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My Legendary Yamahas: Update on the RZ 350 mad restoration challenge

25th November 2024, 15:55 by Kanad Kalasur

The excitement keeps building up with every part going back on the bike and gives the same amount of joy the engineers at Yamaha would have felt when they were assembling the first production spec RZ 350 in 1980.

BHPian SnS_12 recently shared this with other enthusiasts:

Quote from BHPian that_sedate_guy:

As you have also mentioned, solid rotors have higher heat retention and lesser debris blow-off ability even though those were the original types. Does it make sense to use compatible drilled rotors in these scenarios or would that do more harm than good? Just curious.
Phenomenal restoration by the way. That chassis upon assembly must've given a big scoop of satisfaction

When I got the bike it had drilled rotors and even though they are better I wanted to have the solid rotors as my aim with this rebuild is to get it looking as period correct as I can. That is why I went with the same paint scheme as original as this is a very rare JDM spec RZ 350. In Japan you will mostly find 250’s as they were easier to buy for beginners because of restrictions and very few 350’s from the initial batches were sold.

This is one fast 2stroke even in stock form and I am sure the braking power even with twin rotors is not going to be as potent as the current gen bikes which would be far better even with a single rotor. So, since the bike will remain stock and rebuild to the factory spec I am ok with these compromises and am prepared to re skill my riding technique for this special 350 and that is what truly will give a sense of the experience off how it felt to ride one in the 80’s.

But, on the braking front we have found out today that the callipers have been upgraded and are from the YPVS model which were better than the ones which came on the earlier models. And I found this because of a small rubber part that I had ordered which didn’t fit the bike and Eddie from Ebay UK had an answer immediately when I enquired with him.

I shared the picture of the bracket where this particular rubber boot fits and the one I ordered from Yambits is smaller in size compared to what was on the bike and that is when he told me that the bracket is from the first series of ypvs know in UK as the RD350LC2 YPVS 31K. Although the ypvs calipers of that type fit the 4L0 they're not the type of Calipers that the bike came with from the factory. So, the ones currently on the bike are from the first ypvs models which came in 1983. So, I guess one of the previous owners made that upgrade and maybe that is the reason why it had the ypvs meter console as well?

The other change that was done on the later models which was shared by Eddie was that the carburettors were modified/improved. The early models had 4L0-00 stamped carbs which had mid range fuelling issues so we're upgraded and modified by Yamaha in 1981 by different internal drillings and combinations of jetting, needles etc, those ones are stamped 4L0-01, and this is the spare set that I have got from Eddie and which will go on the bike. Now, tomorrow we will check if the carbs on the bike are the 00 ones and if yes how different are the internals. You keep learning something new and with that there is always a new requirement of parts

Carried back 55kg of parts in three trips whist is almost 1/3 of the bike weight and we still need the parts. Luckily I have people like Eddie who is a real Genie when it comes to 4L0 parts and I have friends to carry them back home when I can’t. The rectifier original wirings are a mess and the 2t tank oil sender gauge is spoilt. I looked at Yambits and unfortunately the rectifier is out of stock currently. So, checked with Eddie who had one three pin oil sender gauge and the correct rectifier both used but in working condition and in stock. So, once I check on the bike again tomorrow I will ensure that no further parts are required from Eddie and place the order.

This is one MAD restoration challenge that we have taken over but the excitement keeps building up with every part going back on the bike and gives the same amount of joy the engineers at Yamaha would have felt when they were assembling the first production spec RZ 350 in 1980.

Some pictures…

The rubber bin boot I ordered from Yambits

It is the correct part for the model year bit since the callipers on the bike are ypvs ones they don’t fit. You can see the size difference from one on the top left portion of the bracket.