RZ/RD 350 & Misc. 2-Stroke Tech BBS

bitzz wrote: ↑Sat Aug 13, 2022 10:48 am It's simple to make a case for why you DON'T want an aluminum swingarm, steel is better.
A 4130 swingarm is lighter, stronger and returns to shape faster than aluminum.

aha, so that's why all modern race bikes use steel swing-arms.

oh no, wait ... it's the other way round ?

small Chistmas present update in the first post

Yamavarna wrote: ↑Tue Nov 07, 2023 7:30 pm Sorry I was referring to the very dismal gains with the +4 crank over stock

everything else the same ? timings, compression, ...

Yamavarna wrote: ↑Mon Nov 06, 2023 10:43 am That’s very interesting I wonder how well it translates to the real world?

I find it very normal that more cc's need a bigger stinger

b-bike393 wrote: ↑Tue Oct 10, 2023 7:44 pm

JanBros wrote: ↑Tue Oct 10, 2023 4:55 pm a full rebuild of the engine means it's not the same engine anymore and it may need the carb's to be set-up differently.

Are you talking just jetting?

yes. play with the eedle to see if you ccan improve it. mains is only for full throttle.

a full rebuild of the engine means it's not the same engine anymore and it may need the carb's to be set-up differently.

You're actually leaning out your air-fuel mixture when you put in too much oil. That probably won't matter much if you're running rich anyway, but if you're right on the edge of running lean it could. Your plugs will foul more quickly, too, with twice as much oil as the bike needs. Stick your finge...

Darrell wrote: ↑Sun Jun 25, 2023 5:54 pm And just as an aside, it's a bad idea to run premix AND oil injection.

why ?
no engine has ever been hurt from more oil. as opposed to less oil.

So So many if not most RZs here and other venues have died here over the years when guys start adding programmable ignitions and or advanced timing with compression increases.... you want the burn-time to be as short as possible. original ignition is not going to help you doing that. so if you've s...

don't believe everything that is on the internet...

if that was true, we wouldn't need any sort of engine cooling, just pick the right spark plug. run your RD without water and use a BR1ES, it will draw another 700° C of heat from the combustion chamber

I tried switching from BR9ES spark plugs on both cylinders to BR9ES on LH and BR8ES on RH cylinder, expecting to see a diference. But there was absolutly no difference in the EGT :smt021 why would you expect to see a difference ? a spark is a spark. if you had measured the temp of the spark plugs t...

Frits Overmars has published a rule of thumb to get that diameter: https://4.bp.blogspot.com/-MgZiKNYsFws/UrGD6ifMgPI/AAAAAAAACso/_BHY05ZOm5I/s400/fos_ex10.gif that is an older version, here is an updated one from 2017 : https://www.dropbox.com/s/z0l77u5pe9tm4p5/FOS%20exhaust%20concept%202017.png?d...

you feel my comment was disrespectful ?
you say it is still relevant, It still is a good book to understand better how a 2-stroke works, but people who don't know better may use his book as is and calculate stuff with formula's which history has proven to be wrong.

Gordon was a brilliant mind and even though that article was written in the 70's based on experiences racing Kawa triples and early TZ's it is still very relevant today to any two stroke guy. Everything he writes is spot on. except his exhaust port formula's. don't use them as he uses the entire po...

due to a new post from Frits : https://www.kiwibiker.co.nz/forums/show ... r/page2494
new links in first post
I made a small correction to the calculation of the target Bd and transfer STA to get the correct target-value spot-on again with the new BMEP of the RSA