jetting/spooge

[darringer]

The PWK should work fine in that bike. As far as the spooge issue... I ran the Motul 800 at 32:1 in various bikes and never really got rid of the spooge. The bikes were jetted crisp and ran excellent. It seems that if you stay at the upper revs with the Motul, there's very little spooge. I jetted for seat-of-the-pants feel and ignored the spooge. It's odd to me that you are running such a large pilot in the PWK. Usually they like lean pilots. For example, my '99cr250, '02cr250, and my current cr500 all have run pilot jets in the low 40's. Could you possible have an air leak somewhere?

 

[jason33]

darringer- thats what i was saying about the oil not burning completely-
jetting is fine , ratio might be fine-
a lot of oils don't burn completely,or clean- klotz does its a clean burning oil

 

[motox--]

When you say the PWK should work fine, do you mean the 38mm or 36mm?

I doubt I have an air leak, idle doesnt change and the plug is black. I found a thread similar to this one and a guy with an older CR (94 I think) used a 65 pilot jet, maybe older CR125's need to be jetted rich on the pilot?

 

[just_a_rider]

I'd go with the 38mm, that the comon for todays and past 250's. Spooge happens most of the time and what solves it is your exaust temperatures, if the exaust temperatures are not hot enough to keep it burned out it will spooge. What makes an engine run hotter thus increasing the exaust temperatures, leaning. If it's hot enough the spooge will burn and blow out rather than remaining runny.

 

[motox--]

Im still pretty keen on getting the 36mm carb, as it seems that unless some cylinder work has been done the stock engine wont breathe enough to make a gain, so with the 36mm carb I should have the same top end power, but with more low-mid range power (which my bike needs so badly!) It seems to be a win-win situation with the smaller carb. I still think I will stick with a keihin after reading about people switching out mikunis for keihins on CR's. Plus I get to use my old jets :) If someone still disagrees please let me know!!!

 

[whenfoxforks-ruled]

Nope ,no argument, stock carb and stock engine means it should run properly without being in nomans land trying to jet. Keep that bigger carb, I bet It would work good on a 144 kit! Suspension will make you faster, more than the engine.

 

[darringer]

FWIW, my '99rm125 came stock with a 39mm PWK and I was able to jet it very crisp. Either there is a problem inside the carb, or there is another mechanical problem that is being overlooked. A 38mm carb on the 125 might give away a bit of throttle response, but should still be able to be jetted and run cleanly. I still find it hard to believe your #50 pilot is too lean when 1) it's 35 deg. celsius (Hot!), and 2) with the PWK that usually likes lean pilot jetting. There must be some other underlying condition causing problems. If not air leak at the intake tract, what about the left-side crank seal leaking air into the bottom end? As far as the black plug. It could be the Motul not burning completely because the plug is too cold. It doesn't necessarily mean rich jetting.

 

[motox--]

The plug is black because I think the needle is too rich, and thus cant be lean enough to create enough temperature in the combustion chamber to burn all the oil/fuel, causing that damn spooge :bang:

As for the crank seal, how do I check if its leaking without a leak down test? Like I said my top ends didnt have any dirt scratches on them and it idles well (doesnt change or anything) I think I read somewhere about putting talcolm powder or something on the crank seal while the engine is running to see if it leaks?

 

[motox--]

And another reason I dont think it can be the crank seal is because I need to go leaner on the needle... not richer like the pilot jet..

 

[darringer]

I've used carb cleaner sprayed at the left-side crank seal when the motor is running to see if there is an idle speed change. If so, the seal is leaking. In an earlier post, post #9 I think, you stated that the bike ran well with the 45 pilot and the choke on. Regardless of which pilot is in the carb, if the choke is on and the bike pulls through the midrange well, that would mean to me that the needle is lean, too, since the pilot has no influence after about 1/8 throttle or so. Still sounds like an air leak. Spooging could be throwing you off. No matter how well my bike was jetted, with the Motul 800 it would spooge if not revved enough.

 

[CRazy250]

its the fact its a 250 carb on a 125, it flows way too much for a 125 and even if you did jet it in correctly your probably gonna lose power because you had to jet it to the extremes and compensate performance because of the extreme jetting. just because its a bigger carb dosent mean more performance.

 

[darringer]

Not true. A carb will only flow as much air/fuel as the motor can pull through. That carb isn't that big either. Shouldn't be a problem to jet it clean. RM125s still use a 38mm carb. And the KTM125SX still runs a 39mm carb, so the carb size isn't the problem.

 

[motox--]

with the 45 pilot and choke on, the higher the revs went the worse it got.... it sputtered from about 1/2 to full throttle.

 

[whenfoxforks-ruled]

Using the choke to tell you if it is rich or lean is one method for testing your jetting, it does require a choke that has different adjustments, The example I read was using a banshee with a choke on the first click, I don,t know nothing about that, except it sounds like you are flooding that engine with yours. I would suggest reading Rich's,http://dirtrider.net/forums3/showthread.php?p=736901#post736901 <maybe read it twice!

 

[250racing]

with the 45 pilot and choke on, the higher the revs went the worse it got.... it sputtered from about 1/2 to full throttle.

the pilot should only work from fully closed to 1/4 so your jetting woes should be somewhere else.

why dont you try a stock keihin from a 1999 cr 125 the 1999 and 2000 engines were almost the same?

i had a 99 cr 125 that i jetted with the manual specs for my altitude and temp and it worked great with no spooge even thou i ride tight enduros where i dont rev out the bike much.
i ran motul 800 at 40:1. and br8eg plug from ngk.

 

[KX02]

the pilot should only work from fully closed to 1/4 so your jetting woes should be somewhere else.

why dont you try a stock keihin from a 1999 cr 125 the 1999 and 2000 engines were almost the same?

i had a 99 cr 125 that i jetted with the manual specs for my altitude and temp and it worked great with no spooge even thou i ride tight enduros where i dont rev out the bike much.
i ran motul 800 at 40:1. and br8eg plug from ngk.

The pilot jet circuit is always active, it does not shut off.

 

[250racing]

The pilot jet circuit is always active, it does not shut off.

yes but it works in conjuction with either the needle in 1/4 to 3/4 of the gas and the main jet from 3/4 to fully open. why not try the same pilot and a different clip(richer) first? if your bike starts cold with no choke the pilot is too rich. if your bike starts easier with the choke on when its warm then the pilot is lean. also the turns out with the air screw are a good indication.