Topic: '73 CL350, project "Lola"

[Frankenkit]

boy I hope not, but I suppose I oughta take a look.   Do you think I need to worry about the blackness on the one plug?  It seems to have a texture like old varnish or semi-dry spray paint... other than that I'm not sure what to think.  (if it's oil or just gas fouling) The fact that the air mixture screw didn't seem to have much effect when more than 1 3/4 turn out tells me something in that circuit is awry as well, but I don't know that that alone would cause the ... erm... black and white results we're seeing.

[Frankenkit]

ok, I do see one thing going on. I drained the tank and took it off to get a look at the throttle cables, because when I turned full lock left, the rpms would rise to 3k. @ full lock left, the left idle screw wasn't even touching its base. So I'm going to adjust and sync the cables again (hopefully...) and see if that gives me more leeway. Still doesn't explain the bogging idle, but it explains just a fraction of the weirdness going on.

I wish I were just a little better at getting the carb throttle arms to raise and lower at the same time.   Anyway, Paul, I will prove to you that I really was paying attention when you were showing me how to do what.  Also, I really want to point out that I wouldn't d!ck with any of Paul's settings without really good reason because his judgement is probably way better than mine.  His experience is certainly greater. 

...also... I hope I'm not screwing things up by trying to fix this high throttle at full lock left/tight throttle cable thing.   Still don't know what to do about the (possibly?) gummed up idle air mixture screw on the left... or the way the right runs cooler and richer (oilier?) than the left... but I'm hoping that by just getting the throttle cables synced (turning the adjuster @ the handlebars for more slack down below, then adjusting tension@ the carbs) the other stuff might work itself out with time and energetic riding.  I AM checking the diaphragms for pinhole leaks, though, just in case.  There are none in the left, however.  We'll see about the right.

[Frankenkit]

ok. Dun for tonight.  Checked right carb diaphragm for pinholes and saw none there, either.

Synced the cables again.  I've read of two or three different ways people do it- watching both, listening for both, and watching one while having your thumb on the other.  I used all three of those methods many, many times to make sure they moved simultaneously.  Then I adjusted for the amount of slack I created at the handlebar by putting the throttle screw a full turn in on both sides. Might be a little much. I guess we'll see.  The amount of 'room' in terms of open threads up by the handlebar is now pretty much the same as it is on my 650, so I could turn it out about half, maybe a full turn while warming the bike up, and throttle sleeve play seems reasonable, again the same as my 650's @ about 1/4".

I left the tank off tonight though just in case anyone had any other ideas for what I ought to check.  I really, REALLY hate the way those tanks go on and off.

While I was out there, I started pondering my coils.  How exactly would I test for poor coil output?  Just ground the spark plug against the engine and hit the starter?  IIRC, both of my coils are the originals and the right (the side that is prone to fouling) had the wire glued in rather messily.  It would explain to me why it seems one cylinder drops out occasionally when the bike's warm, but would it explain why it seems so hit-or-miss when it actually does it?  Unfortunately, it only seems to happen when I'm trying to ride it, so maybe MickeyX is right, and the main fault source is the nut that connects the handlebars to the seat.

One step at a time, though.

[Hush]

Neither of those plugs look right? But it could be something a lot deeper that fiddling won't cure, like wear on the rings!
If it was me I would buy two new plugs and put some miles on them, then pull them and see the results.
It could also be something as minor as a blockage in the carb galleys but the only way to cure that would be the removal of the carbs and a good dunking in some carb cleaner.
Yes Kit I know you cleaned them already but a small bit of crud that suddenly moved from the tank or gas line could cause that too.
Question, what would happen if say you swapped the coil HT leads across and the LT leads as well, twin cylinder technology is in my past so I'm guessing this might work to test the faulty coil theory.

[paulages]

Hey kit- New condensers? I don't think we changed them when I did the tune-up before, as we were focusing on the carbs. Bad condensers can cause all kinds of problems, though I'm not sure the effect they'll have with the HM ignition, as they seem to serve less of a function in that system.

