1975 Yamaha GP-246F

vmaxdad8657

vmaxdad8657

New member
Joined
Dec 29, 2004
Messages
76
Age
67
Location
Upstate New York
I'm restoring a 1975 GP246F and I'm trying to find the original carb for this sled. It is a Mikuni BN38-34SH. I also need the top bracket that accomodates both the throttle cable and oil injection cable. One of them is adjustable with a locking nut. If I can't locate the original carb, I still would need that top bracket, so that I can reinstall the factory oil injection. This model has the oil injection pump located on the outside of the recoil, it is not under the carb. This oil injection is controlled by a cable, not a small connecting rod to the oil pump. There is currently a Tillorson HR on the sled and it's running a pre-mix.
Thanks for any and all assistance. STAN D.
 
i bought a brand new carb for one of mine off ebay last year. The 246 is pretty hard to get engine parts for since it was only made two years. I have two, and my uncle has one, and also a spare engine. No carb though. Sorry :-( Good luck with the restore. I will be doing the same shortly.
 
I was going to switch the motor to a GP-292 motor since it would be easier to locate a motor with the oil injection on it and then be able to get the oil injection up and running. But too many people have been advising me to leave the matching motor and chassis together to maintain the value as a "vintage" sled. So I'll patiently wait for the right carb and linkage to come along.
 
sled

If you wanted to just get it up and running put the 292 in it as long as it fits with out modification to the chassis. Then save the original motor for when you decide to resell to keep the vintage value.
 
It's currently running with a Tillotson HR carb on it
( running pre-mix since the oil injection is not hooked up )
It runs very strong. It just needed a new set of points.
On the jack stand, and fine tuning the high speed jet,
this little GP-246 was pushing 68-70 mph.
Lately, it has been popping a little bit, which I still think is because of the Tillotson that is on it.
 
I just took mine down the highway after there was an inch of hard packed snow on it, and it did 57 on the speedo. I found out that the odometer is 19% off. My sled has about 1300 actual miles instead the of the 1600 that is says. Oh yeah!! The popping could be the timing. The 246 seems to be pretty fussy about that stuff. These also pull 22 hp @ 6500 rpm's just in case you were wondering. :rockon:
 
Last edited:
I've been running a premix through the Tillotson carb!
I had it fine tuned while on the jack stand and the speedometer was reading between 68 - 70 mph.
It was idling nice and running real strong, but lately it does tend to pop more.
Do you think it's the timing?
There are brand new points on it, but it wouldn't hurt
to go back in there and gap 'em again.
The service manual says 0.071+/- 0.004 in (1.8+/-0.1 mm)
 
I think I found the reason it was popping,
After reading your comment about timing, I took a look at the points again, and found the black wire going to the points had been rubbing against the flywheel, wearing down the black insulation and exposing the copper wire.
I taped it up and made sure it clears the flywheel. I ordered another set of points and condenser and I'm going to start from scratch with the electrical system. I know what the gap is supposed to be, but I'm going to let a Yamaha mechanic set the points for me, and then it's the carburetor that's really acting up, running way too rich at idle. If I can't find an original Mikuni BN38-34SH, I'm thinking of installing a Mikuni BN38-34 jet ski carb, and just change the jets to a #130 or #140 main, with a #75 low speed jet as recommended in the factory service manual. I guess it takes patience.
Waiting for the correct parts.
 
Any of you still messing around with the 246 I have one with 2000mi but need a motor they put a 250 enticer motor in it
 
246

Sorry guys if I confused anyone as after reading what I wrote I confused myself I want a 246 motor and take the 250 out and can't seem to find a motor thanks guys
 
You must log in or register to reply here.


Back
Top