Carb hose and other sundry questions

Started by bdfinally, April 04, 2015, 09:53:24 AM

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ducpainter

Quote from: bdfinally on May 23, 2015, 03:28:51 PM
Pulled both, look like the cup of coffee with creamer in I'm having. What's aggravating is they wrote on the back of work order that they test rode it.
Well, it ran fine for you for two days, and they might not have taken it on a top end run.

Does the shop have a dyno?

Am I correct in that it didn't have these issues before the carbs were rebuilt?
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."



bdfinally

Don't think they have a dyno. I'm going to blow that vent out in the morning and check that it isn't chinked somewhere.

Ran fine during the morning ride of the day I started pulling the carbs off.
The tyranny of the rat race is not yet final...HST

ducpainter

Also check the little rubber nub that sits under the cap. They can get deformed and lock the vent hole in the cap.

I removed mine which makes the routing of the hose not critical.
"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."



silas

Bd/ Nibor, have the emissions lines and pods been removed from the stock carbs ?   Before I got flat slides I had the same occasional bogging down at high speed or hwy winds. 98 M900.   If I slowed down to 60 mph it would stop bogging and eventually pull clean again until the next big wind or sustained higher speed run( over 70mph). Then it would start bogging again.  My mechanic at the time, who is very experienced w these bikes, said that it happens at higher speeds on these bikes w OEM carbs when their emissions system is removed. I trice many things and never got rid of it on the old carbs. (Didn't have or want emissions stuff anymore) . Hwy trips were stressful but I succeed to the FCRs. 



Quote from: bdfinally on May 23, 2015, 06:39:49 PM
Don't think they have a dyno. I'm going to blow that vent out in the morning and check that it isn't chinked somewhere.

Ran fine during the morning ride of the day I started pulling the carbs off.
Ride fast, ride safe
'98 M900, '92 Yamaha TDM850

silas

Following up From my prev post...the air pressure differential gets messed up on stock carbs at higher speeds when the emissions system is removed, causing fuel starvation at high speed and high winds. 


Quote from: Nibor on May 23, 2015, 08:35:50 AM
I had some intermittent problems with fuel starving/flooding/something on the 750. basically when I was giving it stick, especially over $1.20, for a while, it would stutter and die. if I caught it quick and rolled off I could drop to 60 and limp for a while, otherwise i'd be on the side of the road for 10min before starting up again.

no idea what it was, but i've got some FCR39's for the rebuild  [Dolph]
Ride fast, ride safe
'98 M900, '92 Yamaha TDM850

Howie

Quote from: silas on May 24, 2015, 08:53:08 AM
Following up From my prev post...the air pressure differential gets messed up on stock carbs at higher speeds when the emissions system is removed, causing fuel starvation at high speed and high winds. 



Good possibility.  If this is the case, run the vent hoses down the back of the engine so they are in quiet air.

bdfinally

Yes, pods are gone. I've run those vent lines up under the battery tray and up behind it. Same as they were before this adventure began. I'll check to make sure they're not pinched or kinked under there. Blew the tank vent line out and the hole in the gas cap with compressed air. That rubber nipple has be gone for a couple of years. Opened up the air box and cranked it, slides seem to be moving fine. Just took it for another test ride and once I get up to 45+ in 4th. gear it'll start sputtering.
The tyranny of the rat race is not yet final...HST

Howie

Too lazy to go through the four pages.  How is the fuel pump/  The fuel line between the pump and carbs?  The filter in the carb inlet?

koko64

Or if the vacuum tap is restricting flow at higher revs. They come up here a lot.
2015 Scrambler 800

bdfinally

Quote from: howie on May 24, 2015, 02:57:00 PM
Too lazy to go through the four pages.  How is the fuel pump/  The fuel line between the pump and carbs?  The filter in the carb inlet?

I rebuilt the pump a month or so ago. Fuel lines are all new, except for one five-six inch section from my manual petcock that makes that crazy turn into the pump. Filter into carb don't know, I assumed the shop took a good look at that when they rebuilt the carbs.
The tyranny of the rat race is not yet final...HST

ducpainter

Quote from: bdfinally on May 24, 2015, 05:46:10 PM
I rebuilt the pump a month or so ago. Fuel lines are all new, except for one five-six inch section from my manual petcock that makes that crazy turn into the pump. Filter into carb don't know, I assumed the shop took a good look at that when they rebuilt the carbs.
We all assume.

Still...it worked before it got make the beast with two backsed with and now it doesn't.

Just sayin'

"Once you accept that a child on the autistic spectrum experiences the world in
 a completely different way than you, you will be open to understand how that
 perspective
    is even more amazing than yours."
    To realize the value of nine  months:
    Ask a mother who gave birth to a stillborn.
"Don't piss off old people The older we get, the less 'Life in Prison' is a deterrent."



koko64

Manual tap - Tick [thumbsup]

Wonder what the float level settings are now. Should be 14mm for those Mikunis.
You know, bypassing the pump with a full tank of gas will reveal a lot.
2015 Scrambler 800

bdfinally

I hear ya, DP.

Looking at the parts diagram is that filter just pushed in loose.

The tyranny of the rat race is not yet final...HST

bdfinally

Quote from: koko64 on May 24, 2015, 06:07:18 PM
Manual tap - Tick [thumbsup]

Wonder what the float level settings are now. Should be 14mm for those Mikunis.
You know, bypassing the pump with a full tank of gas will reveal a lot.

You think the pump is not pumping enough? I guess I could have screwed that up, but it looked awfully straight forward to me.
The tyranny of the rat race is not yet final...HST

koko64

Worth double checking. You never know for sure until you double/triple check ;D
2015 Scrambler 800