DKW Engine Progress

I have made some progress on the DKW engine build.  It's been a fun process, but I have run into a few "issues" here and there.  But nothing I couldn't overcome.

Step 1 was reassembly of the clutch.  Top photo shows the assembly back together.  Middle photo shows it being assembled.  Getting all the "teeth" on the discs and basket lined up, while keeping the springs in place was sort of comical.  And realize this entire assembly is about 3" in diameter, so lots of fiddly little parts.  The third photo shows the entire assembly spread out.  Like other moto clutches, this uses a series of discs and steel plates, that all clamp together.  This way you can fit more clamping area inside a small diameter.

Then I got some of the internals installed into one half of the engine case.  I had to buy a few NOS parts, including a new 1st gear, new layshaft, and of course all new bearings and seals.  Doing the bearings was actually kind of fun.  Stick the cases in the oven for a few minutes so they expand a little, and slip the bearings in with a little bit of pressing.  Then as the cases cool, the bearings are nice and snug.

I took a lot of photos during disassembly, which was good.  The factory engine manual is very helpful, but in a weird 1970s translated german to english sort of way.  So a few sentences are confusing, and the terms they use for various shafts and shims made me scratch my head a few times.  But everything went back together fairly easily.

The only real problem I ran into was there were apparently many different types of 1st gears, which was the only gear I need a replacement for.  The original had a tooth knocked off.  My 5-speed engine needed a 106-100 part#.  The guy I bought the NOS parts from accidentally sent me a 106-200, which looks identical.  But when I finally got around to fitting it, I realized it must have been a 1st gear from a 6-spd trans, as it was thinner.  Luckily my source down in LA sent me a correct gear asap.  But when I got it, it was labelled 106-000.  It was the correct thickness, but the back side of the gear was lacking a small chamfer cut into.  Without this chamfer, the backside of the gear lightly rubbed the aluminum case on the inside.  Long story made even longer, my new little Mini-lathe came to the rescue.  I chucked it up, and was able to cut a light chamfer into it, so it fit just fine.

At this point, I pulled out my NOS gasket kit.  As the seller mentioned, the gasket we're laying very flat anymore.  He didn't charge me much for a full kit, and it included the seals too, so I was expecting to have to recreate a few new gaskets.  The big center case gasket was indeed shrunken a little bit, making it so that all the bolt holes were not lined up.  So I scratched my head, and set about making a new gasket.

I used a spare wooden shelf board, and marked and drilled all the case bolt holes into it.  This way I could stick the case bolts through it, based on their real position using the case as a guide.  Then I carefully stretched the NOS gasket over the bolts, and marked around it.  Then I trimmed the new gasket out with a razor, applied a tiny bit of permatex to one side of the case, set the new gasket on it, and let it sort of bond for 30 minutes.  This helped it lay out flat, and kept all the holes in position.  The last step was to turn that side of the case upside down, and fit onto the case half with all the gubbins in it.  I was expecting this to be a pain in the arse, having to line up multiple shafts, multiple case holes etc., and fight a gasket lining up.  Reality was it just slide down and fit easy.  Sorry for the random order of the following four photos.  Sometime blogger has a mind of its own.

DKW Engine Removal

Snatched the motor out of the DKW this morning. It had a little water in it, but hopefully enough trans fluid to keep demon rust from forming. The brown milkshake was fairly clean, and easily washed off the clutch side of the engine.

Combustion chamber shows signs of abuse, and the piston is a bit tattered around the top ring land. Pin came out easily enough, and the small end needle bearing looked great.

And either the intake ports have been ported, or ze germans did some clean up work at the factory.

Suzuki K10P - Top End Assembly

I did a bunch of top end assembly work this afternoon on the Suzuki engine.  New piston, piston pin, clips, rings, base gasket, cylinder head gasket etc.

New standard size piston with pin, clips and rings

Top end all together, with great compression just turning it over by hand

Suzuki K10P - Engine

I snatched the engine out of the K10, and threw it on my little bench mount.  Overall condition looks excellent, with just a bit of corrosion around the piston.  Cylinder head and combustion chamber were very clean, and the ignition side of the engine looked very tidy too.

