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trackbike


dorset

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okay

you folks have got me hooked on trying out track days. but i don't have a machine to run that way, so i'm gathering up parts for a 650 triumph, because that's what i understand. got a frame coming from georgia, and a rear section i already have with fuel and oil tanks, pegs, motor mounts, tin ware, controls and instruments, an ignition and carburetors left over from another project, and even a seat. no wheels until i found a guy north of detroit who had these:

E850OZY.jpg

two twin leading shoe front wheels in the bunch, plus a couple of 50s-60s front wheels i can flip to pay for what i needed out of the lot. there was more i brought home, but the 60-year-old stuff isn't useful for what i need here, except to sell on eBay to help pay for it.

the motor and head are street-tuned stuff i have left over from the mile bike. if i put in a hotter cam along with a rebore, i might have something that can hold its own in the corners, although the straights will be a totally humorous matter.

most of the fork assembly is coming from northern california, a late 60s unit with rebound damping. hard to get those these days, so i'm building it up with old hard parts and new tubes.

this will be a slow-motion build, as i don't have time or money much to spare, but it will happen.

stay tuned.

Edited by dorset
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2 hours ago, what said:

You might have something to race at vintage days once this thing is together. 

you're right at that. i was originally going to build a 750 and put a disc brake on the front, at least. but then i thought, well, maybe it would be interesting to compete with it after all. for the AHMRA stuff, the machine would be in "classic sixties," which nixes increasing the bore, and limits the machine to period brakes, suspension, and carburation. that puts some pretty severe limits on things, but the forks are in pretty good shape, anyway:

eWxpZUbl.png

just need some tubes and new rubber bits

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  • 2 weeks later...

frame!

nG2R7NPl.jpg

a 1965 TR6SR frame from a brit in georgia. the TR6 was the single carb 650, SR means that it was a roadster frame, as opposed to a scrambler. identical except for the numbers to the two-carb bonneville engine, which will bolt right in. here's a TR6 about that same age from hollywood:

 

Edited by dorset
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32 mm carbs-- VM mikunis

aig9kvQl.png

got these cheap from a a friend of mine who took them off something odd he bought. i've been running round-slide mikunis on various machines for years, so i have pilot and needle jets, needles and main jets. plus some extra slides with different cutaways. the mikunis are easy carbs, very similar to the later british amals, mostly because the companies  merged back in the 1930s and shared technology all the way into the 70s.

Edited by dorset
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  • 2 weeks later...

well, the shop is 25 F, so work is sporadic, but i've gathered enough bits to make a stab at something. the front frame is a 1965, the rear fram is 63-70. i have a 1970 650 motor with a fresh head, although the motor will have to come apart. forks from a 69-70, fuel tank, oil tank, and miscellaneous bits left over from the mile bike that i didn't use:

NRgOpyel.jpg

ulHU8Bhl.jpg

 

Edited by dorset
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rocker assemblies from something or other will work fine with the head. the head itself is stock, with just oversize valves and beehive springs good for far more lift than the current camshafts are capable of.

cunrWzGl.jpg

got enough bits to put a clutch and primary drive together:

ZlV9O0al.jpg

and an electronic ignition module to fit alongside the early battery box. i thought about running a fixed-advance magneto, but i already have the ignition, so we'll try it for starters.

Gwm3AIzl.jpg

i'm running a four-speed gearbox on the mile machine, but i thought about converting it to a five speed, which can be done by hand with a dremel, if you have the right parts. these are from somewhere in the 1970s, and may be a better choice than the existing four-speed for a track bike.

2Bb4kXUl.jpg

the pegs won't work, as i'll have to come up with rear sets, but the motor mounts will work either way. these are chromed, from some forgotten chopper years ago.

SJePu4Sl.jpg

i tune with a stopwatch and an AF gauge. the numbers from the gauge aren't really useable without calibration, but once i establish baselines with a stopwatch, the oxygen sensor is invaluable for repeating the mixture settings under different situations.

NPBLiwxl.jpg

tach doesn't read below 2000 rpm, but that's okay, as all the tuning there is by ear anyway.

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and then i have some fiberglass. something to sit on, and something to tuck in behind.

HbAV70Xl.jpg

Lk8fFR9l.jpg

lot's of separate bits at the moment, but when things warm up i'll accelerate the build.

 

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