I am rebuilding a 1970 Thunderbolt.
I have replace the two moving gears, which seem to slide freely.
But it gets stuck between neutral and 2nd.
In the vice some wiggling of the main shaft gear allows it to move to 2nd, but when I put the cassette in it is locked solid.
Similarly 3rd and 4th need a bit of help.
I have check the shims and taken it apart many times and I think it is correct.
The fact it does not work suggest it is wrong.
Any suggestions to the problem?
Maybe the new gears have too much friction? I have cleaned and oiled them
Thank you
Matthew
Remove the mainshaft, fit the 113 thou shim onto the cover plate side of the lay shaft, fit nothing on the other side. Use a DTI and measure the end float. Fit the correct shim (or shims) on the output side until the correct free play of 1-2 thou is met.
There's been some BS going about where someone is telling people to fit the same amount (equal) of shims to each side. This might work where your fitting .113" on each side, but it can also lock the box up or jump out of gear if using thicker shims. (Obviously that person never read the WSM)
Hello Allan
Thank you. You make a good point about the WSM.
Re reading it I missed that the forks are different.
I will try it tomorrow the correct way round.
With it in the end float is about 5 thou. I'll need to find an appropriate shim after measuring what is in there.
Thanks
Matthew
Nice one Mathew,
5 thou is acceptable, 2-3 is better. You want to ensure enough dog is held into the gear as possible. Its nature wants to fling the dogs out of the female gear, when it starts doing this it loads the gear against the fork, ultimately wearing both parts. Also check for movement between the roller and the cam plate. You want enough for it to move, but not too much so that it allows the fork to float. I fitted a NOS cam plate which had too much free play... not something I had experienced in 20 years and why it wasn't checked. I check each one since.
Double check the value in the parts book and WSM. I'm saying it's .113-.115" but it's been a little while since I checked. It's most certainly the thinnest one goes on that timing side.