Im stumped

[Dave223]

My 84 250R, completely stock. I am at sea level, with temps in the high 70s. I just picked up a carb from an 84 from trikeDude, went thru it and its totally clean and set to factory specs with the exception of the main jet, its a 140. My manual says it should be a 130.
I pulled an checked the reed valves and replaced the intake gaskets.I couldnt find the specs on the gap for em, is there supposed to be one an whats the gap? The intake I have is Aluminum and has a port on it that hooks to a canister, it also has DG and PERF on it, what is this for?
The plug is new, NGK BR8ES (I beleive, I know its an 8), gapped at 28 as per the manual, with nice blue fat spark.
I installed a new head gasket torqued to 21 ft lbs as per the manual, with the head checked for warpage at a machine shop, none found.

The problem Im having is whenever Im above 1/2 to 3/4 throttle, it just falls on its face. What I mean is, I can take off at little throttle, get into it and the front end comes up , when I get to that certain point in the throttle, the trike will just drop the front end and lose power. If I hold the throttle wide open in neutral, it will just sputter and bog, and not wind up at all, but it will sit and idle smoothly all day.
With no air filter on it, I can see it spit small amounts of gas out the back of the carb at all throttle positions.As a matter of fact, it has no airbox, just a K&n i made fit till I get one.Also, the idle mixture screw makes no changes to it whether its closed or set to 1-1/2 turns like the manual shows

I will order a rebuild kit for the carb this week, as it comes with a new needle jet,and new jets 130 & 50.

Do you think that the 140 jet is too big causing it to run really rich? If I pull the plug, its wet and black.

This is my first 2 stroke and I know squat compared to a 4 stroke, I love this trike and want it to rip, but Im starting to get aggrevated and disgusted....Please help, Dave

[Kintore]

if the plug is wet and black, its too rich!

I would drop a main and try from there, do a plug chop and report back. Wet and black, nasty!

[Troll 2]

Sounds like simple jetting. Keep going down on the jet size and rechecking the plug. Good luck.
Heres some good info; http://www.dfn.com/benkaren/jetfaq.html and http://www.dansmc.com/Spark_Plugs/Sp...s_catalog.html

[moose 53]

Before you go to far down on jet size make sure that the needle seat in the carberator is not leaking and flooding the bowl.My KTM540 drove me nuts trying to make it run, ran the jets down 5 or 6 sizes but still did not run good. I did have a temp probe on the pipe so I could keep from seizing my motor. I fixed the carberator and it ran fine with stock jetting.

[Dave223]

this is what my plug looks like, not quite as caked with oil, just wet,shiny black.
Thanks for the info guys, every little thing is helping out
I will order a carb rebuild kit soon, comes with the right jets and needle..I think this is my problem! On a side note, what are the symptoms of a bad crank seal? Thanks, dave

[Dave223]

this is what my plug looks like, not quite as caked with oil, just wet,shiny black.
Thanks for the info guys, every little thing is helping out
I will order a carb rebuild kit soon, comes with the right jets ,the needle thats attached to the slide and its seat..I think this is my problem! On a side note, what are the symptoms of a bad crank seal? Thanks, dave