Topic: 64 cb77 resto-mod

[02z06dave]

I don't hear the noise you are describing, Dave.

Turn up the volume and listen close

[02z06dave]

After checking it out with the tappet covers off and plugs out, I can see that the valves are definitely not hitting the pistons. It appears to just be the sound of the valves closing.

I finished getting all the wiring done and have gone about as far as I can go until the ignition parts and carb bowl gaskets come in. I got the front and rear brakes adjusted and ready to go, but I'm failing on the clutch. It doesn't seem to want to engage.

I recently upgraded my cb450 with a bi-xenon hid headlight. I really like the improvement so I went with the same setup on this bike. I used an h4 conversion headlight from 4 into 1 and installed a 35w/55w 3000k bi-xenon bulb. Luckiky, these old twins don't have much in the headlight bucket, so i was able to fit the ballast and relay inside.

[Stev-o]

... but I'm failing on the clutch. It doesn't seem to want to engage.

Not sure I understand.  So, when you pull on the clutch lever, there is nothing happening?   Did you check the plates for sticking??

[02z06dave]

... but I'm failing on the clutch. It doesn't seem to want to engage.

Not sure I understand.  So, when you pull on the clutch lever, there is nothing happening?   Did you check the plates for sticking??

The plates are all new, so probably not sticking.  I probably just need to turn the adjuster some, but i can't get it to turn. I'll have to take the side cover off and get it cleaned and lubed up

[02z06dave]

I had a few minutes this evening to mess with the clutch some more. The adjuster in the right side has suffered some abuse at some point in it's life resulting in an inability to move within its bore.



I filed down the gouges and greased it up and it's moving again. Once back together, I was able to get it and the cable adjusted appropriately and the clutch is now working. 

I should have the rest of my parts by Thursday and will hopefully have a runner by the weekend.

[02z06dave]

My new electronic ignition, coils, and reg/rec came in the other day. I got them installed friday and finally had a chance to fire it up today. 1 of the coils is bad, so that's a bummer. It did run for a second on 1 cylinder. The metal on metal hanging noise was very loud so I shut it down pretty quick. I took the plugs out and tappet covers off and found my problem pretty quickly.



Left piston was hitting the spark plug. I don't even remember now which website had this plug listed for this bike, but it was wrong. I find it strange that the left was hitting but not the right. Anyways, from what I can see there's no damage to the piston. I did another quick search and found out which plugs are correct and I had some new ones already. I popped them in and fired it up again, this time just noisy valves. I adjusted the valves again, followed by a double and triple check and it's a little better now. From what I remember from my previous 305s, they are kind of noisy engines so I think it's fine. I just need to get another new coil and thing should be good to go.

[Stev-o]

Oh #$%*e!

[02z06dave]

Oh #$%*e!

That's what I said! I'm jyst glad I figured it out and there's no damage to the piston. I was about the start tearing it apart to drop the engine, when I decided to check on valve to piston clearance again and saw that plug

[02z06dave]

Here it is all together (except air filter tubes) after I took it for a ride down the street and back.





It was not a great ride. I got back with a list of issues to correct. Front brake needs adjustment as well as the clutch. Brake light is no longer working. It's leaking oil from the left side cover as well as from the oil filter cover as on the left side. It's not running well, needs the carbs adjusted. And the worst of all, the shifter is very stiff. I had to stay in first gear because I was unable to get the shifter to move. It shifted fine before the rebuild and I didn't touch the bottom end so I'm not sure what the problem is. I could move it into second gear by hand by yanking on it hard, but it should be easy. Hopefully it's an easy fix, but I don't know really where to start with it.

[02z06dave]

gear shift issue fixed. I just had the linkage set up wrong, the angle was wrong. easy fix

[Stev-o]

gear shift issue fixed. I just had the linkage set up wrong, the angle was wrong. easy fix

Thats good to hear, Dave.  The other issues are quite typical after a major restore...

[02z06dave]

gear shift issue fixed. I just had the linkage set up wrong, the angle was wrong. easy fix

Thats good to hear, Dave.  The other issues are quite typical after a major restore...

Yeah. I got through a bit more of the list pretty quickly. The brake light is going to be a bit of a pain. I've ruled out the switch, the bulb, the socket, the tail light sub harness and the connection in the headlight bucket. Which leaves likely a break somewhere in the main harness. I think rather than unwrapping the whole thing looking for the problem, I'll make a new little subharness to the switch and hook it up to known good connections

[MoMo]

You may want to check the gear change mechanism, possibly spring or selector detent problem....Larry

[jgger]

Check your breather hose for the crankcase vent. If it is misrouted it can get pinched off by the center stand stop when the stand is in the up position. That can cause all kinds of oil leaks. Happened on my CL72 and pushed out the seal on the counter shaft where the clutch pushrod goes through.

