Honda Twins banner

1 - 20 of 42 Posts

·
Registered
Joined
·
58 Posts
Discussion Starter #1 (Edited)
Working on a Candy Gold Metallic '75 CB200T as my first bike to restore.
Kind of debated on whether to specify the "lady wrencher" part but if it inspires more women to tinkering around with mechanics, then I'm all for it.
I'll be asking stupid questions and for sage advice throughout the project. I've already gotten great help on individual posts in other parts of the forum. You guys have been so awesome. Thank you.

So, I'm going backwards because I've already torn the bike apart. What started as "I'll just clean this bit of rust off of this fender" went straight to a million baggies of pieces. Having so much fun.

POLL : Should I split or not split the cases?

Granted I've never even taken an engine apart, should I not touch it and reassemble the bike back from here? (see pics)

Also, I'm not sure what is used here to seal the cases. If I'm encouraged to open the cases, what do I use to break this seal? You can see some of this liquid metal type stuff pooling on the engine mount area on the bottom case.

ToSplit001.jpg ToSplit002.jpg ToSplit003.jpg ToSplit004.jpg ToSplit005.jpg ToSplit006.jpg
 

·
Registered
Joined
·
13,085 Posts
What you see on the seam between the case halves is sealer from the factory. We don't know exactly what they used when it was new, but we use Hondabond/Yamabond/Threebond during re-assembly. First, do you have a known need to split the cases? Or is it just to be sure all is clean inside? No worries on any questions, the stupid ones are the ones you don't ask. We are here to help, we enjoy it and there are plenty of people here with a lot of knowledge from working at the dealerships during the era these bikes were new and current, so whatever you run into can be solved.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #3
Annoying left side engine mounting plate

Also, this is very annoying.
The bolt is blocked by the crankcase so I can't get this engine mounting plate off. No amount of jiggling is letting me "sort of bend" the bolt out. Seems like a very strange design to make one have to split the cases. I'd like to send this piece to get powdercoated. Do I need to cut the bolt and get a new one?

EngineMount001.jpg EngineMount002.jpg
 

·
Registered
Joined
·
13,085 Posts
Is the bolt somehow stuck in the left motor mount plate? Honda would never have designed something with that issue, they were much smarter than that. Seems like you could move the plate inward a bit and get the head of the bolt past the crankcase, then the plate would be free. I'm not as versed in the smaller twins, and never worked on a 200 but they are very similar to the 175 before it, and that has never come up in the 3 years I've been here. Worst case scenario, cut the head off the bolt and when you re-assemble the bike, put the bolt in the other direction
 

·
Registered
Joined
·
58 Posts
Discussion Starter #5
Thank you, ancientdad. That's really cool that people here have worked at the dealerships when these bikes were sold.

Well, to be honest, I was trying to pry the cylinder head cover off (not noticing the inset 9th bolt. I was looking at the diagrams so closely!) thinking the gasket was sealed stuck and put a screwdriver in. WRONG MOVE. I swore and sulked a couple of days because.... a piece of the screwdriver head broke off into the engine.....

I'm pretty sure I got the piece out in draining the oil out but I'm not positive. I also poked around as best I could with a tiny magnetic probe in the crankcase where the transmission sits and found nothing. But still, I'm not 100% sure.
 

·
Registered
Joined
·
13,085 Posts
First rule of working on vintage Hondas - Honda was much smarter than so many manufacturers back then and built their engines to be properly disassembeld wihtout ever having to force anything between parts and pry... I know it's after the fact, but this won't be the first encounter you'll have (since you want an older 350) and it's best to start early with little tips and understandings of these machines to make your future life easier. Yes, there will be extreme cases where parts are stuck together as if they are one, but it won't be that often - and never fail to ask here first before going beyond the point of comfort. There's always that little voice... :D at the age of these engines and the fact that the bottom ends of them were more reliable than the top ends for the long term (and taking into account bad ownership/maintenance, which kills top ends far sooner than bottom ends on these ball and roller crankshaft and rods bottom ends), so it can't hurt to go ahead with a full teardown. While you're there, depending on your plans for the bike, you should replace the cam chain if there are a lot of miles on the engine, and inspect the transmission gears and shift forks as well as the kickstarter mechanism and gears, since if decide to you keep it a while you'll never have to do that again and right now the engine is already out.
 

·
Registered
Joined
·
58 Posts
Discussion Starter #9
Fantastic. Thanks for the heads up. After I take the bolts out do I gently tap the cases open with a dead blow hammer? Or is there another recommended method?

Also, if I choose to cut the bolt to free that frame plate, should I buy a replacement bolt from David Silver Spares or can that bolt be found at a hardware store in the metric fasteners section?

