My dream project...can I make it happen?

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vile1
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My dream project...can I make it happen?

#1 Post by vile1 » Wed May 10, 2006 1:35 pm

I've been racing mototrcycles since I was 5 and my dad was an old school roadracer back in the 80's. In 93 he got ahold of an 86 RZ500 and ever since then I have wanted one so bad.

Now, today Im 22, quit motocross, road raced for 2-3 years on a 929, a ZX-7, and even built my own little CR80 powered Honda RS125.


But I want more. I was raised on 2 strokes and I have premix in my blood.

I want 4 pipes.

Here is my situation: I have recently been given an MC21 NSR250 frame and forks/triple clamps. I thought about putting an RM250 engine that I can get ahold of fairly easily in it...but i dont want that. I thought about an RZ350/Banshee motor but those are getting rare now and you either 1) cant find em or 2) they are upwards of $1000 (on ebay at least).

So it leaves me only the other option of: step up to the big boys. But where to find an RZ500 engine? that is the engine I really want but will settle for an RG500 or even an NS400 engine.

I have the resources and the know how and especially the drive, to complete such a project. I just need the opportunity. And this frame was just the kick start i needed.

Any help from anyone would be greatly appreciated.


btw-Im new to the board but I have been browsing around from way back when the BBS was a wacky text basted HTML board.

Shaftoflame
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#2 Post by Shaftoflame » Wed May 10, 2006 5:00 pm

Hi Vile
You are in the right place, you will get loads of assistance - if you ask specific questions - but you know that anyway, mind the answers may contradict.
My guess is a RD500 lump will cost pretty much as much as a Banshee - it should anyway! But they are just sooooo nice and so understressed that there is loads of scope for playing with them. Just the intake restriction and possible rear bank cooling probs to really feed a fly in the ointment - mind both issues have many and varied fixes. So best of luck, I will nto take my lump out of the frame - but if you need any measurements and I can help - please ask.

Rinnnnngggggggg dingggggg dinnnnngggg dinnngggg.

R
Dreaming is not a failing, it is what makes us climb bigger mountains, make better bikes and love. However it can take up an inordinate amount of time...

vile1
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#3 Post by vile1 » Wed May 10, 2006 5:51 pm

haha thank you man I sppreciate it!

Yeah I really do think the RZ has the greatest potential for modification because it is so durable.

It may not have the cassette transmission of an RG500 or the lightness of 1 crank like an NS400, but its stout and reliably can make upwards of 120hp.

RG500's transmissions i hear crumble and chunk when you start tuning them and NS400's just cant even make it to 90hp without serious amounts of re-engineering/tuning.

I would really like an RZ engine as well because its characteristics are that of the NSR250 engine that went in the frame, i.e. 90 degree V. It also sits in the frame very similar to the NSR lump.

The problem isnt really price, it's availability! i cant even FIND an RZ engine.
So if anyone has a spare or one willing to sell, please let me know! Even a seized/wore out engine is fine as I would rather rebuild it myself anyways:)

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hybrid
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#4 Post by hybrid » Wed May 10, 2006 9:43 pm

First thing you want to do is measure the width of the engine and the inside of your frame.

Originally I was going to put the 500 lump in a TZR parallel twin frame, but the RZ engine was too wide even for that frame.

The NSR is a 90 degree twin yes, but the 500 engine has two cylinders across as opposed to the NSRs one cylinder.
You may well have enough clearance, but thats the first thing I would be checking.

vile1
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#5 Post by vile1 » Thu May 11, 2006 12:20 pm

I get the frame and front end on saturday, I will photograph it and measure all of the dimensions and get back to you guys ASAP.

If any of you have dimensions for the RZ frame please let me know!

much appreciated,

Tony

Questo vecchio rz
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Re: My dream project...can I make it happen?

#6 Post by Questo vecchio rz » Wed Dec 01, 2021 12:40 am

Okay here we go... My advice based on a " race bike" point of view.

A NSR is a special "lil" bike outside if a factory TZ or NSR/RS typically the best instrument ever to come out of Japan.
Now a race bike IMO needs to be Lightweight no exceptions regardless if displacement.

Here's some things to consider, ad stated above fitment...I personally doubt the RZ500 motor will fit in a NSR, but you'll have to determine that, along with pipe routing options, YPVS controller, electronics ,battery etc and clearance both within the frame and ground and front tire, basically n/s east & west have to be calculated.

The RZ500 motor, is quite heavy..if I recall about 150 lbs !! That's a LUMP! And expensive w electronics consider 5k + just for a motor, and NOT necessarily rebuilt either.
Also there may be a few 120 h.p. RZ500s out there, but I've never seen one and I've owned and seen quite a few. I realistic expectation is 90ish (Real) h.p. for a tuned motor.

A RG500 motor will assuredly set you back 5k or more, but much more potential for speed. A Gamma can be breathed on all day and night to 100+ h.p. with many aftermarket parts available including big bore kits ..
Then the weight is substantially lighter than the Big Ol V4 Yamaha at around 120ish lbs. You will still have all the clearance considerations to determine and work around, to see if like the RZ500 motor it's even viable.
And yes a couple years transmissions need to be looked after but it needs to be rebuilt anyways if you're building a race bike in the modification can be done then. Nothing on a Gamma or an RZ500 motor is cheap..

