the lack of clear photos of the area near the battery can someone out there email or post some clear photos of where all the wires go in the battery area ...? do i even need a battery given the kicstarter ... thanks you in advance ...Michael ....littlecroatia@gmail.com

    ReplyDelete
  2. Hi John, I was reading through your posts and was wondering about the BMV hack... Haven't been able to find it and would love some info. I realize this post is 2 years old, but figured it was worth a try. Also, your blog is awesome!

    ReplyDelete
  3. I would also like to know about the BMV hack... I also need the petcock!! Can't find one anywhere

    ReplyDelete
  4. Anyone get their champ running with the bad BMV???

    ReplyDelete
  5. Anyone get their champ running with the bad BMV???

    ReplyDelete
  6. Anyone get their champ running with the bad BMV???

    ReplyDelete
  7. Anyone get their champ running with the bad BMV???

    ReplyDelete
  8. Ebay a yamaha pw80 carburetor and choke cable, they're cheap and bolt right on the intake manifold. I add a open foam style air cleaner also cheap on ebay.

    Just cut and plug vacuum lines at the cylinder head for the Bmv. Next remove the old carburetor all vacuum lines and fuel petcock.No more Bmv....

    Run a gas line from gas tank to new carburetor with a inline shut off valve and filter.Oil injection line will fit on the new carburetor.

    Also the pw 50 big bore kits on ebay are cheap and will bolt right on this bike. You'll get you more speed and take off power. The carburetor and cyinder work very well together. Good luck

    ReplyDelete
  9. So does the PW80 carb require any rejetting. My petcock went bad so I set up gravity feed to engine. When I turn fuel on gas poor out back of carb. Have to assume the carb has a bad float (already cleaned and reassembled) and the vacuum petcock has been hiding the problem. Also will any fuel petcock work on the bike. The original is non existent.

    If I do the pw80 carb should I do pw50 60 bore to help the carb. Assuming jetting is different.

    ReplyDelete
  10. I'm the proud owner of a champ.... And it's for sale! Any interest?

    ReplyDelete
  11. anyone know where i can get a fuel cap from?

    ReplyDelete
  12. where do i find a fuel pump kit??

    ReplyDelete
  13. i have an 81 champ that i will be selling. Blue with 1500 miles. Has the lower fairing which is cracked and a basket on the rear.
    Any interest out there ?

    ReplyDelete
  14. I'm looking for a mellow white front fender - any ideas about where I could buy one?

    ReplyDelete
  15. I should have stated that it's for a 1980 Champ - yellow and white. Thanks!

    ReplyDelete
  16. I have an 1981 Champ that I fully restored with my farther as a fun project. This bike is in "Mint Condition". Brand New fairings & platics. New carburetor, gas tank, fuel lines and hoses, etc. We rechromed the exhaust pipe and all of the other chrome fixtires. This head turning retro mini bike is probably the nicest ones left in operation. I'm I'm looking to sell to fund my new project- Afull suspension mountain e-bike.

    Any one interested in this rare Champ? I have tons of pictures amd the title.

    Please call Tony at 646-737-5273

    Or email universalbulliongroup@gmail.com

    ReplyDelete
  17. I inherited a 1981 Champ with 3,000 miles on it after sitting in my Dad’s garage for 36 years. The headlight was burned out. After spending $90 on a bulb and having it burn out in one day, I discovered that the lighting voltage is 9 volts A/C. Not good when it should be 6 volts D/C. I can’t figure out where the diode is that is probably responsible for making it D/C. Does anyone have a clue how to solve this problem? Otherwise, This Champ is like brand new. It’s Red with white fenders and starts on the first kick.

    ReplyDelete
  18. Can anyone send me a picture of where all these hoses are supposed to go from the carburetor? I just picked this thing up and don’t know what’s vacuum and what’s the fuel lines to the carburetor. It was not assembled when I got this thing. Also I’m looking for a stator cover if anyone knows where I can pick one up if if you have laying around I’m interested.

    ReplyDelete
  19. Anyone ever get you a pic of carb lines or u get it sorted?

    ReplyDelete
  20. Trying to go to gravity feed cause the fuel shutoff leaks.. I plugged carbs vacuum line and tanks main fuel line. I hooked reserve petcock to carb with hose and filter but now it won't run.. Ran before just always leaked on my leg. Any suggestions

    ReplyDelete
  21. Trying to go to gravity feed cause the fuel shutoff leaks.. I plugged carbs vacuum line and tanks main fuel line. I hooked reserve petcock to carb with hose and filter but now it won't run.. Ran before just always leaked on my leg. Any suggestions

    ReplyDelete
  22. Trying to go to gravity feed cause the fuel shutoff leaks.. I plugged carbs vacuum line and tanks main fuel line. I hooked reserve petcock to carb with hose and filter but now it won't run.. Ran before just always leaked on my leg. Any suggestions

    ReplyDelete
  23. Mine just has a generic petcock on it. Doesn't look as good as stock, but no issues from it. Hate to ask if that filter is directional and if it's not backwards? But simple things can sometimes be easy to overlook:)

    ReplyDelete
    Replies
    1. What kind of genaric petcock you have for your champ? I like to get rid on the on off fuel switch. I know the Chappy petcock does not fit!!!!

      Delete
  24. i need help what kind of bulb is this they seem impossible to find the headlight i have mine almost mint its a beautiful red runs so smooth but my headlight is blown ...any suggestions?

    ReplyDelete
  25. From what others have posted, the headlight is nearly impossible to find and very expensive if you do find them. I’ve stumbled across information on this, and apparently retrofitting a newer headlight that fits in your headlight bucket is the way to go. And potentially adding a voltage regulator so as to not burn out new headlight. There is a long thread on mopedarmy.com by member name little croatia. Google (Yamaha Champ lc50 headlight). Good luck

    ReplyDelete
  26. hello boys I am the owner of a champion of 71 and I am giving love and cleaning if someone is interested in the manual I own it, after looking so I found it and printed some interest write 2017542536 or email rodrigo_ortiz_4008@hotmail.com

    ReplyDelete
  27. C70 heading will fit in your chrome ring if you do a little fenessing and it’s cheap and you can just change the bulb if one blows out. You are able to literally take the bulb out of the c70 heading.

    ReplyDelete