crank for q mhr 70

i have a runner with 2k miles onit and i just got a real mhr 70 and wanna know wether i NEED to change the crank from standard?
the bike will also be running
a super9 vars
polini belt
cant remember brand , race clutch green springs
21mm carb
polini reeds
and until i get some more £s a tt pipe

and possibly an unlimited cdi???

Only reason you would need a new crankshaft is for extra power tbh, a longer stroke.. its not essential, probably a better idea to get a gear up kit mate

what about an unlimited cdi??? good idea or not??

Yeah definately a good idea, but could be dangerous, but if you haven't got the money to fix it if it goes wrong I wouldn't

a few things:
you are running the original pipe? If yes, then this one is shutting down at about 9-10k rpm. The MHR has its power at about 11.5-12.5k rpm. So you definitely need a new exhaust. Then you also need a racing crankshaft. If your crankshaft aint exploding (and damaging most of your engine) it will be your bearings...
Definitely install a longer transmission!
Also, the TT pipe: You mean the Leo Vince TT right? That stuff is crap, especially with a MHR cylinder. Go with a Stage 6 1200, a malossi MHR, a polini Evo, Yasuni c20+, Roost, Romano, etc. All the other things won't make you happy.
If you're interested in porting your Malossi cylinder or engine let me know. I can also help you adjusting your engine block to the cylinder as I'm riding the same engine cylinder combination.

Best,
D

boon132 said:

Only reason you would need a new crankshaft is for extra power tbh, a longer stroke.. it's not essential, probably a better idea to get a gear up kit mate

That is some shockingly terrible advice.


Yes on a proper MHR you will have to change your crank or as above me said either your crank or your main bearings or both will go bang very quickly.

right the situation has changed it is an mhr rep not real
ill have all the same other parts (in the post)
so will i still need a crank and/or cdi?

and as a side not it pretty much tops out now at 10.5k (only mods are leovince tt air filter bore n jetted)
and i know what exhausts i need just gotta wait for some money to come through (month or so) was gonna get a c21 but now its a rep im gonna get a c16
because of this thread:
http://www.scootershack.co.uk/scooter-tuning/exhaust-barrel-matching-guide-t2948.html

You will probably need a crank. MHR Rep is deffo on the edge. I ran one without a crank but it was a very low mileage bike and I didn't do a lot of miles on it.

CDI you may also need and they are pretty cheap so you could always fit the rest and wait and see.

ok kool i have mosta my bits in the post ready for tomorrow
21mm carb
polini belt
polini super9 variator
polini reeds
race clutch green springs

so all of that is goin with the mhr rep and leo tt pipe but i will be getting a crank,cdi and c16 as soon as i get enough £s

thanks all much appreciated

also will let you all know how this setup runs