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- 72 CB350 fuel delivery/carb problem
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08-08-2022 #1
72 CB350 fuel delivery/carb problem
I have this 72 CB 350 that I bought at the beginning of summer. Compression on both cylinders is around 170. Points are set properly. I’m having some type of fuel delivery/carburetor issue. I put on brand new petcock, new in-line fuel filters and cleaned the carbs. When I turn the fuel on I only get a trickle in one of the fuel filters coming from the dual lines in the petcock. I was under the assumption that the carbs create a vacuum and will pull fuel into the float bowls but I think I'm wrong. When I ride the bike I hear a very weird sputter that comes from the left side. It’s almost like a sucking sound coming from the left pod. After the bike has been running for a while the idle hangs when I blip the throttle and I’m assuming it’s not getting enough fuel. What are my options here? What do I need to do to fix this?
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08-09-2022 #2Senior Member
- Join Date
- Dec 2017
- Posts
- 2,794
got original CV carbs? If so, are the diaphragms in good condition?
Did it do this before you "put on brand new petcock, new in-line fuel filters and cleaned the carbs"? what type of petcock - with vacuum connection?
float height set right? gas tank clean - debris not causing fuel flow issue?
possible air leak at manifold?
Electrical system all good with fully charged battery?
maybe something here:
TECH INFO & HOW-TO GUIDES
CB / CL 350
https://www.common-motor.com/CB350-C...L350_bc_1.html
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08-10-2022 #3
It´s a common problem. Mostly a mix of petcock and carb problems. My solution is XL125 petcock (single port with y-tube) and VM30s. This works.
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08-10-2022 #4
My money is on the in line filter, new or not (I have found they are VERY restrictive, new or not) , and a crappy/filthy petcock that needs to be replaced
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08-17-2022 #5Senior Member
- Join Date
- Sep 2009
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- 318
I haven't had much garage time this week but I was able to pull off the carb and clean everything again. I double checked the float heights too. I put everything back on and semi synced up the carbs and the bike seems to idle way better, although the idle does seem to hang just a little. I still get a little sucking from the Pod but I haven't tried messing with the mixture screws. Later this week my friend is giving me side covers and the stock air boxes from an old CB. Once I pop those on I'll try to do and mess with the mixture screw.
One other thing, I tried to sync the carbs turning out the throttle cable barrel adjusted until the idle set screw starts to move but I can only do that on one side. The other side doesn't want to work that way so I've been adjusting both sides until the both actuate at the same time.
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08-18-2022 #6Senior Member
- Join Date
- Sep 2009
- Posts
- 318
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