2 Strokes Down Under

OK. Dumb question time. I'm new to strokers. My RZ 250 with a 350 top end seems to be running pretty good. I'm slowly learning how to ride the thing and while I have learned lots riding it lately, I realize I don't actually know how it's really supposed to run. So, if I describe what I'm experiencing, maybe some of you old salts can let me know if the bike seems to be running right.

Setup: 250 bottom end, 350 barrels, pistons, head, oil pump and carbs, TSS billet powervalves, stock airbox (although the bike came with an airbox cover with holes in it which I'm not using at the mo) and BR8ES plugs (the 9's seemed to foul up).

Starting: Two kicks when cold using the choke. I turn off the choke almost immediately. First kick when warm - no choke of course.

Takeoff: I find lots of clutch slip and at least 3 grand on the clock seems to work.

Cruise: I'm finding having at least 4000 revs up seems to work whether I'm in a 50k zone, 80, etc. Just a different gear.

Letting her rip: I'm finding a bit of a vibe in the 5-6 grand area but generally smooth everywhere else. I've revved her out to 10 but I'm finding that at 8-10 grand there's not really much there.

Front brake has good power but I need to use four fingers and give it a manly squeeze. Back brake more than powerful enough.

So, does that sound pretty much par for the course?

Thanks guys, in advance, for the benefit of all your experience.

Been along time since I played with these bikes too.....
Did you use the 350 pv controller as well?Im pretty sure there was a difference between 250 & 350.
Have you adjusted the clutch properly?
As for brakes,sounds like you need braided lines to get some pressure back to the calipers.
Also post up your carb settings,what sizes,where is clip on needles etc.Balanced the slides propely?Also have you double checked the oil pump setting?
Video would be helpful?
Wish I could find some billet TSS pv's

It has braided lines but maybe I could try some different pads.

Clutch adjusted, carbs balanced, oil pump setting checked. Other than that I don't know carb details. Maybe further research required.

I think it still has a 250 pv controller, so maybe that's holding it back a bit.

So, further question. Where's the meat of the power supposed to be on a bike setup like mine? I'm finding it's mostly 5-8 grand. Sort of tails off a bit afterwards. Normal? Or should I be hunting down what's holding it back from 8-10?

the answer..
i stock rz 350 will have loads of effortless torque right of the throttle..no ridding clutch..!!
power between 0-5 thou is smooth and polite as revs start start to build once over 6 grand the bike will transform with a full rush of power witch will pull hard till 11 -12tho..all very smoothly as a 2 stroke twin should top speed should just fall short of 200km

something sound out of wak with urs...

does your servo motor actually work? or is it jamming the PV shut?

Make sure you have 350 needles in the carbs and not 250 ones, huge difference. In fact check all the 350 bits are on the bike as you have a 250 with 350 parts fitted.

My power valve is a new TSS item. Replaced the control box and it seems to be working fine. Does the test thing when you turn the key and it starts to pull ok from 3 grand. Nothing really below 3. From what I've read in old reviews, that's normal.

As far as I know the carbs are 350 items. Got them used from Steve at the TSS and my mechanic gave them a going over.

I have just re-installed a holed airbox cover that my bike came with. It seems to give me better top-end and doesn't seem to appreciably affect the bottom end compared to the stock cover. Now my bike seems to pull good to 9 grand before it tails off. Twinrock, you mentioned pulling good to 12 grand. I'm new with these bikes but my tacho has a redline at 10 so I'm not game to give it more. Are you talking a stock bike?

I would check anyway most mechanics these days are not worth a wank when it comes to strokers.

EPApolice wrote:Make sure you have 350 needles in the carbs and not 250 ones, huge difference. In fact check all the 350 bits are on the bike as you have a 250 with 350 parts fitted.

if were talking WOT at 9 grand, it should be the main jet, not the needles yes???

a simple plug chop should answer the carb/fueling question.

Mine had 250 needles fitted to 350 carbs and 350 motor and it would not rev out, changed to correct needles and problem was sorted. I am not saying thats the case here I am just suggesting to check all is as it should be at least then you can look else where.

Well, I found something yesterday. Turns out that the PO had changed the sprockets so that the gearing is higher than stock. Putting stock-sized sprockets and a new chain on it this week and it'll be interesting to see the difference.

Now that the bike is fully broken in after the top-end refresh, I find it does rev better generally. And it does pull from about 2 grand now. Nothing too urgent of course but it's usable for a gentle takeoff.

There's still a bit of a vibe between 5 and 6 grand. Checking all bolts for tightness. Smooth everywhere else though.

Installed stock sprockets front and back (16/41). Pulls much nicer from a standstill now.

Still haven't isolated the vibes between 5 and 6 grand. Pretty smooth everywhere esle though. It's sort of like breaking the sound barrier. Is that the norm for these things or do I have more investigation to do here?

Cheers.

Double post...

Bumpitty.

Do these RZ's have a bit of a vibe between 5 and 6 grand? Mine's smooth everywhere else in the range but I have to push through a vibe at around 5 to 6. Not a huge problem for me but just wondering if that's par for the course.

And when's it gonna stop raining?