News:

Mat Oxley 1986 IOM TT


click above to read more about Mat.

Main Menu

RD-RZ history

Started by teazer, July 05, 2019, 08:15:24 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

teazer

Is there a compilation anywhere that details the changes year to year on R5's through RZ models?

I started with a set of R5 cases and of course they don't have grooves for Main oil seals and not bearing retainer plate. Then I got a set of RD350 cases and RD400 cases with subtle changes, so then I looked at a set of TZ cases which are almost the same but very different in other ways. For example the kickstarter gear spring mounts like an RZ/LC but everything else is more like an RD.  And tehTZ never had a kickstarter so why?

LC cases seem to have wider cases that RDs combined with cylinder stud spacing the same as Air cooled models, so they appear to be half way between RD and RZ. The water pump shaft boss and water pipe hole are like an RZ as well.

RZ appears to be the same as an LC but with new cylinder mounting studs and mouths.

Is there a reference site with all these details and more? 

pdxjim

Yeah, fun to see the evolution of the Yamaha 2T twin.

Next in line after RZ was a few minor changes for the Banshee and then big changes for the 1KT TZR when they moved to case induction.

Fun stuff.
Wasting time on 2T forums since the dawn of the internet. '89 TDR250, '13 300xcw, '19 690smcr, '56 Porsche 356A

teazer

But it looks like no one has documented the changes/history. 

I was mocking up a banshee side cover to a set of RD350 and RD400 crankcases and that's where I started to see more changes than I had noticed when I was rebuilding TZs

EE

I did this with cylinder porting layouts from R5 to RZ, and also TZ, on my website also TZ porting arrangement pics and more in depth cyl development history on the 125, 200 and 250  because 90 percent of what I've done/do is RD/TZ porting. That's on www.erlenbachracing.co
Let's compile a kind of a general engine's differences in this thread then sumrize it and put it in the tech library here for quick reference that would be a nice resource. Ed

EE

Alright i'll start. When I think about RD's and TZ's to give my RD/TZ history some reference to the work I've done with them I've always considered the time span from the 1970 R5 to the 1990 reverse cylinder TZ250 because the R5/DS7 was the first Yamaha to have the horizontally split cases with 4 transfer port cylinder base case layout (2 on each side with a 5th boost port added in the RD series).
This means RD cylinders will bolt directly onto the R5/DS7 cases.
BUT the R5/DS7 only had 5 speeds though it's super easy to swap it all out for an RD 6speed setup (gotta love Yamahas parts interchangeability!)
A SLIGHT variant of these cases was used by the TZ250/350 up until 1980, if fact when TZ racers broke earl TZ cases it was uber common to replace them with RD cases. 
I stop at the 1990 reverse cylinder TZ250 because it was the last of the Yamaha parallel twins.. Ed

EE

o.k. here's some more..
This is a direct quote from the Aircooled RD Club Forum, I read it years ago and went back and dug it up, I've never seen a solid mounted RD400 but there is tale..
"The RD400 originally arrived in the US and australia with a solidly mounted engine hence the un-jointed pipes
this was going to be the production model until the bike was tested in europe and slated for its heavy vibration caused by the longer stroke
this then led to a series of stop gap measures to help this including
a rear rubber mount for the pipes and indeed the jointed type seen on the 250 before eventually settling on the engine mounts and rubber joints as seen on the final 400 model
There were some UK machines around during the early days with variations of either of the above although i know one for certain that had later pipes fitted in 1977
and around 150-200 RD400 "C" models with the solid pipes as pictured above"

Alright some ramblings from my memory..
On RD400 cases I've seen slight differences in the castings, the earliest had a little less material around the cylinder base gasket area at the rear and more ribbing around the right main bearing for sure (and right transmission mainshaft bearing if memory serves me correctly) in later cases.
Starting with Daytona in the US and later UK cases used a different kickstarter mechanism. Daytona I know would take the earlier kickstart mechanism, I "was told' back then that the gear on the "Daytona style" kickstart mechanism which on this new design was not constantly engaged with the idler gear in racing had slid over and engaged on some so common practice was to retrofit the old system when using "Daytona' cases. I did have one customer that would not take no for an answer so I used a throttle slide return spring to keep the kickstart gear positively disengaged when not in use. One drawback with the "Daytona" style kickstart mechanism was that it kicked over more slowly as well.

