Greg Brillus Racer

davidd

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Greg has been working away at building a twin racer. He is now at the point where it is starting to come together. I offered to post some photos for him. These first photos are of the front links and steering stem. Greg was inspired by the "Comet Suspension" thread in which we all discussed the Girdraulics in stultifying detail. He is using the TT made steering stem that was inspired by John Emanuel. He also did a roller bearing and needle bearing conversion to the links.
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I will post some more photos, but I am sure there are some questions and I will turn it over to Greg for answers.

David
 

greg brillus

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Thanks for the photos David, As some of you will know from the thread that was discussed in huge detail re the Comet suspension, this is a take on the subject, and now awaits testing. The whole concept is based on the bad handling characteristics of Girdraulics, backed by the fact that so many owners have suffered some bad and some really bad experiences. The main problem as discussed with Girdraulics is the spring set up in standard form is way too stiff, especially if you are a fairly light rider such as myself, and secondly, the position of the links by comparison to Bramptons is not good. Although there are many of you who are still to some extent very wary of Girdraulics, there are improvements that can be made, and some quite inexpensively, that can reduce the problem. The modifications I have done to the links are to reduce the high level of friction that exists, particularly in the eccentric bushes. The new steering stem has been redesigned to position the rear of the lower link down and aft. This will put the lower link in a similar position to that of the Bramptons lower link without the need to drill extra holes in the fork blades......A mod that most Vincent owners would likely frown upon. These mods and many others I will go through as I assemble the suspension, and the tests will be conducted on the race track. I will go through other details of the bikes build up as I go, but the suspension topic is one that I and a few of you have been interested in. The other benefit of this mod will be to retain as much travel as I can, and to create more ground clearance. The rear of the bike will be lifted, but I will go into that later on. I am using a single coil over shocker unit at the front ( where the original shock absorber was) and the rear. Some of these mods are nothing new, only the entire collection of mods.....may be. Cheers......Greg.
 
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greg brillus

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Hi there Bill, I knew this would interest you as you have been particularly interested in this topic from the word go.....to answer your question, yes they can, only the needle roller conversion requires the bores to be opened out about 2 mm. This could be a reversible mod, but larger bronze bushes would need to be made.....frankly, once done you would not convert them back. For a road bike I think the main benefit would be to replace the eccentric bushes with sealed bearings as I have done. The eyes only need to be opened out very little, and would easily be reversible. We were able to literally hone the original holes out to suit the bearings. The stainless hat section "Hubs" if you could call them, took a little redesigning from the originals that Norman (Timetraveller) had made, as his were to suit the original bronze eccentric bushes. If you look at the top photo, you will see the original type in the foreground, and the new ones to suit the bearing mod sitting next to the stem. Thanks for your interest..........Greg.
 

vibrac

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I cannot tell for sure are the FF7 replacements concentric or eccentric? I am nor sure from the photos if concentric if it is I suppose the FF9 & FF8 go in the bin as well
 

Bill Thomas

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Hello Greg, Can you give us the numbers of the needle bearings , Do you run them on to the bare link or do you bush them with something ?Many thanks, Bill.
 

timetraveller

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The FF7 replacements are concentric but that is not the whole story. Their centre has been moved down and backwards to give a geometry whereby the movement of the front wheel spindle is more like that produced by telescopic forks. Upwards and backwards unlike the girdraulic 'S' shape motion. Remember that what counts is the position about which the lower spindle pivots. That is variable with the standard set up; which very cleverly modified both that and the spring pressure.
The FF8 and 9 are also redundant. Please note that all the credit for the new geometry is with John Emmanuel who very generously allowed me to borrow his modified steering head stem. I then designed what I thought was required to fit to these stems to allow the original lower spindle bushes and top spring box mountings to be used. Shims were also provided to allow sideways fitting of the standard bronze/oilite bushes. From the top photograph you will see that Greg has had to reduce the diameter of the eccentric replacement in order to get them to be a good fit to the inside of his needle roller bearings. Although most of us no longer wish to race we should all be grateful to people like DaveD, John Em and Greg who are prepared to put their money and safety at risk because if the new system is both safer and more comfortable then we all benefit and the mods would not be noticeable to all but the most knowledgeable of viewers.
 
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Black Flash

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Just out of interest, can you tell me what kind of bearing you are using in the lower link instead of the bronce bushes ?
From looking at the pic I cannot see what kind /type you are using

Bernd
 

greg brillus

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There are actually two bearings per side, if you look at the last of the first batch of pictures you can see the two side by side. I will get the part number, or size of the bearings to you all soon. They cost about $85 AUD for the four bearings...these are a sealed bearing. This mod is a worth while one especially with the new steering stem. The needle rollers will work well, but you need to use ground steel spindles, not stainless, as the stainless ones will end up with grooves from each roller needle.....I am using titanium spindles which I hope will handle the needle rollers. The side thrust will be taken up by making some simple bronze thrust washers like the Brampton ones. I will grease them on final assembly. I do not think the needle bearing conversion would be so necessary on a road bike, the set up to machine out the bores of the links is time consuming and expensive, but the bores of the eccentric eyes is not hard, and only needed honing out a few thou. The problem I'm sure you would all understand is doing a "One Off" job like this is an issue, but if several were done, the cost comes down. With the lower link assembled to the stem, the link rotates up and down beautifully with no friction at all. The next batch of photos, shows the engine and crank before final assembly. The crank was built entirely of new parts, and uses RTV flywheels, stepped main shafts, heavy press fit caged big end, and new Argo connecting rods, the latter are made here in Australia, and use the same beam section as original Vincent rods.....I prefer this to the heavier Carrillo rods, and these are the rods that Terry Prince is using in his cranks now. The visible counter weights on the wheels caused me to have to remove some material from the drive side webbing visible in the second photo. Those with a keen eye will note the 5 speed gear cluster sitting on the bench, this was one of the ones Terry did years ago. Reg told me I was mad using 5 gears instead of 4, but I think the box will be smoother and give a better choice of gearing on the corners......Heck I can always put the 4 back if I don't like it. If you are wondering what the small damage is inside the case, this engine had tossed a rod earlier in its life on the right side. This has required a fair amount of repair work to true it all up......Oh and by the way....the total run out on the mainshafts is 0.0003 That's right three tenths of a thou, so it should be nice and smooth, Cheers for now........Greg.
 
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