Bore up EC 125cc of EC 144cc

[Catarallus]

Anyone here with experience to make a EC 125 to a EC 144?
In know, only bore up cylinder will be trouble with the coolant passage.
My plan is 2mm cylinder bore up and enlarged stroke 4mm.

But I'm only try this with used parts, if I find one.
I think I'll need modifications on following parts:
- exhaust valve
- cylinder
- cylinder head
- crankshaft


Sorry for my bad English!
Suggestion for a better English and about this thread are welcome.

[gasgasman]

Your english is VERY good.
Way better than people that were raised speaking english.

Fred Hoess (U.S. ISDE rider) messed around with 144 kits.
He said the biggest problem was the exhaust port was too thin and would crack.

[GMP]

Even the 144YZs are hit or miss reliability wise. I almost bought one to do this, and after talking to some people with experience gave up on the idea. Perhaps there will be a factory 144 or an Athena kit like the Huskys have, they seem very reliable. I imagine production #s would have to go up though.

[noobi]

Eric Gorr does a 144 kit for the GG 125
http://www.eric-gorr.com/international144kits.html
I sold my damaged 125 cylinder to a member on here who got me to send it to Eric to bore out before returning it to him in Australia. Im not sure if he has got it back yet or not, him user name is 'geoffg'

[Nhuskys]

Originally Posted by GMP

Even the 144YZs are hit or miss reliability wise. I almost bought one to do this, and after talking to some people with experience gave up on the idea. Perhaps there will be a factory 144 or an Athena kit like the Huskys have, they seem very reliable. I imagine production #s would have to go up though.

Husky 144 kit and '11 WR150(144) are a factory developed cylinder, not Athena. The TE 310 4T bike prior to '11 model used an Athena cylinder.

[GMP]

I stand corrected. Same point though, its engineered as a 144, which makes the difference. I just can't give up a late model GasGas chassis for a Husky, much less a KTM.

The GG 125 can be made to run quite well off the bottom, I've done it, and that was with a 38mm carb. I would dial it in as a 125 and hope for a factory 144 kit.

Are there many GG125s in Europe? They have been out since '01, so maybe there are more used parts to play with than here in the US. I suspect that factory 152 motor that Berkyboy posted about back in July had some work done to the cyl to beef up the exhaust bridge.

[iancp5]

Originally Posted by GMP

Are there many GG125s in Europe?

In the UK I've never seen one. All the 125's seem to be KTM. Plenty of GG 200, 250 & 300.

[Caravan Monster]

Originally Posted by iancp5

In the UK I've never seen one. All the 125's seem to be KTM. Plenty of GG 200, 250 & 300.

I think I'm correct in saying the TM144 enduro has been around since '07. Never seen one of those either, interesting sounding bike:

http://www.tmukonline.net/Page/56/2010-tm-144-en.html

[Catarallus]

Originally Posted by gasgasman

...
He said the biggest problem was the exhaust port was too thin and would crack.

That's good to know.
I would be laser welding the port for a better stability.

Originally Posted by GMP

I...

Are there many GG125s in Europe? They have been out since '01, so maybe there are more used parts to play with than here in the US.

Not really, I didn't found any parts yet. The most part's are for 250cc & 300cc.

Originally Posted by Caravan Monster

I think I'm correct in saying the TM144 enduro has been around since '07. Never seen one of those either, interesting sounding bike:

http://www.tmukonline.net/Page/56/2010-tm-144-en.html

I have a TM MX 144 '07 too, only for practice ride. This bike gave me the idea to bore up my GG .
The motor has a bit more power in upper rpm, it feel's really good.

[geoffg]

Update on the Eric Gorr 144 poject.

The cylinder arrived in Australia yesterday. All the workmanship looks very good. He tells me that the exhaust port bridge on the cylinder I bought from noobi was cracked. That was good as he has welded it and built it up wider than stock.

I should have it up and running in a couple of weeks. Will post with a report.