Help with petcock problem
#1
Help with petcock problem
I let my bike sit most of last year. I was busy and I wanted to replace the CCTs before I started riding it a lot. So I finally replaced the CCTs last month. I did the "stopper/failsafe mod." Finally, I was ready to have a great summer riding the bike. Wrong. I fired it up and it ran like crap. I could smell gas when I fired it up, it idled horribly and when I rolled on the throttle on the highway it barely accelerated. Ugh. I am 99% certain the problem is not related to the CCTs. I read every post on how to replace them before I attempted the job and verified the timing chain didn't skip. I know I properly measured the 8mm stock I put in the CCTs because, when I released them, I could feel that I got about 1/4 turn of spring tension before the CCT made contact with the cam chain.
After reading a lot of posts on the forum, I saw that the petcock diaphragm was a likely culprit, so I ordered a K&L rebuild kit. (Mistake, I should have ordered the Honda one which is about the same price and has more parts). I replaced the diaphragm and reassembled the petcock. I thought I should verify that, when there was no vacuum, the petcock blocked fuel flow, so I turned the tank over and fuel started draining out both carb tubes completely unimpeded. I took it apart again (twice) and verified that I assembled it correctly but each time the petcock did not block the flow of fuel like it is supposed to. I tried reinstalling the old rubber pieces and got the same result. I am stumped. The petcock is a really simple device - the spring pushes against the plastic disc attached to the big diaphragm, which is attached to the small aluminum cylinder, which is attached to a rubber stopper that is supposed to block fuel flow until vacuum is applied to overcome spring pressure. It's all assembled correctly but it's not blocking fuel flow.
Anyone have any idea why my petcock is not blocking the flow of fuel like it's supposed to?
After reading a lot of posts on the forum, I saw that the petcock diaphragm was a likely culprit, so I ordered a K&L rebuild kit. (Mistake, I should have ordered the Honda one which is about the same price and has more parts). I replaced the diaphragm and reassembled the petcock. I thought I should verify that, when there was no vacuum, the petcock blocked fuel flow, so I turned the tank over and fuel started draining out both carb tubes completely unimpeded. I took it apart again (twice) and verified that I assembled it correctly but each time the petcock did not block the flow of fuel like it is supposed to. I tried reinstalling the old rubber pieces and got the same result. I am stumped. The petcock is a really simple device - the spring pushes against the plastic disc attached to the big diaphragm, which is attached to the small aluminum cylinder, which is attached to a rubber stopper that is supposed to block fuel flow until vacuum is applied to overcome spring pressure. It's all assembled correctly but it's not blocking fuel flow.
Anyone have any idea why my petcock is not blocking the flow of fuel like it's supposed to?
#2
Figured it out. When I assembled the pieces, I put the "plunger" rubber piece on the wrong side of the metal cover. Yes, it was an idiotic move. I was thinking about just deleting the thread rather than admit to my stupidity but decided someone else might benefit from my mistake.
The good news - the petcock works. The bad news - the bike still runs rough. Well, I wasn't doing anything tomorrow anyway.
Updated to add: I found the problem. The front spark plug lead was loose. Apparently, I put it on until it clicked, not realizing that I should have put it on until it clicked 4 or 5 times. It must have vibrated loose and the front cylinder was only occasionally firing (if at all). Took my baby out to put fresh gas in it and when I rolled on the throttle she tried to rip me off the handlebars just like old times. The bike has done very well after sitting for 9 months with minimal care. Now I'll have to do an oil change and clean her up and she's ready to ride this summer. I still haven't replaced the stock regulator/rectifier but I've got one of the later stock ones with cooling fins that are (supposedly) less likely to fail than the earlier non-finned ones. I'll upgrade to MOSFET over the winter.
The good news - the petcock works. The bad news - the bike still runs rough. Well, I wasn't doing anything tomorrow anyway.
Updated to add: I found the problem. The front spark plug lead was loose. Apparently, I put it on until it clicked, not realizing that I should have put it on until it clicked 4 or 5 times. It must have vibrated loose and the front cylinder was only occasionally firing (if at all). Took my baby out to put fresh gas in it and when I rolled on the throttle she tried to rip me off the handlebars just like old times. The bike has done very well after sitting for 9 months with minimal care. Now I'll have to do an oil change and clean her up and she's ready to ride this summer. I still haven't replaced the stock regulator/rectifier but I've got one of the later stock ones with cooling fins that are (supposedly) less likely to fail than the earlier non-finned ones. I'll upgrade to MOSFET over the winter.
Last edited by Danno; 07-13-2019 at 11:03 AM.
#4
Updated to add: I found the problem. The front spark plug lead was loose. Apparently, I put it on until it clicked, not realizing that I should have put it on until it clicked 4 or 5 times. It must have vibrated loose and the front cylinder was only occasionally firing (if at all). Took my baby out to put fresh gas in it and when I rolled on the throttle she tried to rip me off the handlebars just like old times. The bike has done very well after sitting for 9 months with minimal care. Now I'll have to do an oil change and clean her up and she's ready to ride this summer. I still haven't replaced the stock regulator/rectifier but I've got one of the later stock ones with cooling fins that are (supposedly) less likely to fail than the earlier non-finned ones. I'll upgrade to MOSFET over the winter.
https://www.superhawkforum.com/forum...d-coils-35230/
https://www.superhawkforum.com/forum...53-00-a-34792/
#5
Cure for both those issues
https://www.superhawkforum.com/forum...d-coils-35230/
https://www.superhawkforum.com/forum...53-00-a-34792/
https://www.superhawkforum.com/forum...d-coils-35230/
https://www.superhawkforum.com/forum...53-00-a-34792/
Looks like the fix I’m looking for..
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