YZ 125G Barrel

[YZ250H]

Hi Guys,

My brother in law is desperately seeking a 125G barrel as the one he has at the moment has a broken clutch cable holder and a mangled top surface where someone has taken to it with god knows what.  Can probably be fixed with a lot of effort, but looking for something a bit easier first.

It's his first VMXer so he's keen as mustard to get it going 

Anything out there ?

[Digga]

Hi, I have a spare 125G barrel on its last bore so will need a sleeve. Think it was used in a go cart at some stage as it has a plug in the LHS of the inlet manifold. Think they use to use that for fuel boost or something 

Let me know if you/he is interested because I will have to find it in the shed.

What state/city are you guys in?

[baitfish]

Hi Digga,

I'm the brother in law who is on the hunt for the g cylinder. Is the cylinder you have 2mm over? I'm in North QLD.

[Digga]

PM sent

[YZ250H]

Nice work guys.

Baitfish - you want to post up some pictures of the top of that barrel ?

You have to use a sharing site like photobucket.  I think there's a pinned thread that explains how to do that or send me a message 

[baitfish]

Hi YZ250H

Sorry about the slow reply!










It was just recently suggested to me that maybe I could have the damaged section machined down smooth and then adjust the squish/clearance by changing the thickness of the base gasket. The person who told me this said thats how they adjust the clearance on their KTM.

Thoughts?

[sleepy]

Machining down would be a viable repair but changing the base gasket thickness will change the port timing. A thicker head gasket would be my suggestion, they have a simple copper ring and making a new thicker one would be quite a simple job. If I was to tackle it I would first look at what thickness copper is available then machine the top to suit. The welding of the cable lug is a very simple repair job as well. The bore at the top will need a clean up as I can see some deformation adjacent to the dents, honing may clean it up. If that is the bore size on top and it is in good condition it is worth repairing as it has another 2 rebores left in it.

[baitfish]

Just a quick update on my situation,
After talking to a few people and getting a plan together I decided I would attempt to repair the cylinder myself. I took the barrel into work and showed some of the lads what I had in mind. The lads were keen to help, most of them cars nuts and love anything that has an engine.

First up we spun a pipe up to fit perfectly up the bore, a bevel was cut onto the pipe to match the slight bevel on the bottom on the cylinder.  this was to try to help with keeping everything square to the pipe. A flange was welded to the pipe to line up with the mounting holes of the cylinder.


We then stuck the set up in the lath and spent a fair bit of time getting it to spin true. Once that was sorted, we took 0.05mm cuts off the inside face untill 90% if the dents were sorted. We then took the same amount off the outside edge
.





I'm pretty stoked with how it all turned out. Only had to take a total of 0.35mm off to clean it all up. I was expecting a lot worse.

[YZ250H]

Nicely done