tony27

Very nice.I'd say it looks more like a C onwards bike going by the engine covers Who supplied the short header pipe?

To keep the original shield would involve having mounting points welded on Majesty Yamaha sell a cover that looks to just clip over the top

Same part but you may be missing part of the airbox were the rivets attach at the side

That's the correct airbox, if you had the correct lower guard it would have sealant between the airbox edges & the guard & small rivets holding it in place. Unfortunately it looks like part of the airbox on the left side has been cut off, it normally comes partway along the side of the guard if that makes sense This is what the airbox & inner guard should look like, see how there are some rivets at the back that go sideways This is the listing for it, from what I can tell it would probably be cheaper than just buying a new inner guard & you already have the filter & lid. In their other listings is a used rear guard which also has free UK postage so you could sort it all in 1 go https://www.ebay.co.uk/itm/1974-YAMAHA-TY-250-AIRBOX-MOTOCROSS-TRIALS-TWINSHOCK-CLASS/253683358043?epid=24020303214&hash=item3b10b4d95b:g:4A0AAOSwwAdbHpnl

What are you using for a filter? The airbox is attached to the lower guard, normally plenty available on eBay from the states but it would pay to get a new connector tube from Clauss Studios. If you don't want to run a standard airbox a replica inner guard is available from a few different places, majesty yamaha have the inner only for 74s, DC Plastics do both the inner & rear guard for 74s

Ignition cover is 74 model which is not unexpected. Very correct looking bike apart from that

Normally you should be able to find 1 on eBay in the states, finding those sort of parts for the later models is almost impossible

If you have chipping then the gear needs replacing, will only get worse if you don't

Have you seen the A model frame on eBay, looks okay in the photos

If you can find a TRP grab it, I fitted a new 1 years ago & it's so much better than what was fitted standard as would be an Ohlins

That's should be the gasket you need. I forgot that that age motor routed the coolant through the clutch cover to the cylinder, you will need to replace the oil as well

Haven't done the exhaust header yet but it has been repaired with some fairly heavy pipe at some stage End of the chain tensioner mount had been cut & tapped at some stage Both axles are 17mm aluminium, front threads into the fork leg as per the newer bikes I plan on cutting & lengthening the ignition wires when time permits so that they run along the frame, looks tidier & as you say gets them away from the cylinder Carb is standard except for #37.5 pilot jet & #200 main jet. The base of the airbox has had the step at the bottom removed & the filter is now at the top like the modern design of airbox so it breathes quite a bit better. I did think the #200 would have been too big but so far it seems right, it was originally fitted when the motor was worn out & sucking air through the crankseals

You should only need the clutch cover gasket, fresh coolant & gearbox oil although if you lie the bike on it's side after draining the coolant you should be okay for oil but I'd change it anyway with a new bike

Had a good play on our local tree root venue & I have to say how impressed I am with the forks. They do everything you could ask of them Back end grips well & I was turning on roots on a hillside tighter than most guys do on their modern bikes which showed how much confidence I got from the bike straight off Bad points, front brake needs the lever moving 1 spline to give more adjustment. Can't get any real freeplay in the clutch cable & it's a bit far from the lever, can't work out why as adjustment is as per book. Engagement point is very short Next photo for the eagle eyes

Try starting it will the fuel cap off to eliminate that A failing stator can give the symptoms of your original stoppage but generally will start & run fine when cold

More that likely the header will be standard shape although if there is enough stainless purchased we may try something different, never let a toolmaker & a retired fabricator/welder loose on a project as you never know where things will end up. I deliberately turned down using a set of mono forks, would have been cheaper but I prefer to keep the bike looking as close to stock as possible with our own little touches The seat came from Sammy Miller products minus brackets, new name of the company is feked off trials parts. foam is fairly soft but it's a lot better that we originally had The instructions that came with the damper rods etc called for 175cc of oil which isn't really that much more than standard but the height ended up at approximately 95mm from the top of the tube which is higher than the normal 125mm I've used before, quite possible that after giving them a good work out that I'll remove some of the oil. I can say that the springs hold the front up higher than the originals & when we first assembled the forks we tried leaning on each 1 on the floor which showed us they are quite plush & stiffen up the more of the travel is used The quick spin in the dark on over inflated tyres did impress us, just how tight it turns was surprising & the motor even though it's only had 15 minutes of running has a good power spread, it will be interesting to see once it has more time on it what size main jet we end up with, at the moment there is a #200 main from when the main bearings were worn & it doesn't seem too rich, just incase I have a #160 & #170 to try if needed

