Author Topic: 1970 CB750 K0 restoration - going for original (Read 41842 times)

Zaipai · « **Reply #75 on:** May 17, 2010, 10:38:36 AM »

Yes, it is.. be-careful its sooooo easy to get sucked in. However your battery box looks fabulous..

.: Scott :.

egar · « **Reply #76 on:** May 17, 2010, 12:53:27 PM »

Scott,

Thanks for the comment on the battery box. What really sucks is that I forgot to include the little tool tray when I dropped everything off at the powdercoater's. Now I'm debating whether to drop that off, as well as the oil tank and side stand. The side stand will look crappy compared to the center stand. I figure I'm a way's off from that part of the restoration so maybe it won't hurt so much.

Zaipai · « **Reply #77 on:** May 17, 2010, 02:25:37 PM »

Quote from: egar on May 17, 2010, 12:53:27 PM

Scott,

Thanks for the comment on the battery box. What really sucks is that I forgot to include the little tool tray when I dropped everything off at the powdercoater's. Now I'm debating whether to drop that off, as well as the oil tank and side stand. The side stand will look crappy compared to the center stand. I figure I'm a way's off from that part of the restoration so maybe it won't hurt so much.

If you take all 3 in it would be worth it. Other wise if you do a good job with paint yourself it could look just as nice, it would need touching up sooner then the rest but by then it might not matter..

.: Scott :.

egar · « **Reply #78 on:** May 19, 2010, 05:40:27 PM »

Dropped the pistons, valves and heads off at the local vintage Honda guru, Lucien, at AL and L in Melbourne. I plan on writing an article about him for Motorcycle Classics. He's an amazing guy. Anyhow, he recommends that I go back to original sized pistons and is searching for a cylinder head that is in good shape. Which means I'm going to have to buy new pistons, rings, etc. Just like my 550, this bike is going to cost much more than I anticipated, but it comes with the hobby,right? Will provide an update when I hear something from Lucien.

egar · « **Reply #79 on:** May 31, 2010, 05:50:41 AM »

It has been a while since i have posted, but I have been waiting for the shop to hone my new cylinder head and lap the valves, etc. I got a call from the shop Friday and picked up my new cylinder head with the factory size cylinder holes, four brand new in-the-box pistons, four brand new sets of rings, new clips, and a rebuilt valve head, all reassembled. Lucien, the shop owner, also provided me with a new head gasket, showing me how the Honda brand is much better than the Athena knock-off that came with the complete gasket set I bought last month. Total bill was more than I paid for the bike and I have now decided not to keep a tally of what I'm spending. It is just too painful.
Anyhow, I have a question for you experts: Why do the piston ring kits come with five rings? The shop manual lists three for each piston. I have read the threads about using the silver ring at the top and the others below it, but there are two more - including a gold one that is ridged like a Ruffles potato chip and has no break in it like the others.
I know I can call Lucien at the shop, but I hate bugging the guy with too many questions. It's like asking a doctor for tips on how to remove a gallbladder. It's his livelihood and why she he give out free advice all the time?
Photos of the new parts (including the old racing cylinder and the new factory cylinder )are below:

hondaface75 · « **Reply #80 on:** May 31, 2010, 06:05:41 AM »

the two smaller rings sandwich the ruffles one right?

egar · « **Reply #81 on:** May 31, 2010, 06:11:58 AM »

Hondaface, your suggestion would make sense. Anyone else want to confirm it?

Also, I'v read that there are supposed to be marks that should face up on the rings, but I can't see any.

754 · « **Reply #82 on:** May 31, 2010, 07:43:41 AM »

3 pce oilring + 2 thin and a crinkly
Other rings are marked or have a bevel that goes a certain way.. should be noted in ring package or in manual.

Dont toss the old pistons yet, what happened to the sleeves?

egar · « **Reply #83 on:** May 31, 2010, 09:52:38 AM »

754,
I still have the complete head with the larger sleeves and the four high-po pistons. I'm thinking maybe I can sell the whole deal to someone with more expertise than me. It's too bad because I cleaned and painted the cylinder head very nicely and the sleeves are in nice shape.

egar · « **Reply #84 on:** June 27, 2010, 06:27:37 PM »

Haven't posted in a while, but I cracked the cases a couple of weeks ago to clean all the rusty grit that was in the bottom of the case. I then painted the cases duplicolor 1615 silver. I also spent evenings in the living room installing the rings.
Today I installed the pistons, but had an accident when the motor slipped off the stand and ended up breaking the second ring from the top on piston four! AAAARG. Now I have to buy another set of rings and start the process of trying to put the bucket back on.

[IM

G]http://i485.photobucket.com/albums/rr218/egar_photo/GEDC0341.jpg[/IMG]

traveler · « **Reply #85 on:** June 27, 2010, 08:23:15 PM »

Looks good. Keep at it. It will be really nice when finished.

