RZ250/350r resto questions/help!

[S33DS]

Hello all, new too the page and hoping to find a bit of guidance!

My grandad was a big fan of all the old sports bikes and restored them just as a hobby until a few years ago when he was diagnosed with dementia. He was in the process of fixing 4 bikes (kz1100, gs750, gs850 and of course the rz) when all of a sudden he lost his knowledge, very quickly.
Ive always been into dirtbikes and cars, but never got the chance too learn from him about the older bikes and recently he has given me the RZ as I want too bring it back too life and pick up where he left off, which in my cases I dont have a clue as he just simply can't remember, which is what brings me here!

The bike seem to be all there and everything seems to be in good nick,
The frame is a 250 but does have 350 decals so I'm not sure if he did convert it to a 350 or if its still a 250.
I do know my way around dirt bikes and repair and maintain mine and mates, plus plenty of tools too get me by.

But Im not too sure how to start tackling this one so any advice or a basic guide to follow to make a start would be awesome. Thank you in advance, Caleb!
Will post a couple pic once I can get some

[BRG1200]

You’ve come to the right place

[BRG1200]

First up, what are the first three characters in the engine and frame numbers?

[BRG1200]

On Yamahas the first three numbers give you a quite specific model, eg 4L0 is a UK market RD350LC, 5E0 is the same bike in the Australian market. The rest of the numbers give the place in the production run, which can identify certain changes, either just colours or actual mechanical or other changes.
Ideally the engine and frame number should be the same, or the engine has been swapped at some point. That isn’t necessarily a problem, but for mechanical related things you’ll be referring to the engine number etc.

Best place to look up what those codes mean is rd350lc.net

[BRG1200]

For spare parts have a look at rdlccrazy.co.uk

[S33DS]

Had a quick look and a search, RZ250R 1GA MODEL 1985.
And with a bit of luck, the engine match the frame!
Gave it a wash and then had a bit of a once over it too check too see if it all looks there, missing a couple things but nothing major, things like front brake lever and master cylinder, fuel lines and a couple unconnected plugs here and there!

[JonW]

Check the botton edge of the cylinders, what do they say, 249cc or 347cc?

And... Do NOT run this bike if its been stood for some time, it will just cost you money in the long run. you will need to check the crank and fit new seals first, as a minimum.

The 1GA should have a fairing. Check out rd350lc.net and this page for info:
http://2smoked.com/Yamaha_1985_RZ250_YP ... RZ350.html

[S33DS]

[S33DS]

They are 347cc cylinders!
Ive tried to post some photos so hopefully they work

[JonW]

Looks pretty good... er, apart from that seat lol. Tho I guess its there for the QLD mod plate on the frame, single seat rego i bet.

Need to look at the oil pump under the cover and ensure its got a yellow dot, not a red one.

What letters are on the carbs? 1GA, 1XH, 31K, 1UA etc?

[S33DS]

I believe youre right on the money with the seat, it is mod plated for it. Will be on a the hunt for a original seat once its all going and will be getting the wheel painted black, I really like the original look of the bike from factory! luckily theres not to much too change.

Just looking at the bike, the Forks ,rear shock and brakes all need a service which is no surprise and abit of wiring tidy up. Carbs are 1GA.

I will be taking all the panels and guards off over the weekend too get a better look and drain all the old fluids in it.
What else should I be checking for?
With it having 350 top end what else does it need for this swap?

[JonW]

Ok, carbs are 250. There are some internal passageways that differ with the 350, so even with the correct jetting it probably wont run properly at high revs. check the jetting though, you need 350 jetting at the very least - see the 57v parts book on rd350lc.net.

Check the oil pump spot and at the very least pressure/vac test the engine to check the crank seals.... and if you run this with old and dead seals you will kill the crank and poss a cylinder, its much cheaper to renew them now and know they are right. I only give two warnings, youve had em both now

FWIW, I have a recovered black seat that I was going to sell, just not listed it yet, its not got an OEM cover, but they are long NLA now of course. Has all rezinc'd fittings and is very clean. I'd take $150 to move it on - thats just the cost of the parts really - If i have to do ads or use ebay i'll obviously ask more.

Where are you based?

[S33DS]

Well ill start hunting around for 350 carb in the coming weeks once I get on a rolling with this little rocket! My grandad did have an pair of cylinders on the shelf which I'm guessing are the stock ones, so ill get them on my next travels there way just so I can pair the carbs to it just incase! And ill be having a good dig around because I know theres basically another rolling chassis (his 3 bay shed is full of bike parts)

Just ordered a pressure tester too, it is better to be safe then sorry. Im am planning on rebuilding and refinishing it but I just want to make sure It will run before I get to deep and invested in it !

Would be keen on the seat and I'm based in brisbane mate !

[JonW]

I have some 350 carbs in one of my sales posts on this forum that might be the ticket for you. But you also really do need to look for the red or yellow dot on that oil pump...

Good news on the other parts, always handy and you never know you might get the bug to do something else with the others.

Pressure tester is good news... but this is the line i hear so often, and it scares any of us who know these bikes:
"but I just want to make sure It will run before I get to deep and invested in it !"

Seriously, it will run. Look at it, someone (your grandad probably) spent a lot of time and effort on this bike. its no ebay cobbled together bit of crap etc.

Anyway...

No worries Im in Sydney, worth updating your profile I would think. I'll drop you some pics of the seat if you PM me your email addy.

[Gavin]

What jon said.... I had to laugh at the "but I just want to see if it will run" comment. Yeah - guilty as charged