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Discussion Starter · #1 ·
Hi all,
I found this site looking for a good place to ask questions about my current project: a CB175 K6. I found it in a barn about an hour from where I live. The seller said it hadn't moved for thirty years and it sure looked like he was telling the truth :shock:. The odometer reads 3300 miles. So $400 later, I hauled it to my dad's basement where we will be working on it together. He's got a mini-workshop where he restores vintage British bikes - this will be a learning experience for me and probably a piece of cake for him!

Current status: Engine turns over fairly smoothly, but does not fire (duh). Front brake frozen. Battery long gone. We took the carbs and tank off and everything is pretty gummed up. Gearbox seems okay, clutch is rough. I'm planning to just get it cranked up for now until I come back home again after the fall semester. Then we'll do a full rebuild. I've been reading the Honda shop manual floating around online for 125/175's but it's only for K0-K4's. I'm hoping the K6 isn't too different. A Clymer's manual is currently in the mail too.

I've been trying to find information about part interoperability with other Honda's of the same era but I'm having some difficulty. Parts for the bigger twins seem to be a lot more prevalent out there so it would be nice to know what's interchangeable and what isn't. Anyway I'm looking forward to learning a lot from here as I go along, thanks to all for being so helpful and friendly!
 

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Sensei
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Welcome to the group!.....

As you probably know by now, the Hondas won't run without a battery....You can fire it (just to see/hear ) without carbs or a fuel tank though.....

However, after a long "sit", the 175/200 twins are particularly likely to "eat" the camshaft and /or journal on the left-hand side (points side), so I recommend you forego the pleasure of hearing it run until you take steps to assure that won't happen.
I'll be happy to detail my proceedure to do this if you like.... Fairly simple, and it makes things easier when you do tear into it..... Steve
 

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Discussion Starter · #4 ·
Thanks guys.
I believe the emblem is from a dealer or something, not quite sure. I haven't gotten to the tank yet but when I do I'll see what it takes to get them off.

Steve, I'd really appreciate it if you could explain how to check for an eaten camshaft. Does it require taking the head off? Does the engine need to come out of the frame?

We hosed the bike down today, first with a degreaser, then kerosene, then a stronger, caustic degreaser and then water. There seemed to be some cooked oil on the engine which worries me a bit. I hope there's no major oil leaks. Also, is there a way to tell whether there is oil pressure?

Well I'm going to look up a part source for gaskets and O-rings and such. Feel free to recommend your favorites :)
 

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Sensei
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Camshaft check...Start by draining old oil..... look for shards/bits of "shiny" in it.....replace drain plug.....remove engine from frame and set it "rolled forward" so the intake valve adjustment caps are "up" (I put a 2X4 under the exhaust valve adjuster caps to keep it "level")... remove intake side caps.... Fill with a 1/2 &1/2 mix of kerosene and transmission fluid until adding anymore will overflow (more on this later), allow to sit/soak 24 hours.....Tilt engine back to its "normal" position (as it would sit in the frame) and sit/soak another 24....Drain mixture, flushing once with kero....This accomplishes two things...It cleans the camshaft /rockers/journals of burnt on oil, and makes inspection easier, and the second "sitting" will pre-clean/ free up the clutch plates and lower end.....
Inspect camshaft at journals for visable wear, especially if the old oil contained metal particles... ANY axial space between the camshaft and journal is a bad sign, and will require some further tear down (I recommend you do the tear down anyway, it's simple, good practice, and you'll be sure you are riding a "fresh" reliable engine...but it's your choice)....
If you decide to run as-is, waste a qt of clean oil kicking the engine through to pump it throughout the engine, and drain it too.... This will clean out any 'trace" kero and mung.....then Add fresh oil to proper level.....If you opt for disassembly, we'll continue in the next posts.....(find/order a complete gasket set )
 

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Discussion Starter · #6 ·
Thank you Steve!
Unfortunately I don't think I will have enough time to tear down the engine before I leave. I really don't want to do it and then leave it in pieces for three months and come back to it in the winter. If I break it down I'm going to put it back together within the month.

I'm trying to get in touch with my local dealer. They have a great parts diagram listing for the CB175K6.. I just don't know if all the parts listed are actually available. Does anyone have any experience with Motions in Marietta, GA?

Since the mufflers are completely rusted out, I cut them apart from the headers. But unfortunately one of the headers is smashed in. It's a pretty serious dent. I don't know if we will be able to repair it, but I'm trying the freezing/thawing method now and we'll see what happens. If it's a no go... well I'll have to continue on my search for new headers I guess :( .
 

