Building RZ350

[Sledge]

Hi,

I am a 23 year old female rebuilding an 85 rz 350,
I have cleaned an reconditioned the bottom end and have put new everything in it.

Upgraded oil pump, water pump, crank (new athena heads) stroked by 4mm and heads are slightly bored so i will end up with a 421cc bike.

Now my question is are there any specific things that i should be worried about once i have put my parts back together as i have not ridden any 2 stroke bikes with or with out power bands and have not ridden bigger bikes as i have not got my open bike licence.

I have 96 rgv front end and swing arm.

Will not be anything like the original and i know this may ruffle some feathers but would like to make it modern and maintain some of the original linage to show its history.

Will up load some pictures of the build and keep updating and asking questions as i go.

Any advice will be muchly appreciated.

Am wondering if i will need a steering damper and am unsure as to how i will be able to handle the bike.

Cheers Sledge







The valves are plastic with rubber surface. The plastic is more responsive than a metalic ones.
I painted the engine my self along with the shockies.
Swing arm is at the shop getting a crack repaired.
the frame looks black but when in the sun has a pink glow (i am a girl after all)

[JonW]

when you say 'athena heads' do you mean the cylinders? If so, can I ask why you bored them? they are 421cc if you run a +4mm crank as standard. Also, please do have the domes recut for the +4 stroke, else it will end very quickly

RGV parts, very cool... no hassle with those mods here, and its easy to do on an LC or RZ, just a 5mm spacer.

steering damper... yeah, could be useful!

pics are good... add whatever you have

[Sledge]

the heads haven't been touched. sorry thought they were bored as well, they are just straight from the shop.

[hybrid]

Welcome to the forum!
Good to see a young lass enjoying an old stroker.
My wife (around your age) rides my 350LC which I will hopefully be building an engine like yours for.

You'll be fine on the bike - it will be nice and light, and only as fast as your right wrist.
Being a non-power valve engine, the power band could be quite lively (great fun), so be ready for it at around 5500rpm or so.

You shouldn't need a steering damper. My 350LC has RGV forks and swinger (older model RGV than yours), and it handles fine. The longer RGV swinger will slow up the steering a bit anyway.

[Sledge]

thanx, have really enjoyed learning about the engine, taken too long to do my liking but will be worth the effort when I take her for the first ride. jon w I have had the cylinders machined to suit too and the domes (I've called them cones in my pic learning correct terminology still) are the correct ones. have had help from a fella in cairns who provided me with the parts made sure I got the right bits and did the necessary modifications to suit. he seems not to have bum steered me at all and was happy to help.

glad to not have to put a steering dampener on less work to do

[Jeram]

Hi and welcome, nice choice for a project!
Where do you hail from?

If its you first time building and setting up a two stroke let along a performance motor be sure to do the following

Get pipes to match the motor, wicked racing does rz421 pipes

Use an exhaust gas temp gauge and a coolant gauge

These cylinders won't like the 70 degree thermostat so either get a 55 degree thermostat insert or buy a two stroke shop bipass thermostat.

Don't use cheap oil on a motor like this, use the best you can afford as it will save you money in the long run as it will prevent engine failures and part wear.

Be sure to get a zeeltronic or ignitech ignition as the stock ignition will severely limit power, I've got all the maps if you need them.

That's all I can think of off the top of my head that hasn't already been said.
And I'm sure Steve (the fella from cairns) has already sorted the above items out for you

[JonW]

Ok, so if youre buying from TSS in Cairns I would think you would have the parts you need. I would also get some larger carbs and a manifold that will lift them over the clutch arm, and also a stronger clutch... See my website ( www.2smoked.com - tho it does need an update as more of the stories are done I just havent had time to update it yet) for my 421 build as it shows what I mean and also what I did with my LC motor (an RZ with Athena and +4 TSS crank). You will also need big pipes too... Lozza on this forum was talking about doing some, else speak to Wicked as his are designed for the larger cc motors and what I used and have been happy with. Most of my stuff came from Wicked and if you speak to him tell him I sent you and link these posts on the forum so he knows what you are building etc.

Jeram, I used the Kartelli remote thermo, its a nice kit for use on a 421 imho. Sledge, you should drill and tap the head for the sender tho... just my 2c.

I'd not wager about the damper, these bikes will wheelie and so you may decided later to fit one, I know I will to mine...

[JonW]

Just noticed the pics, any chance of them being larger?
Did you port match the cases and what are those reed blocks? Banshee?
Domes look recessed enough so that is good, but turn it over slowly when built to make sure it doesnt hit. I assume you have not fitted a spacer as I cannot see one, thats good news, spacers do not work properly.

[JonW]

Oh... and as Jeram says, buy a Zeetronic ignition. Simple and easy to set up and well worth it.

[fred99999au]

Amazing the amount of excitement a new 421 stroker brings out. I am in the middle of a similar project, but I am intending to keep it looking like a stockie. Except for the Athena Barrels and heads. And larger radiator. Both of which I am thinking of hiding behind stock looking black paint.

And I bought a pair of the PWK28 carbs on a whim to see what they were like.

Keep going with the build thread and keep posting pics.

Probably no point in me taking too may pics of my project as Jeram can vouch for the state of my shed.

[hybrid]

Not sure if the PWK28's will be enough for the 421?

They are great carbs though.. I have them on both my bikes.

[fred99999au]

yeah, thought about that. I also have a pair of r6 throttle bodies and a microsquirt, a la Smurf, but in terms of making sure that things go bang in the right order etc these should be better than the broken mikunis I had.

We'll see when we get a bit closer to screwing the box together. Need to get the rear caliper onto my original RZ today (bolts just turned up fro powersports plus) and get my newly cleaned and tyre refitted wheel onto the front.

I can't believe the useless mechanics I took it to last time lost a caliper bolt and replaced it with whatever grade 4 bolt they had lying around with a washer. It had better be the correct thread. I asked them to clean the wheels and remount both tyres, but they mounted a new tyre on the front and cleaned neither wheel, so, I had at max 4 hours rider time between tyre inflations.

[hybrid]

I would not inject it personally... been there, done that.

[fred99999au]

You cant just leave it there tiger. how why why not?

Everyone seems to say it is a disaster but nobody can say why.

[hybrid]

Two stokes don't have enough vacuum for it to work properly.

I was running mine on alpha-N to compensate for it, but IMO, the amount of time you spend to PERHAPS get it right is not worth it when you can bolt on a set of PWK's and have it run nicely.
I've put the ECU on my mustang instead.