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Dies with sudden stop

Old 05-29-2017, 06:44 PM
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Dies with sudden stop

Ladies and gents,

I did the caliper+M/C mod on my bike. I used 929RR calipers, and a non-ABS M/C from a 2013 600RR. As far as I could determine the 929RR calipers are the same size pistons as the stock SH's, and the 600RR/2013 M/C I believe is around 17.5 mm diameter. Everything was straight bolt-on with the calipers needing a little grinding (which I learned is standard) to let the lower mounting bolt mate up. I'm still evaluating the brakes but they stop pretty good w/ EBC sintered pads and braided steel lines. The lever's a little spongier than I like so right now I've got a tie-wrap on the brake lever and the lever fully depressed; I'll remove the tie-wrap in the morning. I think the 'spongy' issue is just air; I don't suspect the caliper-M/C combo.

I took the bike out to a deserted street on the backside of my tract and tested to see how well it stopped. It stops really well even without the pads bedded-in. The downside is I discovered the bike dies every time I do a hard stop. Starts up after a moment. Not immediately, but within 5 seconds.

The bike died once last week as I was rolling down the road at 70. I thought I hit the run/stop button by accident (I was fiddling with the right mirror).

A day or two later it died as I was leaned over pretty good as I was 'swooping' into a parking space at work.

I suspect most of these events, if not all of them, are related to the same root cause...

I thought the fuel pump was starving for fuel. Then I read and learned there is no fuel pump. Gravity. Now my theory is the pickup in the tank is going uncovered with the surge of fuel to the front of the tank during a hard stop (or to the side when leaned over), the carbs suck air, the bike dies. There was a little less than 1/2 tank today, as I was doing my stopping tests.

I've read about the vacuum petcock, as well. I have no insights into how it might be related to this issue. Running down the road, I can roll on and accelerate without issue. It's just the hard stops that are killing the engine. And possibly turns at 20* or more. (I think I DID hit the kill switch when it died at constant velocity at 70 the other day...but...)

Any of you folks had a similar problem, or have an idea what might be going on?

Addendum: I just went out, opened the gas cap, and looked into the tank w/ a flashlight. I can see a 'structure' slightly offset from the fuel filler that protrudes upward into the tank. I suppose the other side (external to the fuel tank) feeds the petcock? If that's the fuel pickup its base (the level of the tank where it sits) is only covered by about 1/4 inch of gas (with the bike level) at an indicated 1/2 tank on the gauge.

Tomorrow I'll fill 'er up and conduct additional experiments.

Thanks,
alan

Last edited by AlanS; 05-29-2017 at 07:16 PM.
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Old 05-29-2017, 07:31 PM
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Check carb hoses for proper position.
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Old 05-29-2017, 07:37 PM
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Ok. I'm looking at the service manual and I'll check the bike in the morning. Thanks, thetophatflash.

Alan
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Old 05-30-2017, 05:09 AM
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Did it repeat the issue with a totally full tank?
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Old 05-30-2017, 07:19 AM
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Originally Posted by thetophatflash View Post
Check carb hoses for proper position.
IIRC this is a service bulletin item. From what I have read it fixes the issue.
Strangely my bike use to do this and then stopped, (see what I did there?) I did not reroute the hoses.

Take a look at this thread. https://www.superhawkforum.com/forum...ke-mods-13176/
Some of the soft feel of the lever might be the slight mismatch of caliper/master ratio. Have read that the 32mm/30mm caliper w/17.4mm master is the sweet spot for these generations of brake components. It's what I'm using and the feel and control is good. Had the smaller stock master for a short time and the lever was never really solid, as in a little spongy.

You'll know better when the zip tie comes off.

Last edited by xeris; 06-01-2017 at 06:50 AM. Reason: sp
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Old 05-30-2017, 10:28 AM
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The brakes feel pretty good to me. They are certainly more powerful than the stock brakes. I thought the stockers would be ok. Then I had an occasion where I wanted a little more brake. I don't like the sense of nearing the limit on braking; I like some 'reserve'. As for the lever feel, it's good. I'll have to ride it a bit, break in the pads, maybe bleed it once more after a couple of days to be content. Xeris, I tried to hit that 'sweet spot' but not sure of the 2013 M/C diameter. I guessed it was about 17.4mm (LOL). Even so, I can certainly live with the current lever feel, and I might even prefer it so long as the brakes don't fade if I get spunky and/or do a track day/class (I want to do Code's Level II on this bike).

Wolverine, it stalls on a full tank. This is not a fuel issue. Or at least not related to the tank level. I have not checked the carb hose routing yet, as a couple of you have suggested. But if that's an issue, then I have at least two things going on...

There's something 'electrical' that's amiss. Even with the bike rev'd to 3K, when I apply the brakes I see the other lights dim a bit. Now, randomly (at least I haven't established a pattern other than it's at or near idle) the bike dies suddenly. It starts right back up. Also, sometimes at low RPM when I'm moving the bike (at least I don't believe it's me! LOL) makes a weird, 'groaning' sound. It doesn't always do it at low speed, but when it occurs it's always at low speed/RPM.

Because the bike ran so well when I got it, I'm pretty sure one of the mods I made have affected something adversely, either directly or indirectly...or, something has failed. As for the carb hose routing, I might not have noticed that sooner because, frankly, I haven't stopped as 'passionately' as I've been doing recently in order to test the brakes.

As always, thanks sincerely for the help...

Alan
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Old 06-01-2017, 06:54 AM
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Not to imply that the set up you have is wrong. Any brake upgrade should be an improvement over the stock components.
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Old 06-01-2017, 07:55 AM
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xeris, no, I didn't take your earlier comment that way.
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