Sprockets on my Domi 88

I want to get a little more speed out of my 58 Domi 88. I ordered and installed a 20t sprocket for the transmission. Then I remembered I had some engine sprockets so I am thinking about installing one with 20t on the engine up from 19t. Do you think this is a good idea or should I leave it as it is with the 19t engine sprocket?

John in Texas

How fast can it go in third gear?

Hi , according to Roy Bacon, 56/59 , domie 88 have 20x42 primary and 19x43 rear, so why not ..........! overall will be 4.75, with 20x42 and 20x43 that will give you 4.51, may be too much....best way is to try 20x42 primary first and test , if your revs are still OK , you could try the 20 teeth on gearbox sprocket and see , but I had never ridden a 88 , just a model 7 long time ago and it was a sweet bike !

marinatlas said:

Hi , according to Roy Bacon, 56/59 , domie 88 have 20x42 primary and 19x43 rear, so why not ..........! overall will be 4.75, with 20x42 and 20x43 that will give you 4.51, may be too much....best way is to try 20x42 primary first and test , if your revs are still OK , you could try the 20 teeth on gearbox sprocket and see , but I had never ridden a 88 , just a model 7 long time ago and it was a sweet bike !

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It is a very sweet bike not over stressed in the least. This coming spring the Zia chapter of the AMCA is doing a ride across New Mexico from Clovis to Alpine Arizona and I want to keep up.

John in Texas

For a long time Norton used a 19 tooth gearbox sprocket on pretty much every bike. The normal way to alter the gearing was by changing the engine sprocket. This is much easier to do than changing the gearbox sprocket. Using the gearbox sprocket size to alter gearing came with the Commando as using a triplex primary chain made changing the size of the engine sprocket impractical.

The added benefit of changing the engine sprocket is that each one tooth change is a less severe change in gearing than one tooth of the gearbox sprocket.

I presume you want more relaxed cruising rather than more speed? I don't think it would be a good idea to run a 60 year old bike flat out for long periods, unless you are prepared for the possible consequences.

Ian

Ok it’s not a top speed question.

An old 500 might keep up 70 mph if in good condition and all the frame fasteners are wired or Loctited.

Messing with the ratios isn’t going to change that much.

Running with old Harley 45's isn't that hard and in all the years I have owned the bike I have never abused it. A 60 year old bike doesn't deserve to be abused. The point of higher gearing is to get a bit more speed while having a lower rev on the engine.
John in Texas

A lower rev on the engine can be a bad thing.

Point taken, I will consider and confer with Comstock and get his take.
John in Texas

Emailed Jim and considering that I'm just going up 1 tooth from stock on the transmission he didn't see any problem. Checked a 57 parts book, don't have one for 58 and it lists a 20t engine for a Domi 88, The transmission sprocket while listed doesn't give a tooth count. But I feel safe only going up 1 tooth.
Thank you all for your input.
John in Texas