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LOOPING OZ |
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The Aftermath - Repairs By Al
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This is for those of you who have been following our tale!
Well, the trip itself is over but now its time to do those repairs that either couldn’t be done on the road or we just didn’t know about.
At first I thought the repairs were going to be limited to rebuilding the differential and fixing the front suspension of the yellow bike. No! I was rudely surprised when I dropped the sumps off both bikes once back in Brisbane and found metal fragments in the sump of Meredith’s red V700, some magnetic and others not. Not a nice thing to find after some 21,000kms but not an overly big surprise after some of the things that happened on the way.
So far the repairs have been very expensive and the front suspension for the yellow bike is still to do, I am still looking for new upper bushes for the front forks. So far the damage bill is well into the thousands. I suppose if we were racing or famous actors we would have sponsorship and it wouldn’t be such a big deal.
The first job was to rebuild the differential for the yellow V7 Special. This cost quite a bit because the bits of metal floating around inside wreaked havoc. Not only were the faces of the crown wheel and pinion badly scored but all bearings were damaged. In fact the big expensive bearing rumbled quite loudly, even with molly oil still on the rollers. In fact I replaced everything for the differential apart from the outer casing and pinion carrier. Yes, even the drive flange was replaced. The differential is now brand new. I was fortunate to locate a new 8 x 35 crown wheel and pinion from Teo Lamers along with many other bits and pieces from Harpers and the local bearing shop just up the road.
The hardest bit with the differential rebuild was making some special pullers to get the thing apart and lining up the crown wheel and pinion. I used bearing blue to assist with the alignment and a full set of shims for both the pinion and the rear drive. Even though I can see how you can approximate the rebuild process you really need a full set to get the job done properly. It took me a while to get the thing lined up as I was continually adding shims to the pinion drive then adding bigger shims then smaller shims to the rear drive until I got that magical measurement and alignment that was mentioned in the workshop manual and the teeth faces of the crown wheel and pinion meshed nice and evenly.
Of course it wasn’t all over, there was still the dilemma of the red v700’s motor. This, of course, meant the motor had to be extracted from the bike and dismantled. This, of course, was done pretty quickly. So far I have been able to purchase all the bits I need from Teo Lamers and GM Cycle. We’re still waiting for original front and rear mains to suit the non filter motor.
I took the crank around to Tom to let him know it would be coming in for grinding and balancing. He took one look at the pistons and the wear on the crank and said we were very lucky the motor made it.
Damage to the motor was extensive. One piston had tried to melt onto the liner, and both pistons and liners were badly scored and scratched. There was a big build up of carbon around the rim of the piston head and all the compression and oil rings were badly gummed up with carbon and aluminum filings. I think the pistons and liners are what you would call US (unserviceable).
The crank is also a mess but luckily able to be reground. I measured the front and rear main and crank pin with my micrometers and found that only the rear main was still within original tolerance, but only just. The crank pin on the other hand was badly worn and if it can successfully be reground to the first undersize I will feel very happy. I suppose it will depend on the machinist. Other than two big grooves on the crank pin the most visible damage is the condition of the main bearings which were pitted, and the white metal for the big end shells. The a section of white metal for one big end shell had peeled away and balling had developed on two others, three out of four isn’t bad!
The crank measurements that I took were:
As you can see from the measurements there was a bit of rattling for the front main and in particular the crank pin. The rear main bearing is still in tolerance but grooving is present in the surface.
The rebuild will take place soon and this will include:
· new cylinders and pistons (nikasil) · reground crank to first undersize with associated bits to new main and shell bearings · new piston pin bushes (these were almost worn through) · new oil pump (gears badly worn and grooved) · a complete top end overhaul that will include new inlet and exhaust valves even though these look as though they could go a bit longer.
You could say the old ’67 V700 will have a new motor. She is also getting a 5 speed gearbox fitted also as I want to keep the 4 speed for the other V700 that is being restored.
~v7~ |
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