Donor Gearboxes

[el chupacabra]

I initially wanted to insert it from the sprocket side, but setting up the shift star mechanism will be a lot harder, I can always change the design later fairly easily should I decide.

I'm pretty interested in the pump. . . what kind of current does it draw?

In regards to the flying web crank, I recall asking on the ESE thread about it a year or two ago when I was dreaming ideas up. If i recall correctly, someone said they had a short service life and were very expensive, I can't remember if that was due to the material used or the hirth coupling.

I would probably need to run larger diameter big ends to make the crank more stable and it would detract from the off the shelf *cheap parts philosophy.

[husaberg]

I initially wanted to insert it from the sprocket side, but setting up the shift star mechanism will be a lot harder, I can always change the design later fairly easily should I decide.

I'm pretty interested in the pump. . . what kind of current does it draw?

I found a rather interesting variable speed electric water pump.
I even have a couple here now thanks to a benefactor
Its used on all manner of BMW's as the primary water pump.

The specs are 2kgs and 125 liters /minute.


It needs a controller to operate in variable speed mode but I am pretty sure something could be bodged up with a 555 circuit and a piggy back. Or an Arduino circuit.
http://www.nomad.ee/micros/pwm555.html



or
https://www.maximintegrated.com/en/a...ex.mvp/id/3530
http://www.reichelt.de/ICs-MAX-1000-...40&LANGUAGE=EN

http://www.tecomotive.com/download/manual_tinyCWA.pdf
The manual for this controller gives out the important specs

Mainly electrical....but its all in the specs


https://www.fcpeuro.com/products/bmw...p-11517586925a

[el chupacabra]

15A is pretty significant, the most I can achieve with an 85 lighting stator is about 45 watts, some Chinese pit bike ones are around 100 watts. I'd need something with around 200 watts to make it work without killing the battery. I wonder if there are any decent stators I can hang off the side. Maybe I run something like that at 1/3 engine speed with a toothed belt instead of electrically.

At this stage I reckon I'll go with the 27L/min Craig Davies one as it only draws 2.5A which wont kill the small stator. If/when it isn't upto the job I will look to add something more significant, either electric or mechanical.

[jato]

Just weighed a SV 1000 based (twin outlet) pump complete and ready to plug into a 10mm spade drive - 660 grams. i would imagine if you started with a s 650 one you would be looking at 500 grams or so. no up rated charging system needed, controller or wiring and associated threats to reliability. sitting on the start line it needs to be light...

[el chupacabra]

I wonder where I can take the Spade drive from, without adding a sprocket to the lay shaft and another shaft as that will probably be what I will have to do then I may need to change the impeller as the lay shaft will have it spinning in the wrong direction. hmmmmmmm. Belt drive from the cranks seems like the simplest solution like the Tul Aris as it'll be spinning the right way.

An R6 pump has a nice built in ball bearing, I wonder if this could be changed with a grease sealed unit which could be replaced at regular intervals I'd make a bracket that could support it on the other side. Pulleys and belts are dirt cheap.

[husaberg]

15A is pretty significant, the most I can achieve with an 85 lighting stator is about 45 watts, some Chinese pit bike ones are around 100 watts. I'd need something with around 200 watts to make it work without killing the battery. I wonder if there are any decent stators I can hang off the side. Maybe I run something like that at 1/3 engine speed with a toothed belt instead of electrically.

At this stage I reckon I'll go with the 27L/min Craig Davies one as it only draws 2.5A which wont kill the small stator. If/when it isn't upto the job I will look to add something more significant, either electric or mechanical.

Thats the max draw at over 116 litres a minute at pressure it draws les than 1/2 that at 50 liters/min its a very clever pump.
https://www.tecomotive.com/download/.../CWA200_EN.pdf
Flow rate: ca. 116 l/min @ 0.45bar / 166 l/min @ 0.30bar

Ktm tpi models have 200w stators available.
honda VT250 ones are 200w

as are old pommy shitter inner rotor alternators which actually would look pretty trick
https://www.lowbrowcustoms.com/produ...mph-bsa-norton

low output ones are even available here and are cheap
https://www.moto1.nz/collections/sta...cts/bri4898650



ktm outer rotors ones that are the same size as this inner is ie 75mm which is cr85 size can go over 100w

Looks like the std 12 Enfield from India was 120watts with similar set up with high output 200w kits available.

https://www.ebay.com.au/itm/295061870502

[el chupacabra]

The stator size isn't too outrageous. Also, I could have the lay shaft extend out of the case and place a pulley on the end.

Here's a pic of the stator size and here's one of the proposed r6 water pump location.

[husaberg]

I wonder where I can take the Spade drive from,

Ktm 50's drive their water pump off the mag stator its build into the cover.

