New ski just wondering if I have to rejet

Slimycoho

Slimycoho

Location
Pg bc
Hey there, new ski to me but long story short, we're I bought it from elevation was 1300 ft and were I live it is 2200 ft. It's a 701 61x case and cylinders, single carb with factory b pipe and msd coil. It has 150 psi in both cylinders and it runs great just don't want to screw with it if I don't have too. It was setup from we're it came from, but I will change jets if I have too.
Thx in advance
 
Slimycoho

Slimycoho

Location
Pg bc
So I took my carb off and it looks like I have a 145 main jet and I can't read the other one but I've looked everywhere for a jetting chart and everything I read is for sea level. The temps around here are anywhere from 15 to 30 ( I'm canadian don't know farenhiet. Sorry) and 2000 to 3000 feet and some lakes are warm and some are cold. The ski came from around 1000 feet and way warmer temps 20 to 35 range. I've bought a sled and dirtbike from sea level and both I had to rejett so I'm thinking this is the same? I'm just wondering is that close or should I go bigger ? I plan on runnin 40 to 1 amzoil. Thx just can't find jet chart anywhere.
 
N

Norcaltrd

Location
Redding, CA
When you go up in elevation the air gets thinner and the engine will naturally run richer, which would require a lower jet.
When going down in elevation the air gets thicker (more concentrated) and the mixture will run leaner, requiring a higher jet.

Check the manual, I think you should be running 50-1 but I hear of quite a few people running a 40-1 mix.
I just know that my manual say 25-1 for break in and 50-1 afterwards.
Not entirely sure of the mixture scenario, not much experience there.
 
Slimycoho

Slimycoho

Location
Pg bc
Ok I see, so if any thing I will be running rich and I would rather that then lean, thank you. I guess I will have to get wet and do old fashion plug test, she's still cold here.lol. As far as the oil goes the guy I bought it from was running 35 to 1 and using walmart oil so I figure I would be ok running amzoil intercepted at 40 to 1 but you run 50 to 1 no problem with b pipe ?
Thx NorCalNorCal
 
N

Norcaltrd

Location
Redding, CA
Yeah Ive been running 91 octane mixed 50-1 with I think its walmart penzoil in both my 1990 6m6 bored 701, and my 2010 62t 701.
I have a b limited pipe, jetting, and flow control on the 701 62t engine.
 
Slimycoho

Slimycoho

Location
Pg bc
Hey NorCal, thanks for all the advice ! I ended up taken the carb into pg yamaha and they did a sonic clean and set the high speed and low speed back to stock settings. The guy I bought it from told me not to touch settings but I think he forgot one screw cause the high speed was turned in all the way and that's why I was thinking it was runnin lean. So I'm back to stock screw settings and 145 main and a 112 pilot. Put the carb back on and she fired up and runs like a dream. I put a full tank of fuel through yesterday at the lake and she didn't miss a beat. I need to do a little tuning but I'm really close just need the water to warm up. Lol . So long story short always check screws even if somebody tells you there good.( I really should know that by now. Lol) ok NorCal thanks again !
 
N

Norcaltrd

Location
Redding, CA
Awesome, Im glad to hear your ski is tuned up and ready to rock! :)
Something you might do is take a white mechanics pen (that stays on through oil etc) and mark the screw settings on your carb.
Put a little dash inline with the screwdriver slot so that you can easily check to ensure the screws haven't worked looser or tighter over time.

Go rip! ;)
 
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