feetupfun

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

Yes the TY250 has a 26mm Mikuni as standard equipment and they work fine. A 26mm to 28mm mm carby of whatever brand is a good size for two-stroke trials motors from 200cc to 350cc

I will take photos and post dimensions later on today when I clean some air filters. Are you telling me that Uniflow Australia will not sell to you?

To use the DT360 piston, you make a new, bigger sleeve to fit into the TY250 barrel. If you use a DT360 barrel, the port timing will be wrong because it the DT360 has a longer stroke than a TY250. 26mm VM Mikuni carby is good for a 320cc TY250 motor

Options 1 Buy some 12mm threaded rod from the hardware/building supply shop 2 Theres a person making stainless steel replicas of many old Bultaco screws, plugs, axles, nuts etc and advertises on eBay 3 Any machining business could thread the ends of a piece of 12mm steel rod for you

My 1977 TY250D air cleaner uses the same type of filter and cage as my TY250A and TY250B. The air box is different though in that it breathes through a slot in the lid on the D model and breathes through two holes in the side of the airbox on the TY250A and TY250B. When you say the 1976/77 model does not have a cage, what supports the filter foam?

Last time I bought a TY250 element from www.uniflow.com.au it came with a new cage in the same bag as the foam element. If you still want to make your own cage, I can measure one up and post details later on today.

Neo it certainly is true for pneumatic-tyred tractors. I know that because I helped my Dad add the water after changing a tyre on our tractor when I was a kid. There was even a special valve nozzle that was in two parts. The outer nozzle section screwed off so you could add the water from a garden hose, then you screwed the outer nozzle on and added the air through a standard schraeder valve. It was useful for tractors because it lowered the C of G. I don't think it would help a trials bike that has rear suspension, but may be of use on a rigid-rear-end trials bike.

They would probably fit your model 125 but it is impossible to say for sure from those weird angle photos on the eBay listing. The listing reads be like they are NOS from a model 199B. The price sound too cheap to me so am a bit suspicious about exactly what they are. The caps are different to what came on the model 125 and all the aluminium bits on the model 125 forks were polished rather than painted black. If it was me buying them I would ask the seller a few questions.

Have a good look at the Honda rims before you get too excited. Some alloy rims from that era have suffered quite badly from corrosion inside the well. Some TLR200 models had gold coloured rims made of steel. Another thing is that the TLR rims would have to be very cheap to compete financially with new rims from asia (in many colours) I have started seeing on twinshock trials bikes around here this year. As far as lacing the two together, if the Honda rims are 36 hole and same lacing pattern as the TY then the only issue would be slight differences in the angles of the nipple holes (caused by the difference in hub flange diameters and the flange spacings), and this can be overcome with patience and a small round file.

Yes there are many standard Yamaha TY175 colour schemes from different parts of the world but I think the USA market C model was the same as our C model (orange and white). Have a look at this. Not all are standard TY175 colour schemes but most of them are: http://www.bikepics.com/yamaha/ty175/