Topic: Terry's horrible K2 Budget Build.

[Terry in Australia]

Thanks David, but you'd need to leave the mating surfaces against the edge of the stainless steel UC for weeks before you did any damage mate, seriously, these engines have been work hardened over 40 years or more, and you'd need a heck of a lot more than an ultrasonic cleaner to do damage to them........

[MauiK3]

Fantastic progress, I love my 10L sink, i have stuffed it many times and it works great. I used 50-50 simple green and RO water to clean most of my K3 (what would fit). It was very effective.
Wonderful project.

[PeWe]

Good idea, Terry!
I have 30L cleaner too, probably same model.
I have had a CB750 cylinder block, cylinder head and a complete carb rack in it. Not at the same time though.

I cleaned my cases with degreaser, followed by put it in a              deep stainless sinc with hot water with dishwasher powder dissolved.
A dish brush scrubbing everywhere. Rinsed with hot water.
Finalized outside with pressure washer with warm water rinsing the oil channels with respect for the rubber plug blocking the oil feed to gearbox.

It can fly with a pop. Happened  me once, I heard and saw where it landed.

[Terry in Australia]

Thanks guys, yep the big ultrasonic cleaner has paid for itself many times over, and the good thing for me is that it’s getting cooler as Melbourne moves towards winter temps, so washing the cases in the nice warm cleaning solution was a very pleasant experience as I have osteoarthritis in both hands from punching heads in my younger days, so not only were my mitts nice and warm, but they came out as clean as those cases!

I had intended to change the (ridiculously expensive) Simple Green Extreme Aircraft cleaner as I had two sets of carbs to clean, but decided to wait until after I washed all the disgusting engine parts first, as the carbs are pretty clean by comparison, so I’ll finish cleaning the horrible K2 engine parts before I change the degreaser for the carbs. I left the cylinder block in the ultrasonic cleaner last night to soak, I ordinarily wouldn’t do that for fear of rusting the bores, but as mine are buggared anyway, no biggie. I might take a look at the head today after work, and see if the valves are save able, more soon.

[Terry in Australia]

Wow, has it really been over two weeks since my last post? How time flies when you're getting old, and have more projects than sense. Did I mention I have now got 2 x K2's to build (one of which will get a 970cc hotrod engine) and 2 x K1's, in pretty much standard trim? I have my 1970 K1 to do, and had a leftover 1971 K1 frame, so found a very close engine to go in it, so that'll be collected from Brisbane in a big wooden crate this week, and I should have it very soon, Covid-19 willing.

Anyhoo, back to the horrible K2. Dion decided that he couldn't be bothered fixing the rusty frame so took it on himself to find a good frame, which he did here in Melbourne, and as he lives so far away, I collected it for him. He'll come pick it up soon and take it away for paint. Suits me.

I kept scrubbing and degreasing those ugly cases, and whenever the sun was shining, hit them up with some "Ceramic" engine enamel in "as close to as I can be bothered" to the original color. Looks a tad better.

Before:

Horrible CB750 K2 18 Apr 2021 9b by Terry Prendergast, on Flickr


After:

Horrible CB750 K2 28 Apr 2021 1 by Terry Prendergast, on Flickr

Before:

Terry’s Horrible K2 Engine Autopsy 16 Apr 2021 6 by Terry Prendergast, on Flickr

After:

Horrrible K2  weekend 2-3 May 2021 by Terry Prendergast, on Flickr

Yesterday after work I used some "Plastigauge" to measure the main bearing clearance, torqued the cases down and then tonight, being freezing cold and wet (what a change from the warm sunny weekend) I undid the bolts, separated the cases and measured the plastigauge and was 'rapt that the clearances were all around .001-.0015", which is perfect, the factory manual allows up to .003" before the bearings need replacing, but these ones are fine, and have saved me some much needed bucks, as I'm bleeding money on bike parts at the moment, and (supposedly....) this is a "Budget Build". The big end bearings are great too, so more moola saved, to be redirected to shiny stuff that can be seen.

I've had the cylinder block in and out of the ultrasonic cleaner, and along with some wire "bore brushes" that mount in my little DeWalt rattle gun, I've cleaned all the corrosion off the fins, and it's silver again.

I heated them up in my industrial oven to 400 deg F, and the old rusty sleeves fell out. Sadly some oil that must have been trapped betwixt the sleeves and the block came out too, so back in the ultrasonic cleaner it has gone.

Horrible K2 engine rebuild 5 by Terry Prendergast, on Flickr

But that's OK, tomorrow I'll shove all the guts back in the bottom end and (hopefully) bolt it all back together, then start thiinking about boring out some sleeves to 65.5mm (849cc) to suit my Cyclex big bore kit. Should be good!

Horrible K2 engine rebuild 4 by Terry Prendergast, on Flickr

   

   

[PeWe]

I think you are a CB750 total restore and build addict!
I'm sure you'll find new projects when the ongoing are done.

Good that the bearings were OK.
I got a little bit loose fit on both my K6 and K2. 0.002"  which was good for oilflow, especially for a modified engine according to other threads on the forum. 
Shop manual recommend 0.008-0.0018", service limit 0.0032".

Used green, tested with brown but not much differed when measure.
Oil pressure OK.

[Terry in Australia]

Yep, the next build/s are already in the works Per, I have another K1 engine on its way down from Brisbane for my 71 frame, the Suzuki T350 frame is being blasted so I can paint it before everything arrives from the US, and as soon as a member here sends me the RC 970 kit I’ll order a cam, rods, primary chains etc from CycleX. Always something to do around here.

[algophobe]

i'm starting to read your post with an australian accent in my head. nice job. pretty amusing (no offense)

[PeWe]

About primary chains.
CycleX chains look like the timing chains for BMW my K2 got.
 BMW 530 1998 68 link chain  Iwis catalog: searched on the G67HP-6 and 50035085 and got 11.31.2.248.729

Here the primary chain thread.
The strongest ones like Classic Cycle City sold and my K6 has are not available as car chains in correct lenght.
Here photos when I compared all 3 chains.
- BMW timing chain (68 links)
- Stock CB750
- Classic Cycle City ( this chain has changed around +0.5mm in slack since mounted 28000 km, 80 - 93 whp, mostly 90+)

Before order an expensive chain look at the photos and compare. I cannot see any difference between CycleX and BMW chain except for the price. The actual BMW chain fits other cars too.
http://forums.sohc4.net/index.php/topic,154183.msg1806548.html#msg1806548