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1982 CB900f Super Sport No Power Help!

2K views 11 replies 6 participants last post by  Blodhgram 
#1 ·
Hey guys! Great site, been reading a lot here!

Last fall i bought a CB900f SS form a friend that gave up on it so i figured id give it a whirl. She only has 15k on it and it is in great shape! The problem is she doesn't have any power over 6k rpm and good luck getting her there! She will fall on her face. Revs right up in N tho, gives a loud backfire sometimes tho just in N. If you crack the throttle over 1/4 (sometimes you can ease it slowly to 1/2) she will bog bog catch bog bog catch. It is a miss across all 4 Cylinders. Keep the throttle under 1/4 and u can ride her right up to 60mph through the gears.


Pulled every jet in carbs and ultrasonic cleaned for 8 hrs @ 150 Deg. Full rebuild kits. Stock Jets (Got to try the new ultrasonic cleaner out yay! They look brand new & shiny! great investment)
Synced with Gauges running at 2k rpm i don think i could get em closer.
Cleaned Pepcock new fuel line with inline filter.
New Plugs
Timing Chain Adjusted to spec
Good Compression across the board , within 5 psi of each other
Stock Air Box and filter, new rubbers between carbs and head and airbox.

I was thinking it was starving for fuel but i see good flow through my filter. Any ideas? Im kinda thinking IGN? I dont know it to well on these bikes. If so i have a CB750 DOHC parts bike, any parts interchangeable?

-Blod
 
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#5 ·
I Know, its been done. All jets are new factory set sir. They went in the cleaner fully disassembled then cleaned with air and carb cleaner.



What airbox/filter arrange,ent and what pipes and have you cleaned the pipes out?
Its the stock airbox and pipes. I have an aftermarket 4-1 racing pipe I haven't installed. i read that these 4's like the stock better.
I haven't pulled the pipes yet but each one of the 4 blows my hand off the pipe at idle so i figured they were good, ill take a look.
-B

Thx for thew replys!
 
#4 ·
So...electrics on the DOHC Honda are pretty terrible. the common fail points are reg/rect, stator, coils, pulse controllers. I have actually replaced all of those things on my brothers 1979 750F, and had a regulator/rectifier go bad on me on both my 900f and my friends 82 750f while riding it.

Get out the multimeter and do everything on this page:
79-83 Honda DOHC charging system procedure for troubleshooting, testing, and performance verification

then check spark on the plugs on all four holes.

Then get get out the timing light and check that the bike is timed correctly.

let us know all results.
 
#9 ·
Great news guys. Took her to work with me and pulled the pulse generator cover, Guess what i found?

The spacing between the pickup and cog was .020 not .002. Reset it with feeler gauges at .002 and she is a new beast!

I do have one cylinder running a bit rich, ill look into that but its totally ride able now! she will red-line! I literally hit 55 in second gear and couldn't hit 25 before!

-Blod
 
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