A crazy little carb.  "Huay" brand, with a tiny little throttle barrel

Cylinder head came off easy, and piston/jug are free to wiggle a little

Clutch cable is on "driver" side, pushing the little rod just above gear shift shaft 

Miyata Details - Stripping and Cleaning

I've spent the past week doing all the dirty work, cleaning up old grungy parts and stripping paint. My least favorite activity in a restoration project. But I've made good progress, especially yesterday and today.

The hardest part to strip was the frame. Lots of little nooks and crannies to get into:

By comparison, the engine cleaned up nicely. I pulled both the magneto side and clutch side covers off, so I could clean them inside and out. I decided not to take off the cylinder, since it looked so good. I did, however take off the cylinder head and decarbonize the combustion chamber.

Chris H.

Miyata Details 1

I couldn't help myself. I wanted to see the condition of the top end on the Miyata Engine. It turns over very nicely, so I knew it wasn't frozen up. As it happens, the cylinder looks fantastic. Very clean bore, no scoring at all. And since I don't have any specs, I was curious what type of carb it runs, and what spark plug. Of course the spark plug has likely been changed, and who knows if it is the correct one. But at least I know the thread pitch and reach are correct.

Interesting combustion chamber shape, with offset plug location:

Amal carb? Really? An Amal 392 to be specific. I'll have to research this monster to see how big it is. PS: I don't have big hands, so you can compare the size of the inlet to my thumb in this pic:

BTW, the spark plug was a Champion L90C. Which corresponds to a NGK B4H.

Edit: For Sean and Mr. A:

I did some google searching on the Amal 392. I found this posted on the VJMC list:

"To help aid in identifying what might have used this 392 Amal I have posted

photos and they are in the 7th group on first page. 20mm bore on mounting
flange with a bolt spacing of 38mm. Thanks for your interest and help.

Wally Skirman"

Kawasaki Engine Install

I got the top end assembled on the Bushmaster engine, and then promptly tossed it in the chassis. It went surprisingly smoothly. Pics below:

I built the front fork brace last weekend, but never painted it. I should get by butt off the couch and get that done today, while the weather is dry.

C'

Kawasaki Engine: Top End Unfreezing

After just a couple days of soaking the piston/cylinder with ATF, the Kawi engine magically unfroze itself. I gave a gentle turning of the flywheel, and it just decided to turn over. I pulled the cylinder off, then drove out the piston pin and removed the piston. I'm now soaking the main crankcase chamber with ATF.

Exciting photo of a clean piston and a dirty engine case:

C'

Kawasaki Engine: Top End

I pulled the cylinder head off the Kawi engine late yesterday, then mounted it to the work bench. It isn't nearly as bad as the BS-7 engine was, but it is frozen. I think a bit of soaking with ATF will help free it up. In fact, I know it will, as I'm already seeing some ATF leaking past the rings and out the exhaust port.

I was lucky in that the flywheel pulling tool for Honda 50 engines also fit the Kawi perfectly. And talk about grimy! The flywheel was massively encrusted in a pasty sort of acid/rust crust. I will need some sort of puller to get the stator off though, as it sits too far inboard of the engine case to get a screwdriver under.

C'

Bridgestone BS-7: Engine Assembly, Back in Frame

I spent some time out in the garage yesterday, cleaning up engine cases, stators, and the cylinder barrel and head. By the end of it, I had an assembled engine ready to go back in the bike. First thing this morning, I got the engine mounted up.

Fan side of engine:

I also got the read wheel assembly re-mounted. The bike didn't have the proper rear axle spacer when I got it, so I had to modify a Honda part to fit. The space needed to be cut down a tad shorter, so the wheel was centered side-to-side properly, so the sprocket would line up with the sprocket on the engine:

Clutch side:

C'

Bridgestone BS-7: Inside the Engine

In preperation for some engine case cleaning and polishing, I pulled the left side case cover off. This is the case that covers up the clutch. It also houses the clutch depresser thingy the clutch cable attaches too (it pivots and moves inward to release the clutch.) And, this is where you fill the engine with oil, and drain it. So I was expecting some amount of gunk buildup. this is what it looked like:

Inside of case:

Looking at the end of the clutch basket:

View from under the clutch basket, showing the drive gear:

I didn't clean anything. Not even a wipe of a rag, or a spray of degreaser. Everything looks great.

