Indian GP Engine Build - Part 4

All shimmed up

The end-plate is removed again ready for trying a 1.7mm shim. I use M6 allen bolts for this but other states have the proper T-Bar extractors in their toolkits (we don't have a full toolkit in the ACT, having only a few local members...). I'm an expert at this now! The best technique is to just start the plate moving with the extractors/bolts and then give it a sharp tap with a mallet on the thick lumpy bit next to the cluster bearing (marked with a blue arrow). Repeat until you can wobble it off. This tapping stops it going wonky - should have reread how to do it the other day...

Before doing the final shimming I check to see that the layshaft is still tight through the bearing. Yep, all good.

Back on with a 1.7mm shim, but it's too small when checked with a feeler gauge. Looking at the AF instructions and they recommend going up sizes until a shim locks the gearbox, and then going back one size, rather than trying to get an accurate measurement with a feeler gauge. The gearbox locks for me with a 1.9mm shim. Checking with a feeler gauge and a 1.8mm shim gives 4 thou clearance - looking good, and in line with the mental arithmetic I did before! Note, the max clearance in the instructions for the AF 5 speed is 5 thou. Much less than the 11 thou recommended for a standard box!

Now I'm happy with the shim size it's time to check that the rest of the box works. Paul Cain had recommended not fitting the cluster until after shimming because this makes it easier to take the end-plate on and off. Everything comes out again, I lube and fit the cluster bearing, and am chuffed to read in the AF instructions that the shim should not be fitted. There's obviously no room with a 5 speed cluster, but there is also a school of thought that the shim just stops oil getting to the bearing. I'd been in two  minds whether to fit it, but problem solved.

Cluster in and refit the loose gears...all looking good.

The final check is to fit the clutch spider, torque it up to 50 foot lbs, and see that all the gears mesh and work. Yep, they do.

The last job for today is to fit the selector rod and bracket, using allen bolts to give more clearance, as suggested by Mark. Fifth is sweet. First is clear, just. All will be good until we get some more wear in the linkages...

Well that was a productive session. Building a 5 speed is much more involved than a standard box, and of course I have to remove the end-plate one last time, to replace the studs I damaged at the end of Part 2. Hopefully Steve Diffey has some in stock.

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