97 GSX bog from idle. Pop-off too low?

[Strizzo]

I went back and edited, I am indeed running a 1.5 n/s and my first apron gave me 25-27 psi.

What restrictor are you referring to? I replaced the fuel line with tygon but kept all the stuff in line, is it the little green valve?


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No there is a small brass restrictor that was in the factory line. It slows the recharge when you let off the throttle so if you let off and then jump back in it won't bog down. Hopefully you didn't throw away the old lines.

 

[Krispy]

No there is a small brass restrictor that was in the factory line. It slows the recharge when you let off the throttle so if you let off and then jump back in it won't bog down. Hopefully you didn't throw away the old lines.

The old lines are gone, I don't think I left anything out but it certainly is possible.

The restrictor is physically in the line? As in covered by the factory line? Not just an inline insert like a fuel filter?

If this is the case and I missed it that would certainly explain the rich bottom end rolling onto the throttle.





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[Strizzo]

Yep I posted somewhere what the size of the hole in the restrictor is supposed to be, but don't remember the exact number.

 

[Sportster-2001-951C-Stock]

Get he pop set where it's supposed to be for the air box you're using and if it still doesn't work there's something else going on causing problems.

These pop numbers are typical for a metering arm properly flush with the bottom of the chamber and not mangled from the factory geometry.

 

[Prime Target]

No there is a small brass restrictor that was in the factory line. It slows the recharge when you let off the throttle so if you let off and then jump back in it won't bog down. Hopefully you didn't throw away the old lines.

I pulled all my lines off a few days ago and replaced with new ones. I still have all the old fuel lines and don't see any type of brass restrictor in the line. I looked through all of them. And they were stock lines. Am I missing something here?

 

[Krispy]

I pulled all my lines off a few days ago and replaced with new ones. I still have all the old fuel lines and don't see any type of brass restrictor in the line. I looked through all of them. And they were stock lines. Am I missing something here?

I did some reading and found a thread about a flow restrictor inside a 951 accel pump line. Apparently they were prone to clogging and many folks removed them. They were added on some? boats for customers who did a lot of on-off-on throttle stuff. Not the problem I was seeing.

I was pretty particular in making sure I didn't miss something when replacing the lines, but something internal to the line I could have looked over. I am glad some one else didn't find one either.




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[Strizzo]

The restrictor is like right in the middle of the inlet line to the accel pump. Without it you get a full blast from the pump every time you let off to idle and jam back on the gas.

 

[Sportster-2001-951C-Stock]

Yes, the 951 calibrated restriction is built into the pump and feed side cover and perhaps prone to clogging but I would bet may be drilled out by accident might occur if the "rebuilder" was unfamiliar with how these carbs are set up.

I suppose the smaller carbs have fixed orifices in the "rubber" fuel return lines which sometimes are accidentally discarded.

 

[Sportster-2001-951C-Stock]

For the 951 there is no restrictor in the accel pump feed line that I know of, the accel pump source is from the PTO carb fuel chamber thus pressure is never more than atmospheric.

Edit: Rechecked this and it appears there is a restrictor in this location of the accelerator pump of the 951, I hadn't noticed before. Item #75

http://partsfinder.onlinemicrofiche...13&make=seadoojb&a=146&b=7&c=0&d=-CARBURETORS

I'll accept the high risk of being flamed for mentioning the 951 out of context, LOL.

 

[Prime Target]

I just double checked my original fuel lines. There is nothing in them to restrict the fuel flow. I guess some people had them, some people didn't. I also have seen posts where certain adjustments could not be made to certain "California" models. Maybe these "California" models are the ones with the restricted fuel lines. One thing is for sure, my machine doesn't have them....

 

[AdamXP800]

Still need the springs? I finally got my carbs dialed in, finally! It's amazing what the right springs and pop off will do

 

[Strizzo]

sportster, not sure why you keep talking about 951s, OP has a 97 gsx with a 787.
[MENTION=73061]Prime Target[/MENTION] - are you talking about the fuel lines or the accelerator pump lines? there shouldn't be a restrictor in the fuel lines between the tank and the carbs, just a small one in the feed line to the accelerator pump to slow the recharge when you let off the throttle so the engine doesn't get bogged down if you let off and get back on the gas quickly.

