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 Post subject: RE: NEW Cast cylinders or Top Case for the RZ500???
PostPosted: Tue Oct 25, 2005 10:48 am 
To follow up with the discussion below.<p>Great comments so far. Many ideas about cylinders have been thrown around in recent years. Some problems to consider before moving forward with any one cylinder fitment design for the top case.<p>1. How are the powervalves driven, from the crank or from a servo like the 500 is now. I know of no MX barrels that are servo driven this could be problematic to retrofit the servo system at a reasonable price.<p>2. How is the cooling system designed, does coolant need to travel up from below the exhaust port, TZ and YZ barrels both use this design. The RS does not.<p>3. To keep conversion cost down the cylinders will likely need to be same bore and stroke to minimize having to change the rods or stroke of the crank.<p>I have seen Randy Norian's setup up close. A marvel of engineering if you ask me, but for around $12K it should be. His setup uses TZ250 barrels, same bore and stroke or nearly as the RG, RZ350 rods to make up for the spacer plate, TZ pistons, a custom spacer plate between the case and barrels with intergral coolant passages machines in for OEM coolant flow through the cylinders. It uses a TZ servo motor and controller wired into the RG harness with several other guages for racing and engine monitoring tied in.<p>Ralf Kras' setup also uses a spacer plate only he welds it to the top case to get away from dual bolting and gasketing issues. Very nicely done but time consuming like porting and completely custom.<p>I would prefer to use the TZ barrels, likely off a 2MA or V twin model as I've been told the 2MA is basically a YZR cut in half. I'm not that familiar with the TZ stuff and would need to look at the cylinders and their layout to see what would be best before moving forward for sure.<p>Great discussion so far.<p>Regard,<br>Bill Wilson<br>Wilson Performance<br>Lee's Summit, MO<br>Member RZ500 Owners Group #573
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WVWRZ500N@aol.com


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 Post subject: Re: RE: NEW Cast cylinders or Top Case for the RZ500???
PostPosted: Tue Oct 25, 2005 1:28 pm 
I like the idea!!!! Price is the biggest object for me. TZ jugs sound cool but I think the cost will get out of my reach. I'm guessing that they will cost at least twice what any used mx jug would cost if not more. Throw in pistons, rings, heads, reeds, intakes (probably custom made) and I'll be broke. Hope my 28mm flatslides will still work. <p>For me to get involved you'll need to find a cheaper route or find cheap parts for me. I suggest looking for jugs that are more common.
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beeks81@aol.com


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 Post subject: Re: RE: NEW Cast cylinders or Top Case for the RZ500???
PostPosted: Tue Oct 25, 2005 2:09 pm 
Hi All<p>Drooooolllll<p>However the moths in the wallet are on starvation rations....<p>However a thought - It is good having it as a 500 - history and all that, but are there alternatives that would land with a higher capacity? Have no idea really.<p>Now I have a TZR 250 2MA engine I am about to put up for sale....<p>R
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rc.key@ntlworld.com


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 Post subject: Re: RE: NEW Cast cylinders or Top Case for the RZ500???
PostPosted: Tue Oct 25, 2005 9:34 pm 
Bill,<p>I strongly agree that this is the type of effort that is needed to keep the breed alive and prospering for those of us who want more than stock or near stock performance. <br>I think there are alot of us who have been thinking along the same lines, but it's a big enough effort to discourage most from going it alone. Like you I have been <br>intrigued by Randy Norian's efforts.<p>I agree that the effort should be built around readily available components where practical to keep costs within reason. Here are some of my thoughts.<p>1. YZ125 cylinders from 1994 to present use a 54.5mm stroke. It appears that there is absolutely no room to stroke the 500 crank, as the rod big ends are within about .030" from the crankcase inside diameter. The case wall is only about .130" thick in places, so you would break thru the wall if attempting to open up the case enough to accomodate the 54.5mm stroke.<p>2. TZ250 cylinders from 1991 to 1999 use a stroke closer to 50mm like the RZ, so using the stock cranks should not pose a problem with these cylinders.<p>3. Whereas the RZ cylinder is 3.530" tall, the 91-99 TZ250 cylinder is 2.995" tall. The difference of .535" allows enough room for an adapter plate to adapt the TZ barrels to the stock RZ case for a dyno mule. The .535 thickness of the plate would probably allow for the two different bolt patterns between case and cylinder. Also for the mule you could build up material to house larger 6 petal reed cages. The YZ would be a great donor for these. The spacer plate would also give room to allow for the wider transfers of the TZ.<p>4. For those of us who dream of being as true to the YZR as possible, the TZ cylinders are about as close as us mortals will get.<p>5. As expensive as they are, the TZ cylinders are a bargain when you start considering the costs of building a new cylinder from scratch. Considering also the years of effort and fortunes Yamaha has spent on the port configurations, it's pretty close to the holy grail.<p>6. If the TZ cylinders and spacer plate work on the mule, I would produce a new upper case via CNC from billet. Depending on the quantities, the CNC approach may still be attractive when compared to the cost of tooling up to produce a casting. Also, in my opinion the upper case is a weekness when producing significant power. A machine from billet upper case would have mechanical properties approximately twice as strong as a cast unit. This may go along way in keeping the cranks together.<p>7. Count me in! I am willing to devote a significant amount of time and effort towards the development of something along these lines, including the CNC machining of a billet upper case. I am not convinced that the TZ cylinder is the only viable approach, I just haven't seen another compelling alternative. <p>Let's put our heads and hearts together and make it happen.<p>Thanks for staring the ball rolling.<p>Dirk Ellis<br>Portland, Oregon
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dirkandpamellis@comcast.net


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 Post subject: Re: RE: NEW Cast cylinders or Top Case for the RZ500???
PostPosted: Thu Oct 27, 2005 10:30 pm 
Hey Dirk,<br>I noticed one of your posts a few weeks ago but for some reason I didnt realize you lived in Portland,Or.<br>I live in Spanaway Wa. I would love to talk to you.If you would like,e-mail me with your phone number and I will call you.I am very anxious for someone with RZ experience to ride my bike and tell me what they think.<br>Art
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4munsons@comcast.net


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