Modern/Current Motor Mods?

[Hellgate]

Hey Everyone,

The last RZ350 motor I built was way back in 19 87/88.

Back then my main guide was the Motorcyclist Magazine "tweak" article.

For my '87 version I did the following:

1) 1st over, Weisco
2) Toomey Y air boot with K&N filter,
3) Spec II pipes
4) Milled head, .030 IIRC
5) Matched ports
6) Medium porting
7) Boyensen Reeds
8) Jetted carbs
9) Blue Print/Balance

I think that was it, I could be mistaken. For my chassis I'd done much more.

What is the current "street" set up? Has anything really changed much in the last 25 years??? What do y'all recommend?

My goal is to "restore" the bike, yet improve it at the same time; eg: IgniTech Ignition. If I do make changes wit will be with Yamaha OEM partsl FZR400 calipers, etc.

Thanks!

[JonW]

Plenty of new technology out there if you want it. A ported 421 or more would be more fun and you could go up from there and be even more modern perhaps... depends on your budget...

[Hellgate]

Thanks very much Jon. Do you have any links you can add? I've done a number of Google RZ350 "Tuning" "Performance" etc, and not found a whole lot.

Thanks!

[JonW]

Im currently traveling but plenty of project threads here an elsewhere, my site (in my sig below) talks about my 421, and its tame in the dmoern world with 500+cc's out there, even 600's...

[This old RZ]

For your average RZ350, Its still pretty much the same as it always has been. A lot of different theories and applications, and they all work to some degree some better than others. I had a RZ very similar to yours, and you really couldn't ask for much more, it was plenty fast, and bullet proof. It was a Spec 2 built engine from the same year as your build. My perferance was Toomey pipes over Spec 2s, they performed better for me, but Spec 2s newer designs are leaving many a rider happy.



What has changed is primarily two things, The crossover of BANSHEE ATV engine components, such as stroker cranks, and large displacement big bore cylinders and heads with interchangeable combustion chamber domes. Allowing fairly easy 90-100h.p. range RZs, that's a good 25 h.p more than the older builds. the draw back to some extent is the deletion of the Factory YPVS system, some kits come with their own powervalve system, but are nowhere as refined as the YAMAHA setup. The kits without The power valves of any kind comes on HARD and FAST some people like it others don't its a preference and riding style for the individual to determine if they like it or not. What the kits make up for in power YOU WILL LOSE RELIABILITY AND LONGEVITY over a lower h.p. stock based build.

The other beneficial advance has been programmable ignitions, Zeeltronic, primarily. They probably don't really add power but make it a lot more useable with the YPVS system and without. In addition probably allow high strung motors to achieve better reliability and longevity through "safer" improved control of the timing. Others here can tell you all about the features they offer.

To a lesser degree there is a plethora of pipes available for the RZ now, for every application and desired rpm range

Pretty much a build such as yours on a stock based build you should expect between 55-70 h.p max. Depending upon porting ,carbs.
the big bore stroker crank engines between 70-100 h.p on average, but there is ALOT of things to consider when building such a strong engine, as the Stock RZ has to be improved on in virtually every area to safely handle the power of such a build, Suspension, transmission,rear wheel components and sprockets easily expire, along with a lot of top end meltdowns and blown head gaskets, you probably wont ever even have to worry about any such issues on a stock based performance build.

Roger @ Wicked ATV has a 385,392 stroker crank that I believe still uses the stock power valves and is DYNO proven to deliver 70 h.p several members here have utilized it and seem to enjoy it. he had a good website, but its down and has been for a long while too.

There are also several pipe designs specifically for stroker based engines Wicked and GPL racing come to mind both have equally good feedback. GPL racing also does O-ringed cylinder head modifications ,similar to Wickeds o ringed head, Wicked offers a fully billet head, that's also easy on the eyes.

Also Tony Doukas of TDR fame, has stated he is researching a "stealth" BIG bore using stock cylinder heads & YPVS ? punched out to I think 400cc. But don't quote me on that displacement. He also offers virtually a dozen big bore stroker combos that are crossable from the Banshees

Gary @ Spec 2 is till at it,45 years and going...lol and delivers a reliable strong build. His website hasn't been touched since like 1999...lol You have to call him for details on what's new in his world.

