facefirst35
Coast to Coast
Isn't that bike a CL and not a CB?
CB350 - Topping out at 45mph??
- Thread starter AlaskaCL350
- Start date
AlaskaCL350
New Member
facefirst35 said:
The guy I purchased it from put the CL exhaust on it, but it is a true CB350.
Looks sweet though.
I will experiment with the turning the fuel on and off game and see what I can figure out.
Thanks Glennwood
AlaskaCL350
New Member
UPDATES:
I have a new rectifier on the way. Tested mine and it was crap. Don't think that is related to my cylinder issue, but it is definitely why my charging system isn't working worth a damn.
I've played with the carbs a ton and realized that the left cylinder has a fuel entry port on both the bowl and on the air intake side... I'm connected to the air intake side since the right cylinder only has that port and no bowl entry.
Could this be a cause for concern / issue??
I have new pistons and rings now... but I'd like to save that project for winter given the possibility that this may be something else.
Here is a video of the throttle response for each cylinder. Hopefully it helps clarify what is going on with my issue.
http://www.youtube.com/watch?v=Yh4nQm1kTv8
Any help is greatly appreciated.
Thanks guys
I have a new rectifier on the way. Tested mine and it was crap. Don't think that is related to my cylinder issue, but it is definitely why my charging system isn't working worth a damn.
I've played with the carbs a ton and realized that the left cylinder has a fuel entry port on both the bowl and on the air intake side... I'm connected to the air intake side since the right cylinder only has that port and no bowl entry.
Could this be a cause for concern / issue??
I have new pistons and rings now... but I'd like to save that project for winter given the possibility that this may be something else.
Here is a video of the throttle response for each cylinder. Hopefully it helps clarify what is going on with my issue.
http://www.youtube.com/watch?v=Yh4nQm1kTv8
Any help is greatly appreciated.
Thanks guys
Redliner
Over 1,000 Posts
That plug on the bottom of the bowl is so it can drain if it over-flows :
Pull the bowl off and blow into that plug to see if it is clogged. If it is not clogged and it is not leaking, then your bowl is not flooding.
OK, let's start with your coils. Swap the blue and yellow leads from the coils. You should have the blue lead from one coil going to the yellow wire-harness-lead and the yellow lead from the other coil going to the blue wire-harness-lead. Then, be sure to swap the spark-plug leads. So the right coil is now connected to the left plug and vise versa.
Does the problem now effect the right cylinder instead?
You should also be cleaning the spark plug every time you try a new solution, as a fouled plug is a revolving door of fouling the plug.
Your bike had power when the fuel drained because it leaned the mixture. You're clearly running very rich.
Turn the mixture screw all the way in until it lightly seats. If your bike can still start with this screw seated, you're getting too much fuel through the jets. They may be the wrong size or over-bored.
Is the slide making a "knock" sound when it closes? Pull the air filter off of the back of the carb and stick a finger (no hard objects) into the carb and push the slide up. Now let it fall and if it doesn't fall straight down and "knock" there is too much resistance. If this is getting stuck open it can cause a rich mixture as well.
Are you doing your compression checks with the engine warm?
Do another compression check on the left cylinder with the engine warm. Now remove the spark plug and drop in about 20cc of oil. Take another reading immediately. Did the pressure go up? If so, your rings are either bad or the gaps are lined up.
If the pressure did not go up, now we suspect the valves. Get an adapter for your air-compressor and do a leak-down test.
Other possible causes:
Cam-chain tension is not set properly. I hope you have a manual adjuster with the nut on the top of the tensioner housing. If so, release it with the engine at 90º after T.D.C. on the compression stroke of the left cylinder.
After adjusting the cam-chain tension, adjust the valve clearance.
It's most likely not your battery/charging system at fault. If it were, you'd notice the right cylinder having such issues because it fires after the left cylinder. The discharge of energy would be greater on the left than the right if we have a weak system.
Pull the bowl off and blow into that plug to see if it is clogged. If it is not clogged and it is not leaking, then your bowl is not flooding.
OK, let's start with your coils. Swap the blue and yellow leads from the coils. You should have the blue lead from one coil going to the yellow wire-harness-lead and the yellow lead from the other coil going to the blue wire-harness-lead. Then, be sure to swap the spark-plug leads. So the right coil is now connected to the left plug and vise versa.
Does the problem now effect the right cylinder instead?
You should also be cleaning the spark plug every time you try a new solution, as a fouled plug is a revolving door of fouling the plug.