[jato]

if the pump had twin outlets it would be easier to get equal coolant flow to all 4 cylinders ... just saying . the sv based pump i weighed has a pair of 10 x 26 x 8 bearings in it. i would imagine the 650 would also use a 10mm shaft. not much side loading with a cute tooth belt

[husaberg]

if the pump had twin outlets it would be easier to get equal coolant flow to all 4 cylinders ... just saying . the sv based pump i weighed has a pair of 10 x 26 x 8 bearings in it. i would imagine the 650 would also use a 10mm shaft. not much side loading with a cute tooth belt

i agree electric looks cool but direct is better but the variable output functions of electric are also neat. and also lessen the need for radiator taping and thermostas cooling fans etc
A full noise all out gp bike needs over 1 liter/min/hp. although frits says later 3x more?
Jan Thiel was going to use an electric on the RSA, but there were none that flowed enough. He wrote it was one of the things he never liked, as it was added as an afterthought

The coolant flow through the RSA125 was 60 liters per minute. You can't talk about optimum performance though, because, who knows, even more coolant flow might have yielded more power, but that would have meant fitting an even larger pump, but none was available.
Adding anything to the coolant is not allowed in the rulebook (spilled additives might make the racetrack unusable for much longer than water would)

The engine was designed and made at Derbi.
And we assumed that the electrical pump used there would be sufficient.
When Piaggio bought Aprilia the engine went there, and Derbi was closed.
At Aprilia some very serious testing was done, with a big waterpump with variable speed.
The result of this test was: the faster the circulation the better!
For cooling as well as against detonation.
So the insufficient electric pump was abandoned.
And a mechanical pump with the same impeller as the Aprilia RSW was fitted.
It was not too beautiful, on the outside of the primary cover.
But we could not do anything else, as the crancases were already finished.
Making the pump inside, as on the RSW, would have meant a whole new design of the crankcase!
And there was no more time to do that.
The outside pump never gave any problems, not even when the bike was crashed!

n 2005 Aprilia and Derbi worked together for a short time on the RSA engine. We at Derbi used Aprilia cylinders, and Aprilia did some cooling tests for us. An electric central heating pump was used for this, with a variable output. This was done using a RSW engine. The electric pump used on the Derbi proved to be insufficient in a big way.... The RSW pump was good, but more water circulation gave more power.
So it was decided to give the RSA more water circulation, fitting a pump from a 250 Aprilia.
This may have caused a power loss through too much resistance.....quite possible.
No further tests were done I think.

Frits Overmars

You're welcome Carlo. The RSA125 had a coolant circulation rate of 60 litres per minute. The RSA250 obviously had more than that, but I don't recall how much more.
As a rule of thumb you might say that the optimum coolant flow requirement is one litre per crankshaft-HP per minute.
Like Jan wrote, a smaller pump on the RSA125 would have absorbed less engine power, but the accompanying rise to a higher coolant temperature might have nullified that initial gain. The RSA produced best power at 40° C and keeping this temperature low over the total duration of a race is very important for a two-stroke.

Compare two cooling systems, A and B. In system B the water flows three times as fast and picks up only half the amount of heat per liter, compared to system A.
Then system B removes 50% more heat than system A! And provided your piston clearance is OK, you just cannot have too much cooling. In the Aprilia RSA125 the water pump circulates 160 liter per minute. That is 3 liter per HP per minute!

Nowadays we have a fine solution for avoiding corrosion; it's called plastic. Saves weight too.

I don't know exactly how the NZ dollar is doing, but that sum will probably buy you two of these:
http://www.hvg-engineering.com/index...id=127&lang=NL

You are right about the KTM (first picture) but I cannot recall any genuine Japanese racing bike with an electric pump.
The RSA125 was originally desiged to work with an electric pump. But as it turned out, none of the available pumps even came close to the flow Jan wanted, so a mechanical pump was fitted as an afterthought. Jan and I both feel that it is the ugliest aspect of the RSA engine. But it works...

[jato]

Top references as always Husa! I don't want to Hijack el chap's design but it's good to have genuine info and reasoned discussion on the various design aspects ... Certainly there is a lot of power to be had from a cool running two stroke. This is an interesting exercise and it'd be great to see the result doing 1m 11 or so around manfeild ( very achievable i believe) so lets get this compact and efficient waterpump sorted...

[jato]

I wonder where I can take the Spade drive from, without adding a sprocket to the lay shaft and another shaft as that will probably be what I will have to do then I may need to change the impeller as the lay shaft will have it spinning in the wrong direction. hmmmmmmm. Belt drive from the cranks seems like the simplest solution like the Tul Aris as it'll be spinning the right way.

An R6 pump has a nice built in ball bearing, I wonder if this could be changed with a grease sealed unit which could be replaced at regular intervals I'd make a bracket that could support it on the other side. Pulleys and belts are dirt cheap.

The lay shaft is forward spinning isn't it ? could you have a plastic gear meshing with the layshafts primary drive on the righthand side ? maybe with the pump outlets built into the right casing. you could then spin the pump at the right speed...

[el chupacabra]

I’ll see what I’ve got for room on the RHS as a delrin gear won’t be too hard to make. And I could just place it on the clutch cover. Maybe I remachine the base of the SV pump so the water doesn’t re enter the engine through the cover.

I’ve already got a plan for how I’m going to cool it. I know the coolant should enter the head and exit under the exhaust last if I remember correctly. But the easiest way is to enter under the exhausts on each cylinder with an equal length tee junction. And also run an equal length tee on the heads and have them join back together entering the radiator.

