Hi all, I am in the fortunate position to receive a free RZ350. So naturally I am considering racing it in some vintage class. The question I pose to all of you is: What are some common and reliable race preparations that are done to the RZ? I am not interested in being extremely competitive, I would rather have a reliable bike that will last the season. I am interested in a bike that will handle good with some sticky rubber. Maybe I will do some jetting/carb work and intake and combustion chambers, but no real internal engine modifications. Any help/suggestions will be greatly appreciated!!
If you are getting a stock US Model RZ350 then you will want to replace the stock exhaust with a aftermarket set of race chamber and jet the carbs to match. Toomey are a good choice but are no longer in production, Spec II offer at least two sets of pipes for the RZ, Moto Carrera is another choice and also check out Jolly Moto pipes. Replace stock reeds with BOYESEN, TDR ,or MOTO TASSINARI V-Force Delta . You will get mixed answers to which is best. Two-into-one type air filter. Front suspension: Race-Tech Gold Value Emulator and Race-Tech springs and correct fork oil. Tapered Steering Stem Bearings Fork Brace from Telefix or SuperBrace Replace stock rubber brake lines with Stainless Steel or Kevlar lines and new brake pads. If you want to use clip-on type bars check out Pro-Flo.com for a quality set at a good price. Rear Suspension: Install a aftermarket rear shock from Fox Racing, Ohlins or Works Performance. Have the flywheel lightened Mill the head If you are going to port the cylinders you might as well work on the bottom end of the motor and do it right the first time. Replace the main bearing as needed and have the crank trued and welded to help keep everything together at higher RPMs As for tires check around for the best race tire that will fit the stock wheels. DO NOT install tire that are to wide for the rims in the belief that wider tires are better. Avon makes a good line of tires in the stock RZ sizes. Check out MotoCarrera.com Pro-Flo.com Good luck!
I race an RZ in Formula 2-stroke. You can e-mail me if you want. I'm traveling all week, so my responses may be delayed. [email protected]
I've raced rz's for 7 years, TKM gives good advice. Depending on what you want to do w/ the bike, you may not need to do all of the things he lists. If your just looking to have a good time and don't care about the results, you can getb away w/ a lot less. If you want to go out and win championships, you'll need to do a lot more. For a fun bike, I would do the pipes, reeds, bars/clipons, 1into2 k&n, fox shock, brake lines and true the crank. Stock porting is good for starting out, but, by all means, if you are going to port it, have the cases matched. If you get it ported, you'll want to mill the head to restore some of the lost compression, but don't do it if you leave the cyls stock. I don't place too much priority on dyno #'s, but stock cyls will get you 50 hp w/ toomey pipes and 2into 1 filter and jetting. Big carbs and radical portwork can net 80hp, but I've always run mine around 70 for reliability reasons. If you put more hp to it, you'll need more goodies to keep it together. Oversized radiator, aftermarket clutch basket and high octane gas for starters. Also when you start getting big hp out of rz's, the stock chassis becomes the limiting factor. Most rz's you see today at the track have some form of hybrid suspension(forks, swingarm, wheels) to help get the power down. Start running the wider wheels w/ modern rubber and next thing you know, the stock frame is seeming quite spindly. Like any race project, the more you want, the more you'll have to do. I can't agree more about the tires. Run the tires that fit the rims!!! Bigger is NOT better. Avon am22/23's work good, but so do the smaller ones(90frnt 110rear) that everyone uses on rd's. Handmade Dunlops are supposed to be the best, and offer the best selection of sizes, but I haven't gotten around to trying them yet as they're quite expensive. Jemco still makes pipes for the rz and they work very good, giving you more rpms than toomy's or spec 2's, but the people at Jemco are a bit difficult to deal w/ (assholes)and you'll probably end up drilling holes in your rearsets to make them fit. I'd love to try some moto carrera pipes, as I've always heard good things about them, but they can be on the pricey side too. Bottom line: If you're REALLY on a tight budget, at a minimum, get the crank rebuilt/welded, good pipes, reeds and airfilter. After that, start going through the items TKM mentioned. I'd start w/ the shock. If you need a reliable source of new/used parts or portwork, Gary Stumm of MRA is an absolute MASTER w/ rz's and always gives very realistic advice on mods. If you want to build the snot out of it, his motors and bikes have won 17 national championships since 1991, including 5 last year. His # is 386-364-1231. Harry Barlow, Lyn Garland, Moto carrerra and Toomey all do good work too. I'm sure there are more, but I think you've got enough to go on. Feel free to e-mail me w/ any specific questions at [email protected] Good luck!! Mark Morrow
