Triton racer gearing and more.

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So I’ve been sorting out an old racer it’s interesting running Grayson cases and about 830cc. I’ve got a 5 speed triumph cluster in a box and could do with some advice on the gearing. I’ll be running a triumph conical rear which I think the lowest I can go down to on the sprocket is 46/45?
I will ride it on the road but want it good for the track. I’m thinking a 22 engine sprocket (Norton crank) 21 gearbox sprocket (cant find a 22 but), standard clutch basket and then go up a bit on the back wheel. Which would then give me easy up or down fine changes?

Has anyone ran a similar set up and can advise me please?

Also thinking of running 2 34mm Mk2 concentrics (have a set of 30’s) any tips on jets would be great.

Thanks
 
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1 , 2 , miss a few . 99 , 100 .

Thats a lot of fancy numbers !

The Pre Unit , single row , a 25 T was a option .

Id gear it for 100 - 110 in third. 140 at redline minimum .
depends if its a tourquer or a rever , as to teeth .

Wots yer inteded RED LINE . 7.200 was Std. knorton , seeing thats the crank .
A triumph will rev a mite past that .

32 carbs'd likely be adequate . the olde 1 5/32 or 1 3/16th . Unless your runing methanol .
Av Gas might liven it up . alow more juice & spark .

I suppose its even got mufflers .

I.o.M. 650 ran 145 + . so a tad past mightnt hurt . If the wheels are bolted on tight .
 

Chris

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Hi Lanks
Stacey Kilworth ran this set up with BHR & CRMC for many years. Fast bike fast rider. He is on facebook.
Also Fast Eddie on these pages ran a big 8 valve T140. He might be able to point you in the right direction.
Chris
 
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Just saw you other querie . Inane speculations await , there .

Need to see some pictures of the machine .

Setting up so you present minimal frontal area , tucked in comfortably , is important , up past ' the Ton ' .
 
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Your gearing depends on the circuit and whether your motor is built to deliver top end power or built to deliver torque. Triumph motors last much longer and go faster if they are built to pull hard rather than gain power by increasing the revs. (do not over-port the cylinder head). If your motor is built to pull, you will not know how fast your bike will go until you raise the overall gearing, but in saying that, you need close ratio gears to get maximum acceleration up through the gears. The close 5 speed Triumph box is pretty good, but there are two pairs of gears available which move 2nd and 3rd gears closer together and up towards 4th. For a small circuit, I would start by running a 24 tooth engine sprocket, 18 tooth on the countershaft, and 38 on the back. But what you use on public roads will probably need to be very different to what you use on the track.
 
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Don't know what all those sprocket numbers add up to, but the 830cc engine suggests some extra power and especially torque, so my experience may not translate. On my 750 5 speed racer, when I used a Triumph spool hub rear, I got two brake drums with integral sprockets, one with 46 teeth, one with 43. With a 20 tooth counter, and a 2 to 1 primary ratio, that gave 4.6 and 4.3 gearing, respectively. The 4.3 was right for Daytona, or maybe Willow, or maybe a few other fast places, Roebling say, and that was about all the gear it would pull, hi 120's mph at 7300 or so at Daytona. But that much gear made first fairly tall and slow off the line with lots of clutch slipping to get going, and also lengthened second perhaps too much and made the gap between second and third noticeable. For most tracks, I used the 4.6 gearing--that gave a shorter first for starts, a shorter but raceable second, and less noticeable gap to third, and let me use third in tighter corners, and was all around faster. The bike spends only a second or two or three at most tracks at peak revs in top, so the benefit of tall gearing is limited, but it sure went around the track quicker with the gearing shortened to 4.6--and I think the game is lap times, not top speed, most places. Don't know what sort of engine you have, but your optimal gearing may be different than 4.6 with all that displacement, you will have to try your gearing out to find an optimum. The trouble with this whole stock parts setup was, it was very heavy, and difficult and slow to change, and did not offer ready options. Simply put, it was a whole bunch of cast iron on a race bike.

Not that you care about this part, but then I got rid of all those heavy and limiting stock parts, put Newby belt drive and a Barnes dirt track quick change hub on the rear, with narrower 520 aluminum sprockets and lighter 520 chain, and with the different Newby primary ratio, I was able to use smaller, lighter sprockets both ends--18-38 for 4.3 gearing if I remember correctly-- and as a bonus I could shorten the chain several links, and with these changes I lost more than 10 pounds of weight in the rotating drive train and got far more gearing adjustability, changeable easily and quickly in the pits. I still didn't vary greatly from 4.3 to 4.6 gearing, but moved around in between more. For what it is worth.
 
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