Honestly, I think you're on the right track "fiddling" with what I did. You really need to understand the tune-up procedure on this bike so you'll be confident riding it around reliably. Those diaphragms weren't torn when I rebuilt the carbs, so I'd be really surprised of they are now. Those CV carbs can really be a pain in the ass... I've had carbs that came out of the ultrasonic totally clean, all passageways blew through cleanly, new pilots were installed, and there were still idling problems. Maybe the slide could be sticking?

Regarding your oily plug: I'd say you could have a poorly sealing valve, leaking oil into the cylinder. If I remember right, your compression wasn't great but was evenish between the two. No matter what I tired engine will never run quite right. Still, the temperature difference between the two definitely indicates mixture issues.

Would you be interested in borrowing a set of VM32s? If they work well, you might consider them an option...

[Frankenkit]

I suppose I could consider the VM32s but I don't know that I'm quite prepared at this juncture to spend that kind of $$ on this bike.  As far as I've seen, the VM30s and 32s cost in the ballpark of $300 new and I'm not sure how much more I can or am willing to put into the bike. I also understand vm32s to be just a bit much on a stock 350 motor, so we'd have to jet it way down, but I'm game if you are, I suppose.

In terms of the poorly sealing valve, is that something that I can just live with, or will it continue to be a problem that really needs surgical intervention?  If the bike only had 5000 miles on it (if the odometer and title are actually correct) could the compression be something that will improve with regular use, as the engine wears in?

The diaphragms weren't torn, so I closed the caps back up, after using a little seafoam deep creep on the slides and cleaning them up some. There was some kind of dirty residue on them.  I know it's a long shot, but does it seem plausible that I could unscrew the idle mix screw (after figuring out how many turns out it was) and use some compressed air on that orifice?  I know I'd probably want to open the carb bowl drain screw so as not to crush the floats with increased air pressure, but it's a last ditch effort to not have to take that godforsaken carb out. 

The condenser is brand new and not really used with the hondaman ignition.  I could disconnect it altogether and see what difference that makes. Are there any special allowances I need to make when running a remote fuel tank, so I can test stuff without constantly having to put the tank on/take it off? 

[paulages]

I suppose I could consider the VM32s but I don't know that I'm quite prepared at this juncture to spend that kind of $$ on this bike.  As far as I've seen, the VM30s and 32s cost in the ballpark of $300 new and I'm not sure how much more I can or am willing to put into the bike. I also understand vm32s to be just a bit much on a stock 350 motor, so we'd have to jet it way down, but I'm game if you are, I suppose.

In terms of the poorly sealing valve, is that something that I can just live with, or will it continue to be a problem that really needs surgical intervention?  If the bike only had 5000 miles on it (if the odometer and title are actually correct) could the compression be something that will improve with regular use, as the engine wears in?

The diaphragms weren't torn, so I closed the caps back up, after using a little seafoam deep creep on the slides and cleaning them up some. There was some kind of dirty residue on them.  I know it's a long shot, but does it seem plausible that I could unscrew the idle mix screw (after figuring out how many turns out it was) and use some compressed air on that orifice?  I know I'd probably want to open the carb bowl drain screw so as not to crush the floats with increased air pressure, but it's a last ditch effort to not have to take that godforsaken carb out. 

The condenser is brand new and not really used with the hondaman ignition.  I could disconnect it altogether and see what difference that makes. Are there any special allowances I need to make when running a remote fuel tank, so I can test stuff without constantly having to put the tank on/take it off?

Those VM32s I have are jetted exactly the same as the customer's bike I was telling you about that ran awesome with them. I understand not wanting to spend the bucks. They are spendy, though I'd consider selling those for cheaper if they work for you. My only plan for them is for the Commando, and I'm leaning towards new Amals anyway. Regarding the remote tank, no extra consideration necessary. Just get fuel to the carbs.

