feetupfun

Frankie your 1978 Ty250 when standard had a 26mm venturi carby made by Mikuni for Yamaha. It is quite different to an off-the-shelf Mikuni VM. If you want to replace the carby, there are many you can choose from including a modern flat slide type. The cheapest option would be to get a standard TY250 carby second hand. Parts are still available for them. Another would be to get a new 26mm VM Mikuni. B&J Racing sells them prejetted to suit the TY250 twinshock.

They are good for letting dusty air into the cylinder

Nice footpegs mollygreen. You have done a nice job there. Here is what mine look like. The height chosen was easy as the bottom side of the pegs is at the same height as the bottom of the bashplate/frame crosstube. I didn't put mine quite as far back as yours but it feels fine to ride so I'm very happy with it. Sounds like you were just as amazed as I was about how much it changes the handling. Regards David

I agree with Bo Drinker. One of the best things about my (standard) Godden Majesty is the way the steering works. I would not change it for anything.

I think you would need to be an ITSA member to see that write up on that bike. It is one in the "Bike of the Month" series. I just read the story again and there is nothing about work on the swingarm pivot after all. It may have been in a string on the TC forum where I read it. Here is the link to the KT story anyway for people who are ITSA members: https://itsa.clubexpress.com/content.aspx?p...module_id=11544 David

Thanks Michael. I do check them when I service the shockies, expecting them to fail at some stage, but they are still fine. I don't like the effect they have on spring rate but I have bigger issues with a couple of other bikes so will probably leave them alone till they give up the ghost. I think I read a TC thread on replacing those bushes with somethine else a few years ago - no it wasn't, it was in the story on the ITSA website about the KT that Bob Ginder worked his wand over. Photo attached.

Yes just machine a bit off at a time, testing between cuts. It doesn't take much change in the size of the weight to make a noticable difference to the engine pickup. In the case of the TY175, I would make the weight thinner rather than reduce the OD (the metal at the OD of the weight provides the most flywheel effect for the least mass).

Thanks Woody

The Yamaha TY250 twinshock has a steel band fitted to the OD of a cup shaped steel magneto flywheel. The Yamaha TY175 motor has a flat steel plate fitted to the outside face of a cup shaped steel magneto flywheel.

Michael Sorry about the Kawasaki spokes thing. I hadn't read your posting about wanting stainless spokes. Our sections often feature tight turns and largish obstacles. Long bikes, bikes that you can't use the clutch properly in turns and bikes with high gearing don't have a chance. If the bike can be ridden slowly enough to do full lock turns and still punch strongly out of the turn, it is OK. A 15 tooth front on a KT250 would have the bike struggling on the first decent size obstacle that had no runup. I'm not saying that trials is the same all over the world, but here, stationary balancing and using the clutch in turns are essential skills for doing the turns found in twinshock class. Some twinshock riders - not me - I'm too unfit - commonly hop the front on their twinshocks as if they were riding a modern bike. I'll post another photo from last weekend that illustrates the sort of tightness found in our sections. It's not that easy to describe but have a look at the squarish rock near where my front wheel is going to land. To get the next bit of the section right, you needed to turn to the rider's right inside that rock on landing. See that I still have the throttle open doing the second blip when the picture was taken and yet have to stop inside that rock for the turn. That's why I use low gearing and have the front brakes working nicely. David

I'm not surprised hearing that the steering geometry of the KT is similar to a mid 70s Bultaco. I would describe the overall feel of the KT as being like a slightly top-heavy mid-1970s 238cc Sherpa T and the steering behaviour in very tight turns is virtually identical. The Sherpa steers better in a straight line over obstacles though. Did you try the Kawasaki shop for spokes? They are good value and you know they are going to fit without any issues.

Heres mine at a trial last weekend

Michael I've had mine for about 5 years and have done lots of minor tweaking to try and make it as easy to ride as a TY250 and reckon what I've done has taken it to about 90% of being as good for trials competition. The big weakness for the KT compared with the TY250 is in tight turns. It will turn tight but you have to manage your body position, the clutch and rear brake very closely to do a tight turn that you wouldn't even have to think about on a TY250. I see the strengths of the KT as: Ergonomics - there is plenty of room to move around and the kickstart is a dream to use compared with most trials bikes. Ground clearance is better than the TY250. Clutch is more positive in engagement than most of the Spanish bikes (is similar to TY250) Great ergos for sitting down riding. Setup: Wiseco CR/MT250 piston Standard porting, carby, exhaust, airbox, timing, cylinder head shape TY250D fork springs, 20WT oil 125mm from top, non-vented fork caps (from TY250) 360mm Falcon shocks with 50lb/in springs Standard rubber swingarm bush arrangement Standard frame (and no tube damage under the motor yet) Standard footpeg position but with grippy pegs Increased leverage for clutch. New plates and springs (standard). Modern low friction cable. Standard flywheel weight Front drum machined and high friction oversize shoes machined to fit the drum perfectly. Modern low friction cable. Standard rims (and no cracks yet) Very low gearing. 12T or 13T front and standard size rear (flat with spacer). 428 chain. Replica KT250 handlebars (much higher and a bit wider than 6" Renthals) Standard fuel tank. Michelin tyres. David Lahey

