1992suburban
I wanna go FAST!!
see.....
come on.. say it
LOL
Its OK
come on.. say it
LOL
Its OK
Roketa 200cc engine.. any input
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1992suburban
I wanna go FAST!!
if the 200cc pushes me 55 I will be happy..
I had a 400ex that wouldnt hit the mathmatical TOP SPEED so I am sure this one wont either
I had a 400ex that wouldnt hit the mathmatical TOP SPEED so I am sure this one wont either
Rickracer
RM250 Race Kart Driver
I've talked with some real gurus on this subject, and not once did anyone say anything about primary ratios, or even ask what mine is, they just told me to run a really high (numerically low) final gear ratio, between 1.7:1 and 2.3:1, now I understand why..... 
:rolleyes3: 
Gear Commander shows 3.0 primary for a 2003 RM 250, till I find out different, I gotta use that number. I think I may be able to get close by counting revolutions of crankshaft vs. the revs of the output shaft in 4th, which is 21/21 in the trans.
:rolleyes3: Gear Commander shows 3.0 primary for a 2003 RM 250, till I find out different, I gotta use that number. I think I may be able to get close by counting revolutions of crankshaft vs. the revs of the output shaft in 4th, which is 21/21 in the trans.
1992suburban
I wanna go FAST!!
well I am shooting for 15/18 and gonna try 12,13,14 too
Rickracer
RM250 Race Kart Driver
Starting to make some sense now, I must be turning the motor harder, at 9500 rpms (which I've seen on my tach's "max rpm" function, it shows me at 74 in 5th. So where did you find that 18 tooth rear sprocket and hub?
1992suburban
I wanna go FAST!!
1992suburban
I wanna go FAST!!
74 is haulin @ss my man!!
1992suburban
I wanna go FAST!!
whats the highest RPM you can pull in 5th realistically
and in 4th???
and in 4th???
Kaptain Krunch
Pro Junk Collector
Rick, i dont know how much different your Rm motor is from mine, but i have an 83' rm 125 and the ratio between the crank and clutch basket must be at least 3:1 if not more. All this talk on gearing makes me think i got mine all wrong, 70 in 6th is a lot of shifting.
1992suburban
I wanna go FAST!!
my question is how many RPMS will it pull in high gear..
I am sure it wont pull to redline..
I am sure it wont pull to redline..
Kaptain Krunch
Pro Junk Collector
depends on what your final ratio, and if its the 10 or 18 horse version. If you can figure out the weight and top speed of the bike, you can base your calculations off that.
1992suburban
I wanna go FAST!!
its the 18.. got the numbers off motor
15/23 gearing will put it back exactly like it was on the bike
advertised 55mph
15/23 gearing will put it back exactly like it was on the bike
advertised 55mph
Kaptain Krunch
Pro Junk Collector
that sounds reasonable to me
modelengineer
Lord of the noise
For my bike engine I'm running 14-50 gearing....
I spose with smaller kart tyres those ratio's would be good.
I spose with smaller kart tyres those ratio's would be good.
Rickracer
RM250 Race Kart Driver
I'd say 9500 is probably close to the max if I want it to live a long time, but I've not had it anywhere I can hold it wide open for more than a few seconds. The one (about a 1/2 mile) road I test on has a pretty bad dip in the middle that will get you airborne at anything over about 55~60. Now that I've got the motor leaned out a bit, it will get there really quick. It was pig rich in those runs at the dragstrip, I've got twice as big a K&N filter on it now, and the plug is cleaning up nicely.
That 18 tooth sprocket and hub is for a 1" bore, my rear axle is 1.25". Might have to snag a sprocket like that one and re-work it to fit my hub.
That 18 tooth sprocket and hub is for a 1" bore, my rear axle is 1.25". Might have to snag a sprocket like that one and re-work it to fit my hub.
What bike motor are you running? What sprocket ratio did the bike have? Generally, you need to divide the bike tire circumference by the kart tire circumference and adjust accordingly to get the same overall ratio. Might check with the Gear Commander site and see if they have your motor/bike in their database, it would be pretty helpful to know all the ratios.
Rickracer
RM250 Race Kart Driver
You mean calculating for the difference in tire sizes too? Or the bike had 15/23 sprockets? If the bike had 15/23, the kart will be MUCH slower, because the tires are much shorter (less distance traveled per revolution).
1992suburban
I wanna go FAST!!
You mean calculating for the difference in tire sizes too? Or the bike had 15/23 sprockets? If the bike had 15/23, the kart will be MUCH slower, because the tires are much shorter (less distance traveled per revolution).
yeah the stock bike tire was MUCH bigger
so with a 11" rear tire I will be close but it may only run 55mph
But thats pretty good from a 200cc motor. I will have to gear accordingly
anyways I go look at the motor and all on saturday/sunday.
if it makes peak power @ 8500 it may turn 9500.. but I based my numbers off 4th gear 8000 I think cause it may not pull in 5th (overdrive .98)
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