feetupfun

Best option is to get someone who owns a similar bike to listen and ride it. Next best is to make a video (with sound) and post it somewhere we can down load it from.

If you are running 428 chain on your TY175 then yes a 16 tooth front sprocket will fit. I used to run a 16 front 51 rear combo on mine when I rode it to work and it would do just under 100km/h on the freeway. Pretty useless on hillclimbs though.

For a standard bore size TY175: Thin head gasket Boyesen reeds Reed case spacer WES two piece exhaust A big bore (205cc) also improves things over standard but if you are going that far with motor mods I wouldn't lighten the flywheel until you are finished.

Dear oceanvibe In the last 10 years I have sourced many parts for Yamaha TY175, TY250, Kawasaki KT250, Montesa 348, OSSA MAR, Bultaco M49 and M198. I've had no experience with bikes that became popular after 1978 like SWM, Fantic and Italjet. Bultaco parts are generally the most abundant but other popular 1970s trials bikes also have their parts suppliers in different parts of the world. There are good suppliers for Montesa parts in the UK and the USA and the same goes for OSSA. Very few genuine parts are available for the Japanese bikes but there are very good reproduction parts available. If you buy a bike that is complete, you can be sure to be able to get it up to competition standard. If it is a popular model, missing parts can usually be sourced from wreckers and on eBay. My advice is to steer clear of buying any model that was rare in its prime, no matter how cheap it seems, unless you thrive on a challenge.

The steering stem is intended to shear before the forks or frame get bent. Instead of forking out big $$$ for new frame or new fork tubes, the steering stem is relatively cheap and easy to replace. Yes making a steel one would probably stop it shearing in a similar crash but if you want a trials bike to weigh 65kg, easily damaged chassis parts are part of the deal. Alternatively the same part could be made from titanium at huge expense but who would want to pay megabucks for a trials bike that was slightly more crashproof?

If you are ever unsure, drain and refill. Level too high or too low in service is bad news.

Hi Mike If your vice is too small, a large G clamp and two blocks of 75 x 50 timber about 250 long usually works for me. David

Yes it certainly is possible to fit the rear wheel from a M137/138 Alpina (or from a left shifting Frontera or Pursang) to achieve a brake drum on the right hand side. The penalty paid for this arrangement is a rear wheel that is heavier than the original M199A wheel because of the different hub design. You may find the rim is a bit wider than the Sherpa rim too depending on which donor bike it came from. Steel LH shifters are easily available.

Dear Austini I didn't need a lobotomy, being born here in OZ. I have found though that the heat does tend to gradually melt ones brain which is probably a bit similar to having a lobotomy, but slower. Anyway, about the fasteners, I have seen two Beta Rev3s, one TY250Z and one Scorpa SY250 all suffer from the frame screws and brake disc screws coming loose in use. I don't think it is a problem confined to SY250s. David

Don't ask me why it works but it does. Instead of loctite on these threads, use a thread antisieze compound.

Hi James I suggest you might get more response if you post your 349 queries in the twinshock forum. I would say it is very likely that the 248 front end would fit your 349 provided you use an axle length and wheel that matches the width of the fork tube spacing of whatever clamps you use. David

Mich Lin Are you having a bit of a lend here? Do you really carry a handgun when out riding? Where I ride we have snakes that leave anything in the "Wild West" of the USA far behind for danger to humans (Australian taipans, eastern browns, and tiger snakes in particular are quite deadly while death adders provide a similar risk of death from a bite to the US rattlesnake) yet all most people do is keep their eyes open. People who like to take precautions carry constricting bandages and some form of hand held communications. Please tell me the snake shot gun thing is really a joke.

2001 Rev 3 270 should have come from Beta with a hydraulic clutch. Betas have had hydraulic clutches standard in all Rev 3 and also the preceeding series which came out first in 1994 (Beta Techno). Are you able to post or email a photo of the bike you are looking to buy?

