TZR250 frame conversion

[lochachi2]

Has anyone grafted the RZ500 engine into a TZR250 frame? If so, are there details/photos/description available anywhere and which year of TZR frame works best?
Thanks

[hybrid]

Yes it's been done plenty of times. Search the forum for 3ma and I'm sure you will find plenty of info.
Just one thread I found.
http://www.rzrd500.com/500phpBB3/viewto ... &hilit=3ma" onclick="window.open(this.href);return false;

[RuZty]

Andy Jones of ATR has built one from a 3XV as well, I think it might have been a tighter squeeze than the 3MA.
http://www.alienracing.net/bikes.html" onclick="window.open(this.href);return false;

[giron]

never never use the 3xv frame for a RZ500 conversion or a RZ350 conversion. I saw the RZ500 conversion with 3XV frame. The bike is at Brian Turfrey shop. Their is no room between the engine and the front wheel. RGVSteve did a conversion for me on TZR250 3XV frame with a RZ350 engine. The same issue no room. Brian will be doing the two conversions for me on TZR250 3MA frame. I learned the hard way, but look first what type of engine came on the frame a parallel engine or a V twin. Also look what Nigel is doing in the UK at NKRacing.

[hybrid]

Yep, parallel should give more room than the v-twin (3XV).
Some have also used the SRX660 frame too, but I think that is also the same as the 3XV, so would have the same clearance issues.

[ns86]

http://www.rzrd500.com/500phpBB3/viewto ... =7&t=13765" onclick="window.open(this.href);return false;
http://www.rzrd500.com/500phpBB3/viewto ... 3xv#p78780" onclick="window.open(this.href);return false;

[giron]

where is the cradle for the front engine support? two 8mm bolts?

[Questo vecchio rz]

It certainlly appears that it can be done and successfully as well without a cradle. They used the motor as a stressed member w CNC mounts, w a total of 4 mounting locations into the motor suspended from frame mounts.
Several of the machines have been used in racing events, & appears they worked as intended. Ive also viewed several RZ500 diffrent frame conversions, Its seems whatever they use works for each indavidual. I suppose its all in the level of detail one is willing to invest in. Im certainlly not able to say which is definitively better, but others seem to get around various issues w a little creative ingenuity.

[lochachi2]

Thanks for the information everyone. That really helps a lot as it narrows down my search for a 3MA model frame.
I've got two RZ500's and I just picked up a RZV aluminum frame. Intention is to have a relatively stock aluminum framed bike and a tarted up 500GP Lawson/Rainey inspired bike. I took delivery of my first 500 on June 7, 1984 ($3200cdn) Brand new. Bike head shook like a rabid dog and then weaved and wobbled like a piece of boiled lasagna noodle once the steering dampner was added. Even with its sh**y handling it remains to this day one of the coolest production bikes ever to come out of Japan. Maybe I'll change my mind once the projects are done and i'll say WTF was I thinking and go back to riding my RSV4 factory

[RZVTokyo]

I have a nice SZR660 frame (similar to the 3MA frame) for sale. PM me with your email for pics if you're interested.

[giron]

Questo

The factory never intended for the RZ500 engine or the RG500 engine head to be used as a mounting point. You mention a race bike. At the same time you need to consider that a race bike is a throw away bike not a street production bike that may still be used on the road for years. I also heard that builders in the UK have been correcting this flimsy motor mount. here are a couple of pictures from a bike that came from Canada. The bike is now at Brian Turfrey's shop. Do you actually think that 4 8mm bolts are a good idea for an engine mount?

[jackson.40]

giron wrote

The factory never intended for the RZ500 engine or the RG500 engine head to be used as a mounting point.

They did try it on the pre-production bike

[giron]

maybe just maybe the Yamaha engineers didn't think to much of it

[Questo vecchio rz]

Questo

The factory never intended for the RZ500 engine or the RG500 engine head to be used as a mounting point.

The bike is now at Brian Turfrey's shop. Do you actually think that 4 8mm bolts are a good idea for an engine mount?

Hows it going Giron? I did see that machine at Brians shop, but I didnt pay too much attention to it at the time. He did point that issue out I remember. Quite a likable fellow helpful , knowledgable and forthcoming as well. I was a little nervous as I had never personally dealt with him and after some research & advice I recommended him to do the work for my friends RZ & RG bikes. After meeting him and good praise from some members here, I feel there may be few whom are more qualified , his enthusiasm and experience are hard to equal. And again such a likeable indavidual. If I end up not being able to do my front end & rear conversions myself, he just might see my RZ as well if my budget allows. Just a great guy and nice bikes, nice stories and parts Id never see outside of a 90s GP Paddock.

I understand both your opinions and concerns regarding the motor as a stressed member and respect everyones opinion as well as the original Yamaha engineers of the late 70s & 80s.
Even though it was never " intended" to be utilized as a stressed member, I certainlly feel it could be. Perhaps not in that particular manner?, I'd have to look at it and decide for myself and "consider" the strenghth of the mounting points perhaps even alter them.
Im not a engineer..but I'm certainlly clever enough as many of us here to envision & enginner ideas.
With some research I'd determine the strength & load required for CNC mounts w the 8mm bolts, the depth etc..and again determine if I'd feel thats enough or something new needed to be devised.

What has me not to worried about it is my old FZR and now nearly all production sportbikes use a stress membered motor, and the fact is many are suspended from the cylinders or motor. My old 140 h.p. 89 FZR was far more powerful than any RZ500 everbuilt, and newer machins even add another 50 h.p & 30 ft lbs more of tourqe on top of that and in the below photo you can see the small dia. bolts that suspend the motor from the frame in a R1, These are motors with double the power output of a RZ500, and this method is standardized. I do feel the average 75-90 h.p. motor could with a little smart thinking be adapted.




There are probably a dozen of so indaviduals that have seemed to make this work in several diffrent ways and makes & models, I beleive some of the ATR machines have survived 15 years or so now as I have old magazine articles showcasing some of those bikes. Im not a very impressionable fellow & I often 2nd guess or at least analyze what proffesionals I hire and think out things to the best of my ability, to see if were on the samw page. c
Common sense tells me its achivable, (perhaps.... in the above case) incorprating thicker plate onto the cylinders or heads and tapping & utilizing larger 10 or 12 mm bolts, but again you do have 4 mounting points and the 8mm hardware just might have been sourced with sufficient grade load strength? That would be a primary point to research. As seen in the photo the cylinder bolts are not really much larger dia, on a machine that delivers much more power and thus stress.

Interesting builds no matter what anyone chooses, We have viewed 500 motors in 2 and 3 series TZRs, TDR frames, Mr. Costin and AYDs home built frames and even in Banshees...lol.
Creative bunch if indaviduals here

[giron]

again I heard from a builder in the UK. He has corrected quite a few RGV with RG500 engines with the cylinder engine mount. Have you ever seeing the motor mounts on the RZ and the RG. Maybe you may ask why they have rubber inserts around the bolts. Can it be to absorb the vibration.