Now..Consider the RZ350 motor...far far lighter than either the above at approx 70ish lbs.
FAR more compact, and easier to position in the frame for optimum balance. I know an rz350 motor fits I used to see several nsr250s out at Willow Springs that had that RX YPVS conversion back in the 80s and 90s
A basic RZ350 with afull race tune can achieve 70 h.p. ...but remember once assembled vs a 4 cylinder your likley looking at 75 lbs less wright...that's HUGE ! Also consider that any Banshee motor can be modified free serious track weapon and with certain available cylinders can be tuned to exceed the power of a built gamma or rz500 at much less expense you can use Athena cylinders CPI cheetah or several cylinders and there's a few others on the market as well. Displacement is anywhere with a stroker crank 4 or 7 mm to 380 cc's all the way up to 535 or more.
In a track bike or canyon Carver... This setup would annihilate either of the other combinations and for the price of just a used motor for the others you could build one very Stout powerful r z / banshee based engine.
you don't necessarily need the ypvs system either on a race bike for most tracks most erasers pin them open anyways back in the day.
Personally I like it.

now be aware if you've raced CBRs or ZX. kawis...chances are they will be ultimately faster than any of these two stroke options unless you went with the rz350 500 + cc combination... There are literally hell on wheels and also would require a very skilled Rider to control safely frankly the Big bore RZ350 based engines are brutal.

Finally don't let this deter you from your dream if your dream is to do a 4-cylinder then go for it they're totally cool no doubt! But with any of these you're basically building a new motorcycle from the ground up everything has to be considered weight balance weight distribution clearance suspension electronics.
Go with your dream. Whatever it may be :grin:
Banshee (Baja) Full Tilt desert race bike
Royal Enfield 500
96 GSXR SRAD, Future Yoshimura TT-F1 Lucky Strike rep.
85 custom Tri-Z
RZ421/YZR track bike(project)
86 VFR750 Flying Fred Merkel replica (project)

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Smoker
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Re: My dream project...can I make it happen?

#7 Post by Smoker » Wed Dec 01, 2021 2:28 am

Questo vecchio rz wrote: Wed Dec 01, 2021 12:40 am Okay here we go... My advice based on a " race bike" point of view.
Can't imagine he still needs advice after 15 years!


...Unless he's as slow as me. :smt003

rd84
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Re: My dream project...can I make it happen?

#8 Post by rd84 » Wed Dec 01, 2021 8:23 am

Hi,

I've got a braced aluminium RZV500R frame , 2CO R6 Swingarm, Ohlin forks and Brembo brakes - and its absolutely solid and stable, but is also very manoeuvrable at the same time - its handling feels like a CBR/ZXR/R6 road bike but much lighter - obviously the 600's have more horsepower, the road 600's also have more weight- but they won't embarrass you if you're a good rider - sadly I'm quite heavy and not a good rider :-) - dry weight is roughly 150kg and about 100bhp at the back wheel - talk to Bill Wilson about engines if you're in the USA or Canada.

There's a thread on my bike on this forum if you need more details ....

Image

Cheers
Paul

Strokingit
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Re: My dream project...can I make it happen?

#9 Post by Strokingit » Thu Dec 02, 2021 3:00 am

The OP hasn't visited this forum since 2007.

My guess, his dream project didn't happen.

rz500guytexas
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Re: My dream project...can I make it happen?

#10 Post by rz500guytexas » Fri Dec 03, 2021 1:19 pm

We all have expectations but some are out of reach and sad part some are started and never completed. Then given away by the kids as it sat in the corner of the garage of their former parent. Life is too short but do what makes you happy and gives you enjoyment. Mine is twisting the throttle on these wonderful two strokes.

rd84
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Re: My dream project...can I make it happen?

#11 Post by rd84 » Sat Dec 04, 2021 11:13 am

Strokingit wrote: Thu Dec 02, 2021 3:00 am The OP hasn't visited this forum since 2007.

My guess, his dream project didn't happen.
I didn't spot the date :-)

However many of us made our dreams come true with these bikes.

Cheers
Paul

rz500guytexas
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Re: My dream project...can I make it happen?

#12 Post by rz500guytexas » Sat Dec 04, 2021 9:35 pm

You really need a plan on these bikes. And do not try to cut corners. Engine is an anchor and trying to put them in a chassis designed for a 250 has always been questionable to me. Most of us are not motorcycle designers. there is a lot that goes in getting weight and geometry correct. Squat, anti squat, steering angle, trail, spring weight, oil viscosity, oil levels. If it is a show bike fine and dandy but if it is going to the track a different story. Took years to get the RZV to be a good reliable bike for track use but it will never match up to the little TZ. I still love seeing the imagination and the finished projects that come from the members.

Luther
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Re: My dream project...can I make it happen?

#13 Post by Luther » Mon Dec 06, 2021 2:26 pm

Well looking on the bright side all the weight we take off makes the anchor engine a positive mass centralization component.
Old thread but it got rd84 Paul to post another killer pic of a 500 on track doing the business. But yeah I have room for a TZ when the right one crosses my path

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