A 42 on the bottom would be gearing it down wouldn't it. If it only goes around 90mph now, I don't want to slow the track speed down. I am thinking of going to a 22 or 23 top for the mountains. I am running the stock gasket, so I think that I will run a 130 main to be safe. Can I run it on high boost more in the mountains because of the tinner air?? I am going to take it to Wyoming on Thursday.
comp
ya with low comp pistons, and a .065" gasket.
actually is prolly 8.3-1 ratio
pistons with stocker = 10.1 - 1
pistons with .057" = 9.1 - 1
pistons with .065" = 8.2 - 1
pistons with .074" = 8.0 - 1
got to be close but I didnt due any chambering to confirm that.
just going by the numbers.
ya with low comp pistons, and a .065" gasket.
actually is prolly 8.3-1 ratio
pistons with stocker = 10.1 - 1
pistons with .057" = 9.1 - 1
pistons with .065" = 8.2 - 1
pistons with .074" = 8.0 - 1
got to be close but I didnt due any chambering to confirm that.
just going by the numbers.
The info that Devin and I got is from the turbo mountain master. Pretty good info for a salesman, and he can ride. Saw him go up Turbo hill in Revy with 20/42, 9 tooth drivers over 95mph uphill thru 3ft of powder snow and wheely over the top, about a 1/4 mile straigth up. So I don't think that you will never need to go that fast for everyday mountain riding. The belt is much happier, works alot better in the trees with deep powder. You are not laking racing a mountain sled, are you?. Each to there own.
spray25
TY 4 Stroke God
20/42 with 9 tooth = 2.10 (Red's 95 mph friend)
21/42 with 8 tooth = 2.25 (this is what Red suggested)
21/40 with 8 tooth = 2.14 (this is stock)
Red, I think you are fogeting to take into account driver size. As far as we know this guy has stock 8 tooth drivers. You told him to gear down to 2.25 by putting in a 42 tooth bottom gear. Your example of your friend going 95 mph was with higher than stock gearing.
I still disagree with the recomendation to gear down.
21/42 with 8 tooth = 2.25 (this is what Red suggested)
21/40 with 8 tooth = 2.14 (this is stock)
Red, I think you are fogeting to take into account driver size. As far as we know this guy has stock 8 tooth drivers. You told him to gear down to 2.25 by putting in a 42 tooth bottom gear. Your example of your friend going 95 mph was with higher than stock gearing.
I still disagree with the recomendation to gear down.
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spray25 said:
21/42 is 2.0 not 2.25
I agree, don't gear down too much. The power is there to pull the gears.
givemeaboost
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Don't you have to figure about 11% gear reduction for 8 tooth verses 9 tooth drivers ? Ken
spray25
TY 4 Stroke God
Uncle Buck,
You too forgot to account for 8-tooth drivers. MPI has a handy little chart on their website for checking FINAL gear ratios. http://www.mountainperformance.com/yama ... _chain.htm
PS silver sleds are slower!
You too forgot to account for 8-tooth drivers. MPI has a handy little chart on their website for checking FINAL gear ratios. http://www.mountainperformance.com/yama ... _chain.htm
PS silver sleds are slower!
gearing
20/42 with 9 tooth is all you will need in the mountains
Randy just gave me a
for that gearing.
just make sure your clutching is setup to match.
try this - 8BU -00 fully loaded with 45X2.0 rate. 51 straight cut and silver spring. 17 lbs of boost.
= 300 hp with 102 octane
Try it out and you will have a ear to ear grin in the steeps
20/42 with 9 tooth is all you will need in the mountains
Randy just gave me a
for that gearing.just make sure your clutching is setup to match.
try this - 8BU -00 fully loaded with 45X2.0 rate. 51 straight cut and silver spring. 17 lbs of boost.
= 300 hp with 102 octane
Try it out and you will have a ear to ear grin in the steeps
spray25
TY 4 Stroke God
Which is pretty darned close to the stock gearing of 21/40 with 8 tooth. Hence my original questioning of the recomendation to gear down by putting a 42 on what I beleive is an otherwise stock drivetrain.
I think that I will try the stock gearing then. I just thought that if you have the horsepower that you should gear it up a little bit. The stock gearing will be a 21/40 with 8 tooth extroverts. I think that if I can go with a 21/38 might be better. What do you think on that combo? I am leaving on Thursday, so I guess that I will just have to try something. I am going to run 130 main jets and leave the rest of the carb stock. Hope this works.
spray25
TY 4 Stroke God
The 38 will be fine (it's a 2.04). EXCEPT that you are supposed to run a 68 link chain wih a 38. If you want to use your same chain go 22/40 for a 2.05. Chains cost a lot more than gears.
You likely won't notice the diferrence on the low end, yet you will gain a few MPH on the top end.
130's should get you pretty close. Just make sure you have a good range of pito jets. You can do a fair amount of adjusting with diferrent pito jets.
You likely won't notice the diferrence on the low end, yet you will gain a few MPH on the top end.
130's should get you pretty close. Just make sure you have a good range of pito jets. You can do a fair amount of adjusting with diferrent pito jets.
