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'54 Dominator 88 gearbox

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The gearbox on my bike is stamped GB 3608, does this sound correct for a '54 model?

Recently the box became rather noisy in 3rd gear, under acceleration, then things got worse! I found excessive end float on the main shaft (the whole clutch body could be pulled in, and out, by about 3/16". On stripping the box, the bronze thrust washer was found to be very badly worn, and the steel shim completely missing. As some will know, I live in Spain (where classic bike bits are virtually unobtainable).

Any advice, on sourcing parts, and rebuilding the box, would be most welcome. John.

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Previously wrote:

The gearbox on my bike is stamped GB 3608, does this sound correct for a '54 model?

Recently the box became rather noisy in 3rd gear, under acceleration, then things got worse! I found excessive end float on the main shaft (the whole clutch body could be pulled in, and out, by about 3/16". On stripping the box, the bronze thrust washer was found to be very badly worn, and the steel shim completely missing. As some will know, I live in Spain (where classic bike bits are virtually unobtainable).

Any advice, on sourcing parts, and rebuilding the box, would be most welcome. John.

Hi John ,

You`ll get all the parts nessary for your rebuild from RGM motors in Cumbria,and or Mick Hemmings,

the rebuild should be straight forward,I`ve found over the years the trickiest bit is locating the new bearings square into a stinking hot gearbox

shell with out burning yourself.Making some kind of special mandrell on the lathe would do the job,but somehow I never seem to get round to it.

By the by,the october issue of "The Classic Motorcycle," has an article on gearbox rebuilds,coincidentally using the Norton box in the article.

So there you go; you`ve no excuse now,get stuck in!

cheers,

Alan H.

Permalink

Previously wrote:

Previously wrote:

The gearbox on my bike is stamped GB 3608, does this sound correct for a '54 model?

Recently the box became rather noisy in 3rd gear, under acceleration, then things got worse! I found excessive end float on the main shaft (the whole clutch body could be pulled in, and out, by about 3/16". On stripping the box, the bronze thrust washer was found to be very badly worn, and the steel shim completely missing. As some will know, I live in Spain (where classic bike bits are virtually unobtainable).

Any advice, on sourcing parts, and rebuilding the box, would be most welcome. John.

Hi John ,

You`ll get all the parts nessary for your rebuild from RGM motors in Cumbria,and or Mick Hemmings,

the rebuild should be straight forward,I`ve found over the years the trickiest bit is locating the new bearings square into a stinking hot gearbox

shell with out burning yourself.Making some kind of special mandrell on the lathe would do the job,but somehow I never seem to get round to it.

By the by,the october issue of "The Classic Motorcycle," has an article on gearbox rebuilds,coincidentally using the Norton box in the article.

So there you go; you`ve no excuse now,get stuck in!

cheers,

Alan H.

To add to my previous,The Classic M/C article uses a Norton lay down box in their magazine,the basic princples apply also to the AMC box.

cheers,

Alan H.

Permalink

Previously wrote:

The gearbox on my bike is stamped GB 3608, does this sound correct for a '54 model?

Recently the box became rather noisy in 3rd gear, under acceleration, then things got worse! I found excessive end float on the main shaft (the whole clutch body could be pulled in, and out, by about 3/16". On stripping the box, the bronze thrust washer was found to be very badly worn, and the steel shim completely missing. As some will know, I live in Spain (where classic bike bits are virtually unobtainable).

Any advice, on sourcing parts, and rebuilding the box, would be most welcome. John.

Hello John this is were I can help you here The Gear box you have is a 1954 Dominator 88 gear box My one has GB and a number stamped on it , in side on the main shaft between 3rd and fourth gear there should be a bronze spacer washer and 16 roller bearings that fits in the 4 th gear if you have not got this gear in and it may of be changed at sometime then I have a spare on I can let you have at the price I payed for it has of the lose roller I know someone who may help so stay with me the gear box internals are not easy to get now and there very different to later models also you my find the you main bearing thats shielded maybe on its way out strip the box you will find it easy if you get the clutch off first then the Nut is be hided bass worm at the other end of the main shaft you need this of to take the inner cover off then undo the rod for the selectors dogs with this out the way the hole cluster will then come out ,also check the selector plate sometimes this moves off its splines and then jams up the gears .you can email me at annajeannette@btinternet.com Yours Anna J

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Hi Anna, it would seem likely that I have the original gearbox in my bike. I have had great difficulty in obtaining a manual, for the '54 "88". I finally got one from Mercian Manuals, this claims to cover the '54, but, a lot of the illustrations are for later models. The gearbox section seems correct, but does not contain a lot of information. The bronze spacer is described as a "thrust washer", and it states that the roller bearing has 13 rollers which mine has ( I counted them when they fell out!). The clutch was the first thing I removed, and there was a lot of end float ( which I assume, and hope, was caused by the worn out bronze spacer & missing steel shim). Stripping the box was easy, getting it back together may be a different matter! Regards, John.

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P.S. I have not got the Dommi up to 90 m.p.h. yet, but did hit an indicated 87, on the way back from the Begonia Rally (loaded with tent & camping gear). Perhaps this was the "last straw" for a tired gearbox! John.

Permalink

Previously wrote:

Hi Anna, it would seem likely that I have the original gearbox in my bike. I have had great difficulty in obtaining a manual, for the '54 "88". I finally got one from Mercian Manuals, this claims to cover the '54, but, a lot of the illustrations are for later models. The gearbox section seems correct, but does not contain a lot of information. The bronze spacer is described as a "thrust washer", and it states that the roller bearing has 13 rollers which mine has ( I counted them when they fell out!). The clutch was the first thing I removed, and there was a lot of end float ( which I assume, and hope, was caused by the worn out bronze spacer & missing steel shim). Stripping the box was easy, getting it back together may be a different matter! Regards, John.

Hello john well inside the Sleeve Gear thats the 4th gear There Should be Two Bronze sleeve bushes as well these you can get From RGM Motors also ask them what else they have that may help you out , Yours Anna J

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Thanks Anna, will contact RGM when I have made a closer inspection of the gearbox. I only want to rebuild it once, so will try to replace any suspect parts. Thanks also to Alan Houghton, for his reply.

John.

 


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