If you think the clearances are off then borescope from the spark plug hole and at the cylinder walls you should see scoring...

 

I actually did just finish doing that, and although it is hard to see, I can actually see some vertical scoring beginning...it is slight, but it is there.

 

So I pulled off the rear cylinder a few days back and it is as I feared. Cylinder was not bored enough to allow for enough piston/cylinder clearance. I will be measuring the bore today hopefully, the wear pattern in the cylinder would suggest that there may also be a high spot in the cylinder as I have localized wear in only 1 spot in the cylinder and only about 20-30% of the circumference. I have spoken to the machine shop and there was alot of "we didn't do anything wrong...until I sent them the pictures. Then it was "send it back and we will fix that for you"... I think i will simply get a piston/cylinder kit from one of the vendors so I can sleep better at night as I do not want to reuse my pistons and machine shop doesn't seem too interested in helping with getting a new set. I simply would not trust using the piston that managed to expand enough in the bore to stall my bike out.

 

I think it's likely that your machine shop did not use torque plates. Torque plates are required to accurately measure the bore as well, so if you don't have them, you're not going to get a true picture of what the bore dimensions are if you measure.

Plenty of 107's running around with stock cylinders bored. I suggest sending your existing pistons and cylinders to a vendor on here. It is possible - likely, even - your current parts are usable if properly fitted.

I don't know where you're located, but it really doesn't matter. I had one of the board sponsors here supply cylinders; fit them to my pistons; and bore my cases to fit the cylinders; then ship all those parts - oh, the heads, too - back to me (I shipped everything but the cylinders there to start with). This was to resolve botched cylinder machine work when I built my all-bore 107 a few years ago.

 

I agree with northeasconfederate; your cylinders and pistons may be serviceable. I had 800 miles on a piston/cylinder set; cylinder bore was not true. Cylinders were scored and pistons scuffed. Cylinders were bored .010" over by a competent machine shop, new pistons fitted, motor rebuilt with no issues. Later, when I was working on another motor, had the pistons miked and checked against spec and while minimally scuffed, the pistons were within factory specs. Had a set of OEM cylinders bored to fit those pistons and that top end is running strong after 15K miles. So both cylinders and pistons were serviceable and re-used successfully. There are no miles on those parts and they have not seen high temps so don't throw the baby out with the bathwater.

 

not a big fan of T max`s,but even if your tune was way off,just starting shouldn't have caused a problem.how hot did the cylinders get? what pistons are being used? I would think if theres a piston to wall clearance problem,they got real hot,real quick.dont really need to see the skirts,the walls will show scoring.

 

Sounds like a mapping issue to me. In the HD ecm, there is warm up fuel every time you start it and it quickly decays - especially when warm. It's like having the enrichner on for a short time. Is Thundermax using the same type of strategy?

Perhaps all this starting has drained the battery as well and that is the poor cranking.

 

Morning. Yes the Tmax does run a warm up fueling feature and it is functioning as intended. I also thought possibly a run down battery and so I got a battery tender and charged my battery overnight to rule out any voltage issues. Unfortunately it is not anything that is easily resolved. It is a cylinder/piston clearance issue and while I can sit here and point fingers and lay blame, the ultimate blame is on me. I should have measured my clearances when I got parts back from machine shop The pistons are V&H 2618 alloy pistons, 2618 alloy requires more clearance built into the cylinder than a 4032 alloy does. Quite a bit more I believe.

 

A couple of points.

Just because you put the battery on a tender does not mean the battery will not fade under load and repetitive starting. The battery should be load tested to insure that it is putting out the necessary cranking amps.

You may very will have a piston to cylinder fitment issue but you won't know until tear down, torque plate the cylinders, measure the pistons and cylinder bore.

If there is such a clearance issue, the fault lies with the machinist who should have checked the required clearance required for the V&H 2618 alloy pistons and bored cylinders to fit. Having said that, one would question the choice for the 2618 alloy piston for your application vis the 4032. The 2618 alloy piston typically requires about .0035" piston to wall clearance for a 4" bore and I believe some will allow up to .004" while the 4032 alloy piston requires .002"-.0025" piston to wall clearance for a 4" bore. Both will rattle on cold start up but run quiet at operating temps.

Having said that, the fault still lies with the machinist who should have checked the required clearance which is very easy to find either on the internet or a call to the manufacturer. I still think your pistons and cylinders are serviceable if the cylinder bore is true. Honing for the additional clearance can be done by a competent machine shop; not the shop that did the original bore job.

 

You might simple have a manifold leak. If the heads were milled, Manifold fit might be too tight, keeping the carb rings from centering the manifold spigots.