Hitchcocks Forum

Merry Xmas and a prosperous 2018, I am pleased to see from recent posts that some people are doing some things for the first time, because that is where I find myself. So sage advice please.
I have been reassembling my 1961 500 twin sports. The gear box has been previously restored and a look inside with out dismantling looks ok, how ever there is some movement (slop) in the main shaft. For the lay shaft to rotate the main shaft means it has to be in the correct position, which also means the clutch basket will sit off the inside of the primary case by 2 or 3 mm. Does that sound right, and if not what is potentially wrong please ?

Sorry Peter but I don't understand the question. I would define "slop" as up and down movement in this location, do you mean that or that the mainshaft can move backwards and forwards lengthways? If so, that would be called "end float" and it isn't something we want on the mainshaft! I'm not clear what you mean by "layshaft rotate the mainshaft" and also what the "2 or 3mm" issue is; what does it clear or not clear and what's your concern if it does clear? Two questions, have you got the scissors clutch fitted (original fitting for a 61 MM) and is the gearbox and clutch fully assembled or only part built at this stage?

REgards, Mark

Hello Mark, the main shaft has end float of 2 - 3 mm. The clutch is the original scissor clutch with new plates. The gear box was on the bike and I reinstalled the clutch. The clutch action worked fine.

So I thought the best thing to do was to take the gear box out of the bike and start from scratch, which will be a good learning experience for me.

Peter, 2-3mm end float is a little excessive but not much, you'll never get it to zero due to the rather sloppy design of the clutch itself. However, the gearbox was designed for some adjustment, this was achieved by adding shims under the oil thrower washer (H71 I think in the parts list,) in the engine timing side end of the gearbox. This is the large stepped washer under the LH thread nut. Unfortunately these were never illustrated or listed in the Parts Book or shown in the Workshop Manual but Hitchcocks have them if you contact them direct. Hope this helps,

REgards, Mark

Invaluable Mark, thank you, I will follow it up with Hitchcocks. The gear box is out, the gears appear to be in good condition as are the shafts. Everything is there and the correct way round etc. I will advise progress.
Regards, Peter

Peter, something to check while the gearbox is apart: check the mainshaft sleeve G2/8. In the late 50s the design of this sleeve was changed. The later type has a long thin phosphor bronze bush inside, this bush can move (rotate) and close off the oil relief holes that are drilled through the sleeve. If there is any sign of this having moved, replace the sleeve gear complete, it is not practical to replace the bush. Movement of this bush only seems to be a problem on the big twins and I suspect a Meteor Minor might not have enough power to cause this. I keep a stock of the earlier solid sleeve gears which I swap from earlier Bullet boxes (the Bullets don't seem to put enough stress on the sleeve for this to happen) and replace any bushed sleeves I find on Twin gearboxes. Once the box is rebuilt the use of a modern multigrade gearbox oil will protect it much better than the oils that were available when they were new. And don't worry about the oil eating phos bronze bushes (someone is bound to come up with this old warhorse) as modern oils won't do this. By the way, I'm working on an early Meteor Minor myself at the moment.

REgards, Mark

Mark M, what "eats" phosphor bronze is molybdenum disulphide additives, which are not normally in oil anyway.

Papa, you are of course right, but that doesn't stop folk repeating the old wive's tale which is what I was referring to!

REgards, Mark

Mark M, that is why I did add EP120 to the gearbox of my Electra X until I found out there is no phos bronze in that gearbox.
The EP 120 I added to the EP90 does have Molybdenum disulphide in it.
I can now select neutral with no problem.
(That is my decision and am not suggesting or recommending anyone else do it.)

I know I'll be shot down - but never mind that! I'm extremely skeptical about these theories of this or that lubricant attacking this or that metal. Almost always my experience has been that nothing of the kind ever happens - and that no one has personal experience of it ever happening. Dont' worry - and molybdenum disulphide to the best of my knowledge is in any case almost inert.