96 GSX Bogging Down - Fuel? Rave?

[thelanger]

Hi All, hoping to get some advice since I'm running short on avenues to fix this problem. I've got two GSX 787's, a 97 and 96 both with around 150 hours. the 96 just recently started to bog down around 3000-3500 rpm, and dies occasionally. It ran great all summer long up until one 10 mile ride where 5 miles in it started just dying at 3200rpm. it idles fine, but bogs down on take off and wont build speed. I've done the following and i'm running out of ideas

• replaced fuel lines
• drained tank and cleaned
• replaced water separator and gasket (twice)
• cleaned out carbs and internal carb filters
• cleaned rave vales and replaced o-rings and gaskets
• new regulator/rectifier (tested and works fine)
• new coil, plug wires, boots, and plugs
• new battery

I've searched over and over on this forum, greenhulk, pwctoday, etc. and I cant seem to find anyone who has the bogging issue and not had it fixed by one of the above parts, so I'm looking for some help/direction.

TIA!

 

[SIMPLEARKANSAN]

Fuel tank check valves been replaced? Replace the fuel selector?

 

[thelanger]

Fuel tank check valves been replaced? Replace the fuel selector?

yup new selector and new check valves, everything blown out and cleaned

 

[thelanger]

i should also mention this motor has bad crank seals and has been hydrolocked twice but both times cleaned out with the plugs out, new plugs and fires up no problem

 

[SIMPLEARKANSAN]

So the fuel selector has an O-ring inside that can dry rot and allow air into the fuel system and cause a lean condition. Even if cleaned out, it's best to replace.

 

[fatblockabody]

Check for soft spots in rear exhaust hose, all the way down to the outlet. The split internally, blow up like a balloon under load, and choke it off.

 

[thelanger]

So the fuel selector has an O-ring inside that can dry rot and allow air into the fuel system and cause a lean condition. Even if cleaned out, it's best to replace.

selector is brand new, also put the same brand new selector in the 97 and havent had any issues

Check for soft spots in rear exhaust hose, all the way down to the outlet. The split internally, blow up like a balloon under load, and choke it off.

i'll check it out today. i feel like i came down hard off a wave and it started having issues. would that make any difference?

 

[SIMPLEARKANSAN]

I’ve heard of that happening to people. I’m not sure structurally what it affects.

 

[POPPS]

Compression??

 

[thelanger]

Compression??

144 front cylinder 142 rear

 

[SIMPLEARKANSAN]

Could it be something to do with the exhaust? I've read where the black rubber exhaust tubing will de-laminate inside and cause a partial blockage.

 

[TheGTIjetguy]

Could it be something to do with the exhaust? I've read where the black rubber exhaust tubing will de-laminate inside and cause a partial blockage.

Definitely check exhaust, an exhaust leak can fill the hull and choke out the engine as well.
When bogging, does gently pulling on the choke help it rev up? That will indicate a fuel supply problem