Two stroke resto mod

A friend has a RZ 490 something with over 100hp. Off the shelf engine parts.

 

Yeah the RZ350 motor in rolling TZ250 chassis was always the easiest back in the mid 90's, most people were stuffing them in the 91 and 92's because the sub frame was bolt on that year.
I think it was 92' they started that....

 

https://www.ebay.com/itm/1986-Suzuk...6281c266:g:0T4AAOSwcWJby-SE:rk:1:pf:0&vxp=mtr

 

Save all your time troubles buy the rg500 previous post. Its the holy grail. Clean it up tune it up don't go overboard on upgrades youll be all smiles and it appreciates in value every day. My sportbike for 20 yrs is an rz500. Fox shock, 01 r1 forks for correct offset and 300mm brakes to keep weight down, tz wheels 4.5 rear for 160 tire for chain clearance and any more is too much and keep the weigh down. Ports cleaned up matched heights and angles, heads cut tighter squish smidge more compression, advance timing couple degrees, joly moto pipes, carb tuning from hell till you get there, the bike flies but its tempermental. 45 pounds off and its almost down to stock rg500 weight. Its on the rich side for safety so starting cold it smokes. Like a lot. When warm the first time you wring it out it makes a cloud then goes cleanish. Some of your friends will bitch if they follow too close. I have it geared tall 16-41 I think. it'll wheelie but not easy like a duc. One issue with 500's and why I don't want more power is how I ride it. I go to Arkansas for tight twisty or Colorado for more open roads. The rz500 loves Colorado where you can wind it up in higher gears. I get 30mpg if I keep it under 7-8000rpm's rolling throttle on and off. Its when you get to long straight roads and friends want to make time that I have to compute how much gas I've got. I'm at 7000r's at 90mph when the motors just starting to sing and it doesn't want to hang at 90 it wants to go FAST and DRINK gas like no tomorrow. Boring straight roads lead to gas pumps so when you see the sign wind the needles past the numbers clutch and kill switch coast in for plug check. Friends all laugh and say didn't you see that Aprilla 1000 on craigs for $2200?
I've done trackdays at Hallett on it and its kind of a handful compared to an sv650. A long track it would at home. And where it shines the sv is a boring piece of crap.
I've rode RG's and I have a 400 getting similar upgrades for my Arkansas bike. Its more hooligan and should suit Hallett really well. Also have FZR400 with RZ350 motor going together for around town bike. A 500 and 400 triple. Oh yeah I've got a machine shop so that helps
If you fix up an RZ350 look at the 3 and 4x17 wheels from R3's, ninjas an KTM 390. Go for the lightest ones and you get to run light radial tires

 

Hmmmmm........RS500 pops into my head. If that is a bit too much fab, RGV500 is a *little* less fab work.

However, you would have to find an RG400 or 500 engine for the transplant, and they are getting tough to find.

BUT.......

Well worth it !!!!!

 

Suzukis aren't on the radar for me. Don't get me wrong, the Gamma is a cool ass bike, but I prefer Yamahas. Besides, RG500s are big bucks and rare. I have no real desire to cut up a rare collectable bike...especially one that costs as much as a Gamma. That ragged out one posted above sold for almost $10,000 on Ebay. I'm pretty settled on using a RZ350 as the base for the project at this point. Currently on the hunt for a ragged out bike with enough bones to serve as the platform to build on.
If anyone knows of one collecting dust in the corner of a garage somewhere, let me know. Plan on replacing suspension, brakes, wheels, and most of the engine, so anything with an intact trans/bottom end, usable tank and good frame with title will suffice. Prefer yellow for the base if the fairings and tank are usable and because I plan on having a black frame. I'll likely powder coat the frame and paint all the trim anyway, so the red/white isn't a deal breaker.
Pretty sure I'm going to make an attempt at converting it to EFI also. It's been done already, so the blueprint is there. Just needs some tweaking from what I've read so far.

 

Also, as per Joe's advice, I'll most likely do the 421cc engine conversion using 68mm Cheetah cylinders and a 4mm stroker crank. If that can be tuned to 80-90hp, that will be plenty for a little corner carver street bike that weighs under 400lbs wet.
Any idea what expansion chambers work best for that engine configuration? Toomey, Lomas, custom unobtanium unicorn pipes?

 

I say go here and look at the Projects section. Then dig through the for sale section. Lots of ideas and a wealth of knowledge regarding building RZs (engines and which chassis mods work).

http://www.rzrd500.com/phpBB3/index.php

 

All depends on what chassis you will use. Tyga does make pipes that fit the Cheetah cylinders and bolt right up to an Aprilia RS250 chassis.

 

The exhaust was one thing I still didn't have a good plan for. Looking through Tyga's website, I'm curious which pipes you are referring to that bolt up the RS250 and fit Cheetah cylinders? I found these http://www.fastfromthepast.com/lftp100gp on Fast From the Past, but can't find anything on Tyga's website that fits the description.

 

Maybe these?

http://www.rzrd500.com/phpBB3/viewtopic.php?f=10&t=15678

 

That design was originally developed by Wobbly in New Zealand (2-stroke shop that went under) and Tyga built the first batch. Jim at Fast From The Past took that design to Jim Lomas and had him make a batch. So, getting a set from Jim would be easier and also a direct bolt up.

 

Holy cow that is a smoking good price and those were the pipes I originally posted about.

 

Joe, so for RZ stock framed bikes with the 421 engine, you recommend the pipes from Fast From the Past?

 

Local Craigslist has a rg400 gamma

https://buffalo.craigslist.org/mcy/d/1985-suzuki-rg400-rg-400-gamma/6718205893.html

 

No kidding on that price. I'd be all over those except I am going into a RGV250 chassis so will likely not be a direct bolt up for me. I'm not sure how different things are between the RS250 and the RGV250 as far as mounting points go and I haven't gotten to the point of mocking that up yet. Still haven't decided which swingarm I'm going to use.

 

Brian Turfrey is the best choice for pipes on the west coast. He will likely need your bike so local is best. He is in Oakdale CA (east of Stockton) and can easily help with the motor placement/mount etc. he’s done quite a number of rz350 engine bikes.

 

No. Those are for a Rs250 frame. I'd recommend a set of Toomey pipes but they would need to be modified to fit the Cheetah Cub cylinders. But, Ed may do this for you upon ordering a set. You would need to call him and ask.

 

the rgv / rs chassis are close enough to where i have rgv pipes on one of my rs' ...

 

This one caught my attention,,,,
https://www.facebook.com/photo.php?fbid=10212611445825129&set=a.10212354060910667&type=3&theater