 

[Krispy]

Still need the springs? I finally got my carbs dialed in, finally! It's amazing what the right springs and pop off will do

Nice, I am at 57.8 with my XP.

I do need the springs, make some room in your PM box please and I will send you a message.

Thanks


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[Prime Target]

sportster, not sure why you keep talking about 951s, OP has a 97 gsx with a 787.
[MENTION=73061]Prime Target[/MENTION] - are you talking about the fuel lines or the accelerator pump lines? there shouldn't be a restrictor in the fuel lines between the tank and the carbs, just a small one in the feed line to the accelerator pump to slow the recharge when you let off the throttle so the engine doesn't get bogged down if you let off and get back on the gas quickly.

None of the lines had any restrictor. I just split the old line from the accelerator pump from top to bottom. No restrictor. They were the original fuel lines from the factory.

 

[Sportster-2001-951C-Stock]

sportster, not sure why you keep talking about 951s, OP has a 97 gsx with a 787.

Response to post #31

Edit: Rechecked this and it appears there is a restrictor in this location of the accelerator pump of the 951, I hadn't noticed before. Item #75

http://partsfinder.onlinemicrofiche....d=-CARBURETORS

Felt compelled to admit my mistake despite risk of being flamed for mentioning the 951 out of context, LOL.

 

[Krispy]

Still in the hunt for a pair of black springs, can't get in touch with [MENTION=60330]AdamA96XP[/MENTION].

 

[AdamXP800]

Crap! I completely forgot. Work has been rough. I'll clear my PMs and get on this when I get off work.

 

[Strizzo]

Response to post #31

Edit: Rechecked this and it appears there is a restrictor in this location of the accelerator pump of the 951, I hadn't noticed before. Item #75

http://partsfinder.onlinemicrofiche....d=-CARBURETORS

Felt compelled to admit my mistake despite risk of being flamed for mentioning the 951 out of context, LOL.

to your credit, you did edit rather than posting again. and i wasn't flaming you, but you did say something along the lines of "in the 951, .... restrictor in the pump" in like 3 consecutive posts, so i thought i'd make sure you knew the subject was a 787 powered machine, not a 951 powered 97.5/98 GSX Ltd.

 

[Sportster-2001-951C-Stock]

Black Springs: Mikuni 80gr p/n 73003033, BRP 270500374

Check my work, never trust the internet!

 

[AdamXP800]

Part 73003033T

 

[AdamXP800]

I'm out of the 80 gram springs and my neighbor is on vacation. But here you go

 

[Krispy]

I'm out of the 80 gram springs and my neighbor is on vacation. But here you go

My springs arrived Monday, finally installed them tonight.

While checking my linkage, I noticed that the MAG accel pump nozzle was clogged, when I would pull the throttle no fuel was squirted into the MAG cylinder.

I cleared that up that blockage and will re test tomorrow if the weather holds up.

 

[IDoSeaDoo]

What needle and seat do you have in there?

1.5 NS with 80 g spring gives you 33 psi +- 10psi.
1.5 NS with 115g spring gives you 76+- 15psi. I think you had these to start off with.

You say this as if +/- 10psi is okay... is it? I have a ton of springs and the same color indeed does give me different readings, but I thought that the two should be exactly the same. How much tolerance do I have here?

 

[Sportster-2001-951C-Stock]

Try to get them within 1 psi if you can, I was able too by using a matched set of springs without bending the lever arm from the factory position. Closer is better but I doubt you will see any difference if they're off by 2 psi.

A clogged accelerator nozzle will make a much, much larger difference than 2 psi!

 

[Krispy]

Well, I took the ski out Thursday. It ran well. It still doesn't have the "jump" on the low end that the XP has but it is plenty smooth in the power delivery. It spins about 6800 rpm up top and has plenty of speed once on plane.

It doesn't seem to cavitate off the line, but it just feels like it is heavy until it breaks out of the water. It is something that I would never complain about if I didn't have the XP to compare it to. The throttle on the XP is like a light switch, the GSX is like turning up the wick on an oil lantern.