Topic: 1972 CB750 Four K2 -- Rebuilt to NEW OLD STOCK -- PIX ON PAGE 50

[edwardmorris]

Fortunately, I had my doubts about using it early on, so I bought another one from Bill Benton. It was in better shape than mine and Bill sand blasted it before shipping. This one came out a lot better with no shadows, so this will go on the bike. The second large piece left was the front axle, finished that up and for once, you can actually see the psychedelic colors after the clear/blue chromate conversion.

[seanbarney41]

Yamiya has the Turn Oil Neutral, etc.

http://www.yamiya750.com/index.php?main_page=product_info&cPath=144_72&products_id=193

That isn't right for the super early K2s unfortunately. Mine cleaned up ok, but you can tell it looks beat up next to all the new powder coat all around it, so I was hoping to find a repop.

Ed, I have one of these if you still want one.  The case has some chipped paint, but panel with the jewels is still nice and black, and it has the correct early k2 labels.

[edwardmorris]

Yamiya has the Turn Oil Neutral, etc.

http://www.yamiya750.com/index.php?main_page=product_info&cPath=144_72&products_id=193

That isn't right for the super early K2s unfortunately. Mine cleaned up ok, but you can tell it looks beat up next to all the new powder coat all around it, so I was hoping to find a repop.

Ed, I have one of these if you still want one.  The case has some chipped paint, but panel with the jewels is still nice and black, and it has the correct early k2 labels.

PM incoming.

[edwardmorris]

Quick update, I asked Bruno, the guy at Kheissner who makes repro VIN plates if he can make the dash plates too. He's hesitant that he can't get it quite as cheap as in Japan, because things are pricey in Switz?? I'm trying to see if he can do a small sample set and see how well they sell, especially the rare early K2 ones, will post back when responds, fingers crossed.

[edwardmorris]

No dice with Kheiisner, so I guess I'll be going with the best used one I can find.

[edwardmorris]

So, some more progress today, part two of the psychotically cleaning the blasted parts complete, with total mineral spirit bath in a wide bin followed by rinse, then a full dunking in hot water Dawn dish soap tub, then a high pressure clean rinse. They are squeaky clean now. Finished up all the masking (top end is missing a few pieces, now that I look at the pix, will plug them up in the morning).

[edwardmorris]

By the time I got this far with the top end, my arms were sore so I quit. Will do the cylinders and head tomorrow while these are baking.

[edwardmorris]

This is the oven I have temporarily hooked into the panel. Hope it works out tomorrow. I also taped up the final drive bearing journals, it looked liked they'd be hard to spray around.

[edwardmorris]

Cases primed, painted and baking right now. Bottom end in the oven, top drying out in the garage, should be done within an hour. I wish I had two ovens so I could do them together and leave them in there overnight. For now, the bottom case has been in there for a couple of hours, so I'll go shut off the oven and let it cool down, then pull it out. Then bake the top case for a couple hours, shut off the oven and go to bed.

[edwardmorris]

Top case all done, now to let it finish baking. Damned thing is about half an inch too long and the oven wouldn't shut. Had to improvise

[Terry in Australia]

Looking great Rafi, and I bet you're now seeing some light at the end of the restoration tunnel? Cheers, Terry.

[tweakin]

Those turned out nice!

[Kickstart]

Way to improvise with the oven and get the job done!

It must have been getting pretty toasty in there

Nice work!

[edwardmorris]

Thanks Terry and Tige, followed as you guys instructed, came out good enough. Next weekend top end. I'm dreading the last 20% taking 80% of time or the 20-80 rule kicking in. Still have a lot to get done, but I really want the engine painted and buttoned up first. Once its in the frame, motivation will find me even after a double shift.

Chris, thanks, yea it was a pain and getting too hot. I had the windows open with a fan stuck to keep air circulating which helped a lot.

