Gear ratios

What sprocket rations do you guys use on the brp. I still have the standard 14/48 , but the bike could easily pull another gear on top end . Has anyone used a 15 front sprocket ? How does it affect low speed grunt ?



Using your numbers would this mean if you were running a 15/47 your top speed would be 107.75? I was just wondering what the top speed was with my gearing.

15/47 would yield about...

Gearing 15/47

MPH 1st....38

MPH 2nd...56

MPH 3rd....71

MPH 4th....89

MPH 5th....106

I run a 15/47 for racing and pre-running in baja and stock for district 37 races.


Jan, I'm currently running 15/48. The extra

tooth adds 7mph in theory. The downside is

you lose a proportionate bit of grunt and also

loose some engine braking. Last summer I tried

the Aussie gearing of 15/41?, the lower revs

for cruising and the improved fuel economy was

fine, but my wheelies all but dissappeared

and engine braking for steep off-road descents

was hopeless. If you are not into trying to

get 106mph from your pig, then 14/48 will

give you the most enjoyment.

I have the HRC piston and cam kit in mine

so I don't notice the loss of grunt I mentioned


cheers, Craig

Here's some numbers to give you an approximate idea of the maximum speeds you'll get in each gear with the following sprocket combos. Please note these numbers are based on a maximum engine speed of 8,000 RPM among many other factors.

Gearing 13/48 14/48 15/48

MPH 1st....33.....35.....38

MPH 2nd...47.....51.....55

MPH 3rd....60.....65.....70

MPH 4th....75.....81.....87

MPH 5th....90.....97.....104

Gearing 14/50 14/51 14/52

MPH 1st....34.....33.....32

MPH 2nd...49.....48.....47

MPH 3rd....62.....61.....60

MPH 4th....78.....76.....75

MPH 5th....93.....91.....89

Where are the district 37 races held? And are all of these gear ratios for the stock 650s with just the manifold, jetting and baffle changes?

The District 37 races are held out in Lucerne Valley and RedMtn. They are held in So Cal. For my bike I run (baja/pre-run(15/47)/district 37(stock))bike's gear ratios are w/ the power up kit and the spark arestor taken out and precision concepts suspension. Our race bike for baja runs 15/47 and it has the Pro Circuit pipe like what the factory honda guys run(not availble to public) and the power up kit, cam, holes in the air-box, and precicsion concepts suspension. Those gear ratios work great. Give them a try and you will proably like them but mess around with them and see what you like. Just about every 650 that races SCORE or Best In The Desert runs a 15/47 gearing.


[ June 28, 2002: Message edited by: dzrtracer400x ]

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