1978 YZ250 oil and gear lube?

yeah been having trouble finding a kit there really is nothing to go bad in these carbs as long as the floats are good as far as i remember.
 
I had a Yamaha IT465 torque monster that did quite well on Golden spectro at 25:1 but as has been said i dont think brand matters as long as spec is there. In the gearbox it was same as all other wet clutch bikes Ive ever owned M1 15-50 or T6 15-40. No clutch slip or chatter and no gearbox problems.

Once you clean the carb really good you need to jet it for the fuel and places you ride. Search the forums the process for tuning this bike is long since been figured out already.
 
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yeah been having trouble finding a kit there really is nothing to go bad in these carbs as long as the floats are good as far as i remember.

The needle and nozzle do wear and make it run richer 1/4 to 3/4 throttle. A dirty main jet can kill your engine wot. Dirty pilot system makes it hard to start/idle and bugs @ 1/8 throttle.
 
Just an FYI, a Mikuni VM carb will work just fine on that bike. You can purchase a brand new one for less than $100. One could easily spend that much purchasing parts for your old carb, such as a new float, needle, seat, jets and slide and still not get it running right if there is internal corrosion. I’m not sure what size the bike currently has, but it may be a 36mm VM.
 
Just an FYI, a Mikuni VM carb will work just fine on that bike. You can purchase a brand new one for less than $100. One could easily spend that much purchasing parts for your old carb, such as a new float, needle, seat, jets and slide and still not get it running right if there is internal corrosion. I’m not sure what size the bike currently has, but it may be a 36mm VM.

A genuine Mikuni vm36 is more than $100. Copies are garbage, do not buy. On top of that, the new carb doesn’t come with the proper brass, you still have to buy all the appropriate nozzle, needle, PJ, AJ and MJ for your application. I have few vintage Yamaha motorcycles with rebuilt VM28, I put 5,000km this summer on my 79 RD400 no issue.
 
A genuine Mikuni vm36 is more than $100. Copies are garbage, do not buy. On top of that, the new carb doesn’t come with the proper brass, you still have to buy all the appropriate nozzle, needle, PJ, AJ and MJ for your application. I have few vintage Yamaha motorcycles with rebuilt VM28, I put 5,000km this summer on my 79 RD400 no issue.

A real VM36 will cost $97 if you look around.

The jetting will be close enough to get the engine started, and possibly the jets and needles are in good enough shape to use from the old carb.


 
A real VM36 will cost $97 if you look around.

The jetting will be close enough to get the engine started, and possibly the jets and needles are in good enough shape to use from the old carb.



My brain was working in CAD$.
 
Lectron and Smartcarb are options if you need to replace your carb and want a bit of an upgrade.
They still make Lectron carbs!?? I put one on a 1973 Penton 125 Six-days. In about 1979...and it worked great...it was very “trick” at the time...
 
Here is pics of bike and carb please help identify carb
 

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it is not the original carb i am pretty sure i have it i will note the differences when i get a chance but the new carb has one less vent tube and one less adjustment screw.
 
i owned a brand new 1981 YZ125H
the 1st watercooler
i think i posted a few pics of my paper can castrol 2cycle oil i used it in when i cleaned out mom's house 3 years ago
in '82 the big change was to the linkage of the swingarm to the monoshock .... no more direct
but still had that stupid radiator between the forks...huge issue with the leaking steering stem

the best oil to use in the gearbox is Pennsoil Type F ATF ... maybe costs $2 per quart
i raced with this in the '98yz250 for 24+ harescrambles and enduros and the clutch pack looked new and tranny sparkled

2smoke oil is whatever ... yamalube R is pretty darn good ... yes mc1 was awesome but cannot be found as it was discountinued
you actually make more hp with more oil as it seals the rings better. 32:1 is good
spooge is all about jetting
I had a brand new 98 and was racing hare scrambles as well. Mc1 is still available last I checked. Currently riding a 2013 yz250 and love it.
 
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