Cranks.... Sp Vs Pro Race [Archive] - Bay Area Two Stroke


View Full Version : Cranks.... Sp Vs Pro Race

03-10-2006, 05:22 PM
well its about time i tore the old girl down and replace her heart. I'm wondering what is the difference between the SP crank and the Pro Race? other than the 20.00 the pro race looks to be cromed.. or is that just polished. what did you go with Dan ?

03-10-2006, 05:53 PM
the difference other than the 20 bucks is the weighting. The pro race is perfectly weighted with the sp is almost as good. I went with the Pro Race when i did it. That and some bearings along with a gasket kit was everything the doctor ordered. Also a good time to match your ports for the base and the head. Gets some good bottom end power from doing that.

03-12-2006, 10:18 AM
hey Dan, when you did your crank did you put the bearings into the cases, then pull the crank into the right side and then drop the left side on ?. because the manual suggests you put the bearing on the left side of the crank and heat up the case to join the 2 together. I've always put the bearings into the case first. I had a really hard time getting my countersunk allen bolt off my shift drum star. need a new screw for sure now.
with the YSR you put in the bearings in the case first, pull the crank into the right side and then the left case slides over the crankshaft and joins. I guess that what i'm asking if its a slip fit installing the left cover.

03-13-2006, 08:04 PM
We put the bearings into the cases and then pulled it all together. Either way is fine i guess though. Do what your used to and then it will always go together correctly.

03-13-2006, 10:17 PM
before you seal the cases.....put them together and by hand go through the tranny gears to ensure that they all work. when they do seal up the cases
then it will be time for a leak test to see if it leaks somewhere. its easy you can do it and were here to help

03-15-2006, 08:04 AM
Well my crank is in. went in rather easy with the right pullers( had to make a new one sice the thread on the crank is 10mm x 1.0 ) I used the stock gasket even if i prefer to use the yamabond to seal cases. Matched my cases to the cylinder while i was at it. [B]What i didn't know was the stock crank has a round main gear with a woodruf key, the pro race crank has a tapered shaft with a small key and you need a new main gear. Now i'm waiting for that to show up today.

03-15-2006, 08:21 AM
Dan when your bike started to vibrate because of the bearings, did you scrap your old crank or leave it on the shelf for a back up for something else? I figure if the crank is still good, just the mains went. i could use it on another bike with new bearings. I have to put my dial indicator on it and see what the runout is on the lathe.

03-15-2006, 06:48 PM
thats nice that you can do that. aaaah tools i dont have

03-19-2006, 12:05 PM
Hey just a question for you guys. Since you put in your Pro race crank did you leave your balancer in or remove it? When you put the new main gear on it doesn't have the balance mark on it. I didn't remove mine. Didn't think about it until it was together, if the crank is perfectly balanced, what do i need the weight for. Ray

03-20-2006, 02:45 PM
We left it in just for fun.

03-20-2006, 02:48 PM
the weight is for higher rpm's with a faster spinup TO the higher rpm's