1968 CL175 repair and build

[medicalmechanica]

Re: 1968 CB175 repair and build

Alright, I removed the points cover and I'm assuming the advancer is the round thing that's right under it. I removed that and forgot how to replace it so that's a problem, and I found a yellow gasket that sits against the engine and is total garbage. Time to hunt for a replacement. Also in the last pic there's some substantial grooving on the end of the cam, is this a huge issue?

 

[adventurco]

Re: 1968 CB175 repair and build

The advancer is the unit in your first photo. If everything is moving smoothly I would just grease it and put it back. That cam looks pretty rough. Go to any Honda dealers website, look up your year/model and find the correct fiche (probably crankshaft or head) to find part numbers for the seal you need


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[medicalmechanica]

Re: 1968 CB175 repair and build

The advancer is the unit in your first photo. If everything is moving smoothly I would just grease it and put it back. That cam looks pretty rough. Go to any Honda dealers website, look up your year/model and find the correct fiche (probably crankshaft or head) to find part numbers for the seal you need


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Thanks!
I've actually made a gasket and I'm going to give it a shot tomorrow, and I learned how to set the points so I'm going to go ahead and fix the timing and change the oil tomorrow, and grab new spark plugs and (hopefully) wires, but I doubt I'll be able to find them in town. If my gasket holds up long enough to tune the carbs I'll be pretty happy, and we'll go from there.

 

[medicalmechanica]

Re: 1968 CB175 repair and build

So I made my own gasket, installed the points, replaced the oil, and now the bike isn't starting. When I kick it, it feels like it wants to stsrt sometimes, but ywo new things are happening.

The first one is that I can feel a kick back in the starting lever against my foot sometimes and that didn't happen before.

The second is that I'm hearing a strange noise when I twist the throttle while I'm kicking it, like a "patuung" noise, sort of like throwing a rock into water.

I'm pretty positive I set the points correctly using a circuit light, and I also rewired the connection from the coil because it was only working intermittently. Pics are attached, any ideas?

 

[medicalmechanica]

Re: 1968 CB175 repair and build

I've opened up the points again and they're way off. I did the cam chain adjustment, but now the point is opening way too early, so I reset it to the L mark, tighten down, and then when I come back around it opens way too early again. Kimda stumped.

 

[medicalmechanica]

Re: 1968 CB175 repair and build

Got the points in the right spot I think, and the kickback from the starter is gone. Still not starting though, haven't been able to figure out why.

 

[medicalmechanica]

Re: 1968 CB175 repair and build

One more thing, I watched some videos of the points and timing, and I wanna make sure I'm on the right mark. Attached is an image of the plate with the timing marks on it, and my point opens at the F mark. I read that it doesn't really matter when it closes again so I hope that's correct. Right now the point breaks at that F mark.

Because the bike ran a couple days ago I'm pretty sure that the plugs and wires are okay. I'm going to replace them anyway, but I'm thinking that the timing is the problem here.

Any advice would be great.


Edit: I buttoned everything back up for now, got some new spark plugs in, and I'm charging the battery again because I think kicking this thing all day may have killed it.

If anyone wants to chime in and let me know if the orientation of my points plate is at all correct I'd appreciate it, I don't see a mark in the casting of the kidney-shaped cover thing that tells me where it's supposed to line up. I have a feeling that may contribute to my point opening early on the intake stroke.

Again, any advice or input would be super appreciated. Thanks!

Edit again: I learned that this bike has a "wasted spark", or a spark on the exhaust stroke, and because I only have one point and both cylinders fire as they reach TDC I'm not so worried about my "Intake" picture below. I'd still like to know if I put the plate that the point is attached to on correctly though!

 

[teazer]

A couple of things. That is a 1968 one year model CL175 and not a CB. The giveaways are the fact that it's a 175 sloper and not the same as a sloper CB160, plus the high level pipes and that tank was only fitted to a CL175. Vintage racers love them because they are cheaper way to get 5 speeds in a sloper than welding and machining a set of CB160 cases.

Other than that, there's not a lot of interest or demand for them. The earlier CB160 is more desirable and later , so called vertical 175s were better engines for racing or fr the street.