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You won't find any "new" headers - as you've already dicovered, they're one piece units, integral with the mufflers.
i have a pair of sawed off headers, but they are pitted. Don't think they have any gouges or anything though......
They're the same as CB200.
 

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That method does work on newer, thinner headers, but I'm not sure on yours. Especially if it's a "double walled" style of pipe.. The vintage pipes are usually somewhat thicker than the new stuff like my motard has. Good luck though, and post up your results if you can.

GB :mrgreen:
 

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66Sprint said:
Camshaft check...<<snip etc etc etc>
Excellent - copied that and sent it to my dad so he can rinse out our CL175 project.

I just ordered an engine gasket set from here:

http://cgi.ebay.com/ebaymotors/ws/eBayI ... 0167798443



I've dealt with him before - no problems other than of course the long wait for shipping. Caution if ordering multiple items - he does not combine shipping.
 

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Discussion Starter · #11 ·
That's the best price on a gasket set I've seen yet. I ordered one too. Thanks for the link.

I got started on the fuel tank today. It was pretty gummed up. I wonder if that engine gasket set includes petcock gaskets... probably not. I'll need to find those now.
The dealer hooked me up with some parts today. They said they'll call if anything is unavailable so we'll see.
As for the bent header, yeah, I think these pipes are a little too thick for the expanding ice trick to do its job.
Bill, do you have any pictures of those sawed off headers you mentioned earlier? I'm interested. :)
 

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Sensei
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It's in the straight section, so you MAY be able to drive something up to expand/make it circular/cylindical again...I'd just replace it....
 

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Here are some quick photos of the pipes.
They're not all that bad, I guess - no big scratches or dents, but there is rust/pitting.
I've done nothing to clean them up at all - I had a pair of slightly better ones that I had re-chromed (OUCH !!$$$).
There's a bit of white paint on one, that's what you see in the photo.

PM or email me if you're interested..........I could run them through MSR and get rid of all the rust for you if you want


 

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oofnik said:
That's the best price on a gasket set I've seen yet. I ordered one too. Thanks for the link.
You're welcome - let us know when you get it. It LOOKS like the right thing and the price is right. I noticed on my C70 Passport that some parts from overseas are 'amost' right due to differences in years and Asian vs North American market. I figure for the price if there are a couple pieces that don't fit I'm still OK (all I need is head and valve cover gaskets).
 

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Hey, guys. I'm new, but I've been reading as fast as I can. Just brought home a 1971 CB175K5 that I hope can be my daily driver before the end of the season. I'll get it up in the Project Logs soon (and in Parts Wanted, of course...)

For now, though, as I dig in to it, I really wanted a little more info on this process...

66Sprint said:
... remove intake side caps.... Fill with a 1/2 &1/2 mix of kerosene and transmission fluid until adding anymore will overflow (more on this later), allow to sit/soak 24 hours.....Tilt engine back to its "normal" position (as it would sit in the frame) and sit/soak another 24....Drain mixture, flushing once with kero....
My questions are these:

How much mix should I prepare? I don't want to buy more than necessary, for $$ reasons, and because it's a pain for me to properly dispose of it when I'm done.

And does it really fill full enough to soak the whole clutch basket? Sounds genius!

Thanks for the help
--Mark
 

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The most "parts cleaner solution" you should need would be about a gallon...(two qts trans fluid, two qts kero)....You may have to add more after you stand it back up, (pull dipstick to check you don't overflow AFTER you stand it)..... This fluid will "drop" the mung it picked up if you let it sit for awhile.... I have 2&1/2 gallons in a large drum that I just submerge entire engines (minus electrics) in......After it sits, you slowly pour off the "clean and clear" and only have to dispose of a small amount...Save the rest for general parts cleaning and the next time.....LOL....
 

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Discussion Starter · #20 ·
Update time. I got the bike running. :mrgreen: :mrgreen:
It was surprisingly easy to start. I just bolted everything back on and it started right up. I forgot I had the throttle screws in all the way so it shot up to 4000 RPM right away after sitting for 30 years :shock: but I got that ironed out quickly. Everything inside the crank sounds pretty good from what I can tell - no knocking or bearing noise. I'm just waiting on a set of Roadhawk mufflers I ordered from CRC2. I ended up taking Bill's headers but it seems that his come out about 1/4" lower than the stock pipes, despite being marked CB175 which is very odd... very little clearance to mount mufflers but I'll figure something out for sure.

I'll be heading up to Chicago for the semester in about a week, and the bike isn't coming with me :(. But I'm planning on doing a full engine rebuild when I come home again in the winter. In the mean time I'll be riding my 50cc moped from the 70's. I'm sure some of you guys on here will remember these things :lol:

Anyway thanks to everyone for all the help - especially Bill - this is a great site with great people!
 

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