|
|
Post by motorhead on Jan 31, 2011 17:13:13 GMT -5
Hello everyone. I am looking for a 15,000 rpm full circle racing crank for my aprilia sr50. I just over revved and bent the stock crank and I need a stronger crank for my scoot. I've been looking at racing cranks like the one in the pic. I've heard rumors that these racing cranks need you to modify the crank case to fit. Is this true? Attachments:
|
|
|
|
Post by 90GTVert on Jan 31, 2011 17:58:51 GMT -5
How much did you see when the stock crank gave up? Was it 15,000RPM or are you just looking for a little headroom? I don't think most of the stock stroke cranks are going to need the case machined to fit. I would advise looking around at www.sip-scootershop.com . They sell a lot of high end stuff, you can selct parts by model of scooter, and the shipping to the US is quick and reasonable. |
|
|
|
Post by troy1896 on Jan 31, 2011 18:14:16 GMT -5
Is this for the same scoot that you are having problems with in the troubleshooting section? If it is, hope that you didn't ruin your top end along with it  |
|
|
|
Post by motorhead on Jan 31, 2011 21:12:19 GMT -5
troy1896This happened on the Aprilia sr50 while going 55mph. And miraculously there is no top end damage. The connecting rod bearing gave and the crank is slightly bent. @ 90GTVert I have no idea what rpm caused this but i know it was high because I had three 3g rollers in the variator going 55-60mph. So yeah, I want max rpm out of my next crank. At the time when I originally rebuilt the bike I was really tight on money so I put a stock chino crank in it  . Yeah, bad idea. So now I want something that can hold up. And yes heavier rollers. I haven't dynoed the bike but I know It's making near 10hp and I want a crank that can stand up to that.
|
|
|
|
Post by lshigham on Feb 8, 2011 12:59:13 GMT -5
10hp is fine for the stock cranks. You just had way too light rollers in it, I use 4.3gr with a 12-13k setup.
|
|
|
|
Post by motorhead on Feb 9, 2011 9:10:57 GMT -5
:itshere: So, my 13,000rpm motoforce racing crank came in the mail yesterday and I spent the rest the rest of the evening re-rebuilding my sr50. This time I have installed 3, 7g rollers to run me at 3.5 grams. I took the bike out for a spin this brisk FL morning now it takes 1/2 throttle to get up to 55mph. Also, I have a little more throttle control now. Before, it felt like a weedwacker I either had the engine going full blast or put put. I am going to add the 3g rollers to bring me up to 5 grams total and then see if I have even more throttle control. Once the weights feel good in my scoot then I'll install my 1,500 contra and clutch springs. :riding:
|
|
|
|
Post by 90GTVert on Feb 9, 2011 10:12:48 GMT -5
If you wanna use the stiffer contra, I'd stick that in there now. There's really no point of getting your roller weight correct and then adding a different contra. The contra will have a similar effect as lighter rollers. So when you get it all dialed in with the rollers, it'll be off when you add the contra.
|
|
. Yeah, bad idea. So now I want something that can hold up. And yes heavier rollers. I haven't dynoed the bike but I know It's making near 10hp and I want a crank that can stand up to that.
