Day at Barber Motorsports Park ends in tears
 

Ok well its not that bad really, I have an 02 Superhawk that is my main track bike, I love this bike for the track and for not having done any engine or suspension mods to her she still seems to be a very capable steed and has no trouble running with the big boys while cutting hot laps.

Here is the teary part. I was running a trackday, the heat here in Alabama was almost unbearable. The temp with the heat index was around 109 and it felt every bit of 120 in the sun with full leathers on.

I just pitted in for lunch and decided that I would have my rear tire swapped out during the break and and went out the first session after lunch to scrub her in so needless to say I wasnt running her too hard yet.

As my friend on a 636 zoomed passed me on lap 5 or so I picked up and tucked in behind him.. This is where it happened.

Coming out of the chicane I went from maintenence throttle to rolling onto full throttle and she went VERY FLAT, not jerky but FLAT no power. Then all of a sudden she had power so I thought ok im low on fuel... Nope gauge was reading fine no issues there.. I pitted in and checked the tank she still had plenty in there.

So I decided to check all my fuel lines and airfilter for obvious stuff or something simple that might have caused it to go flat. Next session I went out full tank of full supposedly clear lines and didnt even get past turn one when she did it again.

It sounds very choppy when running, I can open the throttle and somtimes she will pickup and go flat sometimes she is just flat from the get go. Almost like a fuel line being pinched or some obstruction,...

I was just wondering if this ever happened to anyone else in such a sudden manner. I have never had any issues with the bike, I keep her well maintained and she only has about 24k on her and I replaced the plugs about 5k miles ago.

It happened during a session so I know that the problem is a first and it happend so sudden I feel that it cant be something crazy like a blown gasket or warpped head (hoping).

So I am going to pull the plugs and check those for spark, beyond that I am kinda lost as far as the troubleshooting goes. I checked for fuel flow and when I pulled the lines of they both had a decent amount of fuel in them. So I assumed she was getting fuel. Any ideas or simple troubleshooting tips for an issue like this would be awesome and a big help.

The next trackday is in september and I am hoping to get my girl up and running and get back out there and cut down my lap times!!

Judging from some recent threads and posts, I'd say check the petcock diaphragm. First turn the petcock off manually (so you don't spill fuel all over), then use a vacuum pump to see if the diaphragm holds vacuum. It should hold at least 21 inches of mercury without bleeding down.

Also make sure the fuel tank is venting properly.

I would deffinently check for proper venting on the tank as well. I was actually gonna do barber this weekend as well, but decided to do putnam park in Indiana instead. The heat was crazy there too..

what they said.


would you rather have had you bike come home like this?
Attachment 9729

WOW That happened to me a few years ago so for now I was pleased with the mechanical issue! It always sux to see a broken track bike!

Thanks for all the input I will start with the diaphram and the fuel tank issues..! I will keep you guys posted as to what the ailment is !

i had a similar problem my self once, i ended up finding my main jets laying in the bowls
of 2 carbs.
but listen to these guy check your lines and tank vent also.
make sure you dont have fuel line on the wrong nipple on the petcock also,been there done that!