[MNellis]

I just got home from a 4 day, 2800 mile trip to the east coast and this carb problem that surfaced the day I left has bothered me the whole way. I got home and started the bike and, sure enough, it didn't go away while I was gone.

The bike starts much easily than it did before I took the carbs apart but the the idle just runs away to about 3500 rpm or so. I backed the idle screws all the way out and I can push down on the idle screws with my fingers and it will slow down to about 500 rpm but when I release the pressure it races back up.

When I disassembled the carbs I took the choke plate as well as the throttle plates out and removed the shafts. When they were going back together, it took some manipulating to get them back in there. Could I have not aligned the throttle butterfly plate up correctly? Maybe it's hanging up a little?

It's a pain to remove the carbs on the CL (have to move the exhaust out of the way) but I'll be doing that tomorrow. I just wanted to pop the question here first to get some thoughts.

Mike

 

[johnnyc14]

I think you're right Mike. Sounds like the throttle blades are not quite perfectly aligned in the throttle bores.

 

[tbpmusic]

Don't beat yourself up about tearing the choke and throttle plates out - you have no choice if you're going to do a complete dip-tank style cleaning, because of the nylon bushings on those shafts.

It is possible they're not "seating" properly.
You may also want to check the throttle cable "splitter" under the tank - it's fairly easy to sort of "unseat" the ends that go into that splitter when you put the tank on.

 

[MNellis]

Don't beat yourself up about tearing the choke and throttle plates out - you have no choice if you're going to do a complete dip-tank style cleaning, because of the nylon bushings on those shafts.

It is possible they're not "seating" properly.
You may also want to check the throttle cable "splitter" under the tank - it's fairly easy to sort of "unseat" the ends that go into that splitter when you put the tank on.

Right you are on the cable splitter. I checked that out the other day and one of them was pulled out. It's kind of a pain since it's pretty tight in there under the tank. Anyway, I put it back together but checked it again this afternoon and it was alright. I think I'm going to tape it up with some cool rubberized tape I picked up at the Oshkosh airshow last year. Neat stuff.

I'll pull those things off tomorrow and let you know how it goes. It's really exciting to see how quickly it starts up after the carb cleaning though. I haven't ridden it since I set the points, timing and now the carb cleaning so I'm anxious to try it out.

 

[johnnyc14]

Don't beat yourself up about tearing the choke and throttle plates out - you have no choice if you're going to do a complete dip-tank style cleaning, because of the nylon bushings on those shafts.

It is possible they're not "seating" properly.
You may also want to check the throttle cable "splitter" under the tank - it's fairly easy to sort of "unseat" the ends that go into that splitter when you put the tank on.

Right you are on the cable splitter. I checked that out the other day and one of them was pulled out. It's kind of a pain since it's pretty tight in there under the tank. Anyway, I put it back together but checked it again this afternoon and it was alright. I think I'm going to tape it up with some cool rubberized tape I picked up at the Oshkosh airshow last year. Neat stuff.

I'll pull those things off tomorrow and let you know how it goes. It's really exciting to see how quickly it starts up after the carb cleaning though. I haven't ridden it since I set the points, timing and now the carb cleaning so I'm anxious to try it out.

That's just rubbing it in Mike. We still have a foot of snow here!!

 

[MNellis]

Don't beat yourself up about tearing the choke and throttle plates out - you have no choice if you're going to do a complete dip-tank style cleaning, because of the nylon bushings on those shafts.

It is possible they're not "seating" properly.
You may also want to check the throttle cable "splitter" under the tank - it's fairly easy to sort of "unseat" the ends that go into that splitter when you put the tank on.

Right you are on the cable splitter. I checked that out the other day and one of them was pulled out. It's kind of a pain since it's pretty tight in there under the tank. Anyway, I put it back together but checked it again this afternoon and it was alright. I think I'm going to tape it up with some cool rubberized tape I picked up at the Oshkosh airshow last year. Neat stuff.

I'll pull those things off tomorrow and let you know how it goes. It's really exciting to see how quickly it starts up after the carb cleaning though. I haven't ridden it since I set the points, timing and now the carb cleaning so I'm anxious to try it out.

That's just rubbing it in Mike. We still have a foot of snow here!!