As with anything the more you spend the faster you go. From a stock based performance build @ around $1600.00, from most builders, then around $2500-$3000.00 for a stroker based engine,,,, all the way to the H.P. king of the RZs/banshees ROGER at Wicked can deliver a 175-190 h.p. Billet cased, billet head, monster big bore 500=+,600+ccs alky drinking drag engine for probably around $10,000 dollars.

When it comes to ULTRA high performance..and MEGA power things have changed a lot! All the rest are going to deliver similar results regardless whom builds them, the area where you want the power delivered at higer or lower RPMs varies from builder to builder,each again has their loyal following and good reputations.

Any technical, specific question I'm sure can be answered by many on this forum

[Hellgate]

Wow! Thanks for the responses everyone.

Old RZ I do very much appriciate the detailed response. I figured it hadn't changed too much over the years. Jon thanks again for the leads. I've got lots to research.

I will say the Banshee motors are simply amazing, 600cc! WOW! I can't even imagien that.

For this bike I think, famous last words, I'll build a solid, strong street motor. I've always liked bikes that are rideable with a too peaky of a powerband. That said, as a few people on this board will attest (from the FZ1 Forum), I've been know to throw that conservative idea out the window and go whole hog. Time will tell.

Again thank you all very much for the welcome and the info.

Let the fun begin!!!

[JonW]

I agree mostly... but...

What the kits make up for in power YOU WILL LOSE RELIABILITY AND LONGEVITY over a lower h.p. stock based build.

hmm... Depends on what one you go for and what tune... There is nothing to say a brand new Athena 421 setup is unreliable over the standard 350.

My advice is to do your research, read what people think and decide on your budget. I found that you can spend as much cleaning up, reboring and messing about with a 30year old PV setup as you can fitting a modern new athena kit. Your money, you decide. ive done both. The Athena is more fun and more powerful, Ive not done 10,000miles on each to compare etc but smiles per miles the athena wins for me, and of course you can spend more and go more mental. But decide what is right for you, a 350 can be great, of course, but the parts themselves are getting on a bit now is what i found.

Either way, Enjoy!

[aaronmvrider]

agree with JonW.... if its a classic restoration you are after go with tidying up you existing top end...

and keep it original... otherwise it does get expensive for very little power increase

if its aggressive 2 stroke thrills you are after build a 421 or bigger...

i guess it does come down to coin... and how much you want to part with...

[seahorse]

As above, what John,Aaron and old RZ said.

To add for you basic build there are
Vforce 3 and Vforce 4 Reeds
Some fantastic Pipes JL's, Kenny TSA to name a few
Keihin PWK28 Flat slide carbs ( great work done here by Whyme on the write up)

All of the above can be found, well discussed, by a great bunch of old boys on this forum.

[Hellgate]

Thanks Seahorse! That is exactly what I was looking for.

I spoke with the seller and the shipper today and we are good-to-go for pick up tomorrow. I should get the bike by Tuesday or Wednesday. Would that be a cool 4th of July "present" or what???

[busa1300]

I had my engine done by SPEC II back in 85, Stage 3 porting/welded crank/pistons/milled head/bigger reeds and cages/32 mikuni's/Toomey pipes... It was a screamer then
Just got it fired back up last year, after sitting for well over 20 years or so....and its still just as it was in the 80's...
It's an old bike...leave it old school... old school never gets outdated

[dinamos]

I haven't done it yet but a cosmetic change that's supposed to be an easy swap to loose the chick-let head light for a dual round headlight. Troll Kijiji for an FZ 600, not to be confused with the later FZR. The upper fairing will mate perfectly with the RZ mid fairing. You will need the FZ sub-frame/bird cage strut assembly which is supposed to bolt straight on the RZ. Of course you'll need the lamps that go with fairing, the wind screen and mirrors as well. The RZ instrument cluster should bolt right in.

