ESE's works engine tuner

[TZ350]

Its been done with 2 watercooled MB50 cylinders by Phil Bird. Actually GPR own it for last 20 yrs

Yes, I have seen pictures of it somewhere that Scott posted a while back.

I've looked at RG cases & wondered about a Vtwin conversion that might just fit in the RS chassis. Would be light for a twin which the GT isn't + GT is 5 speed.

RG V twin .... that could be possible, light, good gearbox.

Heavy 5 speed GT, thats why I thought it might be a good candidate for cutting the gear box off and making a CVT out of it.

[husaberg]

Yes, I have seen pictures of it somewhere that Scott posted a while back.



RG V twin .... that could be possible, light good gearbox.

Heavy 5 speed GT, thats why I thought it might be a good candidate for cutting the gear box off and making a CVT out of it.

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[ief]

Perhaps a daft question but wondering none the less. As far as I understand, given the right input, engmod outcome resembles reality pretty good, couple % off maybe? Does that mean the same goes for the exhaust? Logic tells me it is since it's part of the sim but still....

[wobbly]

A huge part of Neels efforts to recreate reality in the sim results is all around the code needed to model the wave action within the pipe.
A 2T lives and dies on the correct timing and amplitude of the particle flow down the pipe, much as a 4T lives and dies on the intake tracts influence.
The latest code change that now has an accurate model of the actual wall temps effects has got the results even closer, without the demon fudge
factors Neels hates with a passion.
The only caveat i would add is that there is still some leeway for idiocy to creep in, and still get a result that seems fine ie 25* diffuser angles.
Go back to the old texts and you will find that very early on in the development of expansion chambers it was found that the angle that gave the best
energy recovery ( amplitude Vs period ) of the depression communicated to the Ex port during the scavenging phase was 16* included.
This is now modified somewhat in that we can and do have up to 6 different cones, all interacting and changing the shape of the negative pressure ratio plot
as seen at the port face when the piston is around BDC, but as is human nature we always think more must be better - even with single malts.
Just keep in mind that any energy used in the diffuser,must then reduce the energy available to be used in the reflection phase - there is only a finite ( and ever decreasing )
energy level available that starts when the piston cracks open the port.

[Flettner]

Wobbly, I assume no Mallory news is bad news?

[TZ350]

... you wouldn't use old 1980's rg50 cylinders would you...........its 2014.

No, maybe not for a CVT 100 twin project, if they were legal for Bucket racing I would prefer the KTM 50 cylinder.

But for our Team ESE F5 racing class 50's we want to use the old school RG50 cylinders/engines precisely because they are from the 80's (and we have collected a few of them, so cheap to start with).

Chambers has been working on a RG50 engine/RS chassis bike for Av. It is currently making 13.5+ rwhp using an original old style single exhaust port RG50 cylinder from the 80's.

Back in the day, we think the norm for the old school Bucket (F5) racing RG50 was 10-11 rwhp so just for the fun of it we want to see how far we can get with them, the ambition is 16-17 rwhp and to show that the humble 1980's RG50 can be more than a match for the newer, more expensive Aprilia and Derbi 50 motors with their aftermarket cylinders.



And it looks like the old 1980's RG50 engine is still being used in the newer RMX 50's.



So still plenty of engine parts available.

And even aftermarket cylinders if you want to go there, but for now, we don't think we will have to, to do better than the current Aprilia and Derbi engines.



With the right sort of (thin deep) ring(s) 50's can run with quite wide (80%+) exhaust ports so you could probably make much more power if you can get away with cutting the bridge out and running it as a single port. If these aftermarket cylinders are legal for F5 racing, then one day we might get one of them to see what can be done, maybe a 20 rwhp RG50 is possible.

I have brought OKO carbs from these guys at Treatland before, https://www.treatland.tv/ even visited them a couple of times, I have found them to be great to deal with.



https://www.treatland.tv/OKO-26mm-re...-block-105.htm

I have been looking at this Honda Dio reed block and manifold they sell with the view of cutting the reed block manifold and welding it into the back of an RG50 cylinder for an easy reed valve conversion. The rubber manifolds suit the OKO 21-24-26-28-30mm range of carburettors.

Wobbly is working on a RG50 project for Gigglebutton, so there could be a few fast RG50's out there next season.

[TZ350]

Fun things to do with a 150cc BSG cylinder.

[peewee]

Where you have an angled exit on one wall like that I use a combination of the flow and chordal width.
In reality the port flow area will be very close to the chordal width, as when the flow exits the duct its effective area
will be less than a straight flow port, but more than the flow area measured vertically as you have drawn it.
In between approximation is the chordal width as i have shown.

i got molds of the original ducts today and im going to make it so theres a radius turn instead of a sharper hook. what do you think about the flow width on the A ? as you can see from the orange and green arrows, the flow width will vary alot depending on which wall you calculate from.
if i use the front wall i get 20mm flow width. if i use the rear wall i get 27mm

[TZ350]

Hi PeeWee I am interested in this too, so what size coin fits in there? and didn't Wob talk about the chordal width being a suitable measurement? It looks like the 20mm green line to me. The moulds look good.

[peewee]

yes he said chordal on the B but the A doesnt seem to be that simple however because of the angle of either wall into the cylinder. a true chordal on the A port would be more like the purple line. thats why im confused on this. was my first time making the molds. gonna try a release agent next time as it was a bugger getting them out of the ducts. grill is useful more than just food

[peewee]

well after looking again, the purple line (chordal) and green line are about the same at nearly 27mm width. the orange line however is alot smaller at 20mm. the B port was 20mm also. it doesnt seem right that both A and B would be the same when the A window is alot wider chordially than B but its the angle that A enters the cylinder that makes it confusing. seems like i should use the green line but i dont know.

[peewee]

ok ill use the green line as that seems to make the most sense to me

[TZ350]

... this was my first time making the molds. gonna try a release agent next time as it was a bugger getting them out of the ducts. grill is useful more than just food

I like the grill idea.

[peewee]

grill worked pretty good. cost me almost nothing since i already had it on the back porch. bought a metal pan from walmart for $10. has a thermometer in the lid. set the dial to maintain 275-300F. took about 15-20min and it was melted perfect and ready to pour in the cylinder

[jasonu]

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What is this bike Husa?