Maybe I don’t use the dual outlet and use an R6 pump and run a Y splitter. Less parts to make. Hmmmm I’ll have a look when I get out of bed.

[husaberg]

I’ll see what I’ve got for room on the RHS as a delrin gear won’t be too hard to make. And I could just place it on the clutch cover. Maybe I remachine the base of the SV pump so the water doesn’t re enter the engine through the cover.

I’ve already got a plan for how I’m going to cool it. I know the coolant should enter the head and exit under the exhaust last if I remember correctly. But the easiest way is to enter under the exhausts on each cylinder with an equal length tee junction. And also run an equal length tee on the heads and have them join back together entering the radiator.

Maybe I don’t use the dual outlet and use an R6 pump and run a Y splitter. Less parts to make. Hmmmm I’ll have a look when I get out of bed.

My memory is the water should enter the cyinder and rise to the head last. Yamaha tended to be a bit suborn and do this in reverse.
It should preferably cool the cases first but that's a lot harder, There is special paint to isolate the cases. Available from EMOT

Having the cold water feeding in under the Exhaust duct is just as wrong as having all the cold water going into the head.
This change was made 2 homologations ago in KZ engines , where the simple but vey inelegant solution was to feed the cold water surrounding the crank , up thru a hose , and into the cylinder
above the top of the Exhaust duct from one side.
The best scenario is to have all the cold water enter the cylinder over the boost port , then run around the bore over the tops of all the transfers - cooling these first.
Then a portion of the return should be directed to a pair of small exit holes on each side under the Exhaust , the remining flow then exits up into the Exhaust side of the head , around the insert and back to the radiator.
This alone is an instant 1 to 1.5 Hp in 50.

Water flow and cooling in general is a very much ignored source of " free " power gains.
Having water flowing around the entire length of the Exhaust duct , where the plugging charge is retained , is super simple , but never done properly as far as I have seen.
These slots in the Exhaust exit surface ( done by hand many years ago in the pit with a battery drill and file ) cools the back of the spigot as well , and reduces the background deto level by around 20% - allowing alot leaner egt level at full power as a result.
This is much easier now with a small 75% exit area and a 6 axis CNC .

Sorry I didnt word my fist description correctly.
If the water is fed initially into the crankcase ( from the front in the Aprilia or the middle as in the TM ) then the main flow from there should be directly up into the cylinder
with a pair of large holes each side of the boost port ( NOT underneath the hot Exhaust duct ) . Another pair of smaller holes should also feed up under the Exhaust port , thus aiding flow around this area separately.
The only exit flow from the cylinder is up into the head directly over the Exhaust port. Thus keeping the water heated up by the Exhaust duct flowing away from the transfers.

This is possible for example in the TM , if the water in the cavity between the case and the gearbox is then also fed forward over the top of the mains ( thus cooling the transfer entry area ) and up
into the cylinder each side of the boost port.

This idea has been applied to old designs , like TZ250/350/750 , where the original flow was completely wrong - but this needs some form of separation plate or gasket between the head and cylinder.
Again , in this case all the flow enters the cylinder thru a new spigot welded in opposite the Exhausts , and all the cold water flows forward across the transfer tops , then exits into the head thru a pair of holes
each side above the Exhausts.

The test was done on a TM by extending the existing water feed hole around to above the boost port. A real 1 Hp free lunch , but not shown in the homologation papers , so probably illegal.
Thus I did the almost as good change , and forced all the cold water away from the Exhaust duct with a hidden manifold inside the cylinder - legal.

Top references as always Husa! I don't want to Hijack el chap's design but it's good to have genuine info and reasoned discussion on the various design aspects ... Certainly there is a lot of power to be had from a cool running two stroke. This is an interesting exercise and it'd be great to see the result doing 1m 11 or so around manfeild ( very achievable i believe) so lets get this compact and efficient waterpump sorted...

i dont want to hijack it either i myself prefer the simplicity of a driven pump mounted low.
if it needs to be under t driven by belt, kart and older f3 cars had special pumps for this it should go under the engine so it can self prime and to limit airlocks.

Ford escape v6 has a remote water pump

https://www.trademe.co.nz/a/motors/c...ing/4193743935
https://www.ebay.com/itm/254603938645

Or Jag
Jaguar Water Pump - Eurospare AJ88912
S-Type, Super V8, Vanden Plas, XF, XJ8, XJR, & more

or this one from the xj6
XJS AND XJ6 JAGUAR WATER PUMP - EBC10566-EBC10967 (INCLUDES BACKPLATE)
https://www.masai4x4.com/defender/ra...late-p34055611

https://www.summitracing.com/parts/U...1/applications

[el chupacabra]

Maybe I need to take a trip to pick a part, I wonder how big that Mazda one is. It looks like something that would work.

If I run an R6/GSXR/similar pump off the clutch cover, I could run it faster At 80-100% engine speed. I do like the idea of a belt driven standalone unit though, for servicing and ease of integrating into the design. It could just bolt under the engine on a plate and either be driven from the end of the crank or layshaft depending on which way I need it to spin. The other benefit of belts is they can raise or lower the pump speed fairly easily.