Author Topic: 78 CB 550K motor rebuild (Read 61456 times)

AlekStooge · « **Reply #275 on:** February 07, 2017, 09:12:22 AM »

I'm thinking now does a torque wrench work when loosing? Never tried it that way. I know the manual says 14 to 16 ft lbs but since these are HD studs and nuts I figured I should go higher. Plus I'll be getting more airflow than stock so it's good to have it tighter, I think.

calj737 · « **Reply #276 on:** February 07, 2017, 11:10:57 AM »

It does, but you need only "crack" them loose in a reverse pattern, then you can release them fully before stepping them back to their proper torque. 18# is ample!

AlekStooge · « **Reply #277 on:** February 07, 2017, 11:42:31 AM »

Crank them loose then go down to 14 lbs following the pattern and then 7lbs. Got it!

AlekStooge · « **Reply #278 on:** February 10, 2017, 08:59:40 PM »

Head is torqued down. I bought a C5 ignition from a forum member. Missing my sprocket bolts so I ordered new ones once those come in the cam and sprocket will be ready to be installed.

I will take a second look at my clutch plates and discs, I didn't really understand what thickness they should be because one plate or disc is a different thickness than all the others and the manual doesn't specify the spec. I probably will end up keeping them.

SOHC4 Cafe Racer Fan · « **Reply #279 on:** February 12, 2017, 02:39:08 AM »

Quote from: AlekStooge on February 10, 2017, 08:59:40 PM

Head is torqued down. I bought a C5 ignition from a forum member.

So that's what became of GV's C5.

AlekStooge · « **Reply #280 on:** February 12, 2017, 02:36:10 PM »

Yep, waiting for that, learning how to find TDC with the head and how to degree a cam. Printed out a degree wheel so far...

AlekStooge · « **Reply #281 on:** March 15, 2017, 04:02:40 PM »

Got a modified cover.

Made a piston stop

And got everything set up to degree the cam and check valve/piston clearance.

I'm rotating my engine on the points side. When I spin it forward I apply a lot of torque and then it jumps forward and I have to repeat the process. When I spin it counterclockwise it goes easy. Can I do my work this way?

calj737 · « **Reply #282 on:** March 15, 2017, 04:45:15 PM »

Use the alternator bolt not the points side bolt.

I'd tip that "piston stop" with something soft, like nylon or plastic. A bolt (should you jump the piston up into it) could damage the piston. And we know about that replacing a piston deal already....

bwaller · « **Reply #283 on:** March 15, 2017, 05:21:18 PM »

Cal with no plugs it's ok to turn it from that side. When using a piston stop you have to turn the engine gingerly". That wheel is small, I like double the diameter, it's just more accurate but run what ya brung, at least sharpen your pointer Alex. Use the longest tool you can find, longer allows easier more accurate movement of the crankshaft, but you have to turn the engine clockwise from the right end. If you miss your mark, turn it through & start again.

DaveBarbier · « **Reply #284 on:** March 15, 2017, 05:46:31 PM »

Yeah, either tip it somehow with some rubber or at least put it on the bench grinder and make the tip round.

When you use the alternator bolt, just be sure you don't unscrew the bolt as you turn it or the degree wheel doesn't rotate separate from the rotor.

You'll find that the motor sometimes is hard to turn over and sometimes it's easy. When the motor is at TDC/BDC it takes very little effort to turn it because they're very little piston movement. When the pistons are all half way up the cylinder bore there's a lot of piston movement so it's harder. You just have to be steady and work through it.

DaveBarbier · « **Reply #285 on:** March 15, 2017, 05:48:35 PM »

And yeah, as Brent says, sharpen the pointer. You want to be able to tell the difference between 32° and 32.25°.

SF · « **Reply #286 on:** March 15, 2017, 06:26:11 PM »

You might want to chase those threads too.

Sent from my iPhone using Tapatalk

MRieck · « **Reply #287 on:** March 15, 2017, 07:42:48 PM »

Quote from: SF on March 15, 2017, 06:26:11 PM

You might want to chase those threads too.

Sent from my iPhone using Tapatalk

They are a bit gnarly.

AlekStooge · « **Reply #288 on:** March 16, 2017, 09:40:26 PM »

Brent: Just curious, why would having plugs in make a difference in allowing you to rotate it backwards?

Dave: "When you use the alternator bolt, just be sure you don't unscrew the bolt as you turn it or the degree wheel doesn't rotate separate from the rotor."

That's what I wanted to do but when I turn it counterclockwise the bolt un-torques as soon as it gets hard to turn over. I could only get it so tight before the crank starts moving clockwise. What did you do?

Also can anyone tell me why it's so easy to turn it over in reverse regardless of which side of the engine I'm standing on and when I turn it forwards I get resistance half way up or down (which makes sense) like Dave mentioned. I mean the motion is the same so it shouldn't feel any different.

calj737 · « **Reply #289 on:** March 17, 2017, 04:45:04 AM »

Quote from: AlekStooge on March 16, 2017, 09:40:26 PM

Brent: Just curious, why would having plugs in make a difference in allowing you to rotate it backwards?

Because you're building compression with the plug holes "plugged". If the plugs are out, the compressed air escapes more easily.

DaveBarbier · « **Reply #290 on:** March 17, 2017, 05:15:39 AM »

Quote from: AlekStooge on March 16, 2017, 09:40:26 PM

Dave: "When you use the alternator bolt, just be sure you don't unscrew the bolt as you turn it or the degree wheel doesn't rotate separate from the rotor."

