2003 CBR600RR won't start hot

[Tricky Mike]

So, last season I was having some strangeness with the track macheen...
It starts right up no problem when it's cold. If I go out and run a solid 20-minute session and the bike gets good and hot it won't start if I shut it off and immediately try to restart it. Bump starts no problem. If I let it cool for 50-60 minutes it starts right back up.

When it doesn't start, it feels like a dead battery. The starter tries to turn the motor over, but generally only gets through one or two cranks with a decreasing amount of power per "crank."

I bought a new Yuasa battery when I bought the bike a few years back (2009?), so it's possible that the battery is farkled. I did swap it with the Yuasa that came with the bike and had the same issue when it got hot. I happened to have a spare starter motor on the shelf so I swapped that out and voila... The problem went away for the second half of last season. On Monday the problem is back. I should probably buy another battery, but does anyone have any ideas here? I may also replace all of the battery to starter wiring with new 4-ga stuff. Any idears?
Thanxxxooxxxoo

_trickery

[DucDave]

I'd leave it. The entertainment value watching you jump start it is priceless....


(Was that helpful?)

[Tricky Mike]

Dave if you do the pushing I think we have a deal.

[shortbus]

With cars no hot start means I would check the starter motor first.

Test the battery first under a load when starting cold or hot etc. (autozone has the load testers for free too)

The starter relay can suck when it gets too hot too, dunno if you can replace it with an off the shelf from an auto store or need a Honda one. Check voltage at starter when hot starting, or test by running 12v and ground directly from battery to starter when it normally won't start.

Try cleaning the starter, if that doesn't work look into a new one?

"Clean the armature, commutator. When you do the stator (windings around the outside) smack the housing a few times and a lot of carbon should come out."

[JohnnyV]

Dave if you do the pushing I think we have a deal.

[Pittenger5]

Leeza's bike wont start cold, maybe if we trade parts it will balance out?

[akira700]

Maybe a Temp Sensor in the fuel management loop malfunctioning? 03 is FI right?
I had a short in the battery that would do that when humid and hot... it had charge but would fail
under load intermittently but not only when hot... So maybe not similar to you.
Get your Batts load tested at a shop to rule that out.

[jasnmar]

FI possibly.

I'd guess starter. Had something very similar with a car just a few months ago.

Get in cold, starts right up. After driving, try to restart, starter would "partially" engage (skipping off flywheel teeth), to do nothing.

New starter, problem gone.

[shortbus]

I'll be at NHMS the 17th and 18th, I can bring my Honda's starter relay if you wanted to test what a known good one does before moving onto the starter.

[aldend123]

What do you know of the bike's history? Is it possible the rings or pistons were replaced a size slightly too large, so when the bike is track-ridden-hot everything swells up and requires massive draw from the starter?

[Tricky Mike]

It's a stock motor. It's just interesting that I already replaced the starter (admittedly with another used part) and the problem seemed fixed but is now back.

[pcakes55]

I would definitely lean towards the relay, its pretty unlikely you'd have the exact same problem with another starter. Definitely inspect the starter as blackbird said though, its pretty easy; I think i used brake cleaner to clean mine.

[Jim]

would the regulator rectifier have anything to do with this?
i'm just guessing

[tsanterre]

How hot is hot?

220+?

How cool is cool (after 50-60min)?

Are you 100% positive it's not starting due to the temp?

[Degsy]

Wirelessly posted

What do you know of the bike's history? Is it possible the rings or pistons were replaced a size slightly too large, so when the bike is track-ridden-hot everything swells up and requires massive draw from the starter?

Holy random.

[Tricky Mike]

yeah, like 220-ish. not sure exactly what temp it's at when it decides to start again. The temp is the only trigger I've noticed for the problem.

[burnham]

Could you get it hot and then try to start it by jumping out the relay? Might rule a couple things out.

[jasnmar]

The only reason I don't think it is a relay is because relays are usually pass / fail.

Relays tend to work / not work. If, under hot conditions there was nothing, OK, I'd give relays a larger possibility.

For a relay, mostly, it works or it doesn't work given a set oof circumstances. It is rarely "partially working" in consistent situations.

The fact that the starter turns over a couple "cranks" is an indication of a power problem. Either the starter requiring to much, or the supply source not providing enough, but relays don't generally fail in that way (don't get me wrong, they can, and the fact that I'm thinking it isn't a relay means it probably is).

$0.02?

[Tricky Mike]

Yeah, that's kind of where I'm at. If it wouldn't crank it would be a different story. Seems it's gotta be either battery, wiring or starter motor.

[Degsy]

Wirelessly posted

I don't think it's the battery or starter.

Ohms law.

There's high resistance somewhere when the components are hot. Either a power connector or a bad ground.

When you replaced the starter, did you replace the cable up to the starter relay assembly?
The large contacts on the starter relay are a common cause for problems. I would check they are screwed on tight.

And Jim is right, the reg/rec is a thermally affected component and can cause no start when hot. Check the connector for brown burns on wiring. This is a sign its bad.

That bike has a Zener diode in the ignition switch unit that can also fail when hot and cause a no start condition. As can the temp sensor on the back of the thermostat assembly (although you would likely have an FI code if that failed)

As always, check the grounds on the left side of the frame and the little yellow ground common point under the fuel tank.

[Tricky Mike]

Thanks Degs. Yeah, I hadn't ruled out the reg/rec. It was (is?) a known Superhawk issue and I wouldn't be surprised if the part is similar if not nearly identical. I'm planning on making all new 4ga cables. Was talking to Eric Colbath about it on Monday and he said he has seen them age poorly. It's also a cheap fix.
Maybe take it from there. The good thing is that the bike runs fine after I bump it, it's just kind of a pain in the ass.

[tsorfas]

I love diagnostics threads.
Degs rocks
Good luck tricky

[Degsy]

Wirelessly posted

I wouldn't say I rock. I have had 2 of these 600RRs absolutely kick my ass for days or weeks with electrical problems and learned a lot in the process.

mike, I suspect the extra draw that is killing the battery is also pulling down the power to the plugs, fuel pump or injectors also. That's why even though it turns over, it won't catch. When you bump it, you aren't using the starter circuit, so it's not pulling power from the low current stuff.

[R7]

My old truck did the same thing you describe when I first got it..start perfectly when the engine was cold, but once warm it would crank slow and sometimes not start. Not sure what sets the ignition timing in newer bikes, but in my case the ignition timing jumped forward a bit (distributer bolt was lose) and was the problem. Once I set it to spec, never happened again. Just thinking outside the box a bit, not all starting issues are starters/power/battery related.

[Degsy]

Wirelessly posted

Ignition timing on the CBR I THINK is from the cam position sensor and/or crank position sensor. Neither can be out of adjustment. Good thought though.