The valve won't reseal itself. It's probably carbon built up on the seat(s) or pitting from sitting. 5K isn't a lot of miles, but I've seen a lot of pitted seats from sitting for years with a valve open a bit letting moisture in.

[Hush]

Why not take up Paulages kind offer and borrow them to see if they cure the problem, it would be a true test to eliminate the carbs if the bike still runs crap.

[Frankenkit]

yarp yarp, there's some whispering going on in the background.  Stay tuned...

[Old75_ratafe]

Hey kit I know you don't want to consider the head gasket (not that those ever go out *whistles softly*) or bad rings.... But an easy way to check is to do a compression test...  Most major auto parts chains will have a loaner tool for that.

[MickeyX]

Okay, so to update this bike, she was firing off weird after a tune up, and not really running right at all. We left it sit for about 2 months because of Kit finishing school, her family visiting from out of state, gearing up to move into a new place and, honestly, it just pissed us off. So, today, when it's 97 deg F out, I decide to work in the hot ass garage. Yeah, I'm real bright. 

Anyway, I pull off the cover for the points thinking maybe it's a timing issue and see oil all over the one point. Like, drippy. I have no idea what that means. I cleaned it all off, cranked it over and she ran pretty well. I dunno if I did anything by cleaning that off or not but I'll take it. At least it's not backfiring weird now. It does seem to be running a pinch rich though.



 

[MickeyX]

I think we'll also check up on that loaner tool for compression check. It couldn't hurt. I know there are different sizes so would it be prudent to take a plug in to compare?

[paulages]

Okay, so to update this bike, she was firing off weird after a tune up, and not really running right at all. We left it sit for about 2 months because of Kit finishing school, her family visiting from out of state, gearing up to move into a new place and, honestly, it just pissed us off. So, today, when it's 97 deg F out, I decide to work in the hot ass garage. Yeah, I'm real bright. 

Anyway, I pull off the cover for the points thinking maybe it's a timing issue and see oil all over the one point. Like, drippy. I have no idea what that means. I cleaned it all off, cranked it over and she ran pretty well. I dunno if I did anything by cleaning that off or not but I'll take it. At least it's not backfiring weird now. It does seem to be running a pinch rich though.



 

I'd replace the gasket and o-rings associated with that side.. the o-rings that go on the rocker shafts can leak, and would definitely cause issues like you guys were describing. I'm pretty sure I have what you need at the shop.

[Old75_ratafe]

Okay, so to update this bike, she was firing off weird after a tune up, and not really running right at all. We left it sit for about 2 months because of Kit finishing school, her family visiting from out of state, gearing up to move into a new place and, honestly, it just pissed us off. So, today, when it's 97 deg F out, I decide to work in the hot ass garage. Yeah, I'm real bright. 

Anyway, I pull off the cover for the points thinking maybe it's a timing issue and see oil all over the one point. Like, drippy. I have no idea what that means. I cleaned it all off, cranked it over and she ran pretty well. I dunno if I did anything by cleaning that off or not but I'll take it. At least it's not backfiring weird now. It does seem to be running a pinch rich though.



 

I'd replace the gasket and o-rings associated with that side.. the o-rings that go on the rocker shafts can leak, and would definitely cause issues like you guys were describing. I'm pretty sure I have what you need at the shop.

Seconded sounds like you have a slight leak on the shaft seal for the points and it is causing the points to short.  When is the last time you changed the oil and are you using synthetic?  I'm not trying to start a syn vs conventional war here.  My CB750K when the oil is getting old and thin or if I use the more slippery synthetic will a weep a bit from our old gaskets in certain spots.

[MickeyX]

Bike porn...

[MickeyX]

More porn...

[Hush]

Cute bike, love the CB tank on it, clever....congrats to Kit on her graduation too....you two planning a road trip to celebrate?