Topic: 71 cb750 rejuvenation etc .. Not calling it a restore

[Restoration Fan]

Subscribed. 
Well done so far.

"A good and cheap chromer" is a bit like a hot woman who is completely logical and sweet and whose father is rich and owns a liquor store....not sure they exist. 

FWIW, unless you're going with a concourse level restoration like Rafi (edwardmorris) did, you shouldn't need to rechrome very much, if anything, on these bikes.

If you're talking about the engine cases and covers, you can sand out scratches and dings and then polish them back to original shine.  Use the increasing #'s technique with the sand paper.  We usually started with 200, 400, 800, 1200, and finished with 2000 grit.  Then, we would polish on the polishing wheel with black rouge, brown rouge and finish with white rouge.  Makes it look like it's brand new again.

You said you're poor...well this will save you more money than anything on the bike...lot of work and tedious as the dickens but very rewarding when you see the pieces' shine come back to life.  Similar to how you did on the fork lowers...good job on those.

Ron

[Salman_z8]

true, i guess i dont want cheap chroming regardless.
Well this isnt a concourse level restore, but i am pretty OCD and like my things a certain way .. especially if i have them all apart. I will talk to couple guys in the new years and see how many of my limbs they want to do a few parts. lol

That pricing will determine if i am going replacement rims or rechroming. They are all apart, drums will get polished and i am dropping stuff off to get zinc plated.

[754]

Dont forget its hard to duplicate original chrome... Which is good and bad. .if the rest of the bike is not overchromed, a few pieces might look odd.. Plus the resto guys will not pay for it..

[Salman_z8]

I have a few updates, some good some not so good ... Okay well they are not good.

Made up 4 brackets to adapt the SOHC motor to an engine stand. Picked up an engine stand for $30 .. yay for kijiji

Tore the top end off, checked cam chain .. seems good, will probably reuse.
Cylinders need a hone, and definitely new rings .. existing ones are out of spec. I am hoping the new ones will bring in spec otherwise one size over then.
But all 4 cylinders have pretty even wear.
Even before when i compression tested, all fours were low, but even ... now the excessive ring gap tells me that most of the compression was lost from rings ... as the oiled compression test did bring the numbers up to 125psi
This was however still a decent running engine.
Rod bearings seem good, not planning on opening them.
Crank journals on inspection seem ok, haven't measured yet.
I have a replacement tranny sitting with me, as i know the one coming out had 3rd and 4th shot.

Now on to split the cases .. and BAM .. bad news.
Seems like at some point the chain broke, and fractured the upper case.
As per norm, how generally PO's are like of such project bikes lol ... JB welded it, from the outside without separating the cases. On of the gear chew of a little edge of the upper case, and i found metal shards in the bottom case. not good.  Luckily all bearing surfaces, seem good.

Now i have almost an 1/16 inch crack in the upper case. Somehow i have to take all the JB off, and then repair.
Same store with the oil pan, there seems to be a hole in the bung .. dont know how that happened .. but i am not buying new cases .. will repair .. i think i can do it.

Should have taken more pics i guess ..

 

[Salman_z8]

you can see the crack in the second image, in the drive sprocket area

[Salman_z8]

First order of business is cleaning .. this engine is filthy.
I mean filthy filthy ... covered in grease with embedded dirt, caked on for years.

Any ideas ... i have used varsol in the past, and then blast off with parts cleaner ..
but this is beyond that. what do you guys use .. curious

[754]

Varsol is probably fine..i would lay out some newspapers or heavy plastic , start washing, get most off.
. If the top case only has a crack , no piece missing..pretty easy fix. . But tell the welder not to grind it down.. They often go under..

[Salman_z8]

Cool cool, i am happy to hear some reassurance on the crack.
Wasnt happy to see that.

Any suggestions on gasket set, seal set to get .. piston rings will be oem.
But i want a complete gasket kit, buy one and be done sort of thing. same goes for seals .. is there any such thing for these engines ?

[edwardmorris]

My preferred way:

All OE o-rings, head pucks, guide seals and dowel pins.
MLS Head gasket (provided you get both the cyl and head milled flat)
Vesrah gasket kit for the rest.

Minimally Vesrah will do but it isn't complete. I went with it because I even tore down the oil pump and Vesrah had a gasket for that too.

[mrbreeze]

I haven't read through this yet but wanted to get in on it. Sounds like you are doing a thorough rebuild.....not restore. I 'm sure I will pick up a few lessons here...... I always do on these posts. Wrench on man!!......

[Salman_z8]

It will definitely be s thorough rebuild.
I will be restoring as much as i can .. seems like i might have a different definition of restore.

