Hi guys, I need some help,

My 99 gs500e runs like a bomb till I hit about 9000 rpm...she the starts to sputter and won't reach red line at all!

Any idea what the problem may be? She's got a really dumb after-market exhaust on her from the previous owner currently....looks like a cut-up drain pipe...you can almost hear the valves through it. Is it a reverse pressure issue or a fuel supply issue?

Anyone else had this problem?

Thanks,

Nutmunk.

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ok....i've checked the plugs...a nice clean colour (not white or black)...so it's not a fuel mix issue...don't think it's a garb clog in the needles, as she's fine in every other rev range...thinking it might be the pipe...anyone else had issues with low back pressure, high-flow pipes?

Sorry I cannot help but just wanted to say you may be right about the pipe?
I would suggest that you may need to clean your carbs/jets if you havent done so already

Thanks codajastal...cars are coming off today for a good clean an re-set. Also going to stick in a new air filter...i'm thinking the previous guy might not have thought of balancing the air flow through the motor after he added the exhaust...a hog rider at the local supermarket nearly sh*t in his pants when I pulled up next to him. That's how loud this thing is.

Quote from: nutmunk on June 17, 2013, 01:02:52 AM
Thanks codajastal...cars are coming off today for a good clean an re-set. Also going to stick in a new air filter...i'm thinking the previous guy might not have thought of balancing the air flow through the motor after he added the exhaust...a hog rider at the local supermarket nearly sh*t in his pants when I pulled up next to him. That's how loud this thing is.

Hahahahhahaha .... You know it's loud when the "hells angels" tell you to keep it down!! 

seriously...the wife has enough time to boil the kettle when she hears me coming home...if I was to open a thread for the loudest gs I think i'd currently win. It's ridiculous. Carbs are soaking in some cleaner overnight...couldn't see any blockage, but better safe than sorry later.

Ya know I do not think back pressure is an issue with a 4 stroke, the only thing I think a 4 stroke might want in an exhaust is good scavenging. If back pressue was needed than why would dragsters run zoomies? I think it might be another issue. Do you know what the jetting is and how many washers it has under the slide needle? It would be awesome to be able to just swap out the exhaust with a stock one and see if it makes a difference on the high revs. BTW I think peak power is about 8.5k RPM and anything above that is just for fun anyway   

Hi calpantera...everything looks standard...not too sure what standard jet size is. One washer. Not so worried about not having power up at the top, but am about the spluttering that i'm getting up there.

 :dunno_black:Just thinking...is it possibly a fuel supply issue then? Standard setup not able to cope with the increased amount of flow in and out of the cylinder? But then surely that would show on the plug and at all rev ranges?

Did you get a looksie at the jets so know what you are running? Also did you do a carb sync?

Quote from: Calpantera on June 17, 2013, 07:54:55 AM
Ya know I do not think back pressure is an issue with a 4 stroke...

Correct, the best thing for a 4 stroke is no exhaust pressure.  The faster you can get the waste out the better, the exhaust pressure relationship is a 2 stroke thing.



Only thing I can think of is it running slightly lean?  Fuel can't keep up with the airflow near redline?

Quote from: Watcher on June 17, 2013, 12:57:03 PM

Only thing I can think of is it running slightly lean?  Fuel can't keep up with the airflow near redline?

Could try running with the petcock on Prime and see if it makes a diff.
My bike would starve out when on the freeway and switching to prime made it stop, so I obviously have an issue wth the diaphram in the petcock.

i may have you beat for loudness...short vid after i completed my custom exhaust (please ignore the comments made by my brother and his friends, they know not what they speak of). did not even have the K&N lunchbox on yet... that adds a good bit of "whhhaaaaaaap" to wide open throttle.

http://s1101.photobucket.com/user/oz353/media/DSCN0529.mp4.html


a buddy of mine says he can hear me coming 5 minutes away

Edit: Also, i do not have any problems hitting redline unless in sixth on a stretch of highway. have not been able to redline sixth ever which seems to be normal. too much wind resistance.

  .. sounds halfway between a mini hog and a rally VW bug!.. hectic! .. 

i love it! 

Quote from: oz353 on June 17, 2013, 04:05:21 PM
i may have you beat for loudness...short vid after i completed my custom exhaust (please ignore the comments made by my brother and his friends, they know not what they speak of). did not even have the K&N lunchbox on yet... that adds a good bit of "whhhaaaaaaap" to wide open throttle.

http://s1101.photobucket.com/user/oz353/media/DSCN0529.mp4.html


a buddy of mine says he can hear me coming 5 minutes away

Edit: Also, i do not have any problems hitting redline unless in sixth on a stretch of highway. have not been able to redline sixth ever which seems to be normal. too much wind resistance.

Bet the neighbours love you

be a good bike to ride... past the ex's house... past your old neighbours that you didnt like.. 

Quote from: oz353 on June 17, 2013, 04:05:21 PM
a buddy of mine says he can hear me coming 5 minutes away

Not 'that' impressive considering its a GS...

LOL

- Bboy

Quote from: BockinBboy on June 18, 2013, 07:44:54 AM

Quote from: oz353 on June 17, 2013, 04:05:21 PM
a buddy of mine says he can hear me coming 5 minutes away

Not 'that' impressive considering its a GS...

LOL

- Bboy

Ha!