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Discussion Starter · #1 ·
Hi all, just joined this forum as i bought a K6 GSXR 600 last month. I found two issues with it recently:
1. The battery drains very quickly when the bike is off ( turns out the sidelights stay on all the time even after the keys are removed). Its a brand new battery
2. The Bike runs rough once it goes above 70degrees, and runs noticeably rougher above 90degrees.

I have just drained the fuel because I have no idea how old it is, and replaced it with Shells premium fuel and ran some injector cleaner through it. I ran the bike on idle for about 15 minutes to let the new fuel properly run through the system, and again once it got to 70 degrees and it started running rougher, and above 90 degrees ran even rougher. Its worth noting that it only seems to run rough at lower revs. Above 5k revs its much better.

I've been told by one person that it could be to do with the aftermarket exhaust its got on it (straight through), and been told by another person (a mechanic) that it sounds like the valve clearance needs adjusting.

I'm replacing the sparkplugs anyway so ill check them when i do so. Maybe the HT leads and coils as well?

Does anyone have any experience with problems like this?
 

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Welcome to the forum.

Rough running at idle could be a number of things.

First off, it is probably not an issue with valve clearances as they usually manifest themselves when the engine is cold. However, checking the clearances is not a bad idea if you have no record of when they were last checked and the bike has over 20k miles or so.

Easy thing first. What is the idle speed when warm? It should be about 1300 rpm.

Next would be a complete inspection of the intake boots and vacuum lines for leaks. That the bike runs better the higher the rpm goes, suggests an intake leak.

A throttle body synchronization might also be called for.
 

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Discussion Starter · #3 ·
Thanks for the info, John.

You're correct that it idles at 1300rpm.

I'll inspect the throttle body at the the same time I change the spark plugs. You made me remember when i had my first bike ( Honda CG125) that it had the same sort of issue. In the end that turned out to be the the intake manifold. It had a large split right down the side.

My only question would be why does this only happen once the bike has warmed up?

In regard to the throttle body synchronization, is this something i could do myself? What's involved?
 

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2004 GSXR 600, 1992 GSXR 750, 1983 XN85 Turbo & some Euro bikes
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As @rv6john already stated, easy stuff first. Change the plugs. If you don’t know when they were last done they could be the factory originals.

I had a similar issue on the yellow submarine where it would start and idle fine and randomly run rough like it was down a cylinder. Seemed intermittent as it seemed it was never the same cylinder that misfired.

I've owned the bike since new so I knew the plugs were factory original. I decided I’d just change the plugs and see what that revealed. FWIW, it ran fine over 4-5K rpm

Upon pulling the #4 cylinder plug, it didn’t look horrible. I’d certainly seen worse. #3 cylinder looked perfect. #2 looked much like #4. Then I looked into the spark plug lead “boot” and saw corrosion on the contact.

I went back and pulled the leads from #3 & 4 to check them also and found #4 had similar corrosion to #2. #3 barely had any. Took care of the corrosion with contact cleaner and some aircraft grade corrosion inhibitor and moved on to #1. It was as bad as #2 & 4.

From this it would appear that A) the leads just needed some corrosion control B) the factory plugs were fine after 18 years and 19K miles C) only cylinder 3 had been firing regularly, all the others had been intermittent and D) even though I live in California corrosion is still a factor
 

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Discussion Starter · #5 ·
As @rv6john already stated, easy stuff first. Change the plugs. If you don’t know when they were last done they could be the factory originals.

I had a similar issue on the yellow submarine where it would start and idle fine and randomly run rough like it was down a cylinder. Seemed intermittent as it seemed it was never the same cylinder that misfired.

I've owned the bike since new so I knew the plugs were factory original. I decided I’d just change the plugs and see what that revealed. FWIW, it ran fine over 4-5K rpm

Upon pulling the #4 cylinder plug, it didn’t look horrible. I’d certainly seen worse. #3 cylinder looked perfect. #2 looked much like #4. Then I looked into the spark plug lead “boot” and saw corrosion on the contact.

I went back and pulled the leads from #3 & 4 to check them also and found #4 had similar corrosion to #2. #3 barely had any. Took care of the corrosion with contact cleaner and some aircraft grade corrosion inhibitor and moved on to #1. It was as bad as #2 & 4.

From this it would appear that A) the leads just needed some corrosion control B) the factory plugs were fine after 18 years and 19K miles C) only cylinder 3 had been firing regularly, all the others had been intermittent and D) even though I live in California corrosion is still a factor
I'll be sure to check for corrosion on mine as well. Thanks for the advice!

It's probably going to be a few days until I get the chance to strip the fairings off and look, but I'll keep you guys posted.
 

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Good question on why it idles worse when warm. My guess is that the bike maps richer when cold so it helps to compensate for an intake leak?

There are some vacuum lines below the throttle bodies that people have found disconnected and cracked as these bikes get older.

No need to take the side fairings off for valve, spark plug and throttle body access. Just lift the tank. You do need to remove the seat and the tank side fairings to lift the tank.

If you have not done it yet, the tank side fairings are a bit tricky. They are held on by a plastic loop on the front and this plastic type velcro on the back.
Take the two bolts that go through the fairings and hold the seat. Lift the seat off. Gently pull the back of the fairing away from the tank to part the velco. Don't lift too far or you will break the front loop. After the velcro is loose, slide the fairing loop back off the tab attached to the tank.

The throttle body sync procedure is in the service manual. You should have the manual anyway before diving into a valve clearance check. Definitely if you actually have to adjust them.
 

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The battery drains very quickly when the bike is off ( turns out the sidelights stay on all the time even after the keys are removed). Its a brand new battery
The ignition key on this bike has a 4 position (in clockwise order):

- ignition off, stearing blocked and parking lights on (key could be removed) - PARKING WITH LIGHT

- ignition off, stearing blocked, parking light off (key could be removed) - PARKING

- ignition off, stearing not blocked, parking light off (key could be removed) - STAND BY

- ignition on, stearing not blockef, parking light and headlight is on (key could not be removed) - RUNNING POSITION

I gues you removed key in the PARKING WITH LIGHT position
 
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