1982 CB900C slowly dies - Page 2

dragracer1951 · 08-08-2012, 09:01 AM

These carbe have weird slide diaphrams....
Is there an Oring at teh top on the orifice that supplies vacuum to the top of the slide?
Might be missing or dried out

ejether · 08-08-2012, 09:16 AM

Originally Posted by dragracer1951

These carbe have weird slide diaphrams....
Is there an Oring at teh top on the orifice that supplies vacuum to the top of the slide?
Might be missing or dried out

They are there and the vacuum resistance when I move the slides is smooth and feels ok. They are fairly rigid though, do you know if they are supposed to be very soft?

dragracer1951 · 08-08-2012, 09:35 AM

Those have metal diaphrams. Yes?
I wonder if there is some corrosion in there binding up the slide

ejether · 08-08-2012, 09:43 AM

Originally Posted by dragracer1951

Those have metal diaphrams. Yes?
I wonder if there is some corrosion in there binding up the slide

Yep, metal.
Everything in there is shiny.

I ordered a new seal kit and air cutoff valve which puts me $100 over budget on this project but I'll make it back when I sell the bike.

dragracer1951 · 08-08-2012, 11:18 AM

It would make sense that the slides are not riseing if those cyl are not fireing. I suspect you are on the right track with enricheners

ejether · 08-13-2012, 10:11 AM

I installed new air cutoff valves and started it back up and it was a little better but still bogging, sucking down gas at an alarming rate.
I removed the air filter and it revved right up.
I'm trying to clean it again but I may end up having to replace it.

Thanks for the tips guys!

Desvio · 08-13-2012, 11:46 AM

Originally Posted by ejether

I removed the air filter and it revved right up.
I'm trying to clean it again but I may end up having to replace it.

Thanks for the tips guys!

Uh, you are trying to clean the air filter???

ejether · 08-13-2012, 11:52 AM

Originally Posted by Desvio

Uh, you are trying to clean the air filter???

Its a UNI brand reusable air filter.

Desvio · 08-13-2012, 12:09 PM

Originally Posted by ejether

Its a UNI brand reusable air filter.

Gotcha!

Not really thrilled with their filters in street bikes, but they work well in most.

ejether · 08-13-2012, 05:41 PM

Cleaned filter and its still shyte.
Removed filter and its lean-popping some.

New filter on order.

dragracer1951 · 08-13-2012, 06:11 PM

Put the stock airbox back in it.
Not enough vacuum impulse to overcome the non resonance of teh airbox being gone walkabout.

ejether · 08-13-2012, 09:24 PM

Originally Posted by dragracer1951

Put the stock airbox back in it.
Not enough vacuum impulse to overcome the non resonance of teh airbox being gone walkabout.

Never took the stock airbox off of it, I just pulled out the clogged Uni filter and it runs much better. Not perfect, but it runs on all 4 cylinders and has really good throttle response to reving.

I tried it without the airbox cover on and no filter and it was surge-y and had a hanging idle. No filter and airbox cover on and the hanging idle is better but it starts to backfire a little at mid throttle.

I've got an OEM style air filter on its way.

I think the previous owner had left the petcocks and either the gas/oil result got pulled into the airbox while it was running, or back flowed into the airbox just enough to destroy the Uni filter over time.


08-08-2012, 09:01 AM	#21
dragracer1951 Joined: Sep 2005 From: Bremerton I Ride: 05 KTM 625smc, 03 Are See fiddy one, 05 DRZ470SM, 95 FZR1040, 69 Combat Commando Roadster, 73 Commando Interstate, 67 BSA B44, 71 BSA B50	These carbe have weird slide diaphrams.... Is there an Oring at teh top on the orifice that supplies vacuum to the top of the slide? Might be missing or dried out __________________ Follow PNW Riders on Facebook and Twitter


08-08-2012, 09:35 AM	#23
dragracer1951 Joined: Sep 2005 From: Bremerton I Ride: 05 KTM 625smc, 03 Are See fiddy one, 05 DRZ470SM, 95 FZR1040, 69 Combat Commando Roadster, 73 Commando Interstate, 67 BSA B44, 71 BSA B50	Those have metal diaphrams. Yes? I wonder if there is some corrosion in there binding up the slide __________________ Follow PNW Riders on Facebook and Twitter


08-08-2012, 11:18 AM	#25
dragracer1951 Joined: Sep 2005 From: Bremerton I Ride: 05 KTM 625smc, 03 Are See fiddy one, 05 DRZ470SM, 95 FZR1040, 69 Combat Commando Roadster, 73 Commando Interstate, 67 BSA B44, 71 BSA B50	It would make sense that the slides are not riseing if those cyl are not fireing. I suspect you are on the right track with enricheners __________________ Follow PNW Riders on Facebook and Twitter


08-13-2012, 10:11 AM	#26
ejether Permit Joined: Jul 2010 From: Portland, Or I Ride: 2007 Yamaha FZ6	I installed new air cutoff valves and started it back up and it was a little better but still bogging, sucking down gas at an alarming rate. I removed the air filter and it revved right up. I'm trying to clean it again but I may end up having to replace it. Thanks for the tips guys! __________________ Follow PNW Riders on Facebook and Twitter


08-13-2012, 05:41 PM	#30
ejether Permit Joined: Jul 2010 From: Portland, Or I Ride: 2007 Yamaha FZ6	Cleaned filter and its still shyte. Removed filter and its lean-popping some. New filter on order. __________________ Follow PNW Riders on Facebook and Twitter


08-13-2012, 06:11 PM	#31
dragracer1951 Joined: Sep 2005 From: Bremerton I Ride: 05 KTM 625smc, 03 Are See fiddy one, 05 DRZ470SM, 95 FZR1040, 69 Combat Commando Roadster, 73 Commando Interstate, 67 BSA B44, 71 BSA B50	Put the stock airbox back in it. Not enough vacuum impulse to overcome the non resonance of teh airbox being gone walkabout. __________________ Follow PNW Riders on Facebook and Twitter

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