Hee, Hee....yea, it is kinda nice. I went to dinner at 8:30 tonight with my wife and I was in a T-shirt, shorts and sandels. I think it was about 75 today. However, I sleep in the back seat of my Dodge 3500 with the engine off when I haul these airplane kits around the country and it was about 15 deg for two nights earlier this week in TN. I like to sleep when it's cold but it about froze my nose off.

 

[Bird76Mojo]

That cable splitter got me once too, when I was jetting the VM34's. I ended up using a little black silicone sealer in the cable ends and it helped hold them in nicely. Not too permanent either, just like the tape.

Just another idea for others.. :roll:

GB :mrgreen:

 

[MNellis]

Well, I pulled the carbs off the intakes but left them hooked to the cables. I found that the cables in the splitter looked correct but they were still pulled out a little. I also found the throttle butterfly plates were not seating correctly so I corrected that.

After correcting those two issues I connected both carbs and air filters back. I used a a piece of thin plastic grocery bag to adjust the idle screw gap so they were both in the same position. I started the bike up and it idled down to about 500 rpm and died. I cranked in one full turn on each idle screw and it idled well and I adjust it from there in 1/8 turns at a time.

I set the idle mixture screw at 1 full turn out but the throttle response is still not quite right. It takes a second or two after blipping the throttle to settle back down.

I sure wish there were some ports on the intake boots to connect a vacuum gage to or, better yet, carb stix. I'll have to go to the manual and read up on how to set the pilot screws. The technique of holding your hand over the pipe to check for idle consistency between cylinders seems archaic and subjective. There's got to be a better way. I was thinking I should pull the plug cap on one cylinder and adjust the pilot screw and idle speed then do the other one the same way.

Again, I'm going to the manual now so I'm just kind of talking out loud to myself.

It's nice to have Bill's CD with me since I'm on a business trip for the next two days. It gives me something to do this evening. I certainly don't need to be studying work stuff.

 

[Bird76Mojo]

I may be TERRIBLY wrong here but should'nt he be adjusting the air screws until he has the best throttle response? Then syncing via thumb on pipe? They don't have to be at exactly one turn out or anything from my understanding...?

GB :mrgreen:

 

[MNellis]

I may be TERRIBLY wrong here but should'nt he be adjusting the air screws until he has the best throttle response? Then syncing via thumb on pipe? They don't have to be at exactly one turn out or anything from my understanding...?

GB :mrgreen:

The "one turn out" was just a starting point since that was the setting that I verified as I was disassembling the carbs. I think I have to adjust the airspeed screw to obtain max rpm but, again, I haven't read the manual yet. I was in a hurry to hit the road this afternoon and just wanted to get it running and ride it around the block to see how the timing adjustments and overall carb rebuild seemed to work. That's been a problem all my life, impatience. Since I don't idle much I was anxious to check the mid and high end performance.

After a good warm up it took it out on the main road and ran it through the gears. It pulled much better throughout the rev range and pulled cleanly to the 10.5 redline. There were a couple of 'flat spots' in that rev range and I'll address that through some verification checks when I get back and sort out the idle adjustments.

I should be riding this thing around the street later this week after I get the registration. I'm thinking about a custom plate that says '69CL350'. Hopefully, it's not taken.

 

[MilestoGo]

Hi MNellis,
I hate to jump in when I don't have intimate knowledge with these carbs...
Did you use a Keyster carb rebuild kit?
Did you replace a needle jet with a Keyster supplied needle jet? (again, sorry - but this is relevant)
If you did, put your old needle jet back in and reset carbs.

I struggled with this for two seasons trying to figure carb issues until 160 experts over at the yahoo groups F160 site told me to scrap the the keyster needle jets and replace them with the originals. It fixed my issue and I no longer get the situation where I set the idle and come back an hour later and find that my nice idle is now about 5,000 rpm. That needle jet was too variable in its machining to be able to seat and maintain a consistent and reliable setting.

Tom

 

[MNellis]

Hi MNellis,
I hate to jump in when I don't have intimate knowledge with these carbs...
Did you use a Keyster carb rebuild kit?
Did you replace a needle jet with a Keyster supplied needle jet? (again, sorry - but this is relevant)
If you did, put your old needle jet back in and reset carbs.

Tom

Thanks for the advice Tom and I'll keep that in mind for the future when I rebuild the 450 carbs. But, in this case, no, they were not Keyster kits. They were NOS Honda rebuild kits and they didn't come with any jets at all, only gaskets. At $17.50/ea a few rubber O rings they were not cheap either.