I believe the oil filter has a real skinny o-ring about the size of a rubber band, easy to miss.

[02z06dave]

You may want to check the gear change mechanism, possibly spring or selector detent problem....Larry

I got the shifter issue fixed. The linkage was just at thecwrong angle. Thanks for the suggestion.  I'll bank that one in case there's a future issue.

Check your breather hose for the crankcase vent. If it is misrouted it can get pinched off by the center stand stop when the stand is in the up position. That can cause all kinds of oil leaks. Happened on my CL72 and pushed out the seal on the counter shaft where the clutch pushrod goes through.

I believe the oil filter has a real skinny o-ring about the size of a rubber band, easy to miss.

I'll check on the breather hose. I hadn't considered that.

The o ring is in place on the oil filter it's actually leaking out of the upper 2 bolt holes. I was thinking maybe those should have o rings too that I forgot about, but I haven't looked into it yet.

[02z06dave]

I had some time this evening and got most of the issues worked out. It's still leaking a little oil but not as bad. After resetting the float height on the right carb, it now is running on both cylinders. When only the left was working, it was working pretty smoothly, now that both are working, the left side is popping through the exhaust at idle. I've checked and rechecked and rechecked the timing and it's spot on. I tried both advancing and retarding it and that didn't have any effect so I put it back to spec. I checked the cable sync and it's good. I have both slide adjusters turned all the way out and the slides are both even. I turned in the air screw about 1/8 turn and that helped, then another 1/8 and that seemed to fix it. I took it for a little spin and it popped when I was off throttle as it revved down towards idle speed. I shut off the fuel and let it run until the gas ran out. As it ran lower it popped more and more, only from the left. I'm wondering if maybe it's running lean on that side.  I'll check the float height and the jets on that side tomorrow.  I'm using stock jetting, which may no longer be right since I'm using the cl exhaust. 

Also of note, it idles rather high. The idle adjustment on the cable is all the way down and the slides are bottomed and it idles at around 1200. On my short ride, I noticed it also really bogs down once I get to around 4k-4500 rpm. This is my first real effort at tuning carbs so I don't really know if it's all related or all separate. I'm just going to try to tackle one thing at a time and hope for the best.

As soon as my gasket comes in, I'm taking out the new clutch springs and going back to the stock springs. They are way to stiff. It would be awful having to work the clutch constantly in stop and go traffic with it like this.

Just for fun, here's a quick couple pics of my 2 twins. A stocker and a rocker...

[RAFster122s]

Carbs are interesting things, sometimes they defy conventional logic.  I would say with some certainty you are running lean despite being at the same setting on the carbs.

Sometimes it is a result of one carb not being clean and the pilot or slow jet passages are not clean.

The popping on deceleration is a classic lean running symptom when you do not have a air cutoff type circuit in the carburator

I would pull that carb and pull the jets to run it through an ultrasonic bath of a good cleaner.  The Yamaha Carb Cleaner is very good and I like the purple Simple Green sold by Home Depot at a 50% concentration.  The 50% solution is safe on aluminum, the regular green Simple Green is very caustic to aluminum.

David

[02z06dave]

Carbs are interesting things, sometimes they defy conventional logic.  I would say with some certainty you are running lean despite being at the same setting on the carbs.

Sometimes it is a result of one carb not being clean and the pilot or slow jet passages are not clean.

The popping on deceleration is a classic lean running symptom when you do not have a air cutoff type circuit in the carburator

I would pull that carb and pull the jets to run it through an ultrasonic bath of a good cleaner.  The Yamaha Carb Cleaner is very good and I like the purple Simple Green sold by Home Depot at a 50% concentration.  The 50% solution is safe on aluminum, the regular green Simple Green is very caustic to aluminum.

