helicoil head with head still on?

[550headache]

put a new throttle cable in my friends fx1 this weekend and decided to pull the carb and clean it while it was in the shop. it still had the oem carb support so I had to pull the 2 head bolts. long story short the bolt closest to the tray is stripped and looks like someone attempted to helicoil it. at 11 foot lbs it just spun and spun. can I repair it without pulling the head, motor and exhaust? looks like the exhaust has to come off at the least to pull the head. is there any other repair systems better then the heli coil?

figure I would do him a favor and end up screwing myself. also found a motor mount on the way out. he dosnt ride much so maybe it will be ok till the fall.....

 

[Pro-pulsion]

As far as I know, either a Helicoil or Timesert is the best/strongest option. Having never seen an FX1 engine, I can only assume it is the same 61x that the 650sn runs and the bad threads are in the cylinder decking. For that the head must be removed as the Helicoils require a fairly large tap drill, much larger than the stock threads and head bolt holes.

 

[Christian_83]

I did ALOT of research about thread repair, after a insert for my midshaft failed. What i found out was, that the best and strongest is helicoil (Coil spring based) because it delivers the stress over more threads than a normal cut thread or timesert. Allso found out that Boeing aviation uses helicoils in their planes, because the thread is stronger and can use smaller size fasteners.
I did an experiment myself, with a 20x20mm alu block, made 1x 8mm WÜRTH timesert thread repair and 1x8mm helicoil, i toruqued them with a torque wrehcn, first 10, 18, 30 and higher to see what and when it failed. The conclusion was, with the timesert the thread repair failed at i think 30NM give or take a few nm.
But the helicoil, the A4 SS 8mm bolt snapped at 35-40NM, and the piece left in the thread could be unscrewed with my fingers, that process was repeated after i snapped 4-5 bolts. I'm using helicons!

Helicoil thread on the left side of picture, timesert (stripped on the bolt) nr 3 from left.

 

[Little_Franny]

Helicoil or time sert is personal preference, but your not doing it with the head on

 

[550headache]

I figured as much. thanks guys

 

[speedysprocket]

I did ALOT of research about thread repair, after a insert for my midshaft failed. What i found out was, that the best and strongest is helicoil (Coil spring based) because it delivers the stress over more threads than a normal cut thread or timesert. Allso found out that Boeing aviation uses helicoils in their planes, because the thread is stronger and can use smaller size fasteners.
I did an experiment myself, with a 20x20mm alu block, made 1x 8mm WÜRTH timesert thread repair and 1x8mm helicoil, i toruqued them with a torque wrehcn, first 10, 18, 30 and higher to see what and when it failed. The conclusion was, with the timesert the thread repair failed at i think 30NM give or take a few nm.
But the helicoil, the A4 SS 8mm bolt snapped at 35-40NM, and the piece left in the thread could be unscrewed with my fingers, that process was repeated after i snapped 4-5 bolts. I'm using helicons!

Helicoil thread on the left side of picture, timesert (stripped on the bolt) nr 3 from left.

I've preached heli-coils for years- thanks for backing that up!