C'

FV "Big" Engine Kablamo Teardown

Roughly a year ago, the "big" engine I had built for the FV went kablamo. I think I over-revved it on a downshift into Turn 14, as I heard a slightly off pitch sound. Then across the finish line it went kablamo in a big way. I found a hole in the block, a loose piece of piston ring, and some chunks of random aluminum.

In anticipation of taking my 1200 motor up to Oregon for Mr. A to rebuild (it isn't broken, just needs a freshening) I needed to grab the flywheel and clutch assembly off the kablamo engine. So I set about getting the car into position for working on:


After an hour or so of work, I had this:


Hello hole, how you doin?


Rockin' the headband and dirt knees:


Cylinder #3. That is what remains of a piston, piston ring, and connecting rod:


Buckets of bits, and a handful of rod, complete with piston pin still attached. I'm thinking the piston took a beating:


The other side of the engine, cylinders 1 and 2. Lots of debris in the cylinder/combustion chamber. Looks like some carnage from cylinder #3 got pulled through into the intake path:


I'll probably split the case apart tomorrow, to see how much carnage the crank and cam suffered.

C'

Bridgestone BS-7/D Engine "Unfrozen"

After removing the piston last night, I had decided to soak the crankcase on the Bridgestone with a mix of ATF and Acetone. This seems to be an internet phenomenon when it comes to a cheap and extremely effective penetrating fluid. As it happens, the Bridgestone BS-7 engine lent itself to this treatment because the center portion of the case that the crank rides in seems to be completely sealed. There is even a tiny little drain plug bolt under the engine that drains just this chamber.

So I filled up this area with the ATF/Acetone mix and let it sit for about an hour. I intended to soak it overnight, but after an hour I went out just to see how much I could rotate the crank. Before the treatment, I got about 5-degrees of rotation by turning the cooling fan back and forth by hand. After an hour, I was able to get another degree or two each time I went back and forth. After a minutes I got about 45-degrees of rotation.

So I let it soak a bit longer, then was able to turn it over a full 360. I drained the old fluid, added fresh fluid, and rotate the crank over several times. After a couple minutes, it turns freely with a single finger's worth of "force" on the fan assembly. I snapped a few pictures.

Central galley where the crank rides:


Circumference of crank is very clean, with no signs of corrosion. The needle bearings on the big end were even shiny:


A bit more progress each day.

C'

Bridgestone BS-7/D Engine "Unfreezing"

The engine on the BS-7 was a bit stuck, so I had been soaking the upper end in penetrating fluid for a couple weeks. Thanks to a little mount I built, I was able to have the engine sitting "piston up" on my work bench. And luckily, the piston was high enough in the cylinder that the intake/exhaust ports were covered up, so the penetrating fluid was able to do its job.

I was able to move the cylinder a little bit by hand, but I needed a little bit of persuasion from a simple puller tool. Thanks to the longish cylinder studs, I was able to pull up on the barrel using a gear puller. I was very careful not to pull up on a cooling fin, and instead used the beefier intake and exhaust port castings:



Success! Don't be fooled by the color of rust, the cylinder is surprisingly free from corrosion and scratches. I think it will hone quite nicely. Also, the piston is very clean too. The piston pin clips are a bit corroded, so I'm soaking them in fluid too. I'm thinking a set of clips from a Honda 50 engine will work as a replacement:


The engine isn't entirely "unstuck" yet though. The connecting rod only moves a little bit with light pressure, so I'm assuming the bottom end has some corrosion issues too. Which is somewhat surprising, as the oil I drained out of it looked perfectly clean. It looks like this engine will require some internal work to bring back to life.

C'