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-   -   87 gsxr stops running @ high speeds (http://www.motorcycle.com/forum/motorcycle-mods-maintenance/7290-87-gsxr-stops-running-high-speeds.html)

sarnali2 03-11-2008 01:15 PM

Quote:

Originally Posted by Mike18212 (Post 180351)
Yeah i have the carbs off and sitting on their heads, upside down when i measure. i have been measuring at the apex from the lip of the carb edge-exactly as described and pictured in the manual. i suppose i need the tool ur referring to cause it's hard to tell if they're right or not. since the problem was the bike running out of gas at high speeds, what would that dictate in terms of the direction the floats need to be bent in? Now speaking in temrs of the carbs being upside down would that mean the floats need to be bent up (down when right side up) or down (up when right side up).


If you're running out of fuel the floats need to be higher up in the float bowl so that they allow more fuel in so bend the tang in such a way that the floats are closer to the top of the carb, this allows more fuel in the bowl. Keep them all even though.

pushrod 03-11-2008 01:52 PM

Long Distance Mechanic-in'!

If someone comes up with, "Do I cut the Red wire or the Blue one?' I'm gonna p!ss myself...

Mike18212 03-11-2008 03:35 PM

Quote:

Originally Posted by pushrod (Post 180360)
Long Distance Mechanic-in'!

If someone comes up with, "Do I cut the Red wire or the Blue one?' I'm gonna p!ss myself...

lol, seriously. hey fk it, i wanted to do it myself, there's only one way to learn. luckilly carbs aren't known to explode... but ill find a way!

The_AirHawk 03-11-2008 04:06 PM

Quote:

Originally Posted by Mike18212 (Post 180351)
Yeah i have the carbs off and sitting on their heads, upside down when i measure. i have been measuring at the apex from the lip of the carb edge-exactly as described and pictured in the manual. i suppose i need the tool ur referring to cause it's hard to tell if they're right or not. since the problem was the bike running out of gas at high speeds, what would that dictate in terms of the direction the floats need to be bent in? Now speaking in temrs of the carbs being upside down would that mean the floats need to be bent up (down when right side up) or down (up when right side up).

Those depth-gauges are cheap - you can find 'em at Mal-Wart for like $3 or so. Set it to your desired-height, and use it as a Go/NoGo template, rather than trying to measure it out. They're graduated in 1mm increments, your spec will probably be something like "11.2mm" or some-such. You'll have to estimate between-measurements. This ain't Rocket Science. If you HAVE to have it dead-nuts on, use your Vernier or Dial-Caliper to measure-out the gauge.

Snarnali or Sezurmama had the right idea - go with a "known quantity" - unless you KNOW that it's got say, a Factory brand or DynoJet brand jet-kit (and the instructions for THAT kit, for THAT bike say otherwise), stick with the stock float-height.

To measure, hold the carbs vertically so the floats "swing" (GENTLY!) like a pendulum (with the "hinge" part facing-up).

Tilt the carb so the gravity acting-on the float closes the needle in its seat - you want it to just close.

Use your Go/NoGo gauge (the tire depth-gauge) to see if you're where you need to be. As someone pointed-out; higher fuel-level or "up" is toward the carb-body, lower or "down" is away from it. If the spec in your manual sez "with gasket", you'll need a new, un-smooshed gasket on the bowl sealing-flange (a bike that old, I have no idea if it has O-ring seals or gaskets on the carbs), or your problems will be exactly the opposite of what you're experiencing now (flooding!). You can make it stick with a dab of grease.

While you've got them out, clean all the jets with air and/or spray carb-cleaner (pilot jets are small, and if plugged may require a soft copper-wire to clear), all the passages, no crud anywhere inside (or outside!) of the carbs, etc. If you can remove them, it's best to unscrew the pilot jets and look-through them at a lightsource. If you can't see light - they're still plugged. Also check the tiny orifices in the side of any emulsion tubes (often next-to or made as an "extender" on the main jet, depending on the carb)

Some carbs have tiny "filters" in the fuel-inlets. Make certain they're clean, or just remove them entirely (but make sure you've installed a fuel-filter upstream of the carbs!).

It goes without saying, PROTECT YOUR EYES when using carb cleaner. That shyte hurts, don't ask me how I know (it's a Stupid Story™).

seruzawa 03-11-2008 04:18 PM

Quote:

Originally Posted by The_AirHawk (Post 180364)
Those depth-gauges are cheap - you can find 'em at Mal-Wart for like $3 or so. Set it to your desired-height, and use it as a Go/NoGo template, rather than trying to measure it out. They're graduated in 1mm increments, your spec will probably be something like "11.2mm" or some-such. You'll have to estimate between-measurements. This ain't Rocket Science.

