problems again

[79XS11F]

That "CHH" sound "may" be a head gasket and if you don't have compression that cylinder will not run well if at all.
Do a compression test to confirm that the head gasket and for that matter the valve seats are good.
Rob

[xsscooters]

petcock

The bike runs perfect with the petcocks on prime mainly the left one . I'm going to take them both apart tomorrow . When its on prime does it have continous gas flow ? I also foung out what the CH sound was there was a hairline crack in the the no 2 cyclinder spark plug ceramic like to never found it .

[79XS11F]

Yes on prime you have continual fuel supply. glad to hear that the "CHH" sound was not a gasket
Rob

[xsscooters]

Prime

Why would the bike run perfect on prime and not on reserve or on main ? i took the petcock apart it was kinda dirty but seems fine . I missing something here ... Mike

[79XS11F]

Because on "prime" the fuel is free flowing without the need or assistance of vacuum from the engine. If the engine is running good on prime but not on the other settings then I would say that your search for your problem should start with the petcocks and or vacuum supply lines. The petcocks must be very clean to work correctly. Also check that the air supply hole in the gas cap is not plugged.
Rob

[Ken Talbot]

Re: Prime

Originally posted by xsscooters
Why would the bike run perfect on prime and not on reserve or on main ? i took the petcock apart it was kinda dirty but seems fine . I missing something here ... Mike

Looking at your profile, I see you've got a Special. Petcocks on a Special are pretty simple devices. More often, the octopus will give you trouble. For instance, if you do not have all that mess of plumbing correct, you may not vacuum to the diaphragm in the octopus, and you will not get any fuel flow. How confident are you in the routing of all the hoses, and in the condition of the octopus?

[xsscooters]

Ken

It does'nt have the octopus anymore . The petcocks look fine but i ordered rebuild kits gonna try that... mike

[Ken Talbot]

Have you tried checking petcock operation with the tank off of the bike? Use some clear tube on each nipple and see what is actually happening as you cycle the petcock handles through their various positions. Sometimes these can be reassembled with parts mixed up from left side to right, and things don't work the way they're supposed to.

[xsscooters]

petcocks

yes i have tryed that gas flows freely on main and reserve but not on prime. thats what i can't figure out because it will only run on prime this is on the left petcock only the right one works fine .

[Erik the Red]

The petcock that doesn't flow... IIRC, there is a disc in there that has three holes in it. Something like 12 o'clock, 3:00, and 6:00. My bet is that when it's turned to Prime, 9:00 (no hole) is keeping the fuel from getting down the fuel line.

Take it apart and figure out where each of the 3 holes in the handle piece of the petcock is and rotate the disc to match. It should work okay then.

[John]

Re: petcocks

Originally posted by xsscooters
yes i have tryed that gas flows freely on main and reserve but not on prime. thats what i can't figure out because it will only run on prime this is on the left petcock only the right one works fine .

Any chance the ring on the petcock that has the functions stamped in it, OR the petcock handle may have been switched at some point in time? That is what it sounds like to me.

[79XS11F]

Sounds like the petcocks are messed up somehow. Perhaps they were taken apart by others and not put back together properly. You should have no gas flow from on and reserve with the engine not running and only see fuel flow in the prime position. Also keep in mind the petcock function is what is UNDER the lever arm in any position.
Rob

[skids]

Read Ken Talbot's reply. I have mixed-up the handles on rebuilds before on a standard. They are not interchangable!

[xsscooters]

petcock

i've had it apart 3 times i"m positive its right . If it was put together wrong why did it work for almost a month before it messed up ?

[79XS11F]

OK you say the bike runs good in the prime position and also say that the prime position is the only position that will not allow fuel to flow when the tank is off the bike or the engine is not running.. If this is correct then I will have to conclude that the engine is being flooded at random times when the fuel petcock is set to anything other then prime. For whatever reason prime is working like on and reserve should. If a fix can not be found just run the bike in prime so long as fuel is in fact not flowing when the engine is off. also ... are these original petcocks?
Rob