ESE's works engine tuner

[Frits Overmars]

Pretty sure the "Dutch Yamaha Fairy" has built a replica.

I haven't seen my mate Ferry Brouwer being called a fairy before . I'll give him your love, Husa. But Ferry did not build a replica of the Yamaha RD65; he amused himself with the four-cylinder 125cc RA31 (the first bike he worked on as a Yamaha works mechanic) and the 250cc RD05A (and a lot of other Yamaha-related stuff).

[ranasada]

I suppose the diameters on that sheet are external. Internal diameters on a homologation sheet wouldn't make sense; nobody would be able to check those without cutting the pipe up.

thanks a lot

[husaberg]

I haven't seen my mate Ferry Brouwer being called a fairy before . I'll give him your love, Husa. But Ferry did not build a replica of the Yamaha RD65; he amused himself with the four-cylinder 125cc RA31 (the first bike he worked on as a Yamaha works mechanic) and the 250cc RD05A (and a lot of other Yamaha-related stuff).

Pretty sure he did do a OW15 as well "works TA125"

i googled but i couldn't find a RD56 but i bet he has a file of info tucked away.

[Frits Overmars]

Pretty sure he did do a OW15 as well "works TA125". i googled but i couldn't find a RD56 but i bet he has a file of info tucked away.

I was reacting to Twopints question about the 1960's works bikes, but as I wrote, Ferry did 'a lot of other Yamaha-related stuff' as well, from 50 to 500 cc.
That RD56 info may be scarse though. Ferry knows that the RD56 is my all-time favorite Yamaha and I'm sure he would have shown any paperwork he would have.

[Twopints]

To the best of my knowledge neither the RD48 nor the RD56 were ever sold; they were pure works bikes and it won't be easy to find any information about them after more than 50 years. The best I can do is a couple of lists and drawings from the RD56 and the 125cc RA41 which had the same relevant dimensions as the 250cc RD48. Working from the known bore dimension you may be able to extract approximates of the other dimensions you were asking about.
Attachment 334333 Attachment 334334 Attachment 334335 Attachment 334336

You made me curious: what are you planning to do with those dimensions? Build replicas maybe? And while you're at it, you might tell us a bit about yourself as well.

Thanks Frits, i am reverse engineering but not the Yamaha, i have the remnants of the Clisby 24 cylinder motor, the cranks ,barrels and heads have been removed in the late 1960's and are not in my possession and not available to me

I have seen the above drawings before but these look sharper than previous ones , I will give it a go scaling from these

I have found out the Bore and stroke of the Clisby is 56 X 50

Kevin Drage who worked on the project has been kind enough to help me , he looked through his notes and found the original shopping list of parts that he picked up from Pitmans Yamaha here in Adelaide, Yamaha crank parts , conrod, pistons ,disk valve, studs , a cylinder ,etc, Kevins list has the prices of the parts but sadly not the parts numbers other than for the points and cam lobe for the ignition these are common Lucas parts

After a bit of googling i decided that the Yamaha YA 6 was the source of the parts as it was available in Australia at the time , had the 56 X 50 bore and stroke so it fit the bill, so i bought a NOS crank piston and disk valve , and a replacement liner , the crank won't fit in the crankcase as it is 110 mm in dia. ,the crank case is 94mm ID , the conrod is 120mm C to C and the Piston has 30mm from pin to top of the piston, the overall height is to tall,

I have no really good photos of the complete engine ( sharp focus and at 90 degrees) to scale from but i think the height of the cylinder would be closer to 95mm rather than the 120mm from the YA 6 cylinder

This all led me to looking further and it left the RD48 and RD56, i was apprehensive that Pitmans could have sourced such exotic parts, and sold to a member of the public
but i believe Pitmans were the local importers and did have access directly to the factory

At the end of the day i would like put the 24 cylinder together as a display motor and possibly get a single engine unit (125cc) running

i only need to make one pattern and core box for the cylinder and one pattern and core box for the head, and lots of repetitive machining, ( for the display motor) but i am not confident with my scaling to start with the pattern work

I have the port timing from Kevin but i don't know how to post photos here other than a general arrangement drawing of the complete 24 cyl i don't think any other drawings have survived but i do have the drawing index but no drawings to accompany the numbers

There are photos of the Clisby floating about the internet ,mine is the 2 Stroke not the 4 stroke V6 that Harold Did as well

http://collingrovehillclimb.com.au/s...alve%20jpg.jpg

http://collingrovehillclimb.com.au/s...head%20jpg.jpg

at the end of the day none of the Yamaha YA 6 parts that i have don't seem to match the proportions of the Clisby other than bore and stroke

the picture of the single cylinder engine has a splined output shaft , does this look like the shaft on an inner crank half ( the one the couples with the other cylinder ?) the YA 6 crank has a short spline on the disk valve side, the drive side is a taper

for any one that is interested a bit of a write up on Harold http://www.collingrovehillclimb.com.au/haroldclisby/

any help is appreciated

Your mates work on his replica bikes is epic

Cheers

Fred Radman

[diesel pig]

at the end of the day none of the Yamaha YA 6 parts that i have don't seem to match the proportions of the Clisby other than bore and stroke

Have you looked at Production Yamaha Road Racers model TD1 to TD2B which have the same bore and stroke?

