1976 Kz 900 A4

A fairly reliable rule of thumb is using sealer on holes that go through into the crankcase, as opposed to holes that are blind.  Some of the cylinder stud holes are also open into the crankcase. ThreeBond 1184 is probably as close as you will get to factory original?  I know we used ThreeBond,  but I don't know if that is the original number, It is gray, as original. I used a locktite product on my last engine and it was blue, you don't want that showing on an original appearing build. A LITTLE gray sealant squished out on the crankcase seam would be the most original appearing as on the engine assembly line I'm quite sure they didn't take the time to wipe the seams clean like I did during the assembly process. Assembling engines was always the most enjoyable part of my job, at least while I was Production Mechanic.  Have fun with it!

Mike

Thanks Mike, can I use the three bond 1184 as thread sealer also?

I was thinking about the loctite being red. Definitely not good with the rivet counting finish I’m looking for. 

I've used 518 (and it's red) with an accelerator on the opposite side of the case.  I switched to 3 Bond and won't go back.  Easier to apply, less mess.  Just put down a very thin bead and go over it lightly with your finger to spread it.  Try to stay away from the inside of the case.

Do what Krazee said for sealing bolts...I just use 3 Bond on the shaft and install.  Seems to have worked.

I’ve been working on the head. I found a local engine shop that had no problem welding up the broken fins. I cleaned the up today, I need to take the head back at least one more time to do a little more weld build up. They it off the be glass bead, I’m hoping that will blend in the repairs. Then to my Vapor Hone guy, and finally back to a different shop that’s been building metric engines for 30+ years. 

 

 



 

That fin repair looks very good!

Vapor blasting with glass bead tends to leave behind some bead clinging to the workpiece.  Don't know it it's due to surface tension or electrostatic attraction.  To check for bead remnants, be in a dark or dimly lit place where you can be at least a few feet away from the workpiece.  You'll also need a bright, point source light.  A bright handheld LED flashlight with a spot beam works very well.  Hold the light just below eye level & shine it at the workpiece.  Any glass bead will reflect, making it easy to see what needs additional cleaning.  A strong detergent solution, brushing and directed stream of water will remove the remaining bead.

Good Ridin'
slmjim & Z1BEBE

A tip I picked up for post-bead cleaning is to submerge the piece in warm water and hit all the passages/threads with compressed air.

After using the vapor hone for 20 hours or so, on multiple different metals and finishes (parkerized etc).I now soak the whole dang part in e85 gasoline before(let soak 10 min) and after blasting it,I dunk and swish around about 6 times. Then I water rinse air blow out. The glass is so fine its crazy, add that to a bit of oil and it sucks. Slimjim Z1bebe is 100 percent on about using l.e.d .to see it .Super shiny like a pearl paint. I use the storage totes that people throw out on trash day , when they get too much goo in em strain ,rinse ,refill.
That head is looking great, very nice repair for first round of welding for sure.

Well, life distractions and just forgetfulness made me forget I needed to pay Z1KZONLY for shipping of the cam chain axles. I reached out to him asking for his email again so I could complete the transaction. He said it was just a few bucks shipping and was more then willing to contribute to my project. 

I wanted to give Marty a public thank you for his help. We truly have a great bunch of members here.

Marty, Thank You!!!

Baby steps. 

 

Hi Matt. Thanks! That praise is worth more than it all!

Marty

While I’m waiting on the head to be welded up the second time, hopefully I can profile the fins with the second build up and move on to the head rebuild. So I’ve taken to getting lower end parts out and inspecting them pre build. A quick reminder of where I’m at. The engine I bought for this build was an early ’76 without the oil volume cast into the upper case. It’s an unknown to me. Upon tear down it looked good but I didn’t dig deeper than the cases. They were my concern at the time so I could get them out to be vapor blasted. I did notice the pistons were 70mm wiseco. I didn’t want to use them so I have been searching for a good 66mm OEM set. I found them but no wrist pins included. I thought no problem I can use the pins I have out of the Wiseco. I dug the pistons up this afternoon and not pleased with what I find. The pins appear to have metal to metal transfer or gauling. I need advice please. I can get new pins but what if anything needs to be done to the small ends of the rods. Obviously I need this corrected before I build the lower. The backyard mechanic in me checked out the rod small end with my pinkie and it feels smooth but at the oil holes, the edges feel sharp. #2 appears to be the worst.

I have another set of 70mm stock pistons out of an engine claiming to only have 4K on it before it was wrecked and parted out. I included pictures of them for comparison.