Snarnali or Sezurmama had the right idea - go with a "known quantity" - unless you KNOW that it's got say, a Factory brand or DynoJet brand jet-kit (and the instructions for THAT kit, for THAT bike say otherwise), stick with the stock float-height.

To measure, hold the carbs vertically so the floats "swing" (GENTLY!) like a pendulum (with the "hinge" part facing-up).

Tilt the carb so the gravity acting-on the float closes the needle in its seat - you want it to just close.

Use your Go/NoGo gauge (the tire depth-gauge) to see if you're where you need to be. As someone pointed-out; higher fuel-level or "up" is toward the carb-body, lower or "down" is away from it. If the spec in your manual sez "with gasket", you'll need a new, un-smooshed gasket on the bowl sealing-flange (a bike that old, I have no idea if it has O-ring seals or gaskets on the carbs), or your problems will be exactly the opposite of what you're experiencing now (flooding!). You can make it stick with a dab of grease.

While you've got them out, clean all the jets with air and/or spray carb-cleaner (pilot jets are small, and if plugged may require a soft copper-wire to clear), all the passages, no crud anywhere inside (or outside!) of the carbs, etc. If you can remove them, it's best to unscrew the pilot jets and look-through them at a lightsource. If you can't see light - they're still plugged. Also check the tiny orifices in the side of any emulsion tubes (often next-to or made as an "extender" on the main jet, depending on the carb)

Some carbs have tiny "filters" in the fuel-inlets. Make certain they're clean, or just remove them entirely (but make sure you've installed a fuel-filter upstream of the carbs!).

It goes without saying, PROTECT YOUR EYES when using carb cleaner. That shyte hurts, don't ask me how I know (it's a Stupid Story™).

Float height usually doesn't have to be adjusted when installing jet kits. If the engine started to use enough fuel to pull the fuel out faster than gravity will push it in then increasing float height won't help. The difference in actual fuel usage is pretty slight.

The_AirHawk 03-11-2008 04:22 PM

Quote:

Originally Posted by seruzawa (Post 180367)
Float height usually doesn't have to be adjusted when installing jet kits. If the engine started to use enough fuel to pull the fuel out faster than gravity will push it in then increasing float height won't help. The difference in actual fuel usage is pretty slight.

Some of the older DynoJet kits called for a height-change. I was never really able to figure-out why, though. I did tell him to go with the stock-height, unless he KNEW it had a kit that said to do it for THAT kit, for THAT bike.

That said, I don't really like DynoJet crap all that much, either.

I figure, if the problem is his height is off - it's because the P.O. dinked with it, tryin' to be a "Masta' Tuna' ".................

sarnali2 03-11-2008 06:40 PM

Quote:

Originally Posted by The_AirHawk (Post 180369)

I figure, if the problem is his height is off - it's because the P.O. dinked with it, tryin' to be a "Masta' Tuna' ".................



That's it right there, some dipsh*t with his Wal*Mart tool kit f*ckin' around until the bike barely runs, then unloads it on our boy here.

That's why you only buy virgins..............

seruzawa 03-11-2008 07:13 PM

Quote:

Originally Posted by sarnali2 (Post 180384)
That's it right there, some dipsh*t with his Wal*Mart tool kit f*ckin' around until the bike barely runs, then unloads it on our boy here.

That's why you only buy virgins..............

C'mon! You know that Xtreme Joe with his GED can do a better job with a drill and screwdriver and a hacksaw than those experienced engineers at YamSuzDucHonKawHDGuz. Jeez. That Hie Skool self-esteem training does wonders!

Mike18212 03-12-2008 05:37 PM

well in light of all these recent conversations on my behalf [much abliged] i think it may actually be wisest to take it to the shop before i become "some dipsh*t with his Wal*Mart tool kit" and make it worse. Well, actually i kind of already did that but i certainly haven't broken anything. I took em apart and measured it as best i could with a ruler resting on the edge of the carb body-just how they show it in the manual minus the proper measuring tool. It looked almost correct but just off a little. so i bent them to allow more fuel in (toward the carb body)as evenly as i could. I went from a height measurement of 14 to 13. manufacturer suggests 14.6 +/- 1mm. i put everything back together, left the bike on prime for a while to refill the carbs and tried it. it started and ran but i could tell it was still fkd. I could fiddle with this thing till my nuts reach my knees and potentially not get it right and patience aint a virtue i got. I figure, it's time to take it to a pro. Thankfully, it's tax return time. I may try one more time and just set it to manufacturer specs but since my prob was running out of gas it seems that they should be set the other way...

And as for buying virgins.. one day... one day.


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