advice needed please

[bazza3004]

hi , I am getting a fair bit of vibration through the scoot , this varies depending what revs im doing, from an acceptable amount of vibration to quite a bit . The engine mounts don't look in bad nick visually so I am thinking my crank is slightly out.
My set up is:-
Latest Imola kit
30 phbh
franny race pipe
li 150 15/46
sil 2kg flywheel
AF Rayspeed crank with welded pin. (never been totally happy with this , it was bought 2nd hand)

So , I am thinking of fitting a mec crank and want to no is it worth fitting the 60 mil and if so will it fit my 1979 gp casing without needing the case channelled for the big end. Or would you just stick to a 58 mil stroke crank?.
Any advice or help on this would be appreciated . Thanks.

[coaster]

Possibly worth checking that you haven't over tightened the engine mounting bolt and that nothing is touching the frame or bodywork when you are sitting on the bike.

[bazza3004]

cheers coaster I will check that.

[mickjr]

sounds crank related mate,get a bgm one ,its german made

[sean brady scooters]

remove flywheel cover and check visually the gap between the edge of the flywheel and the lip on the flange whilst turning it around .

[bazza3004]

Good idea , didnt notice anything untoward when i was strobing ut but probably spinning to fast to notice when engine running. It seems ok when doing say 30mph in 4th but if i accelerate the vibes are quite noticable by the time im doing 45mph and if i keep winding it up they lessen to a degree the faster i go. I realise tuned lammys vibrate to some degree but this is defo more than normal. Il do the checks you kind folk have mentioned tomoz (at work now) and see if i have any joy.

[bazza3004]

Ok had a look at a couple of things today. Dropped the rear shocker an jacked the frame up so rear wheel off the floor and engine bolt was defo not to tight (or too loose). Also checked that nowt on motor was touching frame when on scoot (or off) which it wasnt. Any hows ive a new 60 mil stroke crank onway so il be stripping top end to replace the 58 with this and do bearings & seals at same time plus ive some porting work to do to case & barrel while its off and hope the new crank cures the vibration problem at same time. Cheers, baz.

[Special X]

I'm running a MEC 107/60 in my cast 230. I had to channel the case quite a lot to clear the big end.

[bazza3004]

I'm running a MEC 107/60 in my cast 230. I had to channel the case quite a lot to clear the big end.

cheers for that special x ,il get the flap wheel ready

[Dave h]

If running a 107 /60 ,you will need to take a bit off a base of the piston.