ESE's works engine tuner

[speedpro]

I used Frits’s empirical FOS method to design the 3 pipes for the world famous slider engine. Seeing I don’t have EngMod, the FOS method is quick & easy and the slider is just so different, I figured that it’d be shitload better than me throwing darts against the wall.

Just finished adding the convergent cones and tailpipes. Note that it hasn't run with these, but so far they haven’t not worked !!
We based the styling of the tailpipes, fortunately or unfortunately, after some well-known twittering dude.

Attachment 328571Attachment 328572

I looked at that and immediately thought about a 3 cylinder version in a motorbike. It'd be a good test of the pipe builder.

[Niels Abildgaard]

The Youtube : https://www.youtube.com/watch?v=PQ2wOx2jgTE from Katinas look decidedly strange.
Two 180 deegre apart exhaust pulses in a common bulb ?

[SwePatrick]

How about this one?
anyone got info?
it´s an supercharged twostroke from what i can see.
No crankcase like an old diesel twostroke?

[SwePatrick]

The Youtube : https://www.youtube.com/watch?v=PQ2wOx2jgTE from Katinas look decidedly strange.
Two 180 deegre apart exhaust pulses in a common bulb ?

Very common in snowmobiles.
Search artic cat, skidoo, polaris, lynx, yamaha for example.

Pipe is just doing what it should do, one piston is at top when other is at bottom.
Just twice as much pulses in pipe, simple described.

[wobbly]

I searched everywhere and it seems Rekluse does not make a clutch for the Banshee/YPVS.
But knowing Yamaha seems to use common shafts /splines etc for model after model, I would think maybe a YZF250 or 450 MX might be able to fitted
with some work ?

[koba]

Hey all,

I love all of the really interesting talk on this thread however I've not had much input in a long time.
I've got a selfish request though, there is something that's bugging me.

The question is, is there a good guideline for revs that rings can do?

Obviously the mass of a given thickness varies based on the bore...

I'm trying to find the sensible limit that I should work to for a standard MB100.
I know I'd be much better off de-stroking and going to a kart piston, or even better, keeping it square and getting something to fit. (not happening) but if I want to make a basic build with the standard slug and the big fat 1.5mm rings what's a sensible rev number? (I hope I have that right...)
The bore is 50.5mm.

I'd really be keen to know the thoughts on the numbers here.
I think I've been pushing it how it is, things seem to go wrong just after 12,000rpm, I'm wondering if this is the reason.

[koba]

On the sheared bolts on the clutch...

Mechanically ignorant here, but could this be put together with some kind of rivet to avoid the stress raisers in the threads?
Thinking out loud here...
Still, sounds like it is too close to the edge right? More bolts required?

[Niels Abildgaard]

Very common in snowmobiles.
Search artic cat, skidoo, polaris, lynx, yamaha for example.

Pipe is just doing what it should do, one piston is at top when other is at bottom.
Just twice as much pulses in pipe, simple described.

Thank You and sounds OK.
Has it been used on a normal twin-twostroke bike.?

[husaberg]

Hey all,

I love all of the really interesting talk on this thread however I've not had much input in a long time.
I've got a selfish request though, there is something that's bugging me.

The question is, is there a good guideline for revs that rings can do?

Obviously the mass of a given thickness varies based on the bore...

I'm trying to find the sensible limit that I should work to for a standard MB100.
I know I'd be much better off de-stroking and going to a kart piston, or even better, keeping it square and getting something to fit. (not happening) but if I want to make a basic build with the standard slug and the big fat 1.5mm rings what's a sensible rev number? (I hope I have that right...)
The bore is 50.5mm.

I'd really be keen to know the thoughts on the numbers here.
I think I've been pushing it how it is, things seem to go wrong just after 12,000rpm, I'm wondering if this is the reason.

What you are asking about is called ring flutter
The MB100 has rather thick keystone rings. well at least the top one is from memory?

There are CR85 overbore pistons that can be used but they are a little spendy as only Wiesco provide them.
I think it was Bert that used NOS 1980's RM100 pistons on one of his projects. talk to him resizes
I am pretty sure it has room near the top for a dykes ring to be added. Ask Ken about sizes available
The dykes kart ring will handle the revs but will likely wear you bore faster
Anyway Sorry its not metric and it likely only applies for plain rings
Gordon Jennings

For rings having a 0.125-inch thickness, 40,000 ft/sec2
0.094 “ “ 53,000 ft/sec2
0.063 “ “ 80,000 ft/sec2
0.047 “ “ 106,000 ft/sec2
0.039 “ “ 138,000 ft/sec2

http://www.amrca.com/tech/tuners.pdf
PG9
Yours from memory would likely corrospond to .63 or about 1.5mm


12000 rpm and a 49.5mm stroke and 100 c-c rod equals
i only came up with 31K? i must have buggered up?

Anyway TKRJ a while back did a run of RG400 pistons
https://www.tkrj.co.jp/goods/m-AS8060X-21A04-21A14.php
no idea re the rng widths though but they were 14mm gudgeon

[jonny quest]

Wobbly we use the Rekluse on the MX bikes. Sorry I just assumed they had one for a banshee. I'd email them. Hindsight here, they typically use stock baskets with completely new insides. I probably don't have to get into the design if you've Googled them and looked at pics.

[jamathi]

Do you think you would you have had the carbs operating progressively like the Exactweld did Jan?
Also what carb and intake port sizes would you have started with? 2x 30MM?
Pretty sure Flettner could be persuaded to make one to see how it would have gone.
If you give him some basic dimensions. I have some DEA cylinders that could be modified to more closely replicate your originals.

