feetupfun

Are you talking about doing a wheelie or popping the front up as part of riding an obstacle?

My "original" is intended to mean the tank that came on the bike, not the first type of tank (fibreglass) fitted to model 198 and 199. Many 198 and 199 I know of have aftermarket fibreglass tanks that replaced their original plastic tanks that fell apart. I'm hoping that 199 Enduro has a fibreglass tank of some sort on their 199 and not plastic or aluminium, or the advice about epoxy lining it may cause a lot of problems

I hope you are talking about a fibreglass tank and not the plastic tank that originally came on 199s. Epoxy will not stick well to the plastic tank

The initial comment was for 1.6 thou not 16 thou

It's conventional to say "1.6 thou" because saying it that way is easier than saying "zero point zero zero one six of an inch" 1.6 thou could be written just as easily as 0.0016" but when spoken it is a different matter

If you set the tank up properly after you have done the coating, any excess will flow back out whatever hole you choose so it doesn't matter if you put too much in to start with.

Yes Forma Boulders work well for my ample calves. They do take a bit of breaking in though

Clear coat paint on rims usually gets chipped in use and then looks pretty bad. TY twinshock Yamahas had clear paint on the rims and fork sliders from new and it chipped very quickly and looked unsightly.

Both are excellent material choices for a bashplate. I'm keen to see how it ends up looking

You are very fortunate to only have those frame repairs required. The following model Alpina (137/138) was their first attempt at using a fancy alloy steel for the frame tubes and when I rebuilt my model 138, the frame was cracked in about 10 places, which I believe is a fairly common situation. It was worth rebuilding it though. The 138 is a fabulous bike to ride as I'm sure your 115 will be

Neat job. Well done. The 250s are not as sensitive to the condition of the first muffler as the 325s are for smooth running. Yes they are a mechanically noisy motor. I didn't realise quite how mechanically noisy until I watched a video clip of mine and a friend's Bultacos. Probably made worse using my phone to make the video. The late model motors are quite quiet for some reason, maybe the different finning on the head and cylinder and they also usually have fin rubbers.

electric start TRS are selling like hot cakes

As a visual reference, here are photos of a TY250 cylinder I recently had rebored and the Wossner piston that is going in it and a couple of very old original TY250 pistons. The Wossner piston ASSEMBLY is the same weight as an original TY250 piston ASSEMBLY. If you compare just the bare pistons, the Wossner piston is heavier. The Wossner wrist pin is very light.

That combination of Uni brand filter and Yamaha cage that your links bring up works great for me. The only problems I've had over the years with the standard TY250 airbox are the Yamaha brand filter element falls apart quickly and that another aftermarket brand filter was too bulky to fit inside the airbox without it touching the sides.

My model 138 Alpina (engine very similar or identical to model 116) has what I think is a 360 Pursang piston which is not exactly right for the model 138 Alpina but still works great. The Pursang cylinder has a bridged exhaust port so this piston I'm using has holes through the front to lubricated the bridge. The 350 Alpina has an unbridged exhaust port so shouldn't have holes there. The other difference is that Pursangs have additional transfer ports that work in with other holes in the piston and so those piston holes are superfluous in the Alpina engine. Some Bultaco 360/370 pistons might have a shorter rear skirt than the 350 Alpina but from memory the Pursang piston in my Alpina had the same skirt length as the piston that came out. My memory is not that certain though as it was over 20 years ago that the model 138 motor was rebored and I haven't had it apart since then. I don't know of any other brand bikes that use a piston that can be used in a 350 Alpina.

Yes that's the normal arrangement

Engine number prefix will tell you what motor it is. It's not a 350 because it is a round barrel. Lobitos are 100, 125 and 175.

It's not a Sherpa T. It's a Lobito. The frame number prefix will tell you what model Lobito it is.

Some people want to run modern lights (LEDs) which need 12V DC to work so they make that available. Bultacos only came standard with 6V lighting systems. Some Bultaco models had had a rectifier and a battery (so the lights would work with the motor stopped) but Sherpa Ts had no battery and the lights ran on 6V AC

I just tried to post up some contact info for the seller in Australia but suspect I broke a rule for this forum so all I'll say is yes he is still selling them

Jetting a bike using internet forum messages is a bridge too far for me

Over the past few years I've fitted five 26mm OKOs, all from Roger. Some didn't require any change. Some needed the pilot jet swapped and one needed a different slide needle. For that one I bought a range of Keihin needles to try.

Yes those are forwards and down. They are from a Yamaha kit that had those peg mounts, a longer brake pedal, a big seat, a longer swingarm pivot bolt and there could have been a different shift lever too

Yes most of my riding is near sea level and the highest riding in my state is about 4000 feet. When I said it didn't need adjustment when I fitted the B model motor, I meant that changing from one motor to a different motor did not require any adjustments to the carby. Both of the OKOs I fitted to TY250 motors did need adjustment when originally fitted.

Yamaha TY250 trailbike footpeg kit photo