Author Topic: 1972 CB500 - Rebuild Project (Read 30842 times)

Puffin · « **Reply #75 on:** May 26, 2015, 02:48:37 am »

Quote from: Restoration Fan on May 25, 2015, 05:40:31 pm

The polishing looks good. Even though it's a pain in the butt, when you bring those old parts back to looking like their original new self, there is something very satisfying about the process. Almost makes the paint in the butt part seem not so bad, huh?

I agree, I actually find it quite satisfying. I spent about 8hrs the other Sunday just polishing. Man it's messy work though...

Puffin · « **Reply #76 on:** May 26, 2015, 02:58:19 am »

So in my excitement with finally having all my parts I got home from work and installed the top half of the engine.... Didn't go totally smoothly I have to admit.

First time I put the jugs on backwards which meant installing all the pistons twice...

Also had a huge fight with getting the bottom of the cam chain tensioner into it's little slot in the crank case. Ended up taking the oil pan off and using a screw driver to lever it in from below as I pushed it down. It was only by luck I realised it wasn't sitting right as I was checking some other thread on this site when I saw somebody had the same problem.

No photos sorry... Was too caught up in what I was doing

Puffin · « **Reply #77 on:** May 26, 2015, 03:05:49 am »

I have some Permatex aviation gasket sealer that I used on the lower cylinder gasket...

http://www.permatex.com/products-2/product-categories/gasketing/gasket-sealants/permatex--aviation-form-a-gasket--no--3-sealant-liquid-detail

In my haste I also used it on the head gasket but I'm now wondering if that was the right thing to do?

Generally people seem to install that gasket 'dry'...?

I used a new Vesrah head gasket.

Should I be worried at all? Is there any issue with using this type of sealer on the head gasket?

I used some new High Tensile flange nuts that I torqued to the APE specifications. Tomorrow I'll back them off slightly and re torque.

Puffin · « **Reply #78 on:** May 30, 2015, 11:44:04 pm »

Big milestone reached today. The engine is all buttoned up, looking good and sitting on my bench waiting to be installed into the frame.

If anybody has any top-tips about getting it back in the frame I'm all ears. I figure it's either going to be a case of lying it on the floor sideways and placing the frame over or recruit some muscle and see if we can man-handle it into the frame.

Some pictures of the final assembly below....

1) Sealing the rubber 'Pucks'
2) Using the old o-rings from the cam end covers to prevent the rocker-shafts from rotating
3) Aligning the timing mark so that the notch in the Cam-shaft faces to the right of the engine

Puffin · « **Reply #79 on:** May 30, 2015, 11:47:41 pm »

... I guess the jury is still out on whether this prevents the rocker shafts from rotating however it can't do any harm and the theory is good so why not?... it's a quick and free solution. In the least it will delay the process.

Puffin · « **Reply #80 on:** May 31, 2015, 03:45:29 pm »

Aligning Cam shaft with timing mark..

Puffin · « **Reply #81 on:** May 31, 2015, 03:59:10 pm »

I used my new (to me) CB650 CAM... the lobes did clear the case although by the #4 cylinder the tolerance was pretty tight...!

I did think about grinding some of the case away however in the end I left it alone as I couldn't physically make the lobe hit the case by manipulating it manually.

Looking back at these pictures I'm not so sure.. that is one small gap???

If anybody thinks this needs more of a gap to be safe please let me know. It's not a massive job to go back and fix it now.

Puffin · « **Reply #82 on:** May 31, 2015, 04:04:50 pm »

Some pictures of the finished engine.....

Man I'm already nervous about starting it up for the first time??

Puffin · « **Reply #83 on:** June 02, 2015, 02:59:33 pm »

So having slept on it and getting some advice from the Forum I went back and opened up the top of the engine to address the clearance issue between the cam and the engine case. I wish I'd done this before putting it together as I would have been able to do a proper job. Instead I had to struggle whilst working with the engine in the bike. I masked off all the galleries and openings and had a vacuum cleaner and an air compressor on standby to constantly clear up all the dust and metal particles as I progressed.

I'm annoyed with myself because so far I have been trying to do things properly and this felt like a bit of a 'hack'. Anyways the job is done.... Maybe not as good as it could have been but the clearance on all the lobes is now much better.

Puffin · « **Reply #84 on:** June 02, 2015, 03:01:51 pm »

Couple more pics of the increased tolerance...

Puffin · « **Reply #85 on:** June 06, 2015, 11:12:54 pm »

Engine is sittingl in the frame and buttoned back up. Went in like a dream with two people. I took off the sump pan and the breather cover and it slotted straight in.

Whilst I was there I ground off some of the powdercoating from the mounting brackets to ensure I had a good earth from engine to frame.