Mate those forks must be pretty confused with all that swapping around. The forks with the Bultaco sliders should work well with 190ml per leg and so should the ones with the OSSA Betor sliders. If you are ever in doubt, just use the measurement method with the forks bottomed with springs removed. Add oil slowly until it is about 5" from the top of the tubes. As a check, extend the forks with the springs out and caps off and if they snore near the bottom, you need more oil. Fork setup is such a personal thing that I am reluctant to suggest oil weight and spring preload for you but seeing I am also 14 stone of rippling flab you may find my numbers are a suitable starting spot. 75mm of preload with straight wound trials rate springs and 7.5WT oil works pretty well for me in my M49 Sherpa T and MAR OSSA. 10WT is a bit heavy unless you like a slow fork action.

I suggest you ride a few other 349s and compare. The clutch on the 349 and 348 is probably the worst aspect of those bikes for modern trials riding techniques. The drag should be livable but it should not slip. Sometimes slip combined with drag can mean plates that are not flat. Slip combined with drag can also be caused by the springs exerting uneven pressure on the pressure plate. After lots of work, my 348 clutch disengages nicely and doesn't slip, but engagement is still difficult to control in tight turns. It really is a good bike for non-stop events!

With Rev 3s, the riding duration is highly variable depending on how much fuel goes out the float bowl overflow. If you have yours sorted, and have a clean air filter and good jetting, it should do more than 20 miles of steady gentle trail riding on a tankful. That 20 miles would take about 3 hours to cover in the sort of terrain I'm talking about.

The aluminium tanks fitted to the TY250 models after the A model are pretty much the same capacity as the steel A model tank. If it's important that the volume be known, I could accurately measure the capacity of an aluminium TY250 tank. The aluminium tanks are definitely lighter than the steel.

If you don't have enough oil in your fuel, the friction from the rings and piston rubbing against the bore greatly increases. This friction can get the rings and bore and piston very hot. Aluminium expands more with temperature rise than steel and cast iron so as your bits get very hot, the clearance between the piston and the bore becomes too small. If this process goes far enough the parts may stick (sieze) together. Even if they don't get to the point of seizing, running an engine with insufficient oil will make the rubbing bits wear out faster than otherwise. The heating due to rubbing friction has nothing to do with the heat produced when fuel is burned in the engine. The amount of oil in your fuel has only a tiny effect on the amount of heat produced by combustion.

I put lightweight all plastic acerbis hand guards on a trials bike but took them off after one ride because they made the steering feel noticably heavier in the tight bits. I was trying them out after having problems on an exploration ride with the lever knobs catching on vines and branches.

Yes it is a common problem with tubeless fronts on tube type rims.

How can you tell that the knock happens at the top of the piston's travel?

I've had another look at the TY175 engine number/year of manufacture chart and on closer look it appears to be attributed to Australian TY175 researcher Stephen Fox rather than to John Cane. The chart indicates that based on your engine number the bike was made in 1979.

Yes Stuart, I can do photos of the M49. At the moment it is pretty ugly with black frame and paint being stripped from tank and sidecovers. Is there some particular feature that you want to see? Mine is also very early M49000100. Let me know what you want to see and I'll send them to your PM box or email. David

I tried riding the bike with the old Firestone front tyre and by the feel of it I reckon the air might have been from another planet because that is what the steering felt like. Unfortunately I suspect the air was not from such well regarded Trials riding areas as the rocky dry Spain or slippery Yorkshire because it was contained in a tube that was marked "made in Thailand" and so probably was inflated by the previous Aussie owner with nice clean Aussie air.

The oil ratio you use depends on what you use your bike for and the conditions under which you ride it. For trials work (in sections) the engine doesn't need much oil in the petrol. If however you are going to use your bike to ride along a beach in soft sand, or to cruise up the highway at 100km/h, or to climb mountains that require lots of open throttle work, it is prudent to use more oil in your fuel. As well as the type of riding, it also depends on how hot the air is where you ride and if you ride with mud on the fins. Where I ride it gets extremely hot in summer and some bikes just stop running due to fuel vapourisation problems. You can hear the fuel boiling in the carby. Higher engine temperature usage should be matched with more oil per unit of petrol. What one person gets away with in their riding conditions may bring on high wear rates and maybe even seizures in another person's riding conditions.