[This old RZ]

I had my engine done by SPEC II back in 85, Stage 3 porting/welded crank/pistons/milled head/bigger reeds and cages/32 mikuni's/Toomey pipes... It was a screamer then
Just got it fired back up last year, after sitting for well over 20 years or so....and its still just as it was in the 80's...
It's an old bike...leave it old school... old school never gets outdated

CASE AND POINT! In 86 ish I had virtually the same set up by Gary @SPEC 2,with the 375cc mod he did. I've said it a million times, but it never gets old...lol. That lil bike was pretty quick for a sub 400cc bike.
It did mid 11 seconds in the 1/4 mile, and regularly out accelerated many of the performance bikes of the day, not all them as other guy had sleepers too, but regular examples were GPz550s,GPz 750s,Honda Interceptor 700s and 750s,KZ750s,Ninja 600s,Gs550s,Kawi triples 500 or 750s, Yamaha FZ 600s 86-89s, GSXR 750s 86 Honda Hurricanes etc.. beat them all as long as they were close to stock
Granted this was only in the 1/4 mile, after that all of them could easily smack down a easy 30-40 mph on the top speed, and within seconds I would be a speck in their mirrors, but that happened anyways from riding a lil mini bike like the RZ350...lol But most times ,almost always it was just 1/4 mile drag races and street light showdowns, I didn't lose too many drag races,and never once lost to another 2 stroke In addition, I rode that bike everywhere day ,night rain or shine. Cruised the California coast line to the Mountains to the deserts of Arizona, I had over 30,000 hard abusive miles on that poor lil bike, and it never skipped a beat..I loved that lil bike So there a lot to be said for keeping it old skool.

However , I see the potential for a possible 10 second "STREETABLE" hyper RZ with a big stroker setup, so that would be a whole lot of fun. I just don't know If I'd be comfortable attempting all day rides or traveling with such a high strung engine? I suppose if its built right, carbs set up perfect with oil injection and able to withstand ALOT of considerable altitude changes, then it would be like having your cake and eating it to. Like most of us, I'm a good 40 lbs heavier than I was when riding that original RZ, I'm 195 lbs now. A RZ built or not with a 200+ lb rider is going to be challenge, It will put a huge smile on your face, but probably wont win too many showdowns at the O.K. corral, unless you have a MONDO stroker big bore as some of the guys have put together.
I'd like for once for someone to post a 1/4 mile time there getting from these builds, NOT a dedicated drag bike, but just a average stroker / big bore build. But I guess most people don't drag race, I find that utterly perplexing as every person I ever met on a motorcycle does this..but perhaps its a California thing...lol

I really like the Yamaha VPVS system though, it works so darned good on the street, and in impromptu drag races, even against other much higher H.P. displacement 2 strokes, you can really stretch out a jackrabbit start.
Virtually NO chance vs any modern machinery..but that's not the point anymore, now its just a sweet old lil classic bike, with a lot of smiles per mile! Its only 347cc but can be a angry,feistey lil bike as well Its basically the Chihuahua dog of motorcycles

[Hellgate]

Well exactly. I have an '05 R6 that is a dedicated track bike, and an Aprilia Tuono V4R APRC, so the performance spectrum is covered.

That is why I'm thinking an "modernized" RZ350 maybe the way to go. By that I mean current pipes, porting, carb set up, ignition, etc. For the chassis an alu swing, modern shock, and update the fork(Race Tech goodies). I may try to add a wider wheels, but I love how light the RZ wheels and tires are. Light for the time any way.

The FZ600 upper is interesting. I bumped into a few photos here with that mod, looks good. That said my bike is a Canadian '88 so I think I'll keep the fairing stock. That said, is someone like Motoholders makes aluminum sub-frame bits I'd be open to that.

I've always liked digging into the Yamaha parts bin as you can get them for cheap, and they are very high quality.

[dinamos]

A few years ago an Australian co, the two stroke shop. <thetwostrokeshop.com>, offered a 500cc top end with their own power valve design and carburation. They also offered a package that included frame, suspension and fairing in the form of an Aprillia MotoGP class 250. The package came in around $20,000.
If you want "the" latest suspension, frame and brake options along with larger tire profiles, you might want to troll for Aprillia frames.

roger