1962 Superhawk Restoration: Here I go

[jensen]

If both sides are flat, and there are no deep scratches, and the bolts are torqued down and these bolts don't bottom out, and you use a good gasket there should be no problem. If you have a problem, it might one of the above issue's

Jensen

[Spargett]

If I can't find any obvious causes when I pop it off, I think I'll try taping sandpaper onto a large piece of glass and try flattening any subtle inconsistencies out.

[jensen]

Hi,

First determine the error before you do something.
For example, take the clutch cover and check it's flatness on a flat table or something else what is very flat (float glass for example).
If the clutch cover is flat, check with a feeler gauze (0,05 mm) if there's a local space between the glass and the cover, especially around the area where the oil is leaking out.

(I prefer to do this check on all engine cases and side covers before building up the engine)

Jensen

[davomoto]

Scott, I recently had my machinist do 3 clutch covers for me, and all 3 were low in that area. Watching him do them, I could see the low spots, and gradually saw them disappear. Bill Silver says something in his guide about possibly using two gaskets. i haven't tried that one myself.

[Spargett]

So I got around to doing a small list of bugs that have been adding up to less than satisfactory performance. I picked up a compression tester today, how I don't have one, I don't know.

Right side showed just over 150 and the left showed 155. The plugs look pretty good, but could be a little better. I feel like the bike has lost some of it's performance. Lacking the get up and go it had, as well as the top end. Still trying to figure that one out. I've noticed the bike performs "best" (right now) all around when I set the timing dynamically to F at idle (never makes it to the full advance marks, about 65°-50°). If I set it to full advance (which the e-igntion recommends), the power becomes very lackluckster at all ranges. Slow to respond and has a hard time not really getting anywhere special. With timing set to advance idle falls about 15° ahead of F.

I think I have a small exhaust link at the header joint on the left side which pops and runs richer than the right side. I can hear the gentle high pitched sucking in line with the RPM, mostly between 1/4 and 1/2 throttle. I'm not sure how much this affects performance. I think I just need to realign and tighten everything.

I was able to find the source of 2 of the 3 oil leaks I have. The first was under the tach cover on the head. It was leaking down along where the head gasket is, onto the front of the engine across the broad fin, then down onto the starter and finally the ground, one drip at a time. I attempted to reuse an old gasket and don't think it worked out too well.

The second was the left crankcase. I should have paid more attention to the surfaces before I put it on. It was a used part I purchased and had never put it on before. There was a very obvious valley dented into the surface right where the leak was occurring. I also put the case on a plate of glass and took my valve feeler around it. There are two noticeable high points (see photo) leaving a remainder where I could slide the 0.005" feeler under the rest. I'm thinking a very very modest and light application of JB Weld to fill the valley, then slowly sand the entire surface of the case on the sheet of glass to flatten it out (like people do with their carbs).

I'm curious to hear what you think about my performance in relation to timing, or how your CB77 performs. Sorry for all that info at once.

[jensen]

Hi Scott,

Did you ever attempt something to flatten the way you described ? (and measured afterwards ?)
It seems easy, it's not, and I strongly suggest that you practice first on an old part.

The pressure from you fingers on the cover, the type of sand paper and the wiggling of the cover around the high points are very important in the end result.

Always move in a straight line, one way (change 180 degree once in a while). Make sure the longest axe of the part is in the same direction as the movement. Change direction (30 degree's) after a few times and look at the surface every time you changed direction, so you can see where the sandpaper takes off the material (crossed lines). Use 400 to 800 (wet) sandpaper with water and flush it regularly. Make sure the sandpaper is flat (glue it with spray glue over the whole surface, do not tape it).

The grove should be filled after the flattening process !, due to the difference in hardness toward the other material.

Apply a little pressure on the part in the centre of inertia, not on the edges. Just enough pressure to sand, not enough pressure to make it bend.

I saw many surfaces screwed up by people who thought it's an easy job, but having the discipline to do it in the described way will satisfy your needs.

You could also bring it to a machinist like Dave did, it's always better (when the machinist is knowing what he's doing).

Do you use a torque wrench for these bolts ? I suggest you do, because in most cases the lack of not using it will give you curved surfaces like this. After all, these parts were flat when left the factory,

Jensen

[e3steve]

..... I feel like the bike has lost some of it's performance. Lacking the get up and go it had, as well as the top end. Still trying to figure that one out.

You mentioned in one of your posts within this topic that it's hot there. Higher ambient environmental temperatures will drastically reduce performance, believe it or not. The cooler the induction charge the denser it will be, ergo more combustible. Ever ridden in mist / fog? Notice how well a bike performs in such a damp-air environment.

Anecdote:

• When production cars were first turbocharged in the late 70's (I used to tune SAABs as a hobby in the 80s) no intercoolers were used -- an intercooler is a small cooling matrix, similar to a cooling system or a/c radiator, through which the compressed charge passes before entering the inlet manifold. When a gas is compressed it gets hotter; hotter combustion charges cause detonation (you call it 'knocking' -- we Brits call it 'pinking' or, more correctly, 'pinging' -- which ain't good for valves & pistons) creating the need to lower compression ratios on turbocharged or supercharged engines. To overcome this engine manufacturers came up with the intercooler, standard fitment on many big truck diesels, to allow the compression ratio to be partially-restored thus lowering the torque curve (essential for hauliers).
  
  The first 8-valve, injected SAAB Turbo produced 145bhp at the crank. SAAB's subsequent 16-valve intercooled 900 'Aero' produced 30bhp more. I fitted an intercooler and water injection to a couple of 8-valvers; my best effort was dyno-tested at 182bhp at the front wheels -- equal to around 195 at the crank and 50 up on stock -- with 18psi boost instead of 10.3psi stock, all as a result of cooling the induction. No remapping (no fancy management systems back then). And no detonation!