I find it very hard to imagine anyone wanting extra flywheel mass on top of what Yamaha fitted to the TY250B,C,D or E motors. The first model TY250 had a slightly lighter flywheel than the later models and some people might find that model needed a bit more. Micky are you talking about 250cc Majesty motors or 320cc Majesty motors? I've tried a range of flywheel weights on my 250cc TY250 motors and have found that with the band removed, it feels great to start with - nice and peppy for jumping obstacles with no runup, but suffers in the traction stakes in slippery going and tends to stall easily amongst dry rocks. With the standard size band fitted, the motor is on the slow side for most riding but very good in slippery stuff. After 3 tries machining a bit off at a time, I've ended up using the band but with about 1/3 of the width of the band machined off (on stock standard D and B model motors both in very good condition).

Sorry mate I can't understand what you mean

Michael 5mm structural aluminium would be OK if you include lots of stiffening either creases of ribs but they usually end up looking terrible. I reckon 6mm structural is the go. The rubber insert helps a lot with avoiding the plate being bent and also quietens the plate down nicely. Even 6mm structural will eventually bend with use without an insert.

If you seriously want help I suggest you have another go at explaining what the problem is.

Thanks Woody. How far back do you reckon the pegs are from standard?

I love a challenge It looks like a M80. I first thought it was a late series M49 but the footpeg mounts are welded to the frame. Homerlite aluminium seat/tank to meet rego requirements in the UK Sammy Miller front guard mounting because the standard ones wreck the guards Aftermarket alloy mudguards - no idea Low rise handlebars - no idea Ty twinshock headlight and mounts - no idea Non standard speedo mounted up high - to meet local rego requirements Sammy Miller chain guard - no idea

Swooshdave, I'm not just off with the OSSA people, I'm a full-on 1970s twinshock trials nut who has no particlular affiliation with any brand except for not liking Hondas. Yes I'm fixing up my OSSA to make it good enough to ride in competition and look nice, making my M49 nicer to ride, fettling my KT to the point where I'm happy to compete on it, machining the front brake drums on my four twinshock Yamahas (3 TYs and a Majesty), restoring a Bultaco M198 from a basket case and restoring a M138 Alpina also from a basket case. I've been full-on fixing up 1970s twinshock trials bikes since 1995 with a goal of answering a whole swag of questions I have had for a long time about them by owning and riding them back to back. David Lahey

Tim it was me David Lahey who put the link up and no it isn't on trials.com.au yet. Its relatively close (six hours drive) to where I live. If I didn't already have the red 198 I'm currently fixing up I would have driven there and offered enough to buy it on the spot this weekend. 198s don't come up for sale very often around here and that one appears to be in quite amazingly original condition. If someone from overseas wants to buy it (especially kiwis) I can pick it up and mind it for you till you can arrange the transport. David

Thanks Woody I reckon I know what you mean about the L brackets. I'll ask you again in a while when you are happy with the location then I'll make nice looking brackets using what you reckon is the best position. I'm pretty keen to get rid of the original brake pedal too. It really is a monstrosity and reminds me of what was on 1960s Japanese commuter bikes. David

Suggest you have a look for yourself. I wouldn't describe it as tricked up. More like restored using some non-standard parts. You can see the bike advertised on John Cane's website at least it was last time I looked a few days ago.

Woody I have an early type M49 (M49-00100) and am considering relocating the footpegs to make it a bit easier on the body to ride. I'm guessing from your remark about your bike having to be entered in the specials class because it has modern footpegs that you have also moved the footpegs. If you have, please advise what you did with the footpeg location and the footbrake arrangement and what you think of the changes. Thanks David Lahey

Michael I am enough of a perfectionist to have done that sort of experiment you described with moving the pieces of lead around to see if it was noticable. I had solid aluminium handlebars on a standard TY250 twinshock and thought it was not quite as nice in some types of turns as my other TY250s which had tubular aluminium handlebars - particularly turns where rapid bar movement was required. My experiment was to swap the bars between the bikes so a different TY250 had the solid bars. Both sets of bars had the same shape and were the same width. No change to tyre pressures or fuel tank contents or anything else except the handlebars. Yes it made the previously very "nice" steering TY250 noticably harder work to do turns that alternated quickly from one extreme of steering angle to the other. Since then I have been an advocate for minimising mass in the steering particularly at the ends of the bars and the wheel rims/tyres. I find the steering geometry of both my standard TY250s and my Godden Majesty to be quite wonderful compared with the other twinshocks I use in competition (OSSA MAR, KT250, Cota 348) for the type of riding we do here which is dry, tight and with plenty of traction. I suspect that if we rode mainly wet, mossy boulder strewn creek beds, that other bikes like the later model Sherpas might be just as as good or even better. I find Sherpa T steering to be as sublimely pleasurable in those conditions as the Yamaha 250s are sublimely pleasurable in the opposite conditions. For people with TY twinshocks, did you know that the D model TY250 rims are lighter than the A and B model rims and so provide slightly less moment of inertia as Michael has explained. Not sure about C model rims.