shewie

Originally posted by smurf211

This post is an effort to raise awareness of potential damage to the ECM when performing the Fuel System Flow procedure. The procedure is a proposed regular maintenance window to be performed every 8k miles/ 12km. The procedure on page 5-57 in the FSM calls for removing the fuel cutoff relay and placing a jumper between the black/ white wire (12volts) and the brown wire on the plug. This bypasses the ECM and provides a continuous 12 vdc to the fuel pump. Measuring flow for 10 seconds into a marked container, expected results should >220cm3 or 7.3 fl ozs.

If you make a mistake and place the jumper on the brown/black wire, it sends a 12vdc signal back into the ECM and damages your fuel control circuitry resulting in the need to replace the ECM.

Please reference the following two posts, one contained within the other:

http://www.cbrxx.com/engine-airbox-e...tml#post110843

These procedures are to verify flow, pressure and fuel pump operation. What it did for me was indicate that I had a partially clogged fuel filter that was lowering my performance numbers across the graph.

Read the documentation relevant to your year and pay close attention to applying jumpers. A simple mistake can be costly. --- HTH


R/ smurf

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CanadianBird

I know this is probly good advice however at what point would one know this was necessary? My tech told me my fuel system was fine. I don't feel anything amiss. I would have to pay for this test and I would need a reason to request it. I suppose this is the advantage you and others have over a peep like me.

TheDuck

I ran the test when I was getting The Duck up and running. No fuel appeared to be reaching the cylinders (although there appeared to be pressure in the injection rail) so I needed to check the whole system through.
When would the test normally be required? IMO only when the bike has a coughing fit / down on power and plugs and air filter have been ruled out.

smurf211

This test is part of the 8k/12km maint interval. It is vague in the documentation but is also part of the fuel system check in Chapter 5. I performed this test due to poor dyno numbers but also wanted to change the Fuel Sending Unit along with the Fuel Filter. I used the jumper to drain what was left in the tank, < 2 gallons, and performed the test in conjunction with that effort. I did not perform the fuel pressure test. I'm still looking for a gauge just haven't gotten to it yet. As a rule of thumb, if you are having performance issues run the test. There are a couple of threads on here that claim the fuel filter is never a problem. It all depends on the individual situation and circumstances surrounding your bike. I bought my bike from a LEO. It had 8.5k miles on it. LEO put ~2500 miles on it in less than a year. So 6k over seven years, bike sat in the garage for too long, almost a semi storage state. Where the residue in the tank came from I have no idea. I will be changing the filter out again in the winter. From there I am going to regular maint intervals. hth.... smurf

X1rider

Good advice for any unit that as been sitting for a long time with out StaBil in the fuel system.

Wouldn't a large dose of Sea Foam and an extended high speed run help in these matters? Or am I just totally wrong. I have never had to check this on my bike; longest time it sat was last summer while I was working in SoCal. Sat from 5/8 till 7/18, rode hard for a week, then it sat for 4 weeks. With StaBil.

smurf211

I did the Sea Foam treatment and really didn't think it was a problem. I think it was Silverbird that changed his and found low flow when he blew through it. After my Dyno run I was in "process of elimination mode" and I didn't discount anything. I can only think that the original owner did exactly as you described and let it sit for extended periods without any fuel stabilizer. I still can't explain the residue inside the tank. It wasn't much but it was a fine film. The air filter didn't give any clues when I changed it out. I don't know what stale aged fuel looks likes or accumulates as, or what kind of by products it produces. All I know is the problem is solved now and don't discount the fuel filter or fuel pressure regulator if you are having lower than expected performance numbers.
I'd really like to dyno it now. With the intake opened up and the full exhaust, and with this problem solved there is a definite seat of the pants difference. I just can't spring the $250 for a performance tune. Maybe I can get my shop to do a couple of runs just to see the numbers. I'm currently running the Yoshi map form the web page specifically for the full race system. I'll ask and see what he says and how much it will be just to see where we are.

smurf211

Dyno results after all this went from 132/75 to 140/80. Needs tuning but it'll have to wait. //

Attached Images

New Dyno run II_1.jpg (158.6 KB, 10 views)

VideoMike

You guys are certainly right. Yes, the switch transistor can be destroyed along with the foil traces on the printed wiring ass'y (if the ECM wants the fuel pump turned on at that time. Pretty likely.

Good info.

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