ESE's works engine tuner

[Yow Ling]

I tink MVX carbs are 20mm. Too big for your Stinger bucket 2 x 17 = 24mm equivalent

Now I have to go to shed to check

[Strokerhaus]

The theoretical MSV of 38M/Sec you are achieving will work OK, but for only 12200 rpm with 54.5 stroke the squish gap should be down at 0.6mm.
0.65 is useable in a normal 125 spinning to 14000 all day, but your piston is obviously heavyer.
The limiting factor should be that at the peak rpm used, the piston should be just shy of clipping the head.
Thus for the best squish action we end up with virtually zero clearance, so in effect the theoretical MSV becomes irrelevant.

What fuel are you using, race or avgas. I suspect the race fuel, if so, have you tried these MSV's with avgas. I did come across a bath tub combustion chamber on an Enfield GP5 of the late 60's, it had very sharp edges but a shallow almost triangular tapered section at the rear of the chamber. I was never certain of how good it was so never tried it, sounds like I have some more work to do.

Keep up the good work really interesting site.

[F5 Dave]

I tink MVX carbs are 20mm. Too big for your Stinger bucket 2 x 17 = 24mm equivalent

Now I have to go to shed to check

NahnahNah, the Stinger will never be a Bucket. . . .Actually one of them was an ill conceived bucket from down souf, - but its being combined with parts from Rusty the Stinker into a Roadbike as they are super kewl in a late 60s kinda way.

[Yow Ling]

NahnahNah, the Stinger will never be a Bucket. . . .Actually one of them was an ill conceived bucket from down souf, - but its being combined with parts from Rusty the Stinker into a Roadbike as they are super kewl in a late 60s kinda way.

Then use as many as you like , they are 21mm

[wobbly]

The MSV numbers at 38m/sec work for FIM unleaded rocket fuel, as well as they do for AvGas.
Only a few class in USA allow real leaded racegas at 110 octane and over, so not really relevant anymore.
The numbers equate to something around 0.65 squish with around 45% width going to 14,000 + in a GP engine and these always go best when the piston
is on the verge of contact.

[Strokerhaus]

The MSV numbers at 38m/sec work for FIM unleaded rocket fuel, as well as they do for AvGas.
Only a few class in USA allow real leaded racegas at 110 octane and over, so not really relevant anymore.
The numbers equate to something around 0.65 squish with around 45% width going to 14,000 + in a GP engine and these always go best when the piston
is on the verge of contact.

Thanks for that, I guess that will be my next job then.

[husaberg]

2000 nsr500

[husaberg]

One ones that were on Ebay

[Grumph]

Couple of oddities in the pic of barrel and pistons...those are big cutaways on the skirt sides...

And the cutback rear wall is pretty much exactly what I did on an RS125 at the customer's request...and it lost power.

[F5 Dave]

Shift drum is unlike anything I've seen before.

they do love their 26482 loom connectors.

[husaberg]

Couple of oddities in the pic of barrel and pistons...those are big cutaways on the skirt sides...

And the cutback rear wall is pretty much exactly what I did on an RS125 at the customer's request...and it lost power.

6666666666666666666666666

Shift drum is unlike anything I've seen before.

they do love their 26482 loom connectors.

[Grumph]

Shift drum is unlike anything I've seen before.

And it appears to be cast too....If anyone has better resolution and can see tool marks, say so, but if it is cast it's pretty good work.

[WilDun]

And it appears to be cast too....If anyone has better resolution and can see tool marks, say so, but if it is cast it's pretty good work.

It's probably an investment casting, but the cam tracks will possibly be finish machined, too fuzzy to see.
However, producing the wax pattern itself would be quite a challenge!
Then again, I could be wrong.

[husaberg]

Best i can do.............
When you think about it normal shift drums are heavy.......
I seem to remember the 50 i posted having a different set up i had a gif on how it worked and i think (the Sachs) of the 70's had something different.
The brits used a camplate.......

[monkeyfumi]

The discussion about the shift-drum reminded me of this video of the Redbull F1 factory
http://youtu.be/-t6cxIeCIjE

Gearbox stuff is from around 2:20 onwards, but the whole video is interesting, showing stuff like rapid prototyping, machining etc. Even the scale wind tunnel.
Thought some might enjoy it if they hadn't seen it.

As you were