Your bike had power when the fuel drained because it leaned the mixture. You're clearly running very rich.
Turn the mixture screw all the way in until it lightly seats. If your bike can still start with this screw seated, you're getting too much fuel through the jets. They may be the wrong size or over-bored.
Is the slide making a "knock" sound when it closes? Pull the air filter off of the back of the carb and stick a finger (no hard objects) into the carb and push the slide up. Now let it fall and if it doesn't fall straight down and "knock" there is too much resistance. If this is getting stuck open it can cause a rich mixture as well.
Are you doing your compression checks with the engine warm?
Do another compression check on the left cylinder with the engine warm. Now remove the spark plug and drop in about 20cc of oil. Take another reading immediately. Did the pressure go up? If so, your rings are either bad or the gaps are lined up.
If the pressure did not go up, now we suspect the valves. Get an adapter for your air-compressor and do a leak-down test.
Other possible causes:
Cam-chain tension is not set properly. I hope you have a manual adjuster with the nut on the top of the tensioner housing. If so, release it with the engine at 90º after T.D.C. on the compression stroke of the left cylinder.
After adjusting the cam-chain tension, adjust the valve clearance.
It's most likely not your battery/charging system at fault. If it were, you'd notice the right cylinder having such issues because it fires after the left cylinder. The discharge of energy would be greater on the left than the right if we have a weak system.
Redliner
Over 1,000 Posts
I know it sounds crazy, but before going any further, maybe you should swap carbs.
Don't plug the throttle cable in. Just use your finger on the side and see if the problem follows the carb. If it does, then no other system could possibly be effecting it. If swapping the carbs swaps the issue, then bottom line is that the carb is the issue.
OH, and finally, those air filters are going to need some work before they will allow the carbs to function right. I wish I had a camera so that I could show you, but I'm working on a CB450 and the damn UNI filters wouldn't run right until I cut out some of the rubber to allow the air to flow into the jet holes and diaphragm hole on the inlet side. Finally, I also added some bathroom tissue tubes into the filters. Depending on what brand, they will fit perfectly inside the internal filter spring. This will somewhat straighten out the air, which is what CV carbs demand.
Sounds "crappy" but it works. I'll await my "pun"ishment. :
Don't plug the throttle cable in. Just use your finger on the side and see if the problem follows the carb. If it does, then no other system could possibly be effecting it. If swapping the carbs swaps the issue, then bottom line is that the carb is the issue.
OH, and finally, those air filters are going to need some work before they will allow the carbs to function right. I wish I had a camera so that I could show you, but I'm working on a CB450 and the damn UNI filters wouldn't run right until I cut out some of the rubber to allow the air to flow into the jet holes and diaphragm hole on the inlet side. Finally, I also added some bathroom tissue tubes into the filters. Depending on what brand, they will fit perfectly inside the internal filter spring. This will somewhat straighten out the air, which is what CV carbs demand.
Sounds "crappy" but it works. I'll await my "pun"ishment. :
AlaskaCL350
New Member
Redliner, you've given me a full plate. You're awesome!!!
I'll let you know how all these tests turn out.
Thanks
I'll let you know how all these tests turn out.
Thanks
AlaskaCL350
New Member
Redliner said:
Swapped the carbs, the issue followed it over to the other side. ~high five~
Tagged down that the issue is located in the left carburetor. Tore it apart looking for issues. The large spring that lifts the diaphragm was all stretched out. It's been like this for awhile, didn't think it would be an issue... swapped it out either way with a spare I had.
Looked at the jets and the guy before me must have been messing around with them. They both had 115s and 68s installed. Also, found a shredded o-ring in the hole for the screw on the side (I think this is a fuel adjustment screw).
Cleaned everything out as best possible and threw it back together to check it out.
The carbs were both getting full throttle functionality which is awesome. Revved it up a bunch and was pleased with what I was hearing. Swapped them back to their respective sides, and the left side had significantly more power than before... but it wasn't nearly as much as what it was JUST doing. No idea wtf just changed.
Took it for a ride and was getting some more power at low end, but top speed was still lacking.
Need to just get a full rebuild kit and probably get them professionally cleaned / sync'd. No more tinkering around.
I'll let ya know how it goes.
Thanks
Redliner
Over 1,000 Posts
Dude, these bikes are still around because people like you and I have the tools to take care of them and there's nothing that needs to be done with some magical computer.
Did you check mechanical (cam) timing?
