View Full Version : 38mm keihin on stock 82 250R question
pepsicolla
01-16-2015, 12:22 PM
I have a all stock 82 250R with no performance parts except intake. I came across a 38mm round keihin I believe came off a 91 cr250. In know I can mount it up with some stretching, but will a carb that big actually hurt performance without additional upgrades? Maybe I should jet down? If so what would you recommend for jets?
onformula1
01-20-2015, 03:50 AM
That carb is too big for a stock 82. (stock was a 27mm)
Go with a stock 1983-84 250R carb which is 30mm or a 32mm carb off something else.
Also a 91 CR250 has a PJ oval slide carb, not a round slide, measure the intake side of the carb you may have a carb that will work great.
Note- with your set-up you don't need a flat slide type carb.
pepsicolla
01-21-2015, 10:16 AM
Thanks for the reply onfomula1. Ya I was thinking it was overkill. It sucks because I have 6 oval slid keihin carbs but they are all 38mm on the intake side. Looks like ebay here I come.
onformula1
01-21-2015, 11:33 PM
Or have a machinist make a tapered spacer for the intake side.
cr480r
01-22-2015, 04:01 AM
Who cares what size the stock carb is? Sure a 38 may not be optimum, but if you already own it put it on and see. It will probably soften the bottom end some, but it may surprise you... I would use the carb and put the money saved towards other mods.
Does anyone have a speedometer gear box for an 85-86 Honda 250r
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