I wish I had a sand blasting cabinet..... and vapor blasting looks so luscious.
 

·
Registered
Joined
·
703 Posts
What started as "I'll just clean this bit of rust off of this fender" went straight to a million baggies of pieces. Having so much fun.


Also, I'm not sure what is used here to seal the cases. If I'm encouraged to open the cases, what do I use to break this seal? You can see some of this liquid metal type stuff pooling on the engine mount area on the bottom case.

[ View attachment 295588
That's how it usually starts..

You seem to be getting on fine so far Snicks. Not at all sure I'd be rushing to split those cases - whatever that stuff in the picture is, it ain't factory, and looks like it could well prove difficult to split and/or be hiding a multitude of sins on the faces of the casings themselves. If you know or strongly suspect there are issues with the bottom end or in the gearbox, then you haven't got much choice, but if not, I wouldn't go there unless I had to.
My 2c.

Best of luck whichever way you choose to go though.
 

·
Premium Member
Joined
·
2,958 Posts
Is the bolt somehow stuck in the left motor mount plate? Honda would never have designed something with that issue, they were much smarter than that. Seems like you could move the plate inward a bit and get the head of the bolt past the crankcase, then the plate would be free. I'm not as versed in the smaller twins, and never worked on a 200 but they are very similar to the 175 before it, and that has never come up in the 3 years I've been here. Worst case scenario, cut the head off the bolt and when you re-assemble the bike, put the bolt in the other direction
Seems a bit odd. In all the photos I can find, the bolts are inserted in the direction shown here. I've removed those engine plates several times without coming across this issue. So far as replacement bolts go, I've just bought stainless bolts, getting the correct dimensions from the CMNSL website.
 

·
Premium Member
Joined
·
2,958 Posts
Not at all sure I'd be rushing to split those cases - whatever that stuff in the picture is, it ain't factory, and looks like it could well prove difficult to split
I'd disagree. That looks exactly like the stuff the factory used, based on two previously unmolested engines that I've been into. Having got this far into the engine you might as well carry on and split the cases, if only to give it all a good clean. Also makes replacing some of the oil seals much easier.
 

·
Registered
Joined
·
13,085 Posts
Seems a bit odd. In all the photos I can find, the bolts are inserted in the direction shown here. I've removed those engine plates several times without coming across this issue. So far as replacement bolts go, I've just bought stainless bolts, getting the correct dimensions from the CMNSL website.
I agree Richard - I can't understand why the clearance isn't there for the bolt to be normally removed, something unusual has to be in play here... but we didn't get to see the bike complete so we have no way of knowing what might have looked off when fully assembled
 

·
Premium Member
Joined
·
2,958 Posts
I've got a CB200 engine sitting on my bench in the shed, I'll risk hypothermia and have a look in the morning, see if the case clearance on that side differs wildly from the 175's.
 

·
Registered
Joined
·
703 Posts
I'd disagree. That looks exactly like the stuff the factory used, based on two previously unmolested engines that I've been into
I bow to your superior knowledge on that Richard.
Curious - why did they use that on the likes of the CB200 engine, but not the 360 and 450 for example ?
 

·
Premium Member
Joined
·
2,958 Posts
I guess it depended on the production line worker who applied the stuff, how much they used and how carefully they applied it.

Here's a photo of one of my 175 engines, not as extreme as the CB200 pics posted, but definitely similar. I've seen worse, but can't find a photo to back this up.

DSCF1746.jpg
 

·
Registered
Joined
·
58 Posts
Discussion Starter #18
Ha HA! The bolt is out and the plate is free.
Correct. The bolt's head was slightly bent.

Thanks Richard for risking your fingers and toes to check on the engine.

So, after taking out the bolts do I go about just tapping all around to break this factory seal?

FreedMountingPlate.jpg
 

·
Registered
Joined
·
3,537 Posts
You will need to roll it over it over to access the case bolts. Find a way to support it so it isn't sitting on the cylinder studs. There might be brackets for the starter cable. You should photograph these for reassembly. Make sure all the cast bolts are removed. You can compare against the Honda parts fiche. Once everything is removed, you can start to pull it apart. I had to find some surfaces on my 450 to lever it apart. It takes quite a bit of force to break it apart.
 

·
Registered
Joined
·
195 Posts
When it came time to pry apart the case halves of my 350, I used a putty knife. It's thin and broad, unlike a screw driver for instance, so it won't damage the casting surfaces if you tap it in gently and gradually. I found that once you break the seal a little in one spot, the rest of the case separates pretty easily.
 
1 - 20 of 42 Posts
Top