I will let you be the judge of restore/rebuild .. once its all done
It will be a while though.

@edward, seems like by chance i got in touch with JT, he has a store on ebay.
Bought a few things.
Actually picked up the NOS complete seat he had listed, pretty penny .. but i am sure it was money well spent.

[Salman_z8]

I will probably dig into the oil pump as well, usually when i do a rebuild, i go all out.
I will go with oem as much as i can. thanks for the tip, that helps.

Ended up taking the kick starter out too while i was standing in the garage having a cigarette lol.

Now for parts washing, that will take a few days.
new guage faces, jewels and crimp rings are on their way ... i didnt need new crimp rings but i was like what the heck.

I am going with the modular approach so far.
Disassemble, assess, order parts.
Next disassembly. so i can assemble in between part deliveries. i dont know, i just like working this way .. thats my fun.

[Salman_z8]

Edward, do i need to for sure for sure get the head milled ?

[Salman_z8]

compression changes ? are they significant ?

[mrbreeze]

Look for member Elan for the oil pump rebuild. He has kits. I bought one over a year ago and will be putting it in soon. Read the posts about it.
On the head....you can check it with a straight edge and feeler gauges. Straight edge must really be straight. Any machine shop could help you there and you should go by book specs when checking for straightness.

[edwardmorris]

Edward, do i need to for sure for sure get the head milled ?

That depends on what you find after you follow Branden's top end rebuild thread step by step. You'll need to check for true flat surfaces before assembly. Also, MLS works best with milled surfaces.

http://forums.sohc4.net/index.php/topic,107040.0.html

[edwardmorris]

Missed some early Qs.

Buying form JT on ebay will cost you a lot. I can help you get a hold of him directly, should save you quite a bit, PM me if interested.

Marcel is the best source for all things gauges, but if you have your original crimp rings, guard them with your life! Those will go back on a lot easier and tighter than the stainless replacements. While spectacular, SS rings are too damn hard to crimp right without a special too, or at least that has been my experience. I had some help on the K2 gauges from Jerry H (member) but on the K3, I stuck with the originals. They do polish up nice.

Oil pump inspection and rebuild is a good idea while its all apart and like Fred suggested, get a hold of Elan.

[Salman_z8]

So i will bring this project back to life.
There was progress in the background, i kept taking pictures aa i went but never got a chance to upload .. And now i cant find them ..
I will though somehow.

[Salman_z8]

So this is what was done in the last 8 months or so;

Engine rebuilt.
Cases welded, then wen over a million times to fix the warpage caused.
Crank bearings were good, didnt need replacement.
Primary chains were in spec but changed anyways.
Undercut transmission from cycleX, new drum.
Cylinders honed, new piston rings. Didn't rebore.
All new seals.
New clutch plates.
Head milled flat. New guides, seats, seals.
Oil pump seals changed.
No leaks.

Frame powdercoated black, almost even looks painted.
Rear drum polished.
All fasteners and spokes zinc plated, all bolts are the "8" bolts
Original rims, brake pedal, shifter, tail light bracket, grab handle
All new cables.
 Guages reworked, new face plates, jewels, dampener refilled.

Original HM300 Exhaust pipes polished.
I repaired the #2 pipe. But it all turned out better than i had expected, except for a stupid mistake which will show in pics later

[Salman_z8]

New control switches from Yamiya, found that little screw that goes under the throttle grip, from my original grip.
New OEM handlebars, new OEM grips.

Sold the original tank, and sidecovers.
New body set from Yamiya in candy Gold.
New emblems, jewels.

Scuffed up the front rotor a little to clean up, and new pads.
Master cylinder got rebuilt, and the caliper got a new seal. Piston got zinc.

Found a Brand spankin new HONDA seat, still in box and plastic.
Installed with new pins.

New wiring harness, with original regulator, flasher and rectifier.
All 4 turn signals are new honda parts, used with original to the bike lenses.
Same for tail light.
Waiting for a stanley sealed beam to come in. ( in transit )

[Salman_z8]

Got a new honda filter housing bolt, filter and air cleaner .. Damn $47 for honda air filter. Ouch
New velocity stacks.
Carb slide top rubbers.
PO had used hose clamps with the original boots, so couldnt use band clamps now so i got new boots as well.
Carbs got new fuel hoses, and new drain hoses.

Petcocks was also rebuilt, new strainer, washers, screws, and seal.

[Salman_z8]

.

[Salman_z8]

Swinger installed.
Front suspension on, guages done

[Salman_z8]

After the cases came back from the welder, warped

[Salman_z8]

Innards of the instruments
Engine in frame
Wheels on