feetupfun

Hey tony27 you know me well I love Woody's broomstick tool idea but the rattle gun is just so fast. My record for TY250 fork seal change from go to whoa is 20 minutes with a rattle gun. I did make a tool to fit the round-with-two-flats type rod end, but soon after gave in and bought an air compressor. I'm sure the later TY250s have flats but I have a feeling that my 250A model didn't have any flats on the end of the rod. It also has the drain holes in a different place to the later TY250 twinshocks.

Haven't heard that one before Steve

26 or 28 is perfect for 250 and 325

Yes both of the tubes that go from the head to the swingarm pivot are necessary as is the stay that goes from the head to the top tube. On this bike and the 348, these components are not just to steady the head, they are to provide triangulation for the main frame loop. The other issue just means that the indent that holds the starting device on is not strong enough. Does it still have a MK11 AMAL carby?

We are allowed to use aluminium rims in pre-65 Classic trials here so there is not much call for stainless steel rims (or plated steel rims).

Some have circlip grooves, and some don't.

Mate there have been hundreds of forum postings already on this topic. Have a search and you will find what you seek.

Bultaco Betor forks were not the only 1970s forks to have vented caps. Yes non-vented caps can be used to tune the overall spring rate but beware because Bultaco Betors only have friction to retain the the fork seals so if the pressure goes too high you may cause a seal to pop out. I have been running a Sherpa T with non-vented caps and haven't had a problem yet, but that is no guarantee of anything

You couldn't be worse than me PA I tried to test ride a 348 Cota sidecar on flat damp smooth grass and could not get it to move forwards (I could go left but not forwards). Maybe it would have been easier if the passenger was not 100kg but I doubt it would have made much difference. The flat damp grass was outside the scoring tent at a popular trial and after failing so miserably in front of so many people, including the people who campaigned that outfit for many years, I have avoided trying a sidecar again, even in secret. My mate Cedric bought the outfit and the bike has been used solo for years now by his daughter Tharyn.

This reminded me of something which I read in a set of (Canadian?) trials rules "The front wheel spindle must pass the section end markers before the rear wheel spindle" It's fun trying to visualise the situation where that rule may need to be applied

Paul it depends on which tubeless tyre and which tube type rim. At low pressures, Dunlop tubeless rears wont stay in place on any tube type rim while Michelin XII tubeless and IRC tubeless will stay on some tube type rims but not others. Sorry I've not tried any tubeless tyres on Suzuki rims. Pete I suspect you might have had problems if you ran trials pressure in your DRZ400 rear David

TY250 what? Tapered needle roller bearing sets for TY250 twinshock are available as an aftermarket part for about $50 from motorbike shops everywhere and on eBay. For TY250 mono or TY250Z I have no idea what is available

Frank on page 4 of the magazine article at the below address, there is a side view of the rear end of the first model Majesty 250/320 (that was made by modifying a Yamaha TY250 frame) which could be scaled off to get the dimension from the swingarm pivot to the top shock mount. photohttp://www.tytrials.co.uk/trailandtrialsuk/cat_26578-Yamaha-Majesty-Specific-Parts.html David

Yes and it was a nice lunch too but you should know I cannot resist doing stuff in my shed

B&J Racing, Tennessee

Another alternative is to use the clutch lever assembly from a Suzuki RM80X for brake and clutch. They have the bendability properties of original TY levers and are of similar dimensions, have the right look for Japanese bikes of the era, the right cable end dimensions, have the right leverage ratio and are still available from Suzuki dealers. I use AMAL levers on my Spanish bikes and RM80X levers on my Japanese bikes.

Hi squid I've posted some photos of a DT175 motor here http://www.trials.com.au/content/index.php...er&Itemid=6 in the Twinshock and Classic forum Regards David

It is a TY175 that someone had modified by removing the frame tubes under the motor and making new upper shock mounts. Both are very common modifications on TY175s. The early Majesty 175 used a modified Yamaha TY175 frame in which new upper shockie mounts were fitted, but they were done differently to that bike on eBay.

A and D model frames differ in some minor ways but share the same geometry where ot counts so if you have the same extended length and compressed length on your shockies as Frank, you will be able to use the same top mount location. What is important if anyone is intending to move the top mount down to the same distance from the swingarm pivot as on the modified Yamaha frame Majestys, is that the top mount will then be much further from the top frame rail than on the Majesty frame so the bending moment on the frame tube at the top mount, will be much greater than on the Majesty frame. On the left side of the frame, a brace tube can easily be added to take the horizontal component of the load from the new top shockie mount, but on the right hand side of the frame, the exhaust is in the way of where you would want to fit a brace tube. I've seen some pretty strange bracing used to get around this issue, and have even seen one TY250 where the main exhaust section had been shortened at the back end to provide space for a brace.

Squid, the DT175 A,B,C and D models have a 175cc barrel and head that is interchangable with the TY175 and has the same port timing. The compression is probably higher with the DT head but that is easy to deal with. It would look different because the finning is different on the barrel and the sparkplug holes are at an angle. None of that would stop me using a DT175 barrel and head if I had a TY125 that I wanted to make into a 175cc and there are thousands of those model DT175 motors in bike wreckers, on farms and in kids buggies throughout OZ. There have even been postings on this website from people trying to work out why their TY125/175 motor looks different, because it has a DT175 barrel and/or head. I know the port timing is the same because I have both a TY175 barrel and DT175C barrel sitting in my shed and measured them up for someone else. PS I just read that you live in France but I suspect that DT175ABCD motors would be common there too. I can do a photo of one if you want for reference purposes. David

You are not alone David

Sorry Frank not that simple because the Majesty frame based on the TY frame has the frame uprights shortened so a measurement from the top rail is dodgy unless you shorten your uprights exaxtly the same and don't change their angle. I reckon if you are not doing the mods to the main frame only shockie mounts, you need a measurement from the swingarm pivot to the top shockie mount to get the shockie angle right and then position your mount to give clearance to the rear guard and see how far down the swingarm goes. I suspect you falcons will be 4" travel which will probably generate problems ie the swingarm will go too low and/or too high, because the original shockies would have been 3.25 to 3.5" travel. I notice some people have bent up the rear fframe loop on theirs to get around this problem. I can only tell you that measurement for Godden Majesty, which may be different to a modified TY250 frame type Majesty. I'm sure there are people with the Yamaha based Majesty frame that read this forum though.

The TY250 twinshock air filter cage photos and details are here http://www.trials.com.au/content/index.php...er&Itemid=6 Regards David