Thread: Yamaha Go Kart crank rebuild stage 2

Hi Gang,
Regardless of the repair process on the Go Kart cranks at some stage the 2 sections need to be pressed back together. This can be done with some careful alignment but it is easier if the crank is aligned in a jig and then tried up.
So my thoughts are, some where I have some Linear bearing bushes that would work with ground shaft. Mmmm where in the mass of to good to part with are they.
For once my non existent catalogue system worked. So I have LMB in 1" and 3/4". Find some precision shaft and plate, good use for the shaper to clean up and all should be good.
True the plates, bore both plates inline, 2 holes for shafts/bearings, 2 for the crank journals.

Sounds like a die jig,
So here is my out there, has any one acquired some die jigs from an auction that they are hanging onto and are thinking of passing something on. Happy to pay, would just save some time.
Cheers
Bruce

Funny enough I do. I was just wondering the other day where it was and how much rust it had collected. From memory it is about 4" across. Any use?

Michael

Hi Michael,
The crank halves are 8.5 cm diam and basically all that is then needed is an accurate hole bored to locate the crank outputs, so yes a die jig is perfect. Will send you a PM. Thanks

Never used a jig simply scribe a line with some angle iron across the webs and use a good known square to line em up

You are going to have to true it anyway with a lead hammer i hope

I have done it this way a couple of times

I hope you enjoy this

Having had a 4 cylinder press together crank done (and watched the process - was done by a retired guy who for the last 20 years was the go to guy for pressed crank work in QLD), there's no jigging, just press it together by visuals, and then bash it straight!For a sigle cylinder crank, it's a case of clamp the crank by one main bearing,dial indicator on the other, true it with a Lead/Copper hammer and a redgum stump.Twin cylinders you need an indexing rod (ground to fit the small ends, crank centerline should be the same distance to the indexing rod when slid through both small ends), and you clamp the centre bearings.Goes the same for 4 cylinder cranks (except your indexing rod runs through all four small ends). Triples are a pain to index because you can't use the indexing rod the same way.