jc2

If my memory is correct, I think they require diff spacers tho don't they ??

Hi Guys, Can anyone tell me how much a bare Bantam frame & swingarm weigh please? cheers

Trying to find that issue in Australia - can you tell me whats on the cover please. cheers

I'm a bit of a skeptic about the value of larger airboxes on Ty175s too. I've often wondered if its any more than placebo effect. So long as the airfilter area & inlet pipe (carb mouth to airbox) are sufficient to flow freely at max rpm, its difficult to see how airbox volume would have much effect unless the airbox lid/inlet is quite restricted Patrik, you haven't accounted for volumetric efficiency in yr calcs, which is way below 100% in a 2T, especially one set up for trials with a small carb, small ports & little/no suction pulse from the exhaust. And its even lower at part load, part throttle opening & below peak torque rpm (or above it for that matter). So airspeed will be much lower than you calculate Also, I'm not convinced of the relevance of air speed at the carb throat/venturi anyway, even if you could calculate it accurately. I'd have tho't it more relevant in the inlet pipe, which has cross-sectional area 3.7 times that of carb venturi, or at the bottom plate/restrictor in the airbox which has cross section about 2.7 times that of the venturi. Air speed is much reduced at those points compared to carb throat (since its inversely proportional to area). And as I understand it resonance effects come more from the inlet system volume on the other side of the carb mouth - ie crankcase volume + inlet tract volume (to the carb inlet/mouth). I'd have tho't the main pressure drop (& hence performance loss) in the inlet system upstream of the throttle (carb slide) is normally the air-filter element. In the TY175 that bottom plate in the airbox may also contibute, so some slight advantage may be gained from improving those 2 areas, tho I suspect it'd mostly be at hi rpm. If there was any improvement in throttle response at low rpm, you'd nearly have to be Magic Mick to notice it.

Would it be worth trying with the drive side flywheel removed?

Can anyone tell me if a 250 Italjet top-end will bolt straight onto a 350 Italjet bottom-end, or is there diff stud spacing, diff little end dia etc?

It's difficult to tell what hub it is from that pic but looks to me like YZ or RM. Fairly sure its not pursang. Probably YZ.

David, I'm of that theory too, tho expressed as a percentage rather than ratio. I read years ago (in twinshock era) that footpeg-to-rear-axle should be 29% of wheelbase. Thats what I work on as a starting point. (Tho the modern trend I'd imagine would be different.)

Many thanks Nick

Has anybody got a Fantic 200 cylinder on the bench who could help me out & measure up the port heights for me please? I want to compare specs of a standard cylinder (which I don't have) against another

Hi all, Can somebody measure for me the correct port heights for a standard 156cc cylinder from the 200 Fantic please? (from the top of the cylinder) Thanks

The Husky in the original post was built from an RT360 - probably the worst bike Husky ever made, but at least it had a very torquey engine. It consists of little more than jacked up rear-end, rearset pegs & lower gearing. Bike is well built but enormously tall, more-than-a-little heavy &... well, you can see the limitations. Maico has had new gears cut but is still ony a 4speed. Frame mods are done very poorly IMO. Current owner did not do the mods. Even more limitations than the husky

Are they 247 Cota forks & triples?

Woody, Are they Grimeca hubs both ends on that MAR you rode, pictured above? Also, has anybody got a pic of Micks bike?

Thats the one, & it is Miller frame, # SM 294

Does anyone know anything about the early development Suzuki prototypes of Gordon Farley? Or have any pics? There's one pic each in Don Morley's "Spanish Trials Bikes" & one of John Hulme's volumes of "20yrs of Twinshock Trials" & a couple more with a little info in another magazine on trials, but not much. Of the few pics there, most look like modified TS250 engine & prototype RL chassis, but one looks like its a SherpaT rolling chassis w RL engine & tank (said to be in 74). Its certainly a Bul front end. Also, an interesting bike has turned up in Canada: a Suzuki engined SherpaT (maybe Miller frame) with the interesting engine # TS-T-00001 Is Gordon still alive? Anybody know him? Anybody got any more of the story or other pics of the bikes?

I tho't John Cane was already offering that kit - with 71mm piston (= 198cc) & porting developed by Reg May back in the day. Worth remembering that some people have reported a problem w the kickstarter breaking when you go for the big-bore kits.

Hi Guys, just found this interesting thread. In response to TrialsRfun's post #88 asking where the frame nos are: (I tried to PM him but it failed) I don't know about the 60's trials frames, but the 70s MX frames that made it to Oz have the numbers stamped upright (not sideways) on the front of the steering head, running downwards under each other. (By the mid 70s they were 4 digit numbers - well on the way to being 5 digit) However, some are stamped very lightly so its easy to miss them, especially if under 2-3 coats of paint. But, several frames have no evidence of any numbers at all & no evidence of them having been ground off. Love to see more pics of the early Trials bikes

I think you'll find Feetup's swingarm is lengthened 45mm not 75mm

Has anyone investigated if any V-Force reed valves will fit the twinshock TY250? (with or without modification)

Hi, Can anyone tell me the wheelbase, ground clearance & seat height specs for Cota 200 please? thanks

Yeh I know Dave, but they don't seem to have everything listed. I've read in a couple of places (what seems like ages ago) that they were about to have em for sale. I assumed/hoped, perhaps wrongly, that they must have been out there by now. (And as you know, a phone call from down under aint cheap.) In the pics I've seen of the TYtrials 175 in CDB & YOU HAVE USED WORDS OR A PHRASE WHICH ARE NOT PERMITTED ON THIS WEBSITE. PLEASE DELETE YOUR POST/TOPIC. DO NOT TRY TO CIRCUMVENT THE FILTERS IN PLACE ON THIS WEBSITE the pegs look lower than the SM ones (which don't seem much diff to std). Does anybody know if/when they'll be available (if not already)?

Is anyone using the TY-Trials footpeg lowering kits for either TY175 or TY250? How do they compare with the SM ones?

Can any Monty experts tell me if there's any tricks to removing the swingarm's pivot sleeeve (on a late 247)? The swingarm is out of the frame & the pivot shaft/bolt is also out. But when I try to remove the sleeve, which presumably should just slide out of the bushes, it wants to 'pick up' the bush & push it thro the other side (whatever side I try) & basically just seizes up. Has anyone had a similar problem & resolved it? Am I missing some basic 'trick'? Or is it just a case of using more force?

JMcK, I don't know what you are looking at. We are not talking about adjustable triples. We're talking about triples where the bottom one has more offset than the top one so the forktubes are kicked out about 1.5deg more than the steering stem. Most 70s twinshock trials bikes had it, including the TYs & SherpaTs.