Next: that can is stuffed. It will not run very long with that in there. The cam end support that you removed has to be a fairly close fit over the cam end to maintain oil pressure to the rockers and to the big ends as well. The cam needs to be removed and repaired and so does that end housing. You can convert the camshaft to a needle roller inner race and fit a needle roller cage in the outer hosing with some careful machining.

Points should open a certain distance before TDC with both valves closed ( on compression). Because it has a 360 degree crank, the points cam opens the points once per engine revolution anf fires the double ended coil each time. That's known as a wasted spark system. At tickover, it should crack open at the F mark 5 degrees or so before TDC. If it opens too early, adjust the timing.

If yiu don't have one, get a workshop manual.

 

[medicalmechanica]

A couple of things. That is a 1968 one year model CL175 and not a CB. The giveaways are the fact that it's a 175 sloper and not the same as a sloper CB160, plus the high level pipes and that tank was only fitted to a CL175. Vintage racers love them because they are cheaper way to get 5 speeds in a sloper than welding and machining a set of CB160 cases.

Other than that, there's not a lot of interest or demand for them. The earlier CB160 is more desirable and later , so called vertical 175s were better engines for racing or fr the street.

Next: that can is stuffed. It will not run very long with that in there. The cam end support that you removed has to be a fairly close fit over the cam end to maintain oil pressure to the rockers and to the big ends as well. The cam needs to be removed and repaired and so does that end housing. You can convert the camshaft to a needle roller inner race and fit a needle roller cage in the outer hosing with some careful machining.

Points should open a certain distance before TDC with both valves closed ( on compression). Because it has a 360 degree crank, the points cam opens the points once per engine revolution anf fires the double ended coil each time. That's known as a wasted spark system. At tickover, it should crack open at the F mark 5 degrees or so before TDC. If it opens too early, adjust the timing.

If yiu don't have one, get a workshop manual.

Thanks? I figured the cam was pretty close to dead, but I'm going to use it for a little while.

In other news, my bike finally fired and ran for a couple minutes, but the stator cover and the points cover were off, so I killed the bike and put all that stuff back on. Guess what? Doesn't start again.

A couple questions:

Should I be seeing sparks fly from the point? That doesn't seem right, my understanding is that the point opens and the arc travels between the gap.

Second thing, I had my plugs out and plugged into the leads and was getting a spark on the left and not the right. After I put the covers back on I was not getting a spark from either plug.
Am I correct in assuming that this is probably a faulty coil?

I'm pretty concerned about the sparks coming from the point, and since I've replaced the point rocker assembly with a new one I don't think that's the issue. Maybe the gap is way off or something?

I'm waiting on a service manual in the mail so hopefully that'll help

 

[adventurco]

The points will spark a bit, that's normal. If it looks like the Fourth of July, something may be wrong.

You can test coils with a multimeter., the plug wire lead and negative lead should give you a ~12-15k ohm resistance reading and between the two 18ga wires should read between 3k-5k ohms.

If you put the points cover back on and the bike wouldn't run, then your points wires are grounding out to the cover. Double up on gaskets or rearrange your wires accordingly.

As far as the cam goes, you should open up the top end and check the surfaces that the cam rides on. If you're lucky, the top end may be savable, and running that cam further may ruin a good head and rockerbox. I believe someone on here very recently had a similar problem but was able to source parts from eBay.


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[medicalmechanica]

The points will spark a bit, that's normal. If it looks like the Fourth of July, something may be wrong.

You can test coils with a multimeter., the plug wire lead and negative lead should give you a ~12-15k ohm resistance reading and between the two 18ga wires should read between 3k-5k ohms.

If you put the points cover back on and the bike wouldn't run, then your points wires are grounding out to the cover. Double up on gaskets or rearrange your wires accordingly.

As far as the cam goes, you should open up the top end and check the surfaces that the cam rides on. If you're lucky, the top end may be savable, and running that cam further may ruin a good head and rockerbox. I believe someone on here very recently had a similar problem but was able to source parts from eBay.


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Super good info, thanks! I'll have to do this tomorrow I guess. As far as the cam is concerned, I have had a quick look without totally tearing the engine down and all the surfaces I can see are fine. I have probably a month before winter is here and I'll be doing a replacement of the cam then, but I want to at least see if I can get it running before then.