That's what I wanted to do but when I turn it counterclockwise the bolt un-torques as soon as it gets hard to turn over. I could only get it so tight before the crank starts moving clockwise. What did you do?

You need to tighten the bolt more. I used a strap wrench on the rotor to hold it as I tightened the bolt.

Another thing, I "laminated" my degree wheel with packing tape to protect it. But the tape was under the bolt flange acting like a lubricant. It would twist the tape around and wouldn't allow it to grip. I had to cut away the tape around the bolt. Not sure if you have a similar situation. You could also stuff rope in a cylinder when that piston is at BDC so the piston has something to push against. Just don't stuff in all the rope so you can pull it out

Quote from: AlekStooge on March 16, 2017, 09:40:26 PM

Also can anyone tell me why it's so easy to turn it over in reverse regardless of which side of the engine I'm standing on and when I turn it forwards I get resistance half way up or down (which makes sense) like Dave mentioned. I mean the motion is the same so it shouldn't feel any different.

Shouldn't be. If anything it should be harder to turn in reverse if you have the starter installed because you're turning the starter too.

It's in neutral, right? Are you doing full rotations going backwards and forwards and feeling a big difference? Or are you just backing it up a bit and noticing it's fairly easy?

DaveBarbier · « **Reply #291 on:** March 17, 2017, 05:18:01 AM »

Regarding the rotor bolt, you could just do everything from the points side instead of the alternator side. As long as plugs are out.

AlekStooge · « **Reply #292 on:** March 17, 2017, 08:45:06 AM »

Quote from: calj737 on March 17, 2017, 04:45:04 AM

Quote from: AlekStooge on March 16, 2017, 09:40:26 PM
Brent: Just curious, why would having plugs in make a difference in allowing you to rotate it backwards?
Because you're building compression with the plug holes "plugged". If the plugs are out, the compressed air escapes more easily.

Ok makes sense, but why would the side you spin it from matter when the plugs are in or out?

I have the starter gear in but not the starter motor. I could spin backwards all day long with ease on both side the points side and alternator side. When I turn it forwards after about 3/4 turn I get resistance again on both sides.

Guess I'll look for a strap wrench, never heard of it.

DaveBarbier · « **Reply #293 on:** March 17, 2017, 10:06:16 AM »

Its just because of the size of the bolt. You're either turning a bit strong bolt (alternator side) or a little flimsy thing (points side). You don't want to bend the advancer shaft so only turn that if the plugs are out because you'll be fighting compression. See what we're saying?

AlekStooge · « **Reply #294 on:** March 17, 2017, 01:44:22 PM »

Quote from: DaveBarbier on March 17, 2017, 10:06:16 AM

Its just because of the size of the bolt. You're either turning a bit strong bolt (alternator side) or a little flimsy thing (points side). You don't want to bend the advancer shaft so only turn that if the plugs are out because you'll be fighting compression. See what we're saying?

Ahha got you. How about the direction I'm turning in, is not having the starter motor that is making rotating it in reverse easier?

I got a strap wrench.

AlekStooge · « **Reply #295 on:** March 17, 2017, 08:59:01 PM »

Alright I put the starter in and the motor turned easy now forward. I didn't understand why so I took it out and it still worked??? I dunno when I did it this morning it took a lot to move it forward. Maybe the chain was hung up.

Quote from: calj737 on March 15, 2017, 04:45:15 PM

Use the alternator bolt not the points side bolt.

I'd tip that "piston stop" with something soft, like nylon or plastic. A bolt (should you jump the piston up into it) could damage the piston. And we know about that replacing a piston deal already....

How would you tip that piston stop with plastic or Nylon, Cal?

calj737 · « **Reply #296 on:** March 18, 2017, 03:06:03 AM »

Find some plastic cap or rubber tip off something and glue it to the end. Doesn't have to be pretty, just soft. Maybe even candle wax? Just don't smash a bunch off and leave it in the cylinder. If you do, rotate that piston to TDC and vacuum it out.

DaveBarbier · « **Reply #297 on:** March 18, 2017, 04:42:08 AM »

Quote from: AlekStooge on March 17, 2017, 08:59:01 PM

Alright I put the starter in and the motor turned easy now forward. I didn't understand why so I took it out and it still worked??? I dunno when I did it this morning it took a lot to move it forward. Maybe the chain was hung up.

How would you tip that piston stop with plastic or Nylon, Cal?

That's bizarre, if everything feels fine now rotating both directions I'd say it was the devil and you forced him out somehow.

Since the spark plugs go in at an angle and not directly above the piston I bet you can just slip some rubber hose over the threads and leave it sticking out 1/8" or so. I'd think glueing something to the bolt would just fall off after the first bump. Just keep in mind you don't want the piston stop to be too soft. You want to piston to bump against the stop firmly so it stops at exactly the same spot every time.

Honestly, all I did was round over the end of the bolt in the grinder and I didn't have any issues. As long as you use finesse when coming up to the stop you'll be fine. But definitely as you have your stop right now is too sharp.

bwaller · « **Reply #298 on:** March 18, 2017, 07:46:33 AM »

Yupper round the bolt end. Don't mean to disagree Cal but it has to be a "positive stop" so cushioning is no bueno. Just be careful in the knowledge you'll be contacting something hard. Finding absolute true TDC is the goal.

AlekStooge · « **Reply #299 on:** March 18, 2017, 02:02:52 PM »

Since I took that piston stop photo I have sanded it round and then smoothed it with a file. I think it's fine.

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Author Topic: 78 CB 550K motor rebuild (Read 61456 times)