While the rest of the world got electronic ignition in 79/80 we didn't here in the states..
The Daytona did get a new crankshaft without the dreaded lead weights but improper heat treating it's believe causes them to snap the center section under racing conditions..
All electronic ignition bikes got a new LC/RZ style larger taper on the ignition end of their crankshafts.
LC's went to the now well know RZ/Banshee style crankshaft but the LC's still has a 16mm wide big end bearing but with large big end and wrist pin bearing diameters.
An LC crankshaft will fit in Aircooled RD cases, A RZ/Banshee crankshaft is a mm too wide.
I believe Joe Spooner's TZ375 is using an aircooled RD bottom case with an LC top case and said it bolts right on.
The RD/LC/TZ/RZ/Bamshee right side covers all have the same bolt pattern but the RD400 has one more bolt provision in the case at the front but it doesn't mean you can use the other side covers on it as I've installed LC and TZ side covers on all the aircooled RD's (250/350/400).

Jspooner

^^^^^you are partially right on my engine Ed, the LC and AC cases will bolt together (kind of)  but not enough to use them that way. They fit together well enough so that I could use the AC bottom case for alignment in the frame so that I could build motor mounts for the LC bottom end that I used for my TZ375 motor because the LC motor is mounted in the frame exactly like the RZ/Banshee motors. I am using an RD400 left side cover on my engine as well, everything lined up perfectly and the 400 cover can be made to look just like a TZ side cover.
"Just quit brain fucking it and get it done"

teazer

Any TD3, TR3 and TZ250, 350, 700 and 750 top end will drop straigh on to any R5, DS7, RD250 or RD350 set of crankcases but the studs may be the wrong length.  I have a list of stud lengths here somewhere because I have gone through this a few times already.

I have bought and/or worked on TZ and TR/TD motors with replacement unstamped cases as well as RD cases, but RD cases have to be machined for the rubber mounts on the front and they have to be machined to take the pair of C clips for the center bearings and lab seal.

A Banshee or RZ clutch cover will almost fit onto an RD set of cases but the 'Shee and RZ have a liittle more metal in two places.  The RZ/Shee water pump will not work on an RD set of cases because they are missing the rear water pipe passage and the boss to support the pump shaft.

Banshee/RZ and LC all have a longer right crank snout to take the water pump drive gear. That gear cannot be fitted to an RD crank unless the end is drilled and tapped and the drive gears are replaced with straight cut gears.

There are some differences with front mounting screws for a shee/RZ and I think that some TZ and RD400 cases are similar to the Shee/RZ, but I need to check.

RZ cranks are wider across each pair than RD's and will not fit in the crankcases, but I would think that RD cases could easily be machined to take a wider RZ crank but that might cause a primary gear misalignment - I have not checked that possibility.

An RD clutch cover can be cut down around the oil pump and a TZ water pump will be driven through the original oil pump drive shaft hole, but that requires an adapter to fit under the pump.

R5/DS7 did not have teh gearbox input shaft bearing retainer and the grooves to locate crank oil seals were added with the RD series.

LC and RZ have a similar kickstarter arrangement.  On the RZ ( I don't have an LC to measure) the inner end of the short kickstarter shaft is a smaller diameter, so either the cases need to be bushed or a sleeve pressed onto the shaft.  The shaft is longer than an Air cooled motor which is fine if you use an RZ clutch cover.

On an RD, the kickstarter idler gear is a pair of gears.  One engages with the kickstarter and the other with the small gear on the back of the clutch. on an LC or RZ there is only one dished gear which engages with both the clutch gear and the kickstarter bendix.  To complicate matters further the small spring around that kickstarter gear is also different on an LC and RZ compared to an RD and I suspect that design change came with the Daytona.