Valve clearance? Do this only with the engine bone cold.
We need to be certain we're dealing with the stock jets and needles.
Also, that torn up o-ring belongs in the mixture screw hole. You install it in this order; o-ring, washer, screw.
Tighten this screw until it lightly seats. Back it out one-half to one-turn. Then look up guides for tuning and syncing.
This adjustment must be made after adjusting cam-tension and valve-clearance, in that order, and the engine HOT
Before starting:
The idle: Turn the adjustment screw all the way out until it lifts from the idle screw stop. Turn it in until it just lightly touches this stop, then add one half turn. Maybe 3/4 at the most until it's warmed up. Don't let it idle over about 1,200 for long, they will get HOT.
The mix: Turn this screw in until it lightly seats, then turn it one turn out. For reference, turning it in will make it lean and turning it out will make it rich.
Finally, check that the two throttle levers lift at exactly the same time and adjust the throttle cable height as necessary. Slack should be minimal and allow about a millimeter of throttle movement before engaging. Put your finger on one idle-stop-lever very lightly, then stare at the other lever. You should feel it move at the exact moment you see the other move.
1. Don't perform ANY carb adjustments until the engine is HOT. Spit on the veins on the jugs and when it evaporates without hesitating, it's hot. Or lick your finger and wipe it on the top vein, near the spark plug, to be more polite to her.
2. Adjust the idle to about 900-1,000 RPM's by evenly adjusting both carb idles. If you turn the left one in 1/8th turn, repeat for the other. It's important to keep them balanced. You want a low idle because the next adjustment will raise it.
3. Adjust one carb by turning the air screw in or out about 1/4 turn. If the RPM's drop one way, turn back 1/4, then try to turn the other way. You want the RPM's to go up. Wait 30 seconds after each 1/4 turn. Repeat until you turn it and the idle does NOT change. Go back 1/4 to confirm it isn't changing, then continue back by another 1/8. This will keep you safely above lean condition.
4. Now you will have to adjust the idle evenly again to bring it back down to 900-1,000RPM. Do so just like in step 2.
5. Repeat step 3 for the other carb.
6. Finally, evenly adjust the idle screws until you get her right at 1,100 on the clock.
Did you check mechanical (cam) timing?
Valve clearance? Do this only with the engine bone cold.
We need to be certain we're dealing with the stock jets and needles.
Also, that torn up o-ring belongs in the mixture screw hole. You install it in this order; o-ring, washer, screw.
Tighten this screw until it lightly seats. Back it out one-half to one-turn. Then look up guides for tuning and syncing.
This adjustment must be made after adjusting cam-tension and valve-clearance, in that order, and the engine HOT
Before starting:
The idle: Turn the adjustment screw all the way out until it lifts from the idle screw stop. Turn it in until it just lightly touches this stop, then add one half turn. Maybe 3/4 at the most until it's warmed up. Don't let it idle over about 1,200 for long, they will get HOT.
The mix: Turn this screw in until it lightly seats, then turn it one turn out. For reference, turning it in will make it lean and turning it out will make it rich.
Finally, check that the two throttle levers lift at exactly the same time and adjust the throttle cable height as necessary. Slack should be minimal and allow about a millimeter of throttle movement before engaging. Put your finger on one idle-stop-lever very lightly, then stare at the other lever. You should feel it move at the exact moment you see the other move.
1. Don't perform ANY carb adjustments until the engine is HOT. Spit on the veins on the jugs and when it evaporates without hesitating, it's hot. Or lick your finger and wipe it on the top vein, near the spark plug, to be more polite to her.
2. Adjust the idle to about 900-1,000 RPM's by evenly adjusting both carb idles. If you turn the left one in 1/8th turn, repeat for the other. It's important to keep them balanced. You want a low idle because the next adjustment will raise it.
3. Adjust one carb by turning the air screw in or out about 1/4 turn. If the RPM's drop one way, turn back 1/4, then try to turn the other way. You want the RPM's to go up. Wait 30 seconds after each 1/4 turn. Repeat until you turn it and the idle does NOT change. Go back 1/4 to confirm it isn't changing, then continue back by another 1/8. This will keep you safely above lean condition.
4. Now you will have to adjust the idle evenly again to bring it back down to 900-1,000RPM. Do so just like in step 2.
5. Repeat step 3 for the other carb.
6. Finally, evenly adjust the idle screws until you get her right at 1,100 on the clock.
AlaskaCL350
New Member
Redliner said:
I attached a photo to this post with two different air mixture screws. The kind my carb takes is the top, but every rebuild kit I've found seems to have the bottom one. The bike came with two rebuild kits... both included this incorrect air mixture screw and no o-ring / washer for in that port.