David

Thank you! That was just what I was looking for. I'll get that carb pulled tonight and get started on it. Luckily for me, pulling and servicing these carbs is very quick and easy

[02z06dave]

I did a lot of research into the setup and tuning of these carbs last night. The experts say to use 135 and 42 jets in both the cls and CBs. So that should work for me since I have a cb with a cl exhaust. I opened up the carbs to find 140 and 42. I had new 135 and 42 on the table from the rebuild kits so I went ahead and popped them in. I didn't feel like pulled the carbs, so this was all done on the bike. The bike started right up and ran perfectly, no more popping. However, it was then leaking gas from both overflows. Dammit! I adjusted both floats and turned on the gas. No more leaking. Started up the bike.... popping from the left exhaust. I messed with the A/F screw and slide screws a little but nothing really helped. I'm off work tomorrow, so I'll pull the carbs and do a thorough clean and start over with ed Moore's special tuning recipe which is golden for these bikes. Hopefully, I'll have better luck tomorrow.

[Bodi]

Mine pops and backfires (with flames!) from one side when cold but settles down when hot. I've also checked everything and it seems OK, I will replace the insulator O-rings when I can and see what that does. Compression is good (150/150), timing is perfect (electronic ignition... I may try swapping coils and see if it follows but pulling the tank is such a pain with that crossover tube), carbs are clean and floats properly adjusted. It runs super well, no problems otherwise. Idle is all over the place usually high after a highway run, I remember this was rather normal when I had one around 1970 that I put thousands of miles on. There's no vacuum ports for sync so you use the "ears and hands on the exhaust" to do the best you can. I first balance by eye/finger so that the slides rise simultaneously with the throttle. You can just see both slides at the same time with the tank off but watching one with a finger on the other is easier.
It should idle way down with full-closed slides though, mine will idle down to stall. Are you sure the cables are slack? The idle screw taper is really short, I reshaped them on the long gone old bike (ie in 1970) for a slower taper. The slide does get worn where the screw hits, maybe that's hanging up somehow? A vacuum leak at the spacers will screw up your idle big time.

[02z06dave]

Today I pulled both carbs, thoroughly cleaned them and put them back together. 135 main jets, 42 pilots, needles 2nd from the bottom. I set the air screws 1 1/4 turns out and slides all the way down. Cables were synced so the slides move together. I started it up and it seemed to be running great. The idle was low so I adjusted the slides equally to get a steady idle. As it warmed up it ran worse and started popping out of the left exhaust again. Turning the air screws out to richen the mixture made it worse, turning it in made it better. Turning it all the way to only 1/2 turn out seemed to really smooth it out at idle. I took it for a ride and it really didn't do well at higher rpms and still popped on deceleration. Bogged down quite a bit over 4500. When I got back after about a 10 minute ride, it was back to popping at idle. And no amount of adjustment seemed to help. I checked for air leaks and had none. I'm not sure what to try now. I may swap the carbs and see if the problem follows the carb or stays on the left so I can narrow it down to a carb issue vs ignition. I pulled the plugs, both were black as could be.

[Stev-o]

Just throwing some thoughts out there Dave as I have no experience with this model bike/carbs.

A lean carb mix can cause popping on decel but plugs look rich, so thats a head scratcher.

Exhaust leak can also cause popping, did you check that?

Adjusting the air screws is no help, you certain the needles are set correct?

If the plugs are black, need to lean it out.

[02z06dave]

Needles are set to 2nd up from the bottom which is the stock position. There's a shop that deals with vintage bikes not terribly far from me. I'm going to just take it there. I'm sick of spending hours messing with it and getting no where.

[jgger]

Have you tried posting on the 305 forum? It's  not a lot of traffic, like this site, but there is quite a bit of knowledge there.

 http://www.honda305.com/forums/

Was doing a little reading over there, I'm not good at posting links but I'll try.http://www.honda305.com/forums/

Cruise through the carburation section, I found some odd stuff that might help.

[02z06dave]

Have you tried posting on the 305 forum? It's  not a lot of traffic, like this site, but there is quite a bit of knowledge there.

 http://www.honda305.com/forums/

Was doing a little reading over there, I'm not good at posting links but I'll try.http://www.honda305.com/forums/

Cruise through the carburation section, I found some odd stuff that might help.

I haven't posted there but I've read most if not all of the carb threads. In one way or another my issues have been covered before, I think I just don't possess the ability to sort out one of these old bikes.

I can't help but go out and tinker with it more. I put in new plugs tried to start from 0. I noticed the exhaust coming from the left was cooler than the right. significantly. I unplugged the left spark plug, no change in idle (except no popping). I plug it in and unplig the right, it dies immediately. Its definitely getting spark on the left and there is fuel in the bowl as well.  Basically, it's just running on the right cylinder with pops from the left. Somehow, getting the right cylinder firing killed the left. I suppose I'll try a compression test and check the valves and clean the carb again.