ESE's works engine tuner

**tjbw** · 27th November 2017, 16:13

Originally Posted by WilDun

Talked to an old American guy from Nevada who sold Suzukis and when the first fast six speed Suzuki twins came out, (T20) they tried them in desert racing but used the arrangement you are discussing (pistons rising and falling together) and called them "Twingles".

Will, Twingle is also a name used for 'split single' a twin uniflow twostroke, with shared combustion chamber.

https://en.wikipedia.org/wiki/Split-single

**Niels Abildgaard** · 27th November 2017, 18:37

Originally Posted by guyhockley

Think the original Hirth couplings had dual pitch bolt as well... Google isn't finding it so it may be the oldtimers kicking in!

There was a discussion on Michael Moore's MC-Chassis about Hirth couplings fairly recently.

I have seen these Hirth 504 crankshaft parts
http://www.homemodelenginemachinist....&page=3http://

**lohring** · 28th November 2017, 02:56

Originally Posted by Frits Overmars

My knowledge of boats can accurately be described as non-existent, so this may be a dumb question:
why don't you put the stinger under water? You'd have less noise and a bit of thrust as well, wouldn't you?

That was tried at least once that I know of and worked well. Outboards have used this for a long time. However, silencing isn't very popular with racers. We like to hear the sound. Only when the neighbors call the police with noise complaints, as happened in one race I attended, is something done. Europeans have much stricter noise rules than in the US.

Lohring Miller

**Grumph** · 28th November 2017, 06:26

Originally Posted by lohring

That was tried at least once that I know of and worked well. Outboards have used this for a long time. However, silencing isn't very popular with racers. We like to hear the sound. Only when the neighbors call the police with noise complaints, as happened in one race I attended, is something done. Europeans have much stricter noise rules than in the US.

Lohring Miller

Don't outboards release the exhaust into the prop vortex ? I realise the actual plumbing for an inboard wouldn't be hard but wonder at how the external pressure variations as between boat stationary vs moving would affect starting and coming on the pipe.

Noise - I was at a bike race meeting here once where an activist neighbour got the PA shut down as it was over the noise limit at the boundary. The bikes were fine...The neighbour - a doctor - was trying to get the circuit closed down. Once it was generally realised just how much money the track brought into the small town, he lost patients quickly - and soon moved. His legacy though is the tightest noise control at any NZ circuit - and a PA you can hardly hear.

**WilDun** · 28th November 2017, 06:32

Originally Posted by Niels Abildgaard

I have seen these Hirth 504 crankshaft parts

Well the Hirth coupling seems to work ok and the differential (double pitch thread) is a good idea - it's all a lot of work to machine and construct and as Grumph says would no doubt expensive to make!
I've got to hand it to that guy who made the model flat four - he persevered ..... and not a casting in sight!
Only criticism I would make is that he was short sighted when he decided to build a four stroke!

**Michael Moore** · 28th November 2017, 06:56

IIRC Billy Uhl, Penton/ISDT rider, ran a 360 degree crank Suzuki T20/X6 in dirt track and/or hare scrambles in the Pacific NW in the early part of his career. It was converted by a dealer that sponsored him.

Gordon Jennings mentioned that he thought to try the internal stinger in the late 1960s/very early 1970s, and that he later discovered it " . . . was an idea also advanced by an obscure German researcher some several years earlier."

Hans Hintermeier sent me some photos of an adjustable cam he did for an XT500 Yamaha engine (he was making his own lobes too). He used a differential-thread bolt to pull things together. He also sent me a photo from a German magazine showing the Hirth coupling on an NSU Rennmax crankshaft. The crankshaft on the 1957 350GP Guzzi single (among other various Guzzis, some of which used the Hirth coupling) also used the differential threaded bolt to hold it together.

https://www.youtube.com/watch?v=-WacJOVzxmY

Is a video showing the machining of a Hirth coupling for a small crankshaft on a CNC mill.

https://www.youtube.com/watch?v=-JskW3UdZx0

is another machining video and shows photos of the Hirth coupling on an Adler and other crankshafts. The machining is done with a manual mill and dividing head. The dividing head is angled off the X axis of the mill to give the depth change between the ID/OD of the coupling.

cheers,
Michael

**guyhockley** · 28th November 2017, 11:45

Another crank joining method - unsuccessful TZ350 experiment.

