Carburetor Help PLease!!!!!!!

[motox4fun]

My 2001 CR250 has a problem with fouling plugs often and it also leaks alot of oil from the silencer.Throttle response is poor at low rpm and it seems to take forever to "clean out" after running at low rpm for even a short period of time. The bike also smokes more than my friend's bike. I know it is going to smoke some, but is there such a thing as too much? Everything on the bike is stock except for the addition of a FMF Turbine Core II Spark Arrestor and a Steahly 12oz Flywheel Weight. I run a NGK BR8EG plug and Gloden Spectro oil mixed at 50:1 with 102 Octane avaition fuel. Please advise on a solution to my problem.
Thanks

 

[NO HAND]

I hear often the 01 cr250 is known to be jetted way off, like the worse in a long time. You might want to do a search on jetting CR250 2001.

 

[motox4fun]

anymore suggestions?

Thx for the reply, does anyone else have suggetsions or experience with this problem?

 

[jmics19067]

I think jetting is teh way to go but I dont beleive your easily going to find setting s using avgas talking to your local pro or hop up shop are most likely going to give you settings for either race gas or pump gas d

 

[bscottr]

Rich...Plugs wet with fuel or oil?

motox4fun,

My guess is that your plug is fuel fouling as opposed to oil fouling. It may appear that it's oil fouling because the engine can't burn all the fuel/oil it's receiving, causing the spooge out of the silencer from the unburned oil. At 50:1 you have richened your jetting, that coupled with the already rich jetting from the factory may be contributing to your problem. Remember, less oil means more gas in a given quantity of fuel (i.e., rich).

Have you tried experimenting with other premixes? A friend had problems with Golden Spectro and switched to HP2 with good results. Each bike tends to like something a little different.

First I'd drop the main jet one size, then drain your tank (I'm not a big fan of avgas). Mix up some 93 octane at 32:1 (you may try HP2) and run it. It should be closer to what you're looking for.

If you want some information on avgas, read this.
http://www.ericgorr.com/techarticles/avgas_excerpt.htm

Once you've decided on your best fuel/premix blend, then complete the jetting process. Your blend affects the entire RPM range, not just a portion of the range like the main jet, pilot/slow jet, etc. As the temperature changes you can alter your premix ratios to fine tune your bike. Significant temperature changes still require jetting work.

If you've decided on using your current fuel/premix blend and do not want to change, the alternative is to lean out your carbs’ jetting across each circuit.

Here are great guides for carb tuning.
http://www.ericgorr.com/techarticles/carbtuning.html#m
http://www.ecmx.com/bike_tips/jetting.html

For what it's worth we use 93 octane with HP2 @ 40:1 for the bikes below. None have been highly modified other than pipes, reeds, etc. Very little spooge and they run crisp.

'01 KX250
'00 KX125
'99 CR250
'99 KX250
'90 RM250

Keep us posted and good luck!

Scott