~Joe

nancy · « **Reply #86 on:** June 28, 2010, 08:04:45 PM »

Replacing cam chain and primary chains? Nowze your chance..it's only money...

egar · « **Reply #87 on:** June 29, 2010, 03:49:09 PM »

I may regret it later, but I didn't replace the cam or primary chains. I'm hoping I'm OK on this since the bike has 8 or 9k miles on the odometer. Ordered a new set of rings today at my local shop so I can replace the one that broke during my mishap.

egar · « **Reply #88 on:** July 25, 2010, 03:24:48 PM »

I made a horrible mistake during the engine rebuild process - which I also described over in the bike talk thread. I spent many hours today installing the camshaft, rockers, etc., after finally grinding down a socket that would allow me to tighten the two deep bolts in the top of the head. When I went to install the cam chain tensioner, I grabbed the bag containing it and also found this:

I assume I must tear everything apart to slip this cam aligner piece in. Does anyone know if I will have to slide the whole bucket off the pistons to make enough room to slide this piece in? Getting those rings to slip into the bucket was the hardest part of this whole build and I dread the thought of doing it again. I broke two rings last time.

Ed

Zaipai · « **Reply #89 on:** July 25, 2010, 08:35:53 PM »

Ouch that sucks dude, I hope you don't have to. I have no idea tho.. So I am hoping some one can tell you and I hope for you that you don't have to do that.

.: Scott :.

traveler · « **Reply #90 on:** July 25, 2010, 09:49:48 PM »

damn the luck!

MasterChief750 · « **Reply #91 on:** July 27, 2010, 09:16:49 PM »

thinking back to tearing mine apart i believe you onlt need to get the head off to put that in

egar · « **Reply #92 on:** July 28, 2010, 05:03:21 AM »

Masterchief,
I do only need to get the head off, but that's the problem right now. That gasket was so sticky its holding everything together like glue. It was a factory honda gasket without any adhesives added.

MasterChief750 · « **Reply #93 on:** July 28, 2010, 06:38:53 PM »

the head gaskets are pesky buggers. you may need a replacement one if it tears when you try to get it off. you could pull the jugs and the head off in one piece then try to carefully separate them.

jaguar · « **Reply #94 on:** July 30, 2010, 12:16:12 PM »

bad luck.
hope it works out for you

great build.

egar · « **Reply #95 on:** August 01, 2010, 03:02:52 PM »

Well, I managed to split the valve head from the cylinder head by sharpening a paint scraper on a grinding wheel and carefully tapping on either side of the engine with a rubber mallet until the scraper slid in. I heard a sucking sound of the adhesive on the head gasket. I carefully lifted up the valve cover and the gasket did not rip anywhere. I lifted the cylinder head up enough to make room for my fingers to slide the bottom pin through the cam chain guide, which I had dropped in from the top.

Today, I put all the parts back together but found that the two front cam tower bolts stripped. After reading threads on this --- looks like a common problem -- I am going to try and replace them with 1/4 bolts and washers that I picked up at Ace today.
PITA

srook · « **Reply #96 on:** August 02, 2010, 08:47:42 AM »

Why use 1/4 bolts? An insert kit will cost you about $30 with a tap and drill bit and maybe a few days shipping if you can't find one locally. Once you start mixing thread types and pitches you become one of the DPOs that everyone hates. What if a shop or the next owner doesn't realize that you've changed some bolts around and runs one of those 1/4 bolts into a 6mm hole. I know its the difference between $1.00 fixed now or $30 fixed later this week but really consider what you are about to do. Here's some inspiration http://www.mcmaster.com/#inch/metric-threaded-inserts/=88a4iz

Scott

markb · « **Reply #97 on:** August 02, 2010, 10:13:09 AM »

I agree. Better off doing it right.
Mark

egar · « **Reply #98 on:** August 02, 2010, 10:35:10 AM »

Thanks, guys. I want to do things right. Will check out the link you provided.

egar · « **Reply #99 on:** August 26, 2010, 10:33:33 AM »

It's been quite a while since I've posted but I have been busy at work on the KO. Installed the new tapered bearings this morning and it was twice as easy as when I did the 550. I must have learned something! Freezing the neck stem did the trick. I then wrapped the frame with some old bubble wrap that was being used to protect my powdercoated parts and finally installed the motor in the frame. It was a nightmare doing this by myself. Much more unwieldy than the 550 motor and more heft to it. In advance, I had sanded and polished the bolts and replaced any nasty washers and nuts with stainless just for that added touch.
I still have to put that mess back together at the shifting mechanism. An assortment of springs and arms. I also have new fork boots and fork seals ready to go, along with new float bowl gaskets and new chrome rings for the top of the rubber boots. Oh, and new handlebar clamps and new passenger foot pegs.
I also painted the rear inner fender and chain guard with that Krylon fusion for plastic that I've been reading about on this site. Great stuff. Check out that back fender piece.

I'm starting to run low on funds, which begs the question: should I sell the 550 and use the money for paint, shocks, seat and other big ticket goodies?Opinions?

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Author Topic: 1970 CB750 K0 restoration - going for original (Read 41842 times)

traveler

traveler

srook