BTW, TZ and RD crankcases have a few other subtle differences related to how oil drains between the transmission and primary drive.

motodreams

LC and RZ cranks and shifts assemblies are also not the same.  The cranks are different widths as the shift drums are different lengths.  Very slight but there.  RZ/LC studs are different pattern.  They are all very similar motors from the R5 through the TZR when it comes to rebuilding.

m in sc

you =can= use an lc crank in aircooled cases as mentioned, but also as mentioned, you need to mod the end of the crank, OR, as i have done, 'doghouse' the RH cover to take the longer crank. (no oil pump can be used after this mod) the LC crank also allows for a large taper cdi to be used, and yes, an rz or lc cdi will then bolt right on to aircooled cases. you will need to clearance the LH cover to accommodate the cdi pickup.

:twocents:

bitzz

and the keyway on a Daytona crank is 90 degrees off the RD-LC and RZ cranks

teazer

Quote from: motodreams on July 08, 2019, 09:10:01 AM
LC and RZ cranks and shifts assemblies are also not the same.  The cranks are different widths as the shift drums are different lengths.  Very slight but there.  RZ/LC studs are different pattern.  They are all very similar motors from the R5 through the TZR when it comes to rebuilding.

And transmission shafts are also longer on an RZ/Banshee than air cooled models plus they run a three shift forks and not 4.

EE

#12
This is fun.
-Unlike the RZ/Banshee's LC's still had the clutch pushrod that went all the way through and out the left side of the cases to a clutch actuator in the left side cover.
-The LC's use the same part number kickstarter mech as the RZ/Banshee
-Yes the LC kickstart shaft is considerably longer than RD's, twice to use an LC side cover I grafted two early style RD kickstart shafts together to extend them I believe 16mm
-The LC used a three shift fork trans like the RZ but I don't know if the trans was the same as the RZ?
-I didn't know an RZ/Banshee right side cover wouldn't work on an RD.. I'd seen a TZ Dryclutch cover on an RZ or 2 and they are a straight bolt on for an RD as is the LC cover so I assumed..huh
-guys have used RZ cranks in RD's but it takes a little machining
-other guys have used the wider RZ rods in RD's by machining .5mm off the inside of each crankweb.
-The early TZ's used the double kickstart idler gear to drive their tach but the gear ran on a needle bearing.
-Since Daytona and later RD's used the single gear kickstart idler gear they used a longer tach drive shaft and internal gear ratio in the case right before the cable, also a smaller tach drive nylon gear.
-TZ250 and 350 had different primary gear ratios than the RD's so they used 2 different nylon tach drive gears (and 2 different water pump drive gears)
-You can run RZ/Banshee primaries on an RD I've done it a number of times
-The Daytona and later left side covers had a provision for the electronic ignition pickup
-The Daytona had thinner primary gears
-The Daytona 5th and 6th gears had thinner engagement dogs which made them easier to shift into these gears but no good for racing..
-The Daytona and later used a different shift mechanism ratio
-cool i never noticed about the keyway
Hmm let me think some more

teazer

Banshee side cover fits almost all the way around but is just a little thin in two places. A little JB weld or Devcon is fine.  You could probably get away without that, but I wanted to be safe.  That allows a Banshee/RZ clutch assembly to be used with stock or straight cut gears and also allows a lock up clutch to be slipped under the cover.

To use a TZ waterpump instead an an oil pump, use the RD oil pump gear IIRC. Or use an electric waterpump - cheaper and can be switched on only when needed using a thermo switch in a 750 head or tap one in for a 250 or 350 head.

Has anyone tried to get TZ port timing out of an RD400? Long stroke and long rods make life more difficult, but looks like it may be possible with a 6mm lift plate and corresponding amount off the top of the barrels. It will never come close to matching a CPI Cheetah for port time area but might be a little closer.

A set of TZ750D 6 or or OW31 barrels or even 3G3 with reed boxes, might be closer still but not close to what a Cheeta can create.

EE

Probably the thing that has given me the most enjoyment over the years working on RD's is that on an average guys budget with hard work (lots of time, lots of thought, lots of more thought and lots of more hard work yes..) and the patient and persistent application of good science (and yes more hard work..) these bikes can very often just honestly do "more than their supposed to be able to do".... You gotta love em, don't let anybody tell you their not the race bred descendents of the RD56 like their racing cousins like I tell guys when their on the pipe they don't know their not TZ's!!! Gotta love em, all that rolled up in aircoooled simplicity.. No RD's are not CPI cylindered RZ/Banshee megabuck motors but dam can they perform with a lot of hard work and good science.. Ed