Topic: CB400 Carb Throttle Sticky Won't Move Freely - Looking for Help

[Russ McClay]

Hi All --

I'm posting this for a friend. His CB400 throttle has become very difficult to turn.  The problem is with the spring-loaded "connector bar"; I'm not a mechanic but it seems the grease is old or the bushings are shot.  The bike is here in Taiwan. Honda Taiwan and Honda Japan both said they don't have the parts (according to the motorcycle shop). I found a fellow on eBay (based in Tennessee) to whom I described the problem and he said he could fix it.  I sent the carbs to him. A month later and at much expense he merely rebuilt the carbs but didn't fix the problem.  Very disappointing!  I just hope to find someone who understands and can fix the problem.  I can ship the carbs to anywhere in the world.

Thanks for any help, insight or suggestions.
Russ

[Russ McClay]

Here's a link to a video showing the problem:

https://vid.me/qO2f

Russ

[robvangulik]

Tat's from a 400 super four i think? The same kind of mechanics as my CBR.
Try lubing the moving parts with silcone oil, probably a case of dry O-rings on the axle that moves the butterfly valves.

[Russ McClay]

Thanks for the reply.  The shop did try to lubricate the axle that rotates the butterfly valves to no avail.  I'll ask if they know about silicone oil.

Would be great to find a shop or someone in the world that knows how to fix this problem.

[strynboen]

you need to split the carb bodyes from the rack.(just split it in.. the mittel so the 2 shafts can be pulled aut)..then take the butterflys of the shaft...and pull the shaft...and polish  it..its gunk vho are blokate the movent..steel voll can take it(carefull) ..renember to use lockteit to safe the small schrevs...not to mutch.. the shaftcan get lockt by too mutch lockteit)...and you had to split it all Again(..hell job)
and vait to teight the butterflys to all are mounted..then carefull thek them for free moment as the schrevs are teighten..and theu are placed korrekt in the bores..
but there is  more on this forum vho does karb Work..just seargh and find..im in denmark..and are not a specilist..so better find one vho does it daily.(.rutine does the job better)

[Russ McClay]

Thank you for the reply!  I wish I had the tools and a shop to try to do this.  It seems you really understand the problem.  I used to work on vehicles 30 years ago in the States, but here in Taiwan I don't even have a garage.

By the way, great job with your English!

[strynboen]

one easy try is brake kleaner..its thik sticcy oil..vho is vent sirup..is you problem..
.so a kleaner is the vay..not a lube.
.try some spray or acetone..and after it have freed up use some wd 40 to lube it up.
..but first ..try to klean up use a strong kleaner
that is the only "homemade vay" using no tool