Gear Ratios

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csp1971

csp1971

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Okay, I think I have my engine tuned well after 7 tanks. The plug appears to be brown.


The acceleration on my XB is unbelievable, it takes off like a bat out of hell BUT the top speed is lacking (jetpro). I noticed my gear ratio is low (A:29 B:31 C:25 D:25). Has anyone flipped their A and B gears around for a bit of a higher ratio?


It just seems like it can't get over a mid-range "hump". It's quite different than my side dom on my Baja, the side dom on my Ramp MT, and the JetPro v3 on my Baja.


Any suggestions? It's really driving me nuts. I have the high speed set where it should be and the low is great. I did put a copper gasket in place of the original paper gasket on the head. Everything sounds smooth. I think my oil to gas ratio is high on the oil side by accident. Not sure if that would make any difference or not.
 
not trying to jack your thread but how do you like that side dom on your MT? i just ordered one..
 
easyrider said:
not trying to jack your thread but how do you like that side dom on your MT? i just ordered one..
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I love it, it seems to work pretty darn good for my tank of an MT (33+ pounds).
 
RampageHopUps said:
You will probably like the 31/29 combo better. If the take off isn;t enough for you, switch to an 8K spring.
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I have the stock spring on there now and I can't believe how well it accelerates, it spins all tires. I'll switch the gears around. The low end is unbelievable right now.
 
tboracing said:
i want my car go more fast what combo i need
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Right now I have a low gear ratio, line 4 (see chart a couple posts up). I want more speed so I'm going to flip my A and B gear around which will bump me to line 6, giving me more speed. I have an XB.


If you want even more speed, like line 8, order a 35 gear from here:


http://www.rampagehopups.com/product.sc?productId=399&categoryId=-1


Remember that your low end will suffer with the higher gear ratio you go.


Count the teeth on your gears and see what you have.
 
Probably 35? That's just a guess running it in front of my house. Hard to tell though. I switched my gears around tonight and hope to run it this weekend.
 
On my belt drive I'm run the equivalent of the 33/27 or 35/25 gearing depending where I'm running. I've actually run the 35/25 with a race ported 23cc 4 bolt and liked it alot. It was fast. You will need an 8k spring with that setup though or go all out and get a Lauterbacher clutch.


Once you get an 8k spring or good clutch and a good pipe, anything less than 31/29 is wasting top speed.


P.S. I slapped my TS motor with a brand new 27.2 last weekend and blew the motor. It was 20 minutes of pure poop eating grin though. The car was insanely fast. To tell you the truth you need a 35/25 setup to run a motor like that. I got a brand new ESP reed ported 30.5 in yesterday as a replacement and I'm expecting to need a 37/23 setup to keep from blowing the wheels off of it.
 
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