250-500cc WR300 spooge... I'm such an idiot!

After breaking-in my WR 300 on a 24:1 mixture, I started using the same 32:1 fuel as our CR 125. I've gone one down on the pilot and main and dropped the needle a clip due to burbling and the temps getting warmer. Things improved with the jetting changes but I was still getting a lot of spooge no matter what riding conditions I encountered. I've been scratching my head trying to figure it out when today I re-read the owners manual only to discover that the WR 300's recommended mix ratio is 50:1 (actually, "not less than 50:1").

Call me a moron.

I'll be trying a 50:1 mix this weekend and reporting back!

Didn't know you weren't aware of that. I broke my WR300 in on 32:1,...and was planning on thinning it out to 40:1 afterwards. That is until PC made the comment that perhaps one should just jet for 32:1 and keep that ratio. (At least I think you said that PC,...am I right?)

You could tell he's knowledgeