Front fender

The front fender on my bike is not original .. currently it looks like this

While most of the ones I've seen online are like this below (original pic from here).

 

And period ads confirm this. 

While the one currently on the bike works, I started looking for a correct one. First stop was ebay...well there was one alright but at USD150 plus another USD50 for shipping it was too much for me! I then put the word out that I was looking for one on facebook and one bloke responded that he had one. The price was right but the mounts looked to have been shortened a bit. It will be possible to repair but I decided to wait a bit.

Another guy had one for sale and the pictures looked promising, a few holes and dents but fixing that is wayyy easier than repairing cut-off mounts!

It was at this point that it struck me that the original mudguard had only one hole for the upper fork mount but on my bike there were two bosses on the fork for mounting the mudguard.. oh oh ..was the forks swapped out sometime in the past for something from a different model?

But the bolt-on points at the bottom are still there!

 Picture of the two bolt fixing , the lower stay mounts are not used.

Anyway, the vendor for the fender (the silver one above) confirmed that it would fit. It seems that the earlier ones had one bolt boss and later ones two? Anyone can verify this? Or at least confirm that some YG-1 had two bolt bosses on the upper end?

Here's a picture of the two types.

Anyway the price was way better than a NOS ebay one and condition was better than the one with the shortened legs so I bought the fender. A bonus was the seller was local to me and we had a nice chat about bikes!. Its surprisingly solid, it needs a bit of welding and some paint and we're good.

One more thing off the to-do list!

I started looking for cylinder and pistons.

I started looking for cylinder and pistons.

Since the piston was at 1.25 oversize, I did a search on ebay and other vendors (eg CMSL) for a 1.50 o/s piston/rings set but this was not successful. I believe original Yamaha Pistons went up to 1.00 oversize but the aftermarket suppliers did go higher (reliability was not really an issue for those guys) which is fine to get the bike running but once you go too big you run into problems like the ports getting out of shape. This is because the ports (windows in the cylinder for the inlet and exhaust) are only a constant diameter for a very small distance after which they start to taper away. This is especially true for the inlet ports. The size and shape of the inlet ports are crucial to the running of a 2-stroke bike. As how Yamaha designed it, it was a compromise between power and economy. Change the shape and you alter the balance resulting in poorer performance. The guys who know what they're doing can get amazing results with big increase in power but is usually confined to a narrow range of revs which usually makes the bike unrideable on the street.

Anyway I posted on a local facebook page for pistons/rings/cylinder and got a response from Kenny at facebook page "Classic Japanese Motorcycle Parts Malaysia" who had an original NOS cylinder and (std bore) a piston (1st oversize).

A box.. unmarked except for the writing.

the contents.. a NOS cylinder ...

This is the paper stuffed inside the bore..it is some kind of anti-rust thing.

 The Piston kit

 hmm.. its a 0.25 oversize (original bore is 47mm).

 rings

The whole lot.

The marking on the kit and inner boxes show the suffix -00 which I understand is for standard but the markings on the piston is 47.25. Probably some mix-up in packaging but I'll need to measure it up, especially the rings.

So now I have a nice new standard piston but only an o/s one to match. I could bore the cylinder to match but it seems a waste to do that so I went on the hunt for a standard piston and bore.

This is what I scored on ebay.

A standard size piston

And a  set of standard rings

Currently on the way to me here in Malaysia!

In my hunt for a cylinder and piston here in Kuala Lumpur, my regular parts guy told me he had pistons up to 3.00 oversize! I brought my old parts to him and he said no problem. Cost MYR119 for a rebore to 1.50, pistons, rings, piston-pin and base gasket. This works out to around USD 30 at todays rates. For that price I told him to go for it but I think I'll go with the standard size NOS parts I bought for now. The potential problems as mentioned in the opening paragraphs above are not worth it on a bike which will not see much mileage! I should be getting the cylinder and pistons back in a few days and will post pics up here.