Aircooled Monoshocks

Hi,I have recently bought a TY250 mono as an introduction into motorcycle trials, I decided to rebuild the bike from scratch and upon stripping the engine it has thrown up some interesting modifications which I hope someone could enlighten me on. The piston is I've been told is an IT 175 at 66.5mm diameter, the rod is different, Its a 214 but possibly same length as standard. The barrel is 10mm shorter than standard and the crank throw is shorter at around 63.5 in length. There seems to be quite a decent porting job in the barrel as well. It also has a lightened flywheel. The frame no is 15. Someone told me this is an early conversion by John Shirt to build a more revvy m…

Can anybody help with jetting for a Mikuni VM26 for use on the Yamaha TY250R? The carb is new and was supplied supposedly set up specifically for this bike but it is way out. It'll barely run past idle it is SO rich, as if the choke is on. Supplied jetting is - Needle 5L8 Needle Jet 182 N8 Main 125 Pilot 35 Slide 2.0 Or at least I think this is right as I can't see the flipping numbers and had to photo them and zoom in as best I could.. Thanks. Steve.

Hello all, Does anyone know where I could purchase a Piston Kit for 1985 ty250 .75 O/S? I am in Australia and seems to be none here... Thanks Chris

sorry if this has been asked before ,but can anyone recommend a good place to get spares for my 89 250 mono ,,head and base gaskets,in the uk cheers pat....

I was just wondering if the only difference between the Ty250 and 350 is simply the engine size/bore? I can only get hold of a workshop manual for a 350, and wondered how relevant it was to my 250. Looks pretty much the same, but my friend said that once about a girl he met in Thailand...

Having repacked my middle box ive still got a knock on the engine it seems to knock on the top of the stroke so im totaly baffled as there is no play in the big end or small end so all thats left is the piston to replace even though it looks ok . Ive read where a dt250 or a it250 piston will fit as they are the same as a ty250mono piston but a lot cheaper if so is there a certain year for each piston that will fit any help would be appreciated as im totaly baffaled !!!

Hi im new to this forum but wonded if any one has got to the bottom of the pinking rattley engine as the more ive read the more im confused as some say no head gascket some say two are three blocked pipe or poor fuel and to add boost adatives what do i need to do as mine just chaters of idle and on low revs but have had the bike checked out and the guy carnt find anything worn that would coures this .cheers peter

Does any one have any advise on main bearings as it got to be that that clanging away as i rode it yesterday for the first time and it clanged all day but ran ok .What i would like to know as in a month time im going on a weeks trials holiday .Do they just get noisey are do they aventually go bang .Also what kind off expense am i looking at too have a engine rebuild and any recomendaions who could carry out the work any advise would be welcome. thanks peter

Hello all I have just bought an '85 TY250 and want to fit lights. The bike has both coils, but all I can see in terms of powered wiring is one wire that is on the right hand side of the air box. This is giving out 6v, but is the only wire that is available with power. The kill switch and wiring is present, but I cannot find any other wires to power the front light etc. Any ideas?

Any one got any tips on stopping the above snatching?

Hi, Can anyone advise if the TY250R Final Drive Guard Protectors are still available, Sammy Miller no longer list one in the catalogue ? also are there any wide footrests currently available that fit to the original mounts ?

G'day, Just got my restored TY running. It has a new Sammy Miller's alloy silencer, but it's running too loud for my liking. They advised that repacking (more packing) could be detrimental to performance. They make 'em so I guess they're right, but I imagine there's always another view. Anyone have any thoughts on this, or advice on how to quieten the exhaust overall. I burnt out all the carbon/crud from the pipe/middle section before re-installing, so that part of the equation should be fine. Is it worth getting the middle sectioin opened up and packed, or does this harm performance, too? Just thinking about all the options. Even considered that exhaust wrapping ta…

I have a 1991 model TY250R with the plastic tank. I have attempted to put new decals on it but within a day they have formed hundreds of bubbles underneath. Anyone have any suggestions? Is there something I can prime/seal the tank with to stop the vapour seeping through?

Well, since the A/C Mono forum has gone a little silent, I thought I'd throw something in for us to chew on. This 85' TY350 has been in the family since we bought it new and I like to ride it at our Vintage events in Non-Comp, just-for-fun class. It has become a test mule for my wild-hair, "hmmm, what if we did that?" brainfart projects and has been modified so many times it starts to whimper when I walk in the shop door. Photos are of a couple of the latest changes: I revalved a Works Performance shock, added a steel-braided line and a adjustable remote reservoir. The intake is a one-piece reedcage/manifold I made several decades ago and uses early CR125 dual-stage r…

What are you running for gearbox oil in your TY250 or 350?

Hi all, Spent a couple of hours in the quarry on the weekend just having fun and then it happened...bike came down on top of me but I managed to save any damage(bike not me)...as I was holding it up (and trying to think how do I get out of this one) it occurred to me does anyone really give the underside of the engine a really good clean? Just a thought Feet up!

Hi, Sorry but I cant find any of the previous postings about TYR front brake improvment by using YZ shield, Will ask any of you who have done this conversion, what year(s) of YZ front shield is working with TYR front hub? Cheers,

Hello guys, i have a Ty 250 mono and i need some tyre suggestions, im on Pirelli MT43 and it is slightly outdated and really used up, Any suggestions are a big help, Thanks

Simple, thanks again to thai-ty.

Does anyone have any experience of any relly heavy duty stapler guns that may be suitable for upholstering a seat. Not mickey mouse - not focus , b and q diy jobs I need to firmy fix metal staples into plastic and ive tried 3 fairly good staplers and they are not up to the job. The staples bend and the is not enough power. Air stapler ? Electric stapler Any recommendations from experience?