This morning though, when I woke up., I noticed that there was some orange colored corrosion on the valve seats and guides  I had the windows open all night in the basement and it rained, humidity is destroying things! The orange gunk looks EXACTLY like what I saw when the head first arrived from the seller, but it had cleaned up nicely at the machine shop. I'm hoping I can brush this off and move on, but I suspect the gunk in on the inside of the valve guides too, which makes me fear the worst. Pix tonight, I only had time to give things a glance before leaving for work this morning. Cases look better in daylight, so hopefully some better pix of them too.

[edwardmorris]

Here are the pix of that corrosion, how worried should I be? Think I can brush it off and reuse the guides and seats (after lapping)? Or is it gone? Last pic is of the cases in their resting place for the week where they shall cure undisturbed.

[jerry h]

Paint looks good!  I'd clean the surface rust off the steel parts with an oily rag, and keep a fine coat of oil on the bare steel stuff till you are ready to use.   Order some Redline assembly lube (if you don't have some all ready)  - you will use it/need it during assembly, and you could also use it to coat stuff for rust protection until your ready.   



http://www.redlineoil.com/product.aspx?pid=77

[jerry h]

Oh and I forgot, your plated stuff looks amazing!!!  I used a homemade brew/setup which coated fine, but nothing like your results.  You should start a tutorial thread on that sometime when the bike is done and show us your secrets

[HondaMan]

I can't see the orange stuff you're referring to, but if it is surface rust, it can't be much? I'd try a Q-Tip or bore brush with some oil and see if it comes off OK. If the seats seem disturbed, they can be lapped again for a few seconds to clean it back off.

[Terry in Australia]

G'day Rafi, I enlarged your pic of the head and can see the rust, which shouldn't be a problem, but the seats look awful, lots of  pitting, I don't think lapping alone will get you a good seal, I think you'll need to get them re-cut, or you'll be having some compression issues down the track. Sorry to be the bearer of bad news. Cheers, Terry.

[edwardmorris]

@jerry, thanks, no secret, just following Tom Gugliotta's recipe and been in contact with him as I went along. I did a brief write up (page 22? I think) a little while back. I owe you one for helping me with the gauge cases, so if you need any small parts done (non-fastener, these are iffy and require redos a lot) PM me

@Mark/Terry, I will try wiping it off with oil and take some more close ups for review. If lapping isn't going to save the seats, then I can either cut them myself ($$ on cutters) or delay project some more and send it to someone. Thanks for looking into it!

[edwardmorris]

Actually I found some close ups from earlier (click to enlarge), if these aren't good enough, I'll be needing a better camera to focus better on the finer things...

[Terry in Australia]

Yeah mate, those seats definitely need cutting or replacing. Cheers, Terry.

[edwardmorris]

Yeah mate, those seats definitely need cutting or replacing. Cheers, Terry.

Thanks Terry, I think I will go ahead and cut them. Prokop has so very generously agreed to loan me his set of neway cutters, this should save me some time, money and grief hopefully. I will push back painting the head and cylinders till I'm done with the head.

How do the domes look? Should I grind off the high points a bit around the seats or leave them be? Looking at Mike's work, it seems that he almost hemi's the heads and polishes them smooth. I'm planning on gentrly grinding/sanding off the casting flashes in the ports, these are way too high and obvious so I can safely clean them with the tapered bits I have from Eastwood. Anything else I should do with the head before I prep it for paint?

[edwardmorris]

I can't see the orange stuff you're referring to, but if it is surface rust, it can't be much? I'd try a Q-Tip or bore brush with some oil and see if it comes off OK. If the seats seem disturbed, they can be lapped again for a few seconds to clean it back off.

Qtips worked perfectly. Whatever that corrosion was, it was lightly stuck on the top edges of the guides and the insides seemed very clean. Thanks guys!

[HondaMan]

Before cutting new seats, I usually lap them first with fine compound. This highlights if they need it (or not) and helps to outline the areas that need to be watched closely. Cutting is a bit of an art when done by hand.