Engine Strip

I knew after the first few days that something was wrong in the engine department. Although it would start when cold with plenty of choke, it wouldn’t tick over, and it was very difficult to start when hot, if it did at all.

I thought it was the carb, but after stripping and cleaning it, and even trying a new one altogether, it was clear that I needed to get the overalls and toolbox out ………….

 

The head came off first and apart from a small amount of carbon on top of the piston, nothing else looked unusual.

The flywheel was next, and this is where you could see, due to the amount of oil in there, that the mag side seal had gone.

After sliding the barrel off, it was clear that it had been blowing back past the rings, and after checking the gap, it was 3 times what it should have been.  The barrel was checked and someone has done some porting work to it at some time, and was 1st oversize, but the transfer ports don’t look right and are really small, and I am not convinced that it’s the right barrel for this engine. It will be rebored 2nd oversize anyway with a new piston and rings which will hopefully cure the top end problems.

The problem with porting work, if you don’t know who did it, or what was done, is the fact that it maybe never worked correctly after it was done, and you can end up chasing faults that don’t exist. Another correct GP barrel isn’t out of the question yet !

The mag housing was removed which revealed the full horror of the leaking seals. All the bottom end and crank were covered in burnt oil as can be seen from the above photos.

The drive side had also gone, so no wonder it smoked a bit when it started. One good thing was that the screws in the seal retaining plate came out easily. A lot of cleaning to be done in the crankcase though.

A few shots of the drive side strip and the eventual removal of the crank before everything was thoroughly cleaned up. The crank looks standard and in good condition.

The gearbox was checked but was all standard, no problems were found and nothing further was done to it.

Time to get some bits and start rebuilding it !