Two Tranny questions

[berniebee]

Hi all,

I'm hoping to get advice from some experienced tranny handlers. I've just disassembled my '83 SP1000 transmission (Which I've never,ever, ever ridden, but has 40,000 miles) and I've found that the shift drum has 0.4mm of play. There is a 0.8mm shim at the front and and 1.0mm shim at the rear of the drum. The shift forks don't show any wear, so they give  no clue as to which direction I should shim. Should I just replace each shim with a 0.2mm thicker one? I will order enough shims to get every combo that adds up to 0.4mm thicker total shim, but I'm wondering what is likely to be required.

Second question: I've heard that the newer style detente plunger has a flatter tip than my rounded tip, which supposedly makes for easier/nicer/smoother (take your pick) shifting. A new detente plunger is about $50 plus shipping- a pretty penny for a tiny part! So. Is it possible to file and smooth my original plunger tip to work, or will a thin hardened layer be removed rendering my tip soft  and non performing?   

[Old Jock]

I'd try to just shim either side as you stated and then test it, remember to try if before you builld it back up and what I did was try eliminate all play without the gasket.

I seem to remember I came pretty close but could not eliminate it entirely. Box shifted a lot better after the drum was shimmed up, but it will never be Japanese/Ducati slick

I tried a different plunger both were rounded but one had a hole in it. However that was a later model than yours and it made no difference, that I could tell

Sure wiser heads will be along soon

[berniebee]

I'd try to just shim either side as you stated and then test it, remember to try if before you builld it back up and what I did was try eliminate all play without the gasket.

I seem to remember I came pretty close but could not eliminate it entirely. Box shifted a lot better after the drum was shimmed up, but it will never be Japanese/Ducati slick

I tried a different plunger both were rounded but one had a hole in it. However that was a later model than yours and it made no difference, that I could tell

Sure wiser heads will be along soon

Thanks, looks like that's the best answer. I'll order several shim sizes as insurance, but hopefully I won't have to disassemble the box too many times.

[amamet]

sounds right from everything ive read.  im doing the same thing now. never been inside a transmission before this. I can now dismantle it and reassembly it within an hour ive done it so many times in the past week :)