Topic: 1973 cb350f fine tuning question with jetting

[751]

   Hi guys! Got another weird question for you. I have a 1973 honda cb350f, It idles fine, then trying to go down the road it cuts out and hardly gets up to speed??? it has new carb gaskets and needle and seats, floats are set at 24mm, has stock jetting pj 35 and mj 75 jets are original honda and have been ultrasonic cleaned and are spotless, idk what the needle clip setting is, im sure factory setting, timing is on, valves are set correct, has new points and condensers, has been synched last winter, intake rubbers are in good shape, new oem filter, new plugs, fresh gas with premium, has drag pipes though, IDK what to jet it for? It very slowly gets up to 50 and seems to run fine.

 The engine is hot right now, gonna check the plugs asap and repost, Should i set the needle clip position 1 lower than it is to make it richer?

Thanks for any help on this!!!

[fmctm1sw]

Does it run better or worse with the air filter out of it?

[Gordon]

The engine is hot right now, gonna check the plugs asap and repost, Should i set the needle clip position 1 lower than it is to make it richer?

I wouldn't change anything until you get a good reading on the plugs so you know where you're starting from and what, if any, carb changes need to be made.

[camelman]

Please check on these things and report back as they are critical.

1) Did you remove and clean the emulsifier tubes beneath the main jets?
2) Does the air filter look new, or at least white?
3) Do you have the lid on the airbox?
4) Did anyone leave a spare hamster or a stack of $100 bills in the intake box?  ;-)

Let us know.  Those are big power/operation issues with these bikes.

Camelman

[flybox1]

dont change your needle position, yet.
your carb rebuild kit may be causing the issue.
was it an HONDA kit, or something else?
the needle taper on aftermarket kits for these 350F's is often wrong and causes issues.
if you still have your HONDA needles, i'd suggest cleaning and reinstalling them.
and while you're in there, pull that emulsifier tube and verify all the tiny holes along it are clear.
set your air screw to 3/4 turns out.
this should get your running fast enought to do your main jet chop.
i'm suspecting with your dragpipes, you may need to go to #80 mains and 1+ turn on the A/F screw.