Vintage Brake can make those 4LS brakes work quite well.

grandpaul wrote:Vintage Brake can make those 4LS brakes work quite well.

No doubt this is true but if you are going to spend your money, spend it where you need to go. I would focus on a good disk brake set up, available, light weight and easy to maintain.

Matt Spencer wrote:AYE ; looking at the racer test , thart ' 69 ' model has the new fangled timing cover points assembly. ( same set up ) Likelyhood its a ' Build ' rather than OEM
but you dont take it for granted .
http://www.dunlopmotorcycle.com/tirecat ... y.asp?id=9
Heres the dreaded Dunlop Catledog , TT100s are still in production .



This is the old front raceing tyre form around 65 to 75 , pre ' Slicks ' , Michilen PZ2 & Perrili Phantom . Manxes , F-750 Triples & Nortons and every other man & his dog , back then .3 compounds HARD isnt gripy .



You can see the ' TRIGONIC ' nonclementure related to the cross section , short stiff sidewall & oodles of rubber down , leant over .TT100 is road derivitive tho ' R ' spec one is more like it in the carcase .



The ' R ' stamped case is the uprated race carcass that alledgedly allows a Goldwing to cross death valley at 100 mph without poping . Caseing is stiff race type.
for the old drag the ears round the bends brigade . 3.60 & 4.10 19 std , but 4.10 19 F & 4.25 18 R later used ( Thruxton motorcycles 78 & 81 I.o.M. machine .

The others may well be faster , but the chassis suits the original spec in youre into drifting .Meaning to get Pics of a Old Trigonic KR 76 ive got , max tread
on tarmac way over , min upright for less drag - better speed . TT100s ( K81 ) were the roadtrigonic type . Was thought at the time the KR tyres that theyd bend most other than Manx chassis , andcause wobbles . So the KR 76 3.00 19 F & 4.10 dunlop rear initially , but by 74 on the Tridents they ran the TT100
on the front , a 4.10 . 2dy walk down memory lane .

Theres a few areas on the engine to pay particular attention to , includeing a 7000 or 7500 rpm redline . But obviously a Half centurie old so some consideration
to see nothings ' off ' is adviseable .32 mm Carbs in theyre 30s now may slip in , if 34 or 36s wont . The fancy Amal race intakes were worth a few HP & the
bleed arrangement meant the floats didnt misbehave at sustained maximum rpms if youre looking at long tracks .

Not an enourmous component count compared to the newer 4 cyl rice burners , but the bits are bigger . If the fits are right itll stop them rattling around and
parting company .Make haste slowly is probly the maxim , if your not sponsored by Sheik Yamoney .Aeroplane fitter / riggers from the WWII era is the required
mind set . Exactitude & Patiance .And itll go faster if you polish it .

Matt, that tyre is a Triangular, a KR76, a 3.00 is suitable for a WM2 1.85" rim, the TT100, or originally K81 before Uphill's 100mph TT lap on his Bonnie was indeed Trigonic a word Dunlop made up to describe the rounded off triangular profile.

A PR will have run on TT100s, most used 4.10s front and rear, I favoured the slightly better steering of a 3.60 on my Fasback production racer.....very few people I knew ran a triangular other than on an open class racer.....and then they ran with either with a triangular rear 3.50 KR73 or later with a round profile 3.50/4.50 KR83 intermediate.....and when they started moving on to 18 rims in the late '70s the triangular disapppeared.....

If you want to run it like it is TT100s won't limit you too much whilst your are learning track etiquette. First thing is to get it running as best it can without modifying it, except make sure your clutch is not overloaded with oil, your head bearings and your swinging arm bushes and pin are good and that isolastics are set tighter than for rode use,a little tingle in the pegs is about right, then....

As far as I know factory PRs did not use drum brakes, so I suspect it is a look alike, so to complete the look best to fit readily available Norvil single disc front end with AP race caliper, should stop fine, I rode on at Cadwell in late 2010 and it was fine when we changed the pads for newer stock. You need to chek out US rules before yoy go fancier than that on the front brake. Whilst you are at it with a new front hub this is teh time to go for 18" alloy rims and use Avon AM22 110/80 race tyres, though Dunlops seem more popular with some in US racers, probably warmer and dryer at most tracks than in UK, but the Avon have good grip and wear well.

Leave the rear drum as standard, just lace on the new rim and replace the cush rubbers, try some better shocks and refurbish front end completely, as noted Landsdowne dampers would improve it and look fairly stock. Though you might want to ride it with just a refurbed front end before you invest in improvements that depend on your ability to set them up!

Progressively dump the chain for a belt drive, earlier if you get clutch slip, though that will be improved with teh right plates, clean and minimla oil in the case. Dump the alternator and go 40mm if rules allow, or just change 30mm belt a lot, my suggestion is up the primary ratio at this time, but up to you, of course you will need to change final drive to suit, but you are going to be playing with that anyway if you are fitting 18" rims.

You can run the motor near standard and have a lot of fun, or go PW3 cam and better pistons and a minor clean up of teh inlet prots around the back of the valves and 3 angle valve grind....of course you can blow a lot of money, but....from your comments you need to gain a bit more experience before you do that...what you should consider is...

Carbs...match a pair of 32mms with genuine Amal velocity stacks, but get the carb bodies carefully turned out to 33mm, most '70s proddy racers did, works better than bigger carbs for most people...and get some proper peashooters!...as loud as the rules allow...

Bryan,

Your bike looks very much like the one I picked up from ebay two years ago. Mine also appeared to have been off the track for 10 years or so. It turned out to be a very nice bike, built by Herb Becker no less, but there were plenty of minor things that needed fixing after 10 years of neglect. I wouldn't worry about changing anything; just make sure it's safe and go racing. You'll find out what you really want to spend money on and what you can live with.

What's safe and what isn't? My main concern was the miles of "rubber" tubing pushed on to plain metal stubs, fastened with hose clips and the potential for them to empty oil onto the rear tire. The drum brake isn't going to kill you, but take it easy until you get the measure of it. 10 + year old tires? you know you should replace them, but having said that I did find myself taking the bike out in practice with a 15 year old rear tire (kept in the dark) and having no problems at a "knee-down" pace.

Don't forget you're going Vintage racing and the most important thing is to get out there with your old bike; being competitive is optional.

Cheers! ~ Gary

Interesting profile to me as when I let my fronts wear down on my Cdo's 100-110's or 120 on my SV650 they end up wedge slab sided with about 1" flattened center. If was me I'd run 100 on front and 120 on rear in softest compound sold and get at least two rears at a pop. Raciing = wasted money = intense living time while ya can.



Anyone who races on unknown insides w/o going completely through it is asking for bad juju. Heck even just puttering around on unknown insides can bring on a ruined engine when everything seemed perfect just the instant prior. Ugh.