-
Don't overlook our Welcome Package, it contains many links to important and helpful information about functions at VHT like posting pictures and sending PMs (private messages), as well as finding the parts you need.
AD
A C78 project
- Thread starter boddy
- Start date
Looks similar but mine should have a 259 middle number.
In any case a generous member here has offered me a replacement for the price of shipping.
Even if I ground down the lip to the base of the hub, the sides would not be reinforced and with that length of patch, I don't see it holding up for very long.
Another small bite today. Looked at the head and valves to determine next steps. There is a bit of pitting on the seats.
I decided to lightly lap the valves to see how wide the seating area was. The exhaust was about 1.5mm and the intake about 1mm, however there was a groove all the way around both intake valves that almost looks like it was machined that way.
I will contact the machinist to see if he can cut new valve seats and will see about procuring new valves.
I did the roll pin fix for the advancer weights. After reading @ballbearian's thread again I went and did it. I was expecting more grief in drilling the sprocket but the cobalt bit I bought went through very easily. I tapped in the roll pins and then flared the ends so they don't come out.
I decided to lightly lap the valves to see how wide the seating area was. The exhaust was about 1.5mm and the intake about 1mm, however there was a groove all the way around both intake valves that almost looks like it was machined that way.
I will contact the machinist to see if he can cut new valve seats and will see about procuring new valves.
I did the roll pin fix for the advancer weights. After reading @ballbearian's thread again I went and did it. I was expecting more grief in drilling the sprocket but the cobalt bit I bought went through very easily. I tapped in the roll pins and then flared the ends so they don't come out.
Still at it, as time permits. Lots of yard work lately doing the ol spring clean up. Did some work on the rear wheel. Got the tire off without too much trouble. At first I thought it was a Mitsubishi tire but on closer inspection it's a Mitsuboshi - must be a knock off. Tube still held air but I will replace everything rubber. The rim was a little scratched up, looks like from someone trying to get the tire off as there are marks every couple of inches.
Unlaced the rim and started cleaning the spokes so I can re-zinc them. Parts manual shows a different number for front and rear spokes so I wanted to know how to differentiate them. They are identical in length but then I noticed the rear spokes have a slightly thicker shoulder near the hub end of the spoke.
The hub was good, no broken flanges and very little rust on the braking surface.
The sprocket holder was a little chewed up from the chain not being adjusted so I filed the edge just below the sprocket to smooth it out and then sanded with some 320 grit wet and dry. It's not an area you can see once the chain guard is on but I would know it's there LOL.
Waiting for parts to come in for the engine. Have 4 valves on order and I have been looking around for piston rings. Judging by the asking prices for OEM rings you would think they are gold plated. Since I also want to replace the wrist pins, getting a set of IMD piston kits is looking like a better option. Since the kits are .5 OS I will need to get the cylinders bored which will add some additional cost.
Also working on the engine cases to remove the paint so I can have a clean surface for the new paint to stick to. Bit by bit it will all eventually get done...
Unlaced the rim and started cleaning the spokes so I can re-zinc them. Parts manual shows a different number for front and rear spokes so I wanted to know how to differentiate them. They are identical in length but then I noticed the rear spokes have a slightly thicker shoulder near the hub end of the spoke.
The hub was good, no broken flanges and very little rust on the braking surface.
The sprocket holder was a little chewed up from the chain not being adjusted so I filed the edge just below the sprocket to smooth it out and then sanded with some 320 grit wet and dry. It's not an area you can see once the chain guard is on but I would know it's there LOL.
Waiting for parts to come in for the engine. Have 4 valves on order and I have been looking around for piston rings. Judging by the asking prices for OEM rings you would think they are gold plated. Since I also want to replace the wrist pins, getting a set of IMD piston kits is looking like a better option. Since the kits are .5 OS I will need to get the cylinders bored which will add some additional cost.
Also working on the engine cases to remove the paint so I can have a clean surface for the new paint to stick to. Bit by bit it will all eventually get done...
jensen
Veteran Member
The intake valves are toast. the reason is using unleaded fuel, in combination with a too small area (1mm) that has to absorb the hit when the valve closes. An other reason could be a too large valve play, but looking at your valves, it might be a combination these reasons. If you use unleaded fuel, it's important to keep the valve play as small as possible, and increase the contact area width to 1,5 mm.
Leaded fuel was banned here in Canada in the 90's and as of last year even non-ethanol fuel is no longer available. Thanks for the advice on keeping the valve play small and when I get the seats cut I will go for 1.5mm contact area.
jensen
Veteran Member
I know, that's why you have to go to 1,5 mm. the only setback is that the valves will get dirty, the self cleaning of the valves is more difficult due to the larger area. On the other hand, when using synthetic oils in your bike, the chances of build-up of burned residue is way smaller (the full synthetic oils burn almost clean).
Thanks, good to know about the synthetic oils. Since this is a fresh rebuild I could go synthetic, which oil do you recommend for the wet clutch?
BTW, I ordered the IMD pistons today. If you create an account you get a 10% discount and there is free shipping for orders over £50.
BTW, I ordered the IMD pistons today. If you create an account you get a 10% discount and there is free shipping for orders over £50.
Brad I used the IMD piston kits at .5 O/S in my CL77 build and my friend the machinist did the cylinder overbore. He was impressed with the quality of the parts from IMD as a well made product.
Thanks David, good to know