Bloomfield

A while ago I discovered a moped parts place in California- treatland.tv -they have an incredible selection of parts, many of which are useful beyond mopeds. While looking for something in the handlebars/controls section I noticed they had a lot of speedo drives, including many AVIS-VDO and they are quite good at listing things like axle size and thread size in their descriptions.

I think any of the later Alpina (M165 and on) seats, along with their larger tanks, should bolt right on. This is certainly true of the previous generation of frames, which I am more familiar with, but I believe it still holds true with the later models.

CST is just Cheng Shin rebranded slightly. The 23" rim might have been a good idea that Honda experimented with, but nobody else seemed to have adopted it. This was around the same time that Michelin brought out some odd-sized rims for cars like 365 and 390mm I recall; that idea also didn't go anywhere. The Bridgestone TW9 seems to be available in Canada as well https://fortnine.ca/en/bridgestone-tw9-trail-wing-dual-sport-front-tire

Recently I bought M92 and M159 basketcases. I was surprised to see that the front ends were seemingly identical, so I think you can widen your search to include quite a few models.

10/48 is lower gearing so it will accelerate more quickly, but will be slower overall.

I've got no recent experience with overseas shipping, but if you can break it down and crate it on a standard-sized pallet it should be much cheaper than shipping it whole; at least that is very much the case with road freight. Be sure to enlist a customs broker; your shipper may include this service but do make sure beforehand.

Pursang or Alpina (M115/116 and later) yokes will fit; not sure how or if the steering geometry will be affected.

Yes, wear will be fairly evident- if there are obvious burrs on the edges you can clean them up with a fine file. Look at the dogs as well as the edges of the gear teeth themselves. The kickstart ratchet can be quite worn and hooked and may need to be replaced if it is too far gone. Also check for burrs on the selector drum, and the clutch basket too, all these parts need to be able to slide and engage smoothly with one another. Looks like a nice job so far. Is that one of those Indian repro tank units, or did you strip and polish the original? All we see are fibreglass ones over here.

Yeah they are notorious for being difficult; there is some info in this thread and probably many other older ones. It's been so long since I took mine apart that I can't remember much but I know it wasn't easy.

Thanks, I only see M116 pistons at 83.70mm on the In Motion website, which is too small. They show M99 and Sherpa T in the larger sizes but those are shorter stroke so I'm not sure if they are compatible. I will have to check with In Motion and Hugh's.

Does anyone know the maximum overbore for an M116 Alpina? When I bought mine 20-odd years ago it had been left outside with the head off and no piston, just a sad rusty con rod flapping around in the cylinder. A quick measurement with vernier calipers shows the bore is already at 83.8-something mm, so probably was on second overbore (83.75) already, and it is quite rusty. It might just clean up to 84mm, but that could be wishful thinking. I know that at some point they went to a thicker liner that could be bored out further but I'm not sure when the change occured. Currently the liner is about 3.6mm wall thickness so would have been about 3.85mm or so when new. I see there are Wiseco pistons listed in .25mm increments all the way from 83.25 up to 87mm but I'm curious if I can bore this out again or if I should look for a sleeve. It is a 116 stamped barrel, but it's within the last ten produced so some specs may differ from the usual.

There are usually some on ebay in various conditions for not too much. The same primary case is used on various models.

Oil wouldn't be measured in millimetres. It might refer to the stroke of the crank, but I've never seen that stamped on the cases.

What is this referring to?

Hi, I just saw this. Did you get any further with this project? I too have most of an extra Ducati 160 and thought of building a trials bike with it but the sump would dictate mounting the engine quite high. I'm curious to see what you've come up with. Cheers

Ah thanks, I hadn't seen that Divouneh's frame was lacking that extra loop. Mine does have that. One of these days I should start a frame thread, but I'll have to find the cable for my camera first.

Hi feetupfun, I'm curious which bits you're referring to at the rear of the frame. I have a very late M116 frame which has had a few things cut off and added on and I am curious to see how they compare. It would also be a good reference for putting mine back to stock. Thanks

I have a similar problem with a front pipe and box that I bought for my 116 Alpina. Does your barrel have the stub that mounts with four studs? Perhaps it is fitted the wrong way around, and so it comes off the port at the wrong angle. As mentioned above, it could be the wrong pipe as there are subtle differences between models. I think that is the case with mine, but I can cut it and weld it to make it work. edit: Just noticed that the flange rotation was already mentioned above. Good luck

Some people are not at all mechanically inclined and would rather just get rid rather than going to the bother of taking it into a shop and paying to have work done. Trials bikes of any description are so rare in North America that it's hard to say if 'market value' even exists. In that case they are worth whatever you are willing to pay. That looks to be in pretty good condition overall.

Where did you end up getting the seat from? Also, would it be possible to post a couple close-up shots of the frame while it is still bare? Namely the area of the exhaust hanger on the right side seat stay (just down from the shock mount) and also the seat mounting bracket that runs horizontally between the tubes just to the rear of the main vertical tube? Mine has some weird things going on in those areas and I'd like to put it right. Thanks

Yes, I think you are right; that torque arm is like the one on my Alpina (M116) in fact and not the Matador. It has been packed away in a box for far too long now.

That reminds me of a c.1966 4-spd Matador that I used to ride a long time ago, but looking for photos online I can't find anything to confirm. Looking at how the brakeplate sits outside the hub makes me wonder if the two were meant to go together.

There was an XL100 as well as an XL80 at various times, so those parts would be worth a look. I would imagine the brake plate would be shared with another model.

I did, yes thanks. They have them listed but with the exchange rate and shipping it ends up being fairly expensive. Most likely I will end up going that route when funds allow, which may take a while.

Thanks, that is really useful information. I had noticed those holes you mention in photos of Pursang pistons but wasn't sure of the purpose, and I don't have an Alpina piston to compare to. From the sounds of it it would work but maybe would result in more mixture being blown out the exhaust port. I should wait for the proper thing I suppose. What about Sherpa pistons though, or do they have a different compression height due to the shorter stroke?