Scooterotica

Hi all, does anyone know where I can get a tool to check a crankshaft is running true and not twisted ?

ALPHA TRUE BEARINGS of Dudley made jigs for checking crankshafts they come up for sale on eBay and other selling sites or get a set of V blocks and a dial gauge on an adjustable stand

JB Fabrications in North Scarle mark one that works.

Not ideal but if the crank is in the engine and the bearings are good, you can put a dial gauge on the end of the taper and rotate by twisting the front sprocket. I did this after my Richard Taylor GT crank fell off the bench and wanted to be sure it hadn't twisted. My dial gauge told me it had a 2 thou run out which I'm led to believe is within tolerance. Went ahead with the build and it runs as smooth as silk.

Surely if the crank is out of true,your flywheel will be out causing the magnets to catch on the stator plate.

HxPaul wrote: ↑Wed Aug 01, 2018 10:48 am Surely if the crank is out of true,your flywheel will be out causing the magnets to catch on the stator plate.

normal tolerance is within 3 thou total run out that equals 1.5 thou out from centre line and shows up as a total of three thou on a dial gauge doin a 360 degrees rotation if you were running points it would move the points to a maximum 1.5 thou extra on a electronic ignition I don’t thunk a pickup would know

HxPaul wrote: ↑Wed Aug 01, 2018 10:48 am Surely if the crank is out of true,your flywheel will be out causing the magnets to catch on the stator plate.

yes. Worse case it can destroy the bearings, stator and flywheel. When a crank twists it can destroy a lot of bits.

Some will disagree but V blocks are not as accurate as truing the crank from the centers

Thanks Colin and others for responses. The only reason I'm thinking crank 'might' be out of true is because the oil seal has failed after only 3000 miles and I'm a pedantic bugger when I draw the crank through the seal and bearing so I'm sure it went it without damaging the seal and on dismantling the seal looks ok ?could it possibly be slightly ovulating that side causing same symptoms was my thought ? Whilst crank was out wanted to test it, but now I'm thinking of changing it for bigger stroke. It's on a Ts1 what's the max cranki could use and benefit....and should I dremel myself or drop to specialist

Strummer10 wrote: ↑Wed Aug 01, 2018 6:19 pm ..................now I'm thinking of changing it for bigger stroke. It's on a Ts1 what's the max cranki could use and benefit....and should I dremel myself or drop to specialist

I fitted the Grand Tourisimo 62x110 crank that came as part of my GT240 build and cut the trench with the careful use of an angle grinder. It only needed a millimetre or so removed. I think Eden uses a die grinder so a dremel could work too.

Cheers Colin, out in the garage today to see what I need to order. Will take a look at that crank then