37 replies to this topic

[timmy850]

Those markings are caused by wiggling off the primary gear without removing the burr from the c clip

[ACDodd]

Apart from it was removed without removing the burrs on the crank tail before it was pulled off it looks ok. However looks are just that. You need to check the internal bore size of the bushes and measure the crank tail diameters to determine the running clearance and wear.

Ac

[duffdub]

Apart from it was removed without removing the burrs on the crank tail before it was pulled off it looks ok. However looks are just that. You need to check the internal bore size of the bushes and measure the crank tail diameters to determine the running clearance and wear.

Ac

If I were to get a new gear, is it likely there’d be too much running clearance with my crank?

Edited by duffdub, 10 March 2021 - 05:40 AM.

[ACDodd]

It would be likely that here would be insufficient running clearance as the new gears are not sized that well and I usually have to open them up a touch to ensure they don’t bind in the crank.

The point is you much check and set the running clearance accordingly. Just fitting new parts out of the box is just not the way to do it.

I can help here if you send me the parts I can measure.

Ac

[duffdub]

It would be likely that here would be insufficient running clearance as the new gears are not sized that well and I usually have to open them up a touch to ensure they don’t bind in the crank.

The point is you much check and set the running clearance accordingly. Just fitting new parts out of the box is just not the way to do it.

I can help here if you send me the parts I can measure.

Ac

I appreciate any and all info, thank you so much. Shipping to you would cost an arm and a leg haha. You’re in the UK, right? I’m in Atlanta Georgia. What tools do I need to measure? I know I need a micrometer but what do I use to get the internal bore size of bushes?

[ACDodd]

Blimey this is easily achieved in the states! Simply take it along to your local engine rebuilding shop and wake them to measure the engine Maude diameter of the bushes. And then measure the respective tuning surfaces on your crank to determine the running clearance.

After this you can then decide what to do.

Ac

[Dusky]

It would be likely that here would be insufficient running clearance as the new gears are not sized that well and I usually have to open them up a touch to ensure they don’t bind in the crank.

The point is you much check and set the running clearance accordingly. Just fitting new parts out of the box is just not the way to do it.

I can help here if you send me the parts I can measure.

Ac

I appreciate any and all info, thank you so much. Shipping to you would cost an arm and a leg haha. You’re in the UK, right? I’m in Atlanta Georgia. What tools do I need to measure? I know I need a micrometer but what do I use to get the internal bore size of bushes?

A bore gauge :

[Spider]

If you are unable to have them measured - which is the best way to determine the running clearance - you can get acceptable results using a feeler gauge. As we are normally only talking somewhere in the 3 to 6 thousands range, feeler gauges at these thicknesses are flexible enough to 'roll' to these diameters. You are unlikely to be able to get a reliable reading though by trying to slip on in between the gear and the crank with the gear already on the crank, but if you lay the strip on the crank then slip the gear over, you'll get better results. To check the Rear Bush (Top Hat) in this way, fit the gear back-to-front.