These parts were able to be had from any Yamaha dealer in the 1960,s and would of been the highest performance

Yamaha pistons and con rods you could get at the time.

The TD,s are piston port not disc but after looking at your link for Harold Clisby I think a man who built hovercraft and steam engines

converting TD cranks to drive discs would not of been too hard for him.

Cheers

[_____]

Hi everyone!

Here is my recent version.
Attachment 334313

I just clicked a bit of your pipe programm in an excel-sheet. Whilst increasing the exhaust opening duration, the exhaust diameter at the piston (respective X) is decreasing. When I look at this statement:

Regarding your suggestion to base exhaust duct cross flow areas on blowdown time.area, that is what I keep preaching.

This seems not to be right. Is this an error in the programm?

Regards,
Chris

[Grumph]

I'd endorse TD1 too. Pitmans were one of the few sources of parts for those in period. A crank from a twin makes more sense in terms of the OD as less flywheel is needed in that application. I believe - though can't be dead sure - that YDS2 street cranks have the same dimensions.

[husaberg]

Thanks Frits, i am reverse engineering but not the Yamaha, i have the remnants of the Clisby 24 cylinder motor, the cranks ,barrels and heads have been removed in the late 1960's and are not in my possession and not available to me

I have seen the above drawings before but these look sharper than previous ones , I will give it a go scaling from these

I have found out the Bore and stroke of the Clisby is 56 X 50

Kevin Drage who worked on the project has been kind enough to help me , he looked through his notes and found the original shopping list of parts that he picked up from Pitmans Yamaha here in Adelaide, Yamaha crank parts , conrod, pistons ,disk valve, studs , a cylinder ,etc, Kevins list has the prices of the parts but sadly not the parts numbers other than for the points and cam lobe for the ignition these are common Lucas parts

Have you looked at Production Yamaha Road Racers model TD1 to TD2B which have the same bore and stroke?

These parts were able to be had from any Yamaha dealer in the 1960,s and would of been the highest performance

Yamaha pistons and con rods you could get at the time.

The TD,s are piston port not disc but after looking at your link for Harold Clisby I think a man who built hovercraft and steam engines

converting TD cranks to drive discs would not of been too hard for him.

Cheers

I'd endorse TD1 too. Pitmans were one of the few sources of parts for those in period. A crank from a twin makes more sense in terms of the OD as less flywheel is needed in that application. I believe - though can't be dead sure - that YDS2 street cranks have the same dimensions.

They also have a high area above the pin

i have measurements somewhere for them somewhere.

In regards to the disc they might be bridgestone or kawaaski.
although Yamaha did make a KT100 that was disc valve they did a reed valve one to as well as thw well known piston port KT100.
but i cant see it being large enough.
another option is the AT1for pistons.

Yamahas up to about the TDB/yds2 had the clucth on the crankshaft.
https://www.tapatalk.com/groups/yama...grade-t99.html
Yamaha twins of that period had two dia big end pins.

also tha 120mm c-c rod is very long for a piston port yam compared to others in the range
maybe its from the Longer stroke TR2 series or from an outboard do you have the numbers on the conrod

[Grumph]

[QUOTE=husaberg;
also tha 120mm c-c rod is very long for a piston port yam compared to others in the range
maybe its from the Longer stroke TR2 series or from an outboard do you have the numbers on the conrod[/QUOTE]

No...he's saying the 120mm rod from the YA6 is too long to match the estimated dimensions.

I'd go back to YDS2. In period and going through Pitmans, it's what I'd have gone for first.
The bits were available, they probably had at least one crank on hand to show him - and they were relatively cheap.

Knowing how much restoration goes on around Adelaide, Fred, someone will have a DS2 apart....

[husaberg]

No...he's saying the 120mm rod from the YA6 is too long to match the estimated dimensions.

I'd go back to YDS2. In period and going through Pitmans, it's what I'd have gone for first.
The bits were available, they probably had at least one crank on hand to show him - and they were relatively cheap.

