Greg Brillus Racer

greg brillus

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The hardened ground steel ones are available, at least from Neal Videan here in Australia. I will be away for the next three days, so I will continue the discussion when I return. However I have at this time assembled the crankcase and all its contents, the 5 speed cluster, and all belt drive primary/ clutch assembly to which I went to a bit of extra trouble to move as far inboard as possible, this so the primary cover(yet to be made) will stick out as little as possible.....approx. 38 to 40 mm....trying to work out weather to cast one up or machine one from solid alloy....not a fan of the sheet metal ones, even though they probably work ok, I just think a twin deserves something nicer....that's just me. Cheers for now..........Greg. PS: more photos to come soon.
 

timetraveller

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Just a thought here Greg. Several years ago at a French rally I saw a twin with a fibreglass replica of a twin primary chain case and clutch cover. All moulded in one piece in black and fitted to a Shadow engine. Very hard to spot that it was not original and it was fitted over a belt primary drive so there was no problems with potential oil leaks The GRP did not seem to mind the heat. It would not be a big problem to make a mould from original parts and then make copies. Easier, cheaper and quicker than milling one out of solid, unless you have access to both a scanner and a CNC mill that is
 

davidd

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I have to admit that I am partial to TT and Max's idea of fiberglass. I have used fiberglass primary covers for years on the racer with great success. Although there is a bit of work in the plug and mold, once done the parts are generally quickly made and cheap. Considering that the likelihood of damage is relatively high, it is a great solution. Unfortunately, I have only made covers for singles or I might have been able to talk Greg into using one.

The first photo is a copy of the stock cover. The second shows that I made it much deeper so it could be used with or without an inner primary cover. I made a jig to drill four of the original mounting holes to hold secure it. They would be counter-bored like the originals. I had planned to use the existing cap hole to check belt tension, but a cap could be mounted also. The third photo is the cover I used on the racer. Mounted by three tabs (only one is visible in the photo).
Prinary Cover pb_25.jpg
Prinary Cover pb_26.jpg

Primary Racer_PB_1.jpg


David
 

greg brillus

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That's a 250 Lb. spring at the rear and a 190 lb. spring at the front. Axle is approx. 2.5 inches lower than swing arm pivot. Steering damper is going to be mounted better than this.....Just a trial fit of some parts at this stage. The new Joe Hunt magneto hangs out the front a bit, but I'll fabricate the front exhaust to sit neatly around it. These are not the race heads I am using, just some stock ones to see how it looks. Next to modify the fuel tank, to clear everything............Greg.
 

timetraveller

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Hi Greg, if you look under the base of the new steering head you will see that there are three tapped holes. Two are there to allow the lower bearing to be jacked off the steering head stem but can be used for other purposes. The three of them together can be used to mount an additional plate with a hole to take the front end of the steering damper. This means that if necessary you can position the front of the damper more or less where ever you want. These days it would be easy and cheap to get such a plate laser cut out.
The other thing which I guess you will already have thought of is to put in a bare wheel and/or mudguard at the front end before the spring unit is fitted. This will allow the full movement of the wheel etc. to be checked for clearance on the front cylinder or exhaust pipe etc. before you have to fight the strength of the spring. It is looking good.
 

greg brillus

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Norman thanks for the help, I also want to do a check on the axle path, as it is very easy to remove the spring from the shocker unit. I have just picked up the remaining parts from the paint shop, including the front blades, so now I can assemble the front end for more checks. To add extra support to the original upper shock mount lugs, I am making up some simple saddles that clamp to the handlebars in between the two original vertical mounts, these will then extend down and either side of the upper shock mount, whereby a longer 3/8 bolt will complete the upper fixture......hopefully with a little more strength and piece of mind. I spent some time today modifying the fuel tank ( an Indian Repo not an original) this to clear the front cylinder TT carburetor main body and the bellmouth. It came out quite well, with only a couple of leaks to weld up....I found the oxy welding worked really well, haven't done it for years, the MIG welder spoils us a bit these days. For those in the know....Would it still be necessary to use the tabs at the rear for the lower tie through bolt...? I suppose the vibrations would still be an issue for a racer, even though it's use is minor verses a road bike. The only other mod to the tank may be to remove a section to clear the steering damper, as I want to keep it up and out of the way......And not so noticeable...some may think this is a bit over the top, but that is the kind of detail that has gone into this bike from the offset.
 
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