**WilDun** · 28th November 2017, 11:50

Originally Posted by Michael Moore

IIRC Billy Uhl, Penton/ISDT rider, ran a 360 degree crank Suzuki T20/X6 in dirt track and/or hare scrambles in the Pacific NW in the early part of his career. It was converted by a dealer that sponsored him.

Gordon Jennings mentioned that he thought to try the internal stinger in the late 1960s/very early 1970s, and that he later discovered it " . . . was an idea also advanced by an obscure German researcher some several years earlier."

Hans Hintermeier sent me some photos
cheers,
Michael

Unfortunately even though it had high HP at the top, the T20 would have needed some modifications here and there to make it more suitable for the dirt!

I did pay attention to the tailpipe suggestion when I first read Jennings book but I don't think he had actually tried that (and didn't claim to have either) - just suggested it ...... I think a lot of people did try it though!

Great videos - thanks.

**wobbly** · 28th November 2017, 15:23

The internal stinger idea Jennings said not to make it start at 1/2 the fully developed rear cone length as it lost power.I never did check that though
and made them always starting at the end of the belly.
This coincided with finding out about Faths stinger nozzle, so it was easy to make an adapter that held the internal stinger, and as well as allowing slide in nozzles
allowed the overhung internal tube a much stronger weld onto ( further up ) the rear cone.

**marsheng** · 28th November 2017, 16:25

Originally Posted by wobbly

The internal stinger idea Jennings said not to make it start at 1/2 the fully developed rear cone length as it lost power.I never did check that though
and made them always starting at the end of the belly.
This coincided with finding out about Faths stinger nozzle, so it was easy to make an adapter that held the internal stinger, and as well as allowing slide in nozzles
allowed the overhung internal tube a much stronger weld onto ( further up ) the rear cone.

I like the idea of 'free' quieting. I'll give it a try next pipe I make. I will annoy one of the flag marshals as he always loves the sound and smell of my bike.

**SwePatrick** · 28th November 2017, 16:30

In short:

I had the stinger on the middle of the belly, bike ran 'ok', it was nice and silent.
But tests later on showed quite suprising results with the stinger on belly.

When i placed stinger at the end of the cone it suddenly became consistant.
Before the powercurves had their own rollercoasterride *lol*
Stingerdiam also needed to be larger when on belly.

Rgds.

**marsheng** · 28th November 2017, 16:31

I've done some searching but nothing concrete on this so I thought I better ask the experts.

I've popped a crank seal on the Maico 2 days to go before I leave for the MPSC. I can only find a single spring Viton oil seal locally and the 'original' was a double. (I think the original was only a Nitrile one as well) Does the seal need to be double spring with the gearbox oil on one side and 2 stroke on the other ?

Will Nitrile survive 8500 RPM. The last one seems to have lasted 2 seasons.

Cheers Wallace.

**jasonu** · 28th November 2017, 16:50

Originally Posted by marsheng

I've done some searching but nothing concrete on this so I thought I better ask the experts.

I've popped a crank seal on the Maico 2 days to go before I leave for the MPSC. I can only find a single spring Viton oil seal locally and the 'original' was a double. (I think the original was only a Nitrile one as well) Does the seal need to be double spring with the gearbox oil on one side and 2 stroke on the other ?

Will Nitrile survive 8500 RPM. The last one seems to have lasted 2 seasons.

Cheers Wallace.

Your choices are 1, take a risk and fit the 'suspect' seal or 2, stay at home. I know what I'd do.

**husaberg** · 28th November 2017, 17:15

Originally Posted by jasonu

Your choices are 1, take a risk and fit the 'suspect' seal or 2, stay at home. I know what I'd do.

You voted Trump.

**Grumph** · 28th November 2017, 20:16

Originally Posted by marsheng

I've done some searching but nothing concrete on this so I thought I better ask the experts.

I've popped a crank seal on the Maico 2 days to go before I leave for the MPSC. I can only find a single spring Viton oil seal locally and the 'original' was a double. (I think the original was only a Nitrile one as well) Does the seal need to be double spring with the gearbox oil on one side and 2 stroke on the other ?

Will Nitrile survive 8500 RPM. The last one seems to have lasted 2 seasons.

Cheers Wallace.

Take three single lip seals - afaik, your nights at levels aren't spoken for so you've got time to use one seal per day.....