 

[medicalmechanica]

Alright, I got the seat and the tank off just to have some space.

I think I tested the coil correctly. I traced a wire coming from the coil to a "Y" or a "pigtail" (I think), popped out the connectors and tested with a multimeter between those two points. Getting a 1.8ohm reading which I'm pretty sure is bad, and I was getting nothing from either spark plug lead and I know that's bad too.

I'm guessing I should just order a new coil, and they come with wires attached, correct? I've been seeing some talk about using an Accel one for a Harley or something, anyone got info on that?

Pics attached for reference, maybe I measured the completely wrong thing.

 

[adventurco]

So you have a single coil feeding both plugs, correct? 1.8 should be okay. Test resistance between the two spark plug leads.


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[medicalmechanica]

I'm getting about 13k ohms from plug wire to plug wire. I was also under the impression that the coil should put out about 3.5 to 5ohm, so isn't 1.8 hella low?

So you have a single coil feeding both plugs, correct? 1.8 should be okay. Test resistance between the two spark plug leads.


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And yeah it's one coil feeding two plugs. It looks like the universal options in the DTT shop will work if it's necessary.

It seems prudent to note that I'm seeing a spark from both leads but it doesn't look too strong.

 

[adventurco]

If you have spark then more than likely the coil isn't your problem. The value between the leads is good. 1.8 does seem a bit low but you need to check the values in the factory service manual. Generally if a coil goes bad, there's no resistance and no spark.


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[medicalmechanica]

If you have spark then more than likely the coil isn't your problem. The value between the leads is good. 1.8 does seem a bit low but you need to check the values in the factory service manual. Generally if a coil goes bad, there's no resistance and no spark.


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Well that's a relief, thanks! I may get a new coil and leads anyway because they're not terribly expensive and I am almost positive that I should have like 3ohms from the coil, AND the bike doesn't start even with some starting fluid.

That said, I guess I'm having a fueling problem. I'm okay chasing down wires all day for the most part, but getting a set of carbs to work is over my head. Here goes nothing I guess haha

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[teazer]

The trick with carbs is to get a couple of small containers - cold cut containers are fine or small baking trays and put one carb in each. Take your time to strip and clean them.

When you think they are perfect, get a can of carb cleaner or wd40 and spray it through one jet on one carb and repeat for the jet on the other carb. Is the spray the same on both?

After you are sure that the jets are all clean, repeat that process on the bodies. Spray though each drilling one at a time and compare to the other carb. That is the only way for most most of us to know they are clean. Pay particular attention to the tiny holes in the bore just in front of the slide. They clog and are hard to clean.

 

[adventurco]

+1. I use carb cleaner and compressed air first to blow out all the passages. It's worth noting to make sure that your jets have the same numbers stamped on them on both carbs, and that all the brass is the original stuff. I can't speak from experience but I know a lot of people have issues with aftermarket brass.


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[medicalmechanica]

I have a couple aftermarket brass bits in one of them, but that's kinda just what I have to work with right now, I'm going to have to get a rebuild kit too I guess.

I'm hearing some clacking while kick starting, it's happening at the end of the throw of the kick lever. On the CL175 the only place I can see something that looks like a cam chain tensioner is right in front of the engine, so I backed it out and screwed it back in, but it's still giving be a bit of a clicking noise. I'm going to adjust the valve clearance today and see if that helps, but if not I'm assuming I'll have to just tear everything down and replace the tensioner and the chain, is that correct?

If so I'll just go ahead and take it all apart and order the camshaft, tensioner, chain, and rocker arms I guess and rebuild the whole thing which I'd really prefer not to do.

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[medicalmechanica]

She started! A little spritz of starting fluid and a goose and she fired up. The bike won't start without full choke, and it won't continue to run without basically wide open throttle, but it's something. Does anyone have a source for like a writeup or a diagram of what each screw on the carbs do? I ask because I have no idea what any of them are for, and because my left carb is missing two near the top.

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Edit: I redid the cam chain adjustment and I'm not hearing the clacking, and I redid the points afterwards. I tried to get the valve covers off to adjust the valves but I don't have a big enough wrench and I don't want to round them off with a socket.