shortstop20
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My neighbor has a '74 Yami GP 433 with dual carbs. He said it has no jets, just two screws on the carbs to adjust the fuel delivery. I know nothing about these old sleds. He asked if I knew somewhere I could find out how the carbs need to be setup and I said I would. Elevation is 1500 ft. and riding temps would be from 0 to 40 degrees F.
No idea how it is setup now, he just said it spits and sputters alot.
No idea how it is setup now, he just said it spits and sputters alot.
RJH
New member
Start at about 2 turns out - then turn in until it screams -its a fine line. The rpm should go to the factory suggested rpm.
those are very weird carbs. thare is a fuel sight tube on the side also. the fuel level needs to be specific level in the tube. (i cant rember where though). i also think these carbs have accelerator pumps too. can someone else confirm...
RJH
New member
I had the level set between the two middle plates. No pump.
If the screws are off a wisker - you can go from 1st to 10th.....
If the screws are off a wisker - you can go from 1st to 10th.....
shortstop20
New member
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- www.snowmobilefanatics.net
RJH said:
I believe he said it has a low speed and high speed screw on each carb. Do you know how each of them should be adjusted by any chance? What is the correct peak RPM for this machine(just in case he doesn't know).
RJH said:
How do I adjust this?
RJH
New member
Both needles are adjusted to the days air quality. very very important - to get it right. get it up on a stand - is how we did it - it changed mormning to afternoon.
You adjust the fuel level with the two nuts at the bottom of the carb - engine running.
In that era - it liked exactely what the manual said - I can't remember.
If you have stock clutches - (I used GYT clutch parts) its almost impossible to get max HP to the track. The secondary - at that time was woud up max - with new springs every month. Even thou it would run to correct rpm - it was about 5 mph faster with GYT springs woud up.
You adjust the fuel level with the two nuts at the bottom of the carb - engine running.
In that era - it liked exactely what the manual said - I can't remember.
If you have stock clutches - (I used GYT clutch parts) its almost impossible to get max HP to the track. The secondary - at that time was woud up max - with new springs every month. Even thou it would run to correct rpm - it was about 5 mph faster with GYT springs woud up.
Last edited:
Monty Normand
Shortstop - look up Monty Normand on this site. He will have all the answers to your GP/GPX questions or knows who to point you to if he can't answer the question.
Mills
Shortstop - look up Monty Normand on this site. He will have all the answers to your GP/GPX questions or knows who to point you to if he can't answer the question.
Mills