Posted: Sun Oct 01, 2006 12:52 am
A week ago after return from an extended overseas trip I was delighted to find my Wiseco big bore kit had arrived. Down it went to the engine shop for the requiste 2.5mm rebore, taking the J out to 1015cc.
I had fretted over losing circlips and breaking rings during installation of the pistons but this turned out a pleasure. The trickiest part was with my failing eyesight trying to find the gap in the oil expander the hardest job. I found a trick which suited me. I would pin the expander using a small piece of wire pushed through it into the piston oil holes. This stopped it from rotating. Then using a tooth pick I would gently probe sections of the expander which would eventually show where the gap was. I would then remove the wire and rotate the expander until the gap was at the front.
The next step was to insert them in the bores. I made up two wooden rests to hold up the innnermost pistons and attched my ring compressors. The type I use are about 30 year old being clipped circles of spring steel which in theory compress the rings but are fastened so that they will push down as the cylinders are lowered.
I found these somewhat fiddley with them often springing loose partway through.
With the aid of my dear wife we attempted the job. After about three attempts we got the inner pistons in but had an enormous problem with the remaining pair. Sweat was starting to pour down and stress levels were building. Wife was worrying about chipped nails! Third one in and then the compressor came off the fourth just before the oil rings were to pass up the #1 cylinder. B***er!
Now I would have to lift it to start again on #1 & #4. In extracting the compressor off # 4 tore the base gasket. Just great! pulled the whole lot off again; fortunately all the rings were still intact.
So the J is on an emasculating short trip to the dealer. On looking at the cylinders their view was that there was not enough champfer due to the rebore to make the ring entry easy but having done the identical job 30 years ago It was a really humbling experience going in asking for help. Hoped an expert would make a house call but now the j has to suffer the embarassment of being ferried to the shop.
Wifey said: "If I'd know how much the rebuild was going to cost and how much stress it was going to create I would have agreed to you getting a new bike!" Thanks dear, but it really wouldn't be the same.
I had fretted over losing circlips and breaking rings during installation of the pistons but this turned out a pleasure. The trickiest part was with my failing eyesight trying to find the gap in the oil expander the hardest job. I found a trick which suited me. I would pin the expander using a small piece of wire pushed through it into the piston oil holes. This stopped it from rotating. Then using a tooth pick I would gently probe sections of the expander which would eventually show where the gap was. I would then remove the wire and rotate the expander until the gap was at the front.
The next step was to insert them in the bores. I made up two wooden rests to hold up the innnermost pistons and attched my ring compressors. The type I use are about 30 year old being clipped circles of spring steel which in theory compress the rings but are fastened so that they will push down as the cylinders are lowered.
I found these somewhat fiddley with them often springing loose partway through.
With the aid of my dear wife we attempted the job. After about three attempts we got the inner pistons in but had an enormous problem with the remaining pair. Sweat was starting to pour down and stress levels were building. Wife was worrying about chipped nails! Third one in and then the compressor came off the fourth just before the oil rings were to pass up the #1 cylinder. B***er!
Now I would have to lift it to start again on #1 & #4. In extracting the compressor off # 4 tore the base gasket. Just great! pulled the whole lot off again; fortunately all the rings were still intact.
So the J is on an emasculating short trip to the dealer. On looking at the cylinders their view was that there was not enough champfer due to the rebore to make the ring entry easy but having done the identical job 30 years ago It was a really humbling experience going in asking for help. Hoped an expert would make a house call but now the j has to suffer the embarassment of being ferried to the shop.
Wifey said: "If I'd know how much the rebuild was going to cost and how much stress it was going to create I would have agreed to you getting a new bike!" Thanks dear, but it really wouldn't be the same.