feetupfun

Medium silver metallic. There looks to be plenty of original paint there to do a match at a paint shop if you want it to be exact. The wheel hubs are the same colour as the frame. How early is the frame/engine number? I see it has the early type fork sliders.

I seem to remember he said he pushed out the inner steel bushes

I don't know what it is but it is a beautiful design and well-made

To have so little flaking after all these years, you have got a good one. One of mine on a 1975 bike is still perfect while another on a 1978 bike was terrible and had to have a liner fitted. From memory your bike is a 115 or 116 which may have the type of rear hub that came with a ferrous liner from new.

Before you ride it you will need to fit the frame braces that are missing in your photos. They connect the outside swingarm pivots to the lug on the rear edge of the cylinder head

Yes

New piston kits are available. They are usually in the manufacturer's catalogue as YZ250 or DT250 or MX250 rather than TY250. Wossner make a good quality piston kit for them. You may need to source a little end bearing different to the one in the kit depending on what conrod is in your motor.

Yes you can get parts

Yes, the 320 conversion requires a sleeve with a bigger OD.

I would think that using a ball hone in a 2 stroke cylinder would pretty much guarantee an uneven honing pattern, so there would be an unusual visual effect from the rings on the hone marks. New 2 stroke rings usually take 10-20 minutes of gentle operation to bed in, spread over 4-6 heat cycles. Unless you are seeing darkening of the bore surface due to ring blow-by, I wouldn't do anything except ride it.

Shedworks in the UK advertise that sort of tank for other bikes

fordigas, your NZ Yamaha 200 creation looks like it will be great fun and I can imagine it was great fun making it. Well done

No it won't arc across between kill switch contacts. It is low voltage and a proper kill switch is designed to do it's job. I've never measured any but I would expect it would be less than 30 volts. First off you need to test if the kill switch is actually working or not. I suggest you measure the resistance through it with both wires disconnected from everything else.

We have to use lanyard killswitches for trials competition here and popular lanyard kill switches are made by Leonelli and Jitsie and have a magnetic action https://www.google.com/search?q=leonelli+magnetic+lanyard+kill+switch&rlz=1C1GCEB_enAU911AU911&oq=leonelli+kill&aqs=chrome.3.0j69i57j0i22i30l3.11568j0j7&sourceid=chrome&ie=UTF-8&safe=active&ssui=on All my bikes require the killswitch to earth out the LT circuit of the HT coil to stop the motor. These kill switches I mentioned have two wires and either of them can be used to connect to an earth point. It's best to run the earth wire from the kill switch to an earth point on the main frame of the bike, to avoid sending current through the steering bearings, which could otherwise damage the bearings. Most people connect the kill switch earth wire to where the HT coil connects to the frame. Most people connect the other wire from the killswitch to the LT wire near where it connects to the HT coil.

If the reason for your conundrum is that the gasket is acting as a weir then you can test for this by draining the gearbox and seeing if the dipstick is still showing a level

Yes there are listings for when different models were sold but beware that the sales timing was different in different parts of the world, they didn't work to calendar years and they changed things without changing the model number, so it can get a bit confusing to think in terms of the calendar years. Here's one list that may help. There are plenty of other lists available on-line. They don't all agree. https://newellmotorcycles.com.au/pages/bultaco-history

Yes that's the drain hole

On the motor I took the photo of, the drain plug drains from both the clutch casing and from the gearbox. The drain plug hole is open to both sides. I suspect that this could be where your problem lies. For some reason your drain plug may not be draining both compartments. Before I went and found the engine casing to take a photo of, I was expecting that there would be a dedicated hole near the bottom to let the oil levels equalise, but Yamaha have designed it for the levels to equalise via the the shift drum hole and the shifter shaft hole, both of which have rotating components that are a loose-enough fit for oil to pass through.

The first "350" Alpina (model 99) was 325cc and at the time, all Bultaco San Antonio 2 motors 250cc and bigger were 60mm stroke. The "350" Pursang, Alpina and Sherpa T were all 325cc. They didn't want to go any bigger in the bore for that stroke so that's where the 325cc came from. When they wanted to make the Pursang 360cc instead of 325cc, the stroke was lengthened to 64mm. This required larger crank wheels so when they went to 64mm stroke, the crankcase design also changed. The "350" Alpina and "350" Sherpa T also went to the same larger crank wheels design however the Sherpa T stayed at 60mm stroke (325cc) while the Alpina went to 64mm stroke (350cc). The 325cc Alpina (model 99) was sold in 1973. The first 350cc Alpina is the model 116 and was sold in 1973/74. Later Alpina "350" were all 350cc. However, Bultaco are reknowned for changing things in the design of a model during the production period so anything is possible (such as a 325cc motor in a model 116) which is one reason for why when you order engine parts from In Motion they want to know the engine number, not just the prefix.

My first thought is something that is acting like a weir between the gearbox and the primary drive compartment. There's another test you can do before taking the clutch cover off if you want. If you drain the gearbox via the drain plug and yet still have a high level when you dip the primary drive compartment, then that will prove that there is something stopping the oil level from equalising between both compartments. If there is something acting as a weir, it's possible that whoever built the engine made their own gasket and didn't put the bottom hole in the gasket for one of the passages where the oil flows back and forth between the gearbox and primary drive. There are also other possibilities but no matter what it is you or someone will need to take the clutch cover off to find out what is going on

Here is where 1000 ml comes up to on my A model. I put masking tape on the dipstick so the oil would be visible in the photo. The oil level is 12mm from the end of the dipstick. I dipped it without screwing it in.

There are a few possibilities for what you are seeing: 1 Not all the old oil was drained out. 2 The bike was not level when the dip was taken. 3 Not enough time was allowed for the oil to flow out of the primary casing and into the gearbox before the dip was taken. 4 There is a problem with the oil flow path between the clutch casing and the gearbox (maybe gasket covering the passage).

Photos for Tillerman6

I'll post up a photo of an A model dipstick here tonight

I figure that some people don't do them up tight enough because on a TY250D I bought, it developed a base gasket leak that stopped leaking when I re-tightened those nuts