125-200cc It's time for a 144 kit

The ole girl finally worn the top end and now im searching for a big bore kit instead because throwing back a new oem and then going to a machinist will cost 3/4 of the price for a 144. I looked on Ital Husky and saw the 2011 CR150 top end assembly(with cylinder head included) for $990 Canadian. Will everything fit on the 2006 125 or do I need to get the stock 06 head dome milled to 2011 size?

It will fit, but for that amount I would get a 165.

That's dear . You need the 144 head or mod the orginal . Should be able to get one for 4-500 but not many around .

There is also an option of a 139 - Max power conversion . Said to rev like a 125 .

I've vaguely heard about the 165 mod flying around on this site, how is the crank/rod life expectancy and cylinder wall thickness on it? I am more likely leaning towards the 144 just to stay on the long lasting side.

For modding the original head to save a couple bux, Is it just shaving a bit to accommodate the size of the piston?

I don't think there is a significant longevity compromise with the 165. Lots of guys out there with tons of hours on original 165 parts. They aren't perfect but pretty long lived. I have 300 kits out in use or should be in use and I doubt I sell 30 replacement pistons a year and only twice that in rings. There are a couple of cross referenced rings available but the piston is pretty much a one off piece and unless you are going to buy more than 10 double the price I charge. I am not trying to sway you towards a 165 just want you to know that there isn't a huge reliability issue with cylinder strength or piston/ring longevity.

Converting a 125 head for 144 use is very straight forward and as simple as enlarging the squish to accept the piston. This will bump your compression into possible race gas need but simple. Pretty easy to re-chamber the head accordingly so you can maintain pump gas compression. If you are going to all the trouble it makes sense to have the head re-chambered and also machined to reduce the squish to more ideal dimensions. JFYI

300 kits?! Nice work Walt. Bet you'd have double or triple that if they were still bein made n GG or SWM made a 125 with that donk!

Re reading the first post its says the 150 head is included so I don't see why the 06 head would even be used.

Nothing wrong with 165 kits - they are more low/mid end grunt machines

If you just need a 125 top end you should be able to get it for a couple of hundred off here - possibly the newer version as well

Thank you Wally for shedding the light to me, the 144 idea was more of because it's easily available locally and parts come in fast for them. Good thing is, I will have an extra top end lying around for the 165 mod when the project bug bites again!