Puffin · « **Reply #86 on:** June 06, 2015, 11:28:58 pm »

The front end was only mocked up so I finished the final install now that the bike was carrying the weight of the engine.

When it was all tightened up I had a problem with the caliper arm sitting and rubbing on the brake disk. The caliper arm had some vertical movement so I took it back off the bike and dissembled the 'pin' that holds the caliper arm to the fork. Once disassembled the pin looked ok but the o-rings had disintegrated and I noticed that the arm itself had worn slightly at the top and bottom where it sits on the 'pin' which was causing the slack.

I found a thin washer and used it as a shim between the pin and the arm which seems to have solved the problem.

Luckily the o-rings for the caliper arm are also the same size as the O-rings used for the engine valve guides so I had several new o-rings sitting in my Vesrah Gasket Set.

The arm is still quite close to the disk but even with the weight of the caliper it's not touching so I guess that's good enough...

Puffin · « **Reply #87 on:** June 06, 2015, 11:38:12 pm »

Mocked up the new headlight bucket and brackets and popped the tank on. It actually looks like a bike again which makes me feel like I'm almost there...

Headlamp is just a plain matt-black Emgo job... really simple but I like it.

I wasn't too sure about the headlight brackets when I got them, they were a bit shiny. Now they are on the bike though I like them.

Can't quite work out if I have them upside down though?

Puffin · « **Reply #88 on:** June 06, 2015, 11:50:54 pm »

Haven't bought anything for a while so I made up for it by ordering a new Dynatek Electronic ignition. My old points were bent and looked pretty knackered so given that I had already got new Dyna Coils I thought I'd splash out a bit more and get the full system.

Also made a bit of a impulse buy and ordered a set of super wide, old school, black, dirt bike bars with the cross-brace. Not sure if they are going to work on this bike but and I figured I can always use them on something else or sell them. The existing bars have been cut and are too narrow for my liking.... If my new dirt bike bars look daft I think i'll go for a set or Superbike or Tracker bars... something wide with not too much rise or pull-back.

Puffin · « **Reply #89 on:** July 03, 2015, 04:06:46 pm »

My brother living on the other side of the world messaged me the other day wanting to know when my next update was coming... apparently the anticipation is like waiting for the next series of Game of Thrones!

That made me laugh so just for you BombHead....

Puffin · « **Reply #90 on:** July 03, 2015, 04:23:06 pm »

I have been busy on the bike working on the carb re-build. I basically stripped the carbs down and gave them a really good clean. Putting them back together was not too bad... once you figure out the first one the other three fall into place. My advice is to take lot's of photos as you go as there are a lot of little parts in each carb and the Parts Manuals don't show a breakdown of all of the components.

I have spent quite a lot of time on the forum getting advice and reading through other build threads which also helped a lot.

My carbs were in pretty good nick and really didn't need much work apart from new rubber and a good clean. I did get a rebuild kit but ended up also getting better quality o-rings and making sure I re-used the original Keihin brass jets where possible.

I did a bit of a review of the re-build kit I ordered and posted it on the forum if anybody is interested.

http://forums.sohc4.net/index.php/topic,149097.msg1700597.html#msg1700597

Puffin · « **Reply #91 on:** July 03, 2015, 04:32:58 pm »

My old float needles were sticking in their seats and not releasing even after a cleaning so I swapped them out for new ones. The new needles sat slightly higher (0.3mm) than the old ones so all my float heights were slightly too high.

I fashioned a high tech float height gauge out of an old loyalty card and set the float heights back to the factory 22mm.

Later I'll run some clear tube out of the float bowl drain plug once the carbs are back on the bike and double check the actual fuel level just to make sure everything is correct.

Puffin · « **Reply #92 on:** July 03, 2015, 04:45:03 pm »

For no other reason than self-indulgence I treated the carbs to some sexy new Stainless Steel screws and sourced some cool cloth covered fuel line.

The original fuel line was 5.5mm, which is actually tricky to find in the usual auto-parts stores, but I discovered that this is the same size that VW used on their Beetles, Carman Ghias and Camper Vans etc.

The aftermarket supply for these vehicles is massive so once you are armed with this knowledge finding new line is easy.

Puffin · « **Reply #93 on:** July 03, 2015, 04:58:55 pm »

Installed some nice new soft Carb Boots also went on ready for the carbs.

I'm going to run the bowls and the top caps over the polishing wheel and then I guess that's another job done..

One question somebody may be able to help with is where to set the throttle slide height after a re-build? I've basically just screwed the adjustment screws to the point where the throttle slide just barely touches the base of the carb.

Should I add another couple of turns?

Puffin · « **Reply #94 on:** July 08, 2015, 12:08:04 am »

Happiness is.... a bank of fully restored, cleaned, polished and Sync'd Keihin 627b's.