That's a really nicely put together bike David, 1 of the local Queensland riders? Not sure that we'll ever fit a 1 piece tank & seat unit like that but a Majesty tank could be in the distant future plans. After the Kaikoura 3 day next weekend the tank is getting repainted & we plan on making a new header pipe section for the bikes original pipe which has a huge hole blown out at the lower bend

Correct on both the bars & DT250 head. The head is quite a bit heavier but I like the look of the radial heads as both my VMX bikes had them at the time I got this, combustion chamber is very similar. The bar mounts were moved by me by cutting & machining, I had the mounts welded on by a good welder before I blended off the extra weld & part of the original casting that stuck out at the back The forks are now fully Majesty inside, the longer damper rods, progressive springs which feel stiffer than the originals & the adjustable caps. I was surprised at how high the oil level was when using the amount they suggest & will be looking forward to getting some decent time on the bike Friday morning Some of the other mods may take a longer look & some are definitely not visible in any of the photos I have taken already

The angle of the photo doesn't show it properly but the seat tubes are parallel to the ground as I would have expected it would be when originally built, shock mounts were positioned by hanging the bike & letting the shocks come into contact with the rear tubes. From memory the amount was around 75mm difference between centres, I seem to remember reading the measurements from the swingarm pivot to the shock mounts of a Majesty on here somewhere & the positioning is very close I have ridden the bike with the shocks mounted like this & it worked quite well, at the time the motor was very tired with so little compression that I could turn the motor over by grabbing the end of the crankshaft after removing the flywheel with the spark plug still fitted. The steering is really good & it gets good traction, I did find it liked lifting the front which is part of the reason for adding the longer axle plates. I'll measure the wheelbase on Friday to confirm what we suspect has been done to the steering head

My 250c which was finally mobile after dark tonight for the first time in a number of years Rebuilt motor at 70.25mm bore & electronic ignition which is still to get timed with a strobe light. We are really impressed with how the bike behaves, motor is silent & doesn't behave like a 40 year old bike. Visually the steering head is the same angle as a new Beta & the turning circle is amazing Lets see how many little details you can pick up. I'll do some close up photos in a couple of days when I plan on running it in & fine tuning the set up

Easiest way to work out the price of parts for a rebuild is to go to Splatshop's site & start a cart, generally there will be a suggestion at the bottom of each page of other parts that may be needed. When rebuilding Shercos the head does not need removing from the cylinder so there is a saving Basic list of things to buy when doing the mains are Main bearings Viton crank seals for both sides Gaskets - clutch, centre case, base Check the waterpump shaft for grooves & replace if needed, replace the seals there as well A quick look came up with roughly 82 pounds plus freight, cost of the centre case gasket was the major shock at 21 pounds which is higher than the main bearings

From what I remember Clauss Studios having either on their site or eBay listing if you sent them your boot they will take a pattern off it & then start listing them, first moulding is yours. What I had read said that the part didn't need to be perfect, I assume they tidy the part up & go from there I have 1 of their TY250 boots & it fits perfectly

I took the supplied seals off the bearings & only left the standard seal that sits below the lower bearing in place, that gave 1-2 turns more thread which is definitely better. I forgot to take photos but should be able to tomorrow while I'm reassembling the forks etc. Had the freshly rebuilt motor running for the first time in 5 or 6 years, took 4 half kicks which is better than expected, sounds very un-TY like with zero engine noise so I'm really looking forward to getting back on the bike

The squealing fan will be an intermittent thing if it's like mine, you'll be the 1 squealing if you have to replace the fan as they are fairly expensive. There are some japanese road bikes used the same fan motor etc but from memory the plug needs changing & the mounting holes opened up which are easy jobs

If you liked how the clutch behaved with the rock oil use that, a good light gear oil is generally what I use, lately has been either motorex from the local KTM dealer or they have been able to get me Ipone as used originally For a quick clutch some people use ATF which is also the cheapest option Whatever you use make sure it doesn't contain friction modifiers which most car oils have as it isn't designed for wet clutches