Jockey Journal Forum banner
1 - 15 of 15 Posts

·
Registered
Joined
·
84 Posts
Discussion Starter · #1 ·
Hi everyone, i posted this in my intro, but i thought this might be better. I have a 1970 Honda CL350 and it will not run right. When i start it cold it will run and idle ok, but as soon as i start riding it starts bogging and not excellerating and eventually will just not stay running. If i let it cool off then kick it over again it will be fine again till it gets hot? We already cleaned the carbs, checked the points, and put new plugs in. What else might it be? Thanks!

Lil Joe
 

·
Registered
Joined
·
585 Posts
Check the gas shut off on the tank. It should have a filter bowl on the valve. It will have a 10mm hex on it for a wrench. Theres a fine mesh screen in the that if clogged will do just what yours is doing. While the bowl is off, cycle the valve to "on" and "res" and make sure you got good flow and that the tank doesn't have junk it it. Good Luck..
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #5 ·
Primo said:
I don't know if this would affect it but try running it with the gas cap open I guess theres a breather there that can get blocked and will starve your bike of air.

Primo
I forgot to mention that we also did clean that screen. It was not very dirty but had some garbage on it. The petcock on the other hand does not seem to work well, sometimes in the on position we will not get fuel. If we turn it to reserve we will get good flow. Should i replace this? Also, we cleaned the carbs, but we did not tear them down and replace all the parts, should i look into this? Thanks!
Lil Joe
 

·
Registered
Joined
·
798 Posts
Capricekid said:
I forgot to mention that we also did clean that screen. It was not very dirty but had some garbage on it. The petcock on the other hand does not seem to work well, sometimes in the on position we will not get fuel. If we turn it to reserve we will get good flow. Should i replace this? Also, we cleaned the carbs, but we did not tear them down and replace all the parts, should i look into this? Thanks!
Lil Joe
I guarantee you it's a clogged jet. Tear them down and clean every little tiny hole you see...
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #7 ·
Shooty said:
I guarantee you it's a clogged jet. Tear them down and clean every little tiny hole you see...
OK thanks Shooty, why would a clogged jet cause it to run bad when it gets hot though? Cause it runs fine cold. Sorry about the dumb questions, i am just new to bikes.
Lil Joe
 

·
Registered
Joined
·
798 Posts
Capricekid said:
OK thanks Shooty, why would a clogged jet cause it to run bad when it gets hot though? Cause it runs fine cold. Sorry about the dumb questions, i am just new to bikes.
Lil Joe
Does it idle fine when warmed up? Idle-1/4 throttle is controlled by the air screw on the carbs. Once you go past 1/4 throttle the needle jet and main jet come into play. If they are gummed up your bike will run like crap. You also might have the bike running a little rich....they tend to run better when cold if the air/fuel mix is too rich. No dumb questions...everyone had to learn at some point.
 

·
Registered
Joined
·
1,273 Posts
Primo said:
I don't know if this would affect it but try running it with the gas cap open I guess theres a breather there that can get blocked and will starve your bike of air.

Primo
Yeah, what he said....

It sounds like the carbs are starved for fuel. The cap doesn't breathe so you get a vacuum lock in the fuel system. When you let it cool down, fuel trickles down into the bowl and it runs for a minute, but then it stops again.

Run it without the cap, and check for pinched fuel hoses.
 

·
Registered
Joined
·
1,273 Posts
Shooty has some good advice too. Tear the carbs down and clean everything: jets, air passages, bowl vent, float needle and seat.

Here's a good way to clean carbs.

Since the last time you cleaned the carbs, have you ever felt it run at full throttle? Did it ever run smooth, or has it stumbled? Try this: run it till it dies, then open the drain screws and see how much fuel comes out. I'll bet the bowls are dry.
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #11 ·
JEB said:
Shooty has some good advice too. Tear the carbs down and clean everything: jets, air passages, bowl vent, float needle and seat.

Here's a good way to clean carbs.

Since the last time you cleaned the carbs, have you ever felt it run at full throttle? Did it ever run smooth, or has it stumbled? Try this: run it till it dies, then open the drain screws and see how much fuel comes out. I'll bet the bowls are dry.
Ok here is the update. Tweaked with the bike tonight with my Dad. We put some higher octane gas in it and also some sea foam in with the new gas. Now it will stay running even when hot and it starts right up with almost no effort. I actually rode it for about half an hour tonight. It still is not quite right though. One cylinder seems to have lower compression and backfires and sputters. The other seems fine. Does it need a tune up or is it the same carb issue as described before? Thanks!
Lil Joe
 

·
Registered
Joined
·
798 Posts
Capricekid said:
Ok here is the update. Tweaked with the bike tonight with my Dad. We put some higher octane gas in it and also some sea foam in with the new gas. Now it will stay running even when hot and it starts right up with almost no effort. I actually rode it for about half an hour tonight. It still is not quite right though. One cylinder seems to have lower compression and backfires and sputters. The other seems fine. Does it need a tune up or is it the same carb issue as described before? Thanks!
Lil Joe
Did you tweak the air/fuel at all? Also the carbs might be out of sync.
 

·
Registered
Joined
·
1,273 Posts
Capricekid said:
Ok here is the update. Tweaked with the bike tonight with my Dad. We put some higher octane gas in it and also some sea foam in with the new gas. Now it will stay running even when hot and it starts right up with almost no effort. I actually rode it for about half an hour tonight. It still is not quite right though. One cylinder seems to have lower compression and backfires and sputters. The other seems fine. Does it need a tune up or is it the same carb issue as described before? Thanks!
Lil Joe
2 things to look at:
1. These bikes have CV carbs, and the rubber diaphragm on one of the throttle slides may be leaking. This will cause the problem that you describe, if the slides aren't working together. Pull the top of the carbs, pull out the sheet of rubber that's molded to the throttle slide(be careful!) and check for holes or cracks.Be sure to put it back in the right way, it works off manifold vacuum so it has to seal well when you put the tops back on. Otherwise the slide doesn't work.
2. Check your compression with a test gauge, one cylinder may have less compression than the other, and that's the only way to be sure. If they aren't close to the same compression, you're wasting time syncing the carbs.
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #14 ·
JEB said:
2 things to look at:
1. These bikes have CV carbs, and the rubber diaphragm on one of the throttle slides may be leaking. This will cause the problem that you describe, if the slides aren't working together. Pull the top of the carbs, pull out the sheet of rubber that's molded to the throttle slide(be careful!) and check for holes or cracks.Be sure to put it back in the right way, it works off manifold vacuum so it has to seal well when you put the tops back on. Otherwise the slide doesn't work.
2. Check your compression with a test gauge, one cylinder may have less compression than the other, and that's the only way to be sure. If they aren't close to the same compression, you're wasting time syncing the carbs.
Ya, Dad and I played with the air/fuel and it helped, but it did not fix the problem, we looked at the diaphragm when we took the carbs off and they looked ok, but i could replace them it would not be hard. If one cylinder has less compression then what? My Dad was thinking it might need the valves adjusted? Thanks again for all the help!
Lil Joe
 

·
Registered
Joined
·
84 Posts
Discussion Starter · #15 ·
Capricekid said:
Ya, Dad and I played with the air/fuel and it helped, but it did not fix the problem, we looked at the diaphragm when we took the carbs off and they looked ok, but i could replace them it would not be hard. If one cylinder has less compression then what? My Dad was thinking it might need the valves adjusted? Thanks again for all the help!
Lil Joe
I am going over to the local shop to use their compression gage today or tomorrow. What should i do if the compression is different? Would it be a head gasket? Thanks!
Lil Joe
 
1 - 15 of 15 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top