ESE's works engine tuner

[SwePatrick]

I have used the Wossner piston with a single ring pinned at 6 from a CR250 in flat top, and the same for a KTM 250
with a dome - both off the shelf,Wossner part numbers.
All the 250 MX engines are 66.4 with 18mm pins, varying deck heights - so plenty to choose from.

Man, i have searched and searched, looked at pictures, i haven´t been able to find anyone yet.
Can i ask you for an example with domed top?

Edit: oh.. i read too fast.. you actually gives two examples,, sorry

Edit2: is it this one?
https://www.amazon.com/Wiseco-824M06.../dp/B000GVBJU8
don´t mind the wiseco,, just the motorcycle model i´m after.

[mr bucketracer]

Yes. She has had her Bucket bike in the workshop fettling it for the 2-Hour.

i should let her ride a real bike , my 4 stroke lol

[marsheng]

Yes, 909 will settle out in AvGas after only a few minutes of mixing it up - did exactly that to me on the dyno.
We tested for probably 20mins,stopped for a cup of tea,and it would not restart,I could see straight oil in the bowls of the Lectrons.
But add a cup of acetone in 5L and no issues after that.
Motul Kart GP does not do this in Avgas.

The 909 and Avgas "mixing fog" got really bad in Winter. No problems with 98. Just checking that you would recommend Motul Kart GP for the Maico.

Thanks Wallace.

[tjbw]

https://www.youtube.com/watch?v=rxFJfbdCT_k

Thanks for that link Ocean1, very nice tool, in fact I'm going to write a letter to Santa

[adegnes]

all the late model ktm 250 pistons have the peg at 6oclock, how many years this design goes back I don't know. I would assume the cr250 from '02-'07 likely has the 6oclock peg also, before '02 is likely 5 and 7 position. the other japs mostly used cylinder reed valves so I would guess they were 5 and 7 also but im not sure. should be able to google search piston images and get a idea or check photos on ebay

I never made a tool for measuring angles after the fact but I did make some templates for cutting in new aux exh passages and it worked very well. basically I took some measurements in the cylinder of the existing exh passages then drew the new desired exh ducting I wanted on stiff paper and cut it out. then i just grinded the passage floor until the template fit nice. the template was for the aux floor because once you establish that, the walls and roof can be grinded much faster. saved me a lot of guess work and time. unfortunately I must have erased the actual photos of the exh templates I had but heres more or less how I did it. also I made some inner and outer trans wall templates that saved me a ton of time. without templates as a guide it would of been near impossible for me to do the work I did

Great tips! I don't think I've ever seen someone modify a cylinder as extensively as you have!

[lohring]

For small engines I use a set of templates for porting. Since we usually deal with the same style of industrial engine, I just need templates for the two bore sizes typically used. The transfer and exhaust ports are very similar across a series of manufacturers. They have one piece cylinders so measuring the template to set port heights is a lot easier than measuring the cylinder. The extended screw goes through the plug hole and is secured with another nut. It takes one template for the transfers and one for the exhaust. This style reduces the grinding errors, but flat slugs can also be used. The complete article on the method and measurement calculations is in the article Zenoah Porting 101. See the pictures below.

Lohring Miller

[FastFred]

Very Clever. Thanks for the tip.

[wobbly]

Wossner 8090DA is single ring flat top
Wossner 8082DA is single ring domed.

[Hemi Makutu]

Here's a current 'off the shelf' 2T unit, which with a power tune, might make an interesting bike engine.

http://www.recpower.com/3703%20-%203...02%20cycle.htm

[peewee]

thanx for the nice words adegnes. if you ever seen these cylinder before modification, the power is very low.

[SwePatrick]

Wossner 8090DA is single ring flat top
Wossner 8082DA is single ring domed.

Thanks Wobbly,, many many thanks =)

[adegnes]

Very Clever. Thanks for the tip.

+1 Great tip! I think someone else on here have made something similar too. Seems very useful!

Edit: Almost forgot:

E9 is out.
https://youtu.be/NdXS79Le3pw



Made a "channel trailer" too.
https://youtu.be/bhI70X5caeo



Yes I know, pressing + welding the slugs in would be better, but I don't own a tig welder, don't know what alloy the "tungsten" slugs are, and I wanted to get it done fast. It'll be fine!

[Frits Overmars]

Yes I know, pressing + welding the slugs in would be better, but I don't own a tig welder, don't know what alloy the "tungsten" slugs are, and I wanted to get it done fast.
It'll be fine!

Famous last words .
I hope that at least you used high-temperature epoxy. But I wouldn't put my trust in it. I've seen pressed-plus-glued slugs move about and nibble at the con rod.
Screwing-plus-loctiting them in would ge a better way, but cutting a thread on the slugs might be a bit of a problem. Tack-welding would be best.

[adegnes]

Famous last words .
I hope that at least you used high-temperature epoxy. But I wouldn't put my trust in it. I've seen pressed-plus-glued slugs move about and nibble at the con rod.
Screwing-plus-loctiting them in would ge a better way, but cutting a thread on the slugs might be a bit of a problem. Tack-welding would be best.

.... And with my track record of epoxy related engine failures I should know better... Here we go again!

World leader in entertainment at my own expense!

[ken seeber]

Just goes to show, you can't trust the media these days...