ESE's works engine tuner

**dutchpower** · 5th May 2020, 18:43

Nearly all the ktm's have that issue (2 stroke )

**koenich** · 5th May 2020, 20:15

did you do any changes besides ignition and exhaust to get to ~29 hp? friend of mine has a standard 85SX and dynoed it at ~20 rwhp (which was quite disappointing) but ran out of time to jet it down...

**tdc211** · 6th May 2020, 02:15

Originally Posted by koenich

did you do any changes besides ignition and exhaust to get to ~29 hp? friend of mine has a standard 85SX and dynoed it at ~20 rwhp (which was quite disappointing) but ran out of time to jet it down...

I've been modifying these sense 2010. 0r 09
I changed just about everything mentioned in these 2500pages. Pipe and ign will get you little over 24hp.
If you didnt have time to lean it. 21hp is normal. Evertime i.put one on the dyno I tried to improve over the last one

**Flettner** · 6th May 2020, 10:16

piston ring, what would one make it from, nitrided P20?
Or high speed steel, hard chrome wear surface. Or would just 4140 be suitable? Nitrided.

**Brett S** · 6th May 2020, 12:57

Originally Posted by Flettner

piston ring, what would one make it from, nitrided P20?
Or high speed steel, hard chrome wear surface. Or would just 4140 be suitable? Nitrided.

What dimensions do you need?
Going by past history i'm guessing this isn't going to be a conventional ring..
Can you modify an existing ring?

**Flettner** · 6th May 2020, 14:37

77mm larger dia. I see I've made the ring groove 2mm wide, not sure what I was thinking here. Could be I was thinking two 1mm rings side by side. Although It doesn't get the same acceleration / deceleration as a normal ring, mass not so important so probably a single ring will fit the bill.

**Brett S** · 6th May 2020, 16:37

Originally Posted by Flettner

77mm larger dia. I see I've made the ring groove 2mm wide, not sure what I was thinking here. Could be I was thinking two 1mm rings side by side. Although It doesn't get the same acceleration / deceleration as a normal ring, mass not so important so probably a single ring will fit the bill.

Some of the foulstroke 250 mx bikes are 77mm, but have a 0.8mm ring. KXF, RMZ and YZF.
Honda has 78mm and 79mm but i assume also 0.8mm.

**Brett S** · 6th May 2020, 16:42

After a quick google there is other options:

Honda GX270 is 77mm and 2mm.
also a VW engine is 77mm.

**Flettner** · 6th May 2020, 18:26

what are they made of? Cast iron I'd assume.

**husaberg** · 6th May 2020, 18:47

Originally Posted by Flettner

77mm larger dia. I see I've made the ring groove 2mm wide, not sure what I was thinking here. Could be I was thinking two 1mm rings side by side. Although It doesn't get the same acceleration / deceleration as a normal ring, mass not so important so probably a single ring will fit the bill.

Originally Posted by Brett S

Some of the foulstroke 250 mx bikes are 77mm, but have a 0.8mm ring. KXF, RMZ and YZF.
Honda has 78mm and 79mm but i assume also 0.8mm.

Originally Posted by Brett S

After a quick google there is other options:

Honda GX270 is 77mm and 2mm.
also a VW engine is 77mm.

old mitzi colts are 76.9mm and 2 mill
citreon as well
fiat 1500
Honda 76.9
mazda 1500 "323 1490 i think"
some mercs have 2.5mm

https://www.hastingspistonrings.com/...log_master.pdf
http://www.mingyang-group.2u.com.tw/pdf/CAPT-Piston.pdf

**Flettner** · 6th May 2020, 19:33

No matter what I use Im going to have to re manufacture it anyway, so why no start fresh. Surface has to be curved / spherical and it needs to be hard, like a nitrided surface. So I'd guess steel, not cast iron. It will run against a cast iron 'sleeve' as it were. Nitride surface is in the order of 70R surface hardness and slippery but only microns deep.