a couple carb questions

[donebysunday]

Originally Posted by jrm000kc View Post
What's the purpose of the two screws above each fuel port?

Have wondered the same thing.

The 2 screws are to flush internals of the petcock (ON/RESERVE/PRIME routes) clean without having to remove it and or the fuel lines. JMHO

[bikerphil]

RPM 's shoot way up when the clutch is pulled in. Idle RPM is fine

Check for vacuum leaks, cracked port caps, vacuum lines, etc. I would sync the carbs and adjust the idle mixtures, see if it persists. My bet is out of sync. carbs.

[DeanR]

What's the purpose of the two screws above each fuel port?

Have wondered the same thing.

also:

Well the ride down the road revealed something new, which I should know the answer to, but don't.
RPM 's shoot way up when the clutch is pulled in. Idle RPM is fine. What might be the reason for this?

I know you know out there!

[bikerphil]

I'd like to see if I can figure out a way to block that prime port.

Might help...

http://www.xs11.com/forum/showthread.php?t=35443

[jrm000kc]

Okay. Since there's no difference I see no point in messing with the octy. What's the purpose of the two screws above each fuel port? Instead of having to replace caps for the prime port I'll never use again is there any type of single fuel port replacement anywhere?
I probably check/replace the gaskets and the screens on the internal tank petcocks. (I'm sure my tank has a lot of gunk in it.) I'd like to see if I can figure out a way to block that prime port. (Caps work-temporarily. I'd like to figure out a permanent solution.)

[Radioguylogs]

Is there truly any difference in performance between letting the gas gravity feed versus the diaphragm actually forcing gas? I would think the positive force of the diaphragm would deliver a better flow.

The diaphragm does not add any pressure to improve gas flow. The octy is just a valve that opens when it is actuated by the engine vacuum. So, the octy actually restricts the flow a tiny amount (negligibly) compared to removing it.

[motoman]

Wow them are some purdy carbs! Cleaned mine last year-but since I have no filters and the gas leaked out I think my enrichment ports are blocked since I have to give some throttle when I start up.

Don't ask my motives-but Sunday I went through my extra parts and saw the octopus I took off last year. Having some extra fuel line I decided to put it back on. I get about 99% done until I get to the part when I put the tank back on-and its a total PITA to get the darn fuel line to match up with the fuel ports. There's a very small threshold for getting them just right, and I tried about 3 different ways with different lengths of the braided nylon line I bought. Whatever way I tried I'd get a kink somewhere. Do the left and right carb hookups point up or down? Anyhow, I got tired of fiddling around and pulled everything off and went back to my 'H' arrangement-and to my dismay I didn't have any more plugs to put on the prime ports. I thought 'Off' meant what it says, but nope, I had gas running out.

Is there truly any difference in performance between letting the gas gravity feed versus the diaphragm actually forcing gas? I would think the positive force of the diaphragm would deliver a better flow. The Japanese engineers really did an awesome job on the XS as far as keeping things simple, but when I look at the octy I ask myself "why?". I know it keeps gas from flooding out but was that the only reason? I think I'll get some different fuel line and a new diaphragm and have another go with the octy.

None........vacuum pulls diaphram, which opens valve. No vacuum, valve stays closed....hopefully. Nothing magic goin' on there.

[jrm000kc]

Wow them are some purdy carbs! Cleaned mine last year-but since I have no filters and the gas leaked out I think my enrichment ports are blocked since I have to give some throttle when I start up.

Don't ask my motives-but Sunday I went through my extra parts and saw the octopus I took off last year. Having some extra fuel line I decided to put it back on. I get about 99% done until I get to the part when I put the tank back on-and its a total PITA to get the darn fuel line to match up with the fuel ports. There's a very small threshold for getting them just right, and I tried about 3 different ways with different lengths of the braided nylon line I bought. Whatever way I tried I'd get a kink somewhere. Do the left and right carb hookups point up or down? Anyhow, I got tired of fiddling around and pulled everything off and went back to my 'H' arrangement-and to my dismay I didn't have any more plugs to put on the prime ports. I thought 'Off' meant what it says, but nope, I had gas running out.

Is there truly any difference in performance between letting the gas gravity feed versus the diaphragm actually forcing gas? I would think the positive force of the diaphragm would deliver a better flow. The Japanese engineers really did an awesome job on the XS as far as keeping things simple, but when I look at the octy I ask myself "why?". I know it keeps gas from flooding out but was that the only reason? I think I'll get some different fuel line and a new diaphragm and have another go with the octy.

[tcoop]

Possibilities

1. Air/Vacuum Leak some where
2. Choke is still pulled out (BTDT)
3. Idle needs to be adjusted

[DeanR]

Well the ride down the road revealed something new, which I should know the answer to, but don't.
Rpm's shoot up when the clutch is pulled in. What might be the reason for this?

[LoHo]

A tip on fixing diaphragms that may have been covered:
Use the black Plasti-Dip, but be sure to dab it on BOTH sides of the pinhole. That way, it sticks to itself in the hole and forms a little plastic rivet that handles the air pressure from inside and outside the carb, which is its job anyway. Remember to clean around the hole with a Q-tip and appropriate solvent to help the mend stick.

[motoman]

Well, things are finally all buttoned up, starting well, running well in the garage and ready for a quick unregistered and uninsured jaunt down the street.

Thanks for all the help and guidance guys.

Good to hear it's back to life Dean...........now you can resolve that pesky coolant weep on the main ride and give it some test riding time before heading this direction in June.

[Prisoner6]

Well, things are finally all buttoned up, starting well, running well in the garage and ready for a quick unregistered and uninsured jaunt down the street.

BTDT ...

Good job, Dean ... glad you have her running so well!

[DeanR]

Well, things are finally all buttoned up, starting well, running well in the garage and ready for a quick unregistered and uninsured jaunt down the street.

Thanks for all the help and guidance guys.

[LoHo]

Hopefully you put the filters on while the carbs were off, a much simpler task.