Puffin · « **Reply #95 on:** August 07, 2015, 05:26:14 pm »

The bike had no mufflers when I got it and so I ordered a pair of Emgo 17.5inch Reverse Cones. I like the balanced look of a 2-into-1 set up and I would be able to make this work with only minor modifications to the existing headers which had been cut and welded (badly) already. I had read they were pretty loud though and I need to get the bike through a compliance test in order to get it back on the road.

When I took the baffle out the packing was pretty awful... just a tiny amount of what looks like roof insulation.

For $20 I got some proper muffler packing delivered... although I now have enough to pack about 100 mufflers. The new packing is much thicker and much better quality.

The reason for the odd shape I cut is that the mufflers are cone shaped therefore can take more packing as the muffler gets wider. Not sure how much this is going to help yet but I figured it can only help. Process took about 10 minutes.

Puffin · « **Reply #96 on:** August 07, 2015, 05:43:05 pm »

Now that the carbs were on the bike I hooked up an auxiliary fuel line and connected a short length of clear tube to the float bowls using a 5mm 90 degree plastic tube connector.

I'd read a lot of people drilling out a float bowl screw and threading in a brass extension with which to attach the tube but to be honest that just sounded like too much work... this cost me about $5 all up and took 5 minutes to install.... so long as you screw the connector in slightly it works perfect, no drips.

The idea was to make sure the fuel level in the bowls was high enough and even across all 4 carbs, especially as I replaced the OEM float valves with aftermerket parts so I couldn't guarantee the factory float height was still correct.

Looked pretty good. All were about 5mm off the bowl to carb gasket level.

I would have liked the fuel to be a couple of mm higher however but I'm going to have to pull the carbs back off (for reasons I'll explain later) so I may adjust the floats slightly later.

Puffin · « **Reply #97 on:** August 08, 2015, 10:18:07 pm »

So I've been really struggling with getting the front and rear wheels, and the drive sprockets to all line up together... I must have been at it for a month or so now but I keep finding potential issues and It's getting really frustrating.

It started off when I installed the new chain. If I line up the back wheel using the marks on the swing-arm the chain 'rattles'and 'pops' on the rear sprocket. I tried various methods and checks in case the marks are not accurate but no matter what I do I can't get it to sit evenly on the sprocket.

I can see clearly the sprocket is being forced off to one side under the tension of the chain even when the chain is quite slack. This implies to me that the front and rear sprockets are not aligned.

My initial thought was that the rear sprocket is more likely to be the culprit so I disassembled the rear wheel hub in case I had installed a spacer wrong or had the new bearings not seating right. Everything looks good however and I double checked the order of the spacers against the parts fiche...

At one point I had some concerns about the bearing retainer which clamps onto the wheel bearing but has a gap that allows the sprocket holder to 'float'in the hub. The advice I got in the forum however was that this is correct.

Puffin · « **Reply #98 on:** August 08, 2015, 10:31:45 pm »

My next step was to make sure the rear wheel was properly aligned so I used the string method to align the rear wheel with the front wheel.

You can see that my problem now is that the front wheel does not seem to be in the same plane as the rear wheel? I would expect the front wheel to sit evenly between the strings but you can see the gap on the drivers left is significantly greater than on the right...

Reasons for this would either be that this is normal or I have a bent frame or bent forks or I've assemble the front end wrong somehow....

Whilst lining everything up I also noticed that with the front wheel straight the handlebars are not level.... You can't see the bubble in the picture but it is way off to the left.

calj737 · « **Reply #99 on:** August 09, 2015, 05:09:40 am »

Puffin - sort out 1 problem at a time as y have too many alignment issues going on at once. And the front end alignment/bar angle has a nothing to do with the rear sprocket.

It's hard to see from the pictures, but is the rear wheel assembled with the correct spacers? Does the rear wheel (rim) spin freely and without obstruction on the axle? Then, with a metal straight edge, align the outside faces of the sprockets. Maybe snap some clear pictures of your alignment marks on both sides?

For the front end, first thing I'd do is to release the tension on the triple trees and allow the forks to be adjusted. But, is the steering stem bent is my concern? This would show by rotating lock-to-lock and feeling for rough spots in the steering bearings, and leveling the underside of the lower and comparing it to the upper clamp.

Is your front rim (and rear for that matter) completely trued? Aligning a bike off a tire edge is far less accurate than off a disc, sprocket or other machined plane. So if you must;
1 - align drive sprocket.
2 - set up a string box outside the bike on both side. Square it with a tape measure.
3 - measure the offset from the outside string to the center of the tire, front and rear. This will tell you if the tire center lines are tracking straight.

Right now it's impossible to use frame measurements since you have suspicions that something/multiple things appear wrong.

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Author Topic: 1972 CB500 - Rebuild Project (Read 30842 times)