The idea was to start with 34mm.
Progressive opening was certainly thought of, and would surely have been tried.
The engine was to have been made for a Chinese factory.
But unfortunately they decided not to continue their racing program, after a very bad experience with a very 'famous' designer who made a totally useless engine, based on a kart engine fitted 'upside down' in a motorcycle......
It had no power and kept seizing, a real disaster.....

Exactweld has gone to 36 with good results I heard.
But, interestingly, its designer wanted to make a rear-disc engine, that was never finished.

A friend in Holland has made a 50cc twin-disc.
For the moment it is inferior to the single-disc.
Maybe because of the unequal inlet duct length, caused by the primary drive.
2 22mm carburetors are used.

DEA cylinders seem to have narrower A-ports, to make the engine rev more.
That was necessary, he told me, because in karting electronic variable ignition is not allowed.
So the exhaust temperature became too low at high rpm.

[husaberg]

The idea was to start with 34mm.
Progressive opening was certainly thought of, and would surely have been tried.
The engine was to have been made for a Chinese factory.
But unfortunately they decided not to continue their racing program, after a very bad experience with a very 'famous' designer who made a totally useless engine, based on a kart engine fitted 'upside down' in a motorcycle......

Exactweld has gone to 36 with good results I heard.
But, interestingly, its designer wanted to make a rear-disc engine, that was never finished.

A friend in Holland has made a 50cc twin-disc.
For the moment it is inferior to the single-disc.
Maybe because of the unequal inlet duct length, caused by the primary drive.
2 22mm carburetors are used.

DEA cylinders seem to have narrower A-ports, to make the engine rev more.
That was necessary, he told me, because in karting electronic variable ignition is not allowed.

34mm Wow thats a huge carb area eq to about a 48mm carb
36 that like a single 51mm carb.
The Dea ones i have the molds for have been improved in the design of the septums, you could actually shave with them. i feel they would work rather well though if i could get the transfers to go supersonic.
I have always wanted to try a disc valve with a offset disc by about 20mm so it could be uterly huge. Thus fully open for a longer time period for a given timing duration.
Never finished.... is actually my middle name

[speedpro]

Hey all,

I love all of the really interesting talk on this thread however I've not had much input in a long time.
I've got a selfish request though, there is something that's bugging me.

The question is, is there a good guideline for revs that rings can do?

Obviously the mass of a given thickness varies based on the bore...

I'm trying to find the sensible limit that I should work to for a standard MB100.
I know I'd be much better off de-stroking and going to a kart piston, or even better, keeping it square and getting something to fit. (not happening) but if I want to make a basic build with the standard slug and the big fat 1.5mm rings what's a sensible rev number? (I hope I have that right...)
The bore is 50.5mm.

I'd really be keen to know the thoughts on the numbers here.
I think I've been pushing it how it is, things seem to go wrong just after 12,000rpm, I'm wondering if this is the reason.

My 19.9hp MB100 sidecar saw 13,000rpm all the time and lasted at least a few years before a serious dose of over-revving at Taupo saw the crank expire at the next meeting. My 22.5hp MB100 revved to 12,000rpm and lasted 6 years before I exploded it by downshifting at max revs in 2nd.

Technically I don't think they are supposed to rev that high but in fact they seem to be fine.

Standard RG400 rings are 1mm IIRC as I used RG400 pistons in my TS100.

With the kart pistons in my good MB motor it was doing 14,000rpm regularly. The little end cage was in 3 pieces when we pulled it apart and the big end cage had 3 cracks

[dark art]

A friend in Holland has made a 50cc twin-disc.
For the moment it is inferior to the single-disc.
Maybe because of the unequal inlet duct length, caused by the primary drive.
2 22mm carburetors are used..

Maybe the second disc creates a lot of friction for a small engine?

[lodgernz]

Hey all,

I love all of the really interesting talk on this thread however I've not had much input in a long time.
I've got a selfish request though, there is something that's bugging me.

The question is, is there a good guideline for revs that rings can do?

Obviously the mass of a given thickness varies based on the bore...

I'm trying to find the sensible limit that I should work to for a standard MB100.
I know I'd be much better off de-stroking and going to a kart piston, or even better, keeping it square and getting something to fit. (not happening) but if I want to make a basic build with the standard slug and the big fat 1.5mm rings what's a sensible rev number? (I hope I have that right...)
The bore is 50.5mm. really be keen to know the thoughts on the numbers here.

I think I've been pushing it how it is, things seem to go wrong just after 12,000rpm, I'm wondering if this is the reason.

Malcolm, as Jan said a page back, and I think I've heard it said before, most 2-strokes will reach the limits of blowdown well before any ring flutter sets in. However, 1.5mm is a bit of a fatty, so it could be your problem.
What we're talking about is ring flutter (as Husa said), which is reached when the maximum piston acceleration (not piston speed) exceeds accepted threshholds. You need the stroke and rod length to calculate it. Bore does not factor in the calculation.
Here's the formula I use:

Max Piston Acceleration = (RPM^2)*Stroke*(1+(Stroke/(2*RodLength)))/182400 m/s/s

Limits given by Blair (or was it Irving?) correspond to about 26000m/s/s for 1.5 mm rings, but I think that's pretty conservative. I've seen other opinions that suggest 32500m/s/s is more realistic for 1.5mm rings.
You can do the calcs and see if it's the problem. For my engines, 10,800 would be the limit with 1.5mm rings, which is why I use 0.8mm ones on the 50. The 90 runs 1.2mm rings and happily revs to 12,000, which sounds about right.

Please, anyone, correct me if I have any of this wrong.