Red head help

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pinboy122

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Feb 9, 2006
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114
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northern ill
Hi everyone, I've had a bunch of issues with my 97 sx700. Long story short I put a new (used) engine in and re-jetted my carbs to 142.5 across the board. It runs poorly at the low end but great up top. I'm 99.5 sure the carbs are spotless. I came out in the fuel screws more than normal to 2 full turns out. At low speeds it gets boggy and acts like it's loading up and will hesitate a bit when I crack the throttle wide open at which point it runs great. It also idles a little crappy and sometimes doesn't want to start when warm unless I hold the throttle open a bit. Should I be looking at closing the fuel screws a bit? Thanks for any help,Al
 
Stock specs 45 pilot
main cylinder 1. 145 cylinder 2&3 143.8
clip position 3. Fuel screws 1 1/2 turns I run mine at 1 3/4

If it loading up after idling/warming up for a bit that is normal to me. Need to ride a little bit and it clears up. If you flip the choke up and then back down does the bog go away? If so your probably still lean or Pilot jet plugged or to small. If it get worse your probably rich. Too big of a pilot jet, fuel screws out to much.

If it 1/4 to 3/4 throttle then I would check my clip position on the needles

I also have to hold the throttle open when starting after it is warmed up unless I let it sit for ten minutes or so.
 
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Thanks mes, the only thing that's changed since it ran good is the main jets and the fuel screw settings. I can ride the thing all night but it still runs rough on the low end. The choke just makes it worse. I've been searching all over and can't find much about it. I guess what I'm looking for is some insight on the effects of the fuel screws and could them being open so much cause it to run like crap on the low end
 
Check carbs again sounds like a main jet fell out forgot to tighten it? Been there done that.
 
I am just wondering do you have enough slack in your throttle cable? So the tors are not activating. I would think you do since it runs fine at higher rpms. Is the choke cable adjusted to tight. Pulling on the choke.

Fuel screw in to lean out to richen .

Does the sled have triple pipes, head gasket mod, ect or is it stock??

If it was me I would pull carbs double check everything. Check the size of the pilot jet!! Set my fuel screws at 1 3/4 turns out. I am thinking in a different thread you said your mains where 133.5. So the pilot could have been change to. I believe they usually put in a bigger pilot jet and a smaller main jet when jetting for higher altitude. I am guessing the previous owner had the sled set up for higher altitudes. That's why the main jet was smaller. I don't know if they would have changed the needle clip or not. That's why I would check it all. Put it back to stock. If I had no mods/aftermarket parts.

I been looking for a jetting chart and clutching chart for an 97 sx700 but I can not find one.
 
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Make sure your choke is adjusted properly, is moving freely, and returning back to the fully closed position.
 
00sxrjoe said:
Check carbs again sounds like a main jet fell out forgot to tighten it? Been there done that.
Click to expand...

Ahahah x2 on that! I had it the other way around because my main jet fell out, would run great till about half throttle then fall on its face. It would be your pilot jet, worth a look
d8927f55331d04ee315721f7b416932b.jpg


If you flip the choke, does it get worse or clear up?

Clears up---> lean
Get worse---> rich or maybe bad spark.
 
Ahah!!x3. I've done the same thing with the main!!! The mains only hit on the top end so I know it's not that. It gets worse with the choke. Am I correct in saying that the further you unscrew the fuel screw the leaner it gets? I guess I just have to pull the carbs again and check the pilots and while I'm there put the fuel screws back to 1 1/2 turns. I really don't know if it's rich or lean, I drove around for a while in the "bogging zone" and when I pulled the plugs they arnt wet and actually look a little on the lean side...
 
image.jpg These are the plugs right after putting around with the thing sputtering for about 10 min. They are sitting on cardboard for a color reference
 
so its a differnt engine now....it may need the carbs set up to suit it.

have you removed the needles to see where they are set at?
 
pinboy122 said:
View attachment 56906 These are the plugs right after putting around with the thing sputtering for about 10 min. They are sitting on cardboard for a color reference
Click to expand...

they look lean but you cant see the side of the ground strap at all in the pics, but looking at the center elctrode its silver all the way acorss and the insulator looks somewhat lean as well, but again thats all I can see from the angle.
 
No mr.viper,I put in a new-used "short block" after you helped diagnose my out of phase crank last year,or maybe the year before...the carbs are original and I've never checked the needles. I'm going to pull it down over the weekend and go through everything and set back to stock specs except I might leave the 142.5 mains depending if I can get something a touch fatter. It's definately rideable the way it is but knowing myself I won't leave it alone till it's right.
 
ok, I see.

well if your describing the redhead engine stuumble they came with stock, kinda a blubber sound at low speed. The only fix was to use a set of reed spacers and then drop the needles a half spot, and those 142.5 mains, I would still advise to use nothing but 93 premium gas.

I used to peel the head gaskets on them as well but gain the gas these days is questionable so its not a good idea to do unless you are for sure running 93 and when you go on a trip out of town use octane boost.

if you can take some pics from the side of those plugs. differnt angle to see the ground strap and the center electrode.
 
Thanks for the input mr viper. Mes I missed your last post untill just now, and I've been thinkin the same thing about the pilots. I need to go back and check everything on each carb
 
It's just a thought hope that's all it is. Post back and let us know.

If it was set up for higher altitudes I bet your pilots are 60, needle position 2, Fuel screws 2 1/4 turns out. With your 133.5 mains. Which looks to be the setup for 8300 to 10000 feet.
 
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pinboy122 said:
Ahah!!x3. I've done the same thing with the main!!! The mains only hit on the top end so I know it's not that. It gets worse with the choke. Am I correct in saying that the further you unscrew the fuel screw the leaner it gets? I guess I just have to pull the carbs again and check the pilots and while I'm there put the fuel screws back to 1 1/2 turns. I really don't know if it's rich or lean, I drove around for a while in the "bogging zone" and when I pulled the plugs they arnt wet and actually look a little on the lean side...
Click to expand...

thats incorrect, the more you turn the FUEL screws out the richer it gets. make sure you are using plugs with some run time on them oor they always look lean.

it does almost sound like you are talking about the mid range burble, when i first got my sled i thought it was a problem as well, ended up making reed spacers and it fixed it.
 
Well, I took it all apart again and didn't find anything interesting. They were all clean and the correct pilots were in. I put the mains back to stock. And the fuel screw to 1.5.The only thing I didn't do was check the needles because I was out of time. It still runs crappy on the low end. Know I have to take them back off because I found 1 of the tiny washers that go on the fuel screw by the oring.
 
That is to bad you did not find the problem in the carbs . I really have no other ideas for ya. Hopefully someone will chime in.
 
Thanks yammy, reeds are 100%. I hope to get time this week to check the needles, that's about the last thing I can think of. I appreciate all the input. Thanks,Al
 
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