Snakebite68

I'm going to clarify that... I was BORN in the late 60s..! lol

No worries, I'm late 60s... Just picture it as a normal conversation that takes a really long time to get an answer to (and sometimes not at all and you have to give us a poke!). lol

Welcome in! I've split your two identical posts into separate ones...

Can you tell roughly where the noise is coming from? Particularly front or back? If it's back, I'd check the differential first then the drive shafts second. If it's front, I'd check the wheel bearings/spindle. As for the tank slapping, if the bike is still level (not raised or lowered at the back due to the conversion), all I can think of is check your front brake callipers, maybe one is playing up? I've split your two identical posts into separate ones...

Is there anyone out there in Gods Country (Yorkshire, West preferably)?

Looks like a fun weekend!

In all honesty, and within limits, the length of the spring won't matter. What will matter is its strength... A couple of mm either way in length won't matter, but a thicker or thinner wire will (it's not the length, it's the girth!!!). It may even be the case that the slightly longer ones are 'upgraded' ones, or just 3rd party and not quite in spec. If you're really worried or suspicious, go to your local Authorised Yamaha Dealer and get them to order you a set for your specific bike. It may cost a few quid more, but you're guaranteed they'll get the right ones..! And just to answer your questions directly..: 1/ My Haynes manual suggest 36.4mm. The problem with Haynes is that the bikes they take apart for the manuals aren't new (one assumes that would cost a lot to disassemble a brand new bike), so measurements that small may be... Slightly off... 2/ My manual I downloaded suggests 34.9mm. WHAT manual? I trust nothing off the interwebz completely! 3/ The ones I got from Yambits are 34.7mm. Yambits are usually pretty good and I use them a lot, but I did get some petrol tap seals from them that were VERY much oversized (thickness) and were useless (so fat they locked up my tap). 4/ Ones for sale on Autodoc suggest 36mm. Never heard of Autodoc...

That's handy, cheers

Does it have an immobiliser?

Aaah, see now, that makes much more sense! lol

When you say 'rotor' what are you meaning? Brake disk? Something else?

Sent... Get yourself up to the New Members Area and tell us about yourself, and more about this PowerTronic doobery!

Sure you can (done). Go make a post in the welcome area and tell us about yourself & bikes & friends bikes... lol Not a clue about the code clearance thing. I've never actually LOOKED at the file!!!

This might be some use... https://www.ebay.co.uk/itm/185869019073