Starting problems and petcock leaking cb400 SF project big 1

Post by **dobbslc** » Thu Mar 26, 2015 8:42 pm

Good progress! But I would say that cutting out when you shut off the choke means you still have blocked fuel or air ways in the carbs

These are tiny and carb cleaner won't shift the shit out if that green muck has been allowed to dry in there.
Compressed air and ultrasonic cleaning may be the only way to go.
Just had a thought, have you checked the idle adjustment screw?

mykel49 · Post by **mykel49** » Fri Mar 27, 2015 7:50 am

Ok so where is the idle adjustment screw ?

Superjack44 · Post by **Superjack44** » Fri Mar 27, 2015 9:13 pm

mykel49 wrote:Ok so where is the idle adjustment screw ?

Its underneath the carbs , it is a plastic knurled nut accessed from the lefthand side of the bike as you sit on it, bit fiddly and you can get a bit of a burn if the engine is hot.
Having a small hand is a bonus.

mykel49 · Post by **mykel49** » Sat Mar 28, 2015 8:41 am

Hi Dobbsic thanks for that

dobbslc wrote:Good progress! But I would say that cutting out when you shut off the choke means you still have blocked fuel or air ways in the carbs
These are tiny and carb cleaner won't shift the shit out if that green muck has been allowed to dry in there.
Compressed air and ultrasonic cleaning may be the only way to go.
Just had a thought, have you checked the idle adjustment screw?

However, I'm not a 100% sure it is still blocked jets etc.. it's like when I turned choke down to halfway the engine was idling so low it should have stopped anyway, if that makes sense!! so maybe it is the idle adjustment screw, I will adjust that today. Thanks also to Superjack for advice on positioning, and all your advice so far, it's much appreciated.

mykel49 · Post by **mykel49** » Sat Mar 28, 2015 8:48 am

dobbslc wrote: If there is fuel in the oil that means both the tap and at least one carb is letting fuel through.

Re above - Do you think with my jammed float in carb this is the reason I had fuel getting through to engine oil (smell of fuel from oil ) ?

Post by **dobbslc** » Sat Mar 28, 2015 11:17 am

mykel49 wrote:
dobbslc wrote: If there is fuel in the oil that means both the tap and at least one carb is letting fuel through.
Re above - Do you think with my jammed float in carb this is the reason I had fuel getting through to engine oil (smell of fuel from oil ) ?

Defiantly.

mykel49 · Post by **mykel49** » Sat Mar 28, 2015 2:53 pm

Hi there again, well thanks for the heads up, I adjusted the idle screw adjuster when engine running, and hey presto the engine is running sweet and no longer cutting out. this is a brilliant site for advice and guidance.

I also stripped front shocks and replaced corroded dust rings and cleaned up the pitted shocks. I know, I know....I should have replaced the seals and oil whilst I had them off, but seals weren't leaking so just left them for the time being..

untonyto · Post by **untonyto** » Mon Apr 06, 2020 9:51 am

Followed this thread keenly as I am having a similar predicament on my hands. Thanks to the OP for being an absolute hands-on warrior and to all contributors for guiding him through in detail

Starting problems and petcock leaking cb400 SF project big 1

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Re: Starting problems and petcock leaking cb400 SF project big 1