Yes, once again I got screwed by the mod-god. As most of you know I was having problems jetting the 39mm carb. I went riding today and ended up sanding off half the needles' diameter just to get the running temperature down. Low end ended up a bit rich (finally), midrange almost dialed in and top end was pretty good. We start riding in the sand pit and all of a suddon the damn quad starts to rev higher and higher...I turned it off and it kept revving! !@&?*% [img]i/expressions/face-icon-small-mad.gif[/img] The plug then fouled. Would not start. Revved like crazy once again. Would not start, boggy. Plus a wierd hissing/whistling sound towards th end. We ended up having to drive 1/4 mile in 2 feet high whoops with the Jeep and double trailor to pull the damn thing out of the trail. The Raptor could not even pull her to the trailor. As you can see I am pi$$ed! [img]i/expressions/face-icon-small-mad.gif[/img]

I am junking the 39mm and putting the stock 34mm back on. Will it perform alright with the trail ported engine? Will I lose tons of power?

If this does not work the Scram is up for sale. [img]i/expressions/face-icon-small-disgusted.gif[/img]

 

its ok dont worry as for carbs i dont much so dont ask me but here is an easy method to cool down

count to ten
then say...
my polaris will not break down it runs great and i will not sell it then kick all tires and snap your fingers and shazam you polaris runs great and never need any thing for it the rest of its life life.


<< results may very [img]i/expressions/face-icon-small-wink.gif[/img] >>

 

Xplor,

It sounds like you have a leak somewhere. The whistling sound is a dead give away. Plus the fact that it kept revving higher and higher, leads me to believe you have a leak in either the base gasket, or the carb manifold (the rubber piece between the carb and the reed valve). There's nothing wrong with the carb at this point. At first yours sounded like mine does when I forget to turn on the gas but the whistling sound, like I said, is a dead give away.

 

If you decide to put your old carb back on maybe you should have it bored. No it won't give you what the 39 does but it is an improvement and it fits much nicer.
Just a thought.

 

Mine had that same hissing sound right before it blew last winter, It was the gasket between the reed spacer and motor.
The intake was loose and sucked air, and it did idle high at the same time.Mine was in winter and it sounded like snow melting on the engine.
Lucky yours shut down and wouldn't run because you might have saved yourself some big money.
Check your head, base and intake bolts then do a compresion check before you give up on the carb.
My two cents.

 

You should still have the same problem even w/ the stock carb back on because the 39mm carb isn't the problem if your's is the same as mine was. I had the EXACT same conditions. It was like it was running out of gas. I only had problems after running full throttle a few times then it would bog, die, rev high, stall, imposible to start. I tore it down to the piston 3 times, disassembled the carb 2 times &amp; everything you could think of &amp; found nothing. I never had a problem until I put on the cool head so of course your initial reaction is it must be what I just added but thats not necissary the case since you have to damn near take the whole quad apart to preform the installation &amp; messing w/ allot of things along the way. Sorry to say, I still cant put my finger on what the exact problem was, all I know is it's now gone after taking it to my mechanic. I only use him as a last resort, he's really good. It could have been electrical or fuel line routing causing cavitaltion(lots of bubbles)he said but he checked everything including testing the electrial connections, coil etc, rerouted fuel lines, venting jeting etc. The 39mm is usually not a problem jetting &amp; as a matter of fact you dont have to do anything to it normally. Now the 38mm is much more of a problem to jet thats why I use the 39mm. Just guessing, the carb was ok from the beginning &amp; you were maybe sucking air or something else to make it look like the carb was the problem. Hopefully you can get the 39mm carb back to original setup if it wasn't the problem.
Good luck,
Jim Maloney
http://y42.photos.yahoo.com/jim400scram

 

Are you getting enough fuel through the line, maybe your filter is clogged, it could be the plug too.

GOOD LUCK!!!

2000 SCRAMBLER 400 2X4

SCRAMDADDY400

 

Fuel seems fine but I will recheck tonight as I once again dismantal it to put back on the 39mm carb. I am just going to leave the reed spacer off this time. Should I put one of those thin gaskets between the intake rubber amnifold and the engine?? Should i add some of that copper silicone gasket stuff? I am almost 99.9% sure it isn't an air leak because when sanding down the needle it did have a big effect on the richness. I even checked to be sure my &quot;black float thingies&quot; were parallel... they weren't so I adjusted them but with no positive results.

Well... back to the garage!