Fitting new layshaft bushes

[Steverat]

The drive side (i.e. blind ended) of the layshaft is so slack, that the other end of the layshaft waggles around a good 1/4" at the timing side end when waggled by hand with the intermediate case off.

So I thought to replace the bush at the drive side end. Now I have an adjustable reamer the right size range, but how shall I ream a blind bush with it? Or do the bushes come finished to fitted dimensions? Also how to remove the bush - just drive it inwards?

Thanks
Steve

[duTch]

 

The drive side (i.e. blind ended) of the layshaft is so slack, that the other end of the layshaft waggles around a good 1/4" at the timing side end when waggled by hand with the intermediate case off........

 sounds a bit farqued....when I did mine I didn't have a reamer, but as the replacements were close to size, I used a bit of emery tape wrapped around a piece of ally tent pole centred through both cases.....14,000 miles later no complaints

[RDfella]

The blind bush drives out. Not much point heating the cases, because the bronze expands almost as much as the alloy. Different when inserting a new bush, though. Reaming? No, a reamer has a taper so it won't work. Bush needs to be bored to size - shaft dia + clearance + 1/2 x interference fit into case.

[muskrat]

G'day Steve.
I just did mine in the s/a box. Original from the factory the bush isn't "blind" and there is a plug in the case to blank the hole. If yours was replaced in the past the plug may have been removed and a "blind" bush inserted. The bush needs to re removed inwards.
To remove the old bush (if yours still has the plug) I put grease in and insert a shaft with a good hit, the grease pushes the bush out.
Cheers

[KiwiGF]

The drive side (i.e. blind ended) of the layshaft is so slack, that the other end of the layshaft waggles around a good 1/4" at the timing side end when waggled by hand with the intermediate case off.

So I thought to replace the bush at the drive side end. Now I have an adjustable reamer the right size range, but how shall I ream a blind bush with it? Or do the bushes come finished to fitted dimensions? Also how to remove the bush - just drive it inwards?

Thanks
Steve

It’s not uncommon to have to machine the shaft back to round and then use an undersized Bush. Before doing this job you may want to measure accurately what clearance you currently have, you might be pleasantly surprised, or not! Movement of 1/4” sounds a lot but it would be better to know for sure before you start? 

[Steverat]

The drive side (i.e. blind ended) of the layshaft is so slack, that the other end of the layshaft waggles around a good 1/4" at the timing side end when waggled by hand with the intermediate case off.

So I thought to replace the bush at the drive side end. Now I have an adjustable reamer the right size range, but how shall I ream a blind bush with it? Or do the bushes come finished to fitted dimensions? Also how to remove the bush - just drive it inwards?

Thanks
Steve

It’s not uncommon to have to machine the shaft back to round and then use an undersized Bush. Before doing this job you may want to measure accurately what clearance you currently have, you might be pleasantly surprised, or not! Movement of 1/4” sounds a lot but it would be better to know for sure before you start? 

Luckily I’ve been able to secure a lay shaft which looks new - on the eBay pic. at least. Will post when I get my hands on it.

[chaterlea25]

Hi All,
As mentioned the ends of the layshaft are usually worn/ scored, They are not too hard and can be turned down using
ceramic insert tools, Set the shaft up in a 4 jaw chuck and clock in an unworn part
I make the new bushes sizing them by allowing for the shrinkage once they are fitted into place by heating the case and
freezing the bush.
So far this has worked for me

John

[bsa-bill]

took mine to a local machine shop - didn't cost the earth

[Steverat]

I will soon have another layshaft to play with as well as a brand new blind bush.

I don't really like the idea of emery on the phosphor bronze bush, I was taught to avoid that since the emery particles embed in the soft bronze and wear the steel shaft down continuously in service. How about leaving the bush at nominal and emery-polishing the shaft down to size instead? I have a lathe and it would be easy to set it up in the chuck.

[berger]

good idea using engineers blue as your guide to see how your doing, or as has been mentioned  the round wood operation guided by the other layshaft bush with some glass paper like I use on armature coms , I'm with you on not using emery , bad practice -------- BUT it's served dutch well up to now

[coater87]

 Hard to do with a cell phone, but pull both bushings out.

 Make a reamer guide that fits in the blind bushing hole, then ream the inner cover.

 Make another reamer guide that fits the new inner cover bushing and ream the blind bush.

 Finally use a bearing scraper and blueing if you need too.

 Hope that makes sense.

Lee

[Steverat]

Lee that sounds great, but how do you ream a blind bush? All reamers have a taper at the lead in  so I would end up with a conical bore. Not the best.

[coater87]

Lee that sounds great, but how do you ream a blind bush? All reamers have a taper at the lead in  so I would end up with a conical bore. Not the best.

 Thinking back to mine, the blind bush was deeper than the shaft journal was long. I dont remember grinding down a reamer or having one modified for quite a while.

 If you get a second, could you measure the depth of your blind bush and the length of the stub on the lay shaft?

Lee

[Triton Thrasher]

The drive side (i.e. blind ended) of the layshaft is so slack, that the other end of the layshaft waggles around a good 1/4" at the timing side end when waggled by hand with the intermediate case off.

Ok, but how far can you actually lift the drive end of the layshaft, in the Bush?

[morris]

Lee that sounds great, but how do you ream a blind bush? All reamers have a taper at the lead in  so I would end up with a conical bore. Not the best.

There’s taper reamers (standard 1:50) and straight reamers. You’ll need a straight reamer for the bushes