Knowing how much restoration goes on around Adelaide, Fred, someone will have a DS2 apart....

pretty sure there is some YDS3 crank bits apart and my fathers place

[Twopints]

thanks every on for the info so far

I scaled from Frits excellent drawing of the RD56 , allowing for errors and some rounding up of numbers on my part

Rod length 103mm c to c

Piston 56 mm overall and 29mm compression height ( this is from the centre of pin to top of piston edge not the "dome")

the crank is 92mm Dia and 56mm wide

giving me a crank centre line to top of cylinder deck 156mm

Scaling from a grainy Clisby photo a crank centre line to top of cylinder deck is 158mm

this is looking good so far

the RD56 disk valve is 128mm by 3mm thick ,scaled from the drawing

the YA6 disk valve i have is 117.3 by 4mm thick

the Clisby disk valve chamber is 95mm in Dia.

yes i did look at the TD type cranks ,from a Yamaha service news i found they are 93mm in Dia. and 50mm wide for 1 cylinder

From Kevins list the list price i have is $24.98 1966 or 1967 Australian dollars for each half , that sounds a lot to me , any thoughts ?

I am starting to think the disk valve may have been from some thing else ,it was $4.50 from Pitmans ,any thoughts on a 95mm disk valve from the period, but
as per the crank it may have been modified from the purchased part

I had made the assumption all the Yamaha parts were from one engine, but they may have been selected from parts books and what was on the shelf at Pitmans
would any one know if Pitmans were a Bridgestone or Kawasaki agent at the time ?

I am starting to jell at around a 103 to 105mm rod and a piston with a 30mm compression height , pointing to the TD1 ? do these numbers seem ok for a disk valve motor ? as you guys may have guessed i am not that familiar with 2 strokes

The Timing numbers i have are, reading around the chart

0 is at TDC

Inlet closes 60 Deg

Exhaust opens 92 Deg

Transfer opens 120 Deg

Inlet opens 230 Deg

Transfer closes 241 Deg

Exhaust closes 269 Deg

Inlet period 190 Deg

Exhaust period 177 Deg

Transfer period 121 Deg

were they barking up the right track for the time ?

Cheers

Fred

[Grumph]

Re the prices anyway - Pitmans could well have had a stock of used but good crankwebs on hand from warranty work....Would explain the lack of part nos.

$25 or so for a crank half does sound like secondhand to me....

[husaberg]

thanks every on for the info so far

I scaled from Frits excellent drawing of the RD56 , allowing for errors and some rounding up of numbers on my part

Rod length 103mm c to c

Piston 56 mm overall and 29mm compression height ( this is from the centre of pin to top of piston edge not the "dome")

the crank is 92mm Dia and 56mm wide

giving me a crank centre line to top of cylinder deck 156mm

Scaling from a grainy Clisby photo a crank centre line to top of cylinder deck is 158mm

this is looking good so far

the RD56 disk valve is 128mm by 3mm thick ,scaled from the drawing

the YA6 disk valve i have is 117.3 by 4mm thick

the Clisby disk valve chamber is 95mm in Dia.

yes i did look at the TD type cranks ,from a Yamaha service news i found they are 93mm in Dia. and 50mm wide for 1 cylinder

From Kevins list the list price i have is $24.98 1966 or 1967 Australian dollars for each half , that sounds a lot to me , any thoughts ?

I am starting to think the disk valve may have been from some thing else ,it was $4.50 from Pitmans ,any thoughts on a 95mm disk valve from the period, but
as per the crank it may have been modified from the purchased part

I had made the assumption all the Yamaha parts were from one engine, but they may have been selected from parts books and what was on the shelf at Pitmans
would any one know if Pitmans were a Bridgestone or Kawasaki agent at the time ?

I am starting to jell at around a 103 to 105mm rod and a piston with a 30mm compression height , pointing to the TD1 ? do these numbers seem ok for a disk valve motor ? as you guys may have guessed i am not that familiar with 2 strokes

The Timing numbers i have are, reading around the chart

0 is at TDC

Inlet closes 60 Deg

Exhaust opens 92 Deg

Transfer opens 120 Deg

Inlet opens 230 Deg

Transfer closes 241 Deg

Exhaust closes 269 Deg

Inlet period 190 Deg

Exhaust period 177 Deg

Transfer period 121 Deg

were they barking up the right track for the time ?

Cheers

Fred

Disc valve of the period yamaha YL2
https://www.cmsnl.com/yamaha-yl2-196...4.html#results

the oring is 102mm which puts it sub 100mm disc

[Haufen]

When preparing a freshly cast cylinder for the first plating, is it advisable to put a bevel or radius at the end of the bore at tdc? What is this good for? From a combustion chamber point of view I don't like this idea at all.

But as the combustion chamber is going reach into the bore by 1mm anyway, this should not do too much harm. Would you have the same radius at the chamber to minimize trapped volume? I would like to do so, but suspect that the shape of the radius will have changed once plated.

anyone?

will the bevel be filled with plating anyway, or am I going to trap dead volume?