One carb the o-ring and washer are missing currently, the other there is an o-ring but no washer...
~facepalm~
Any idea as to where I can pick up a kit with the correct stuff??
Carburetor is a KEI HIN type 722A
Thanks for all your help.
I'll work on checking all the other things tomorrow. The carbs ate up all my free time today.
-T
AlaskaCL350
New Member
This is the only one I've found searching around tonight, but looking at the kit, I so see a washer / gasket that looks too big to go in that air / fuel mixture hole... I don't really have one to compare too so this is all speculation.
http://www.siriusconinc.com/pro-detail.php?pid=&product_id=2906
Probably the right one, but I'd hate to have to spend $90 just to get those two o-rings and two washers........
Crazy that these things are getting so hard to find.
http://www.siriusconinc.com/pro-detail.php?pid=&product_id=2906
Probably the right one, but I'd hate to have to spend $90 just to get those two o-rings and two washers........
Crazy that these things are getting so hard to find.
facefirst35
Coast to Coast
Apparently that air mixture screw is for the 2C carb. When I rebuilt my carb I had the same thing happen. The float bowl gasket was also too big. I had to cut it down with an Xacto knife and used 3M super glue to glue it back together. Apparently the 3M stuff is resistant to gas.
Redliner
Over 1,000 Posts
Why buy the whole kit? You can buy metric washers and o-rings individually. Whatever you do, do not Google "CB350 o-ring" because they are asking probably ten-times what they're worth because of their magical properties...
In reality, you could go to Harbor Freight and pick up a metric o-ring box that includes the o-rings you need (3x1mm I believe) for about $4. The washer...I unno. Measure yours and ask around.
In reality, you could go to Harbor Freight and pick up a metric o-ring box that includes the o-rings you need (3x1mm I believe) for about $4. The washer...I unno. Measure yours and ask around.
Redliner
Over 1,000 Posts
Oh man...
So I've been working on a few bikes recently, and there's this CB450 that I finally put together yesterday and took out for a ride. The thing topped out at 40 on the dot and seamed real boggy and missed until it died on the road.
So I waited over night for it to cool down. I adjusted the cam chain tension until I could literally feel no slack in the chain and no play in the cams. Then I adjusted the valves again.
Then, get this, I took sand-paper and cleaned the leads that come from the points cover and uh, it's like a whole new bike.
I generally clean all leads, so it didn't come to mind when this post came up. So...clean all your ignition leads!
So I've been working on a few bikes recently, and there's this CB450 that I finally put together yesterday and took out for a ride. The thing topped out at 40 on the dot and seamed real boggy and missed until it died on the road.
So I waited over night for it to cool down. I adjusted the cam chain tension until I could literally feel no slack in the chain and no play in the cams. Then I adjusted the valves again.
Then, get this, I took sand-paper and cleaned the leads that come from the points cover and uh, it's like a whole new bike.
I generally clean all leads, so it didn't come to mind when this post came up. So...clean all your ignition leads!
TheCoffeeGuy
Books, Books, Books, knowledge is within
From your notes I assume its a CL not a CB by the pic
Things I've noticed:
- Left cylinder doesn't always start firing right away and usually needs some help
pull the plug and see if its firing with no load for start up.
- Left spark plug get's kinda black at times (might be just being flooded... hopefully not bad rings / piston)
the shop manual states putting your hand behind each exhaust and test pressure. is this the case on start up, or after the bike is warm?
- Float in left carb was punctured... ordered new one, hasn't been replaced yet
this can be the problem directly related to the black plug.
- Battery is new but will not stay charged, possibly rectifier... (please advise on this one)
rectifier, possibly not.
short, probably,
bad coil wire or coil probably.
chaffed wire probably
short in stator, possible
slow moving advance, probably
petcock issue, maybe
wiring short, maybe
timing off, probably
Sheared or partially sheared flywheel shear pin, possible
JMOs
Things I've noticed:
- Left cylinder doesn't always start firing right away and usually needs some help
pull the plug and see if its firing with no load for start up.
- Left spark plug get's kinda black at times (might be just being flooded... hopefully not bad rings / piston)
the shop manual states putting your hand behind each exhaust and test pressure. is this the case on start up, or after the bike is warm?
- Float in left carb was punctured... ordered new one, hasn't been replaced yet
this can be the problem directly related to the black plug.
- Battery is new but will not stay charged, possibly rectifier... (please advise on this one)
rectifier, possibly not.
short, probably,
bad coil wire or coil probably.
chaffed wire probably
short in stator, possible
slow moving advance, probably
petcock issue, maybe
wiring short, maybe
timing off, probably
Sheared or partially sheared flywheel shear pin, possible
JMOs
AlaskaCL350
New Member
SHE'S ALIVE!!!!!!
Did the following to bring her from 45mph baby to 70+ MONSTER:
- Tore through and rebuilt carbs <----- The carbs ended up being the main issue discovered by swapping their sides and the issue followed the carb
- Swapped jets back to stock (105, 35, and 68 I believe. There is a chart further up in post)
- Properly installed air / fuel mixture o-ring and washer where there wasn't one prior
- Sync'd and properly set carb idle and air/fuel mixture (Step-by-Step process earlier in post)
- Reset cam chain tension
- Reset valve clearances
In addition, some things that definitely helped:
- New points
- New plugs
- Set timing / adjusted points
- Went through and re-wired a few grounds to confirm I was getting solid connections
- New rectifier to fix my charging system issue
- Occasional yelling matches with stripped out screws
There is probably still some room for improvement, as always. I will continue to tinker and play just like I know we all love to do. Anything for a few extra mph, right?
A solid thank you to all of you for sticking with me through this project. I know I learned A LOT about this bike in the last few months. Found better information here than in my Clymers manual which really speaks to the amount of experience the members of this site have.
Hope this topic helps others as much as it has helped me.
Enjoy the summer!!!
TIME TO RIDE!!!
;D ;D ;D ;D ;D ;D ;D ;D ;D
Did the following to bring her from 45mph baby to 70+ MONSTER:
- Tore through and rebuilt carbs <----- The carbs ended up being the main issue discovered by swapping their sides and the issue followed the carb
- Swapped jets back to stock (105, 35, and 68 I believe. There is a chart further up in post)
- Properly installed air / fuel mixture o-ring and washer where there wasn't one prior
- Sync'd and properly set carb idle and air/fuel mixture (Step-by-Step process earlier in post)
- Reset cam chain tension
- Reset valve clearances
In addition, some things that definitely helped:
- New points
- New plugs
- Set timing / adjusted points
- Went through and re-wired a few grounds to confirm I was getting solid connections
- New rectifier to fix my charging system issue
- Occasional yelling matches with stripped out screws
There is probably still some room for improvement, as always. I will continue to tinker and play just like I know we all love to do. Anything for a few extra mph, right?
A solid thank you to all of you for sticking with me through this project. I know I learned A LOT about this bike in the last few months. Found better information here than in my Clymers manual which really speaks to the amount of experience the members of this site have.
Hope this topic helps others as much as it has helped me.
Enjoy the summer!!!
TIME TO RIDE!!!
;D ;D ;D ;D ;D ;D ;D ;D ;D
AlaskaCL350
New Member
First long highway ride today. Broke down on way back... pretty typical vintage motorcycle ride I'd say. Would have been a little worried if nothing had failed it's first day out in the real world.
Pulled plugs on side of road and right cylinder is an oily mess... sweeeeeeeeeet.
Cleaned up the plugs and got it back home. Left a beautiful cloud of white smoke in my wake for the first few miles.
I'll likely be putting rings in her a little sooner than I'd hoped. Sucko.
Pulled plugs on side of road and right cylinder is an oily mess... sweeeeeeeeeet.
Cleaned up the plugs and got it back home. Left a beautiful cloud of white smoke in my wake for the first few miles.
I'll likely be putting rings in her a little sooner than I'd hoped. Sucko.
Redliner
Over 1,000 Posts
Aaaaand you're certain that nothing is inhibiting intake? The air-filters clean? You are using the stock airboxes, correct?
I don't know about you, but more often than not, my first test-rides after a repair go swell. Get back, dial things in a bit, then by the second or third ride every part of her is shining. Then again, I do a lot of adjustments and cleaning before even thinking of trying to start 'em. ;D
I don't know about you, but more often than not, my first test-rides after a repair go swell. Get back, dial things in a bit, then by the second or third ride every part of her is shining. Then again, I do a lot of adjustments and cleaning before even thinking of trying to start 'em. ;D