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1973 Honda CB350G
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4 Posts
Discussion Starter · #1 ·
Hey all,

I recently purchased a 73’ CB350G that was running upon purchase, just not very cleanly. I’ve been trying to follow some of the factory service and maintenance manuals to clean up different parts but have hit a bit of a wall.

The bike starts up fine when fully choked and idles at a good RPM (Don’t have exact RPM, no tach on yet), the problem comes when I flip the choke into any part of the open position. Once moved the bike begins to rev extremely high and doesn’t come down (left it for about 5 seconds before I shut down with kill switch) unless it’s moved back to choke closed position or killswitched. This is with NO throttle engaged.

Things I’ve look at or tried so far:
  • Inspected throttle controls, I do not believe the throttle is staying engaged, it flicks back to regular position with ease and there is no tension where the cables come down at the carb. Can also give some gas and increase revs while choked out.
  • I just synced the idle stop screw position for both carbs and adjusted the pilot screws to their factory directed 1 turn CCW from full close. I can’t even properly adjust the stop screws or pilot screws as the RPM’s rise too quickly.
  • Im not entirely confident working with motorcycles yet so I’m trying to keep things simple and have learned a fair deal over the past few weeks.
  • I’ve read some things on here about air/vacuum leaks causing high revs from the engine but I haven’t seen anything regarding when the choke is opened specifically

Any recommendations on things to try would be awesome. I’m hoping it can be rectified without completely dismantling the carbs but I’m thinking I may need to look inside to see the condition. I can take pictures if that helps any as well.
 

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1973 Honda SL350 & 1970 SL100
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68 Posts
I don’t think you have much option other than to open them up. As you move off choke, you increase the flow of air through the carbs. Since you have CV carbs, the magic is in the diaphragms. Their condition, seal, leaks, etc. all play a part. As do the various jets, which may be clogged. CV carbs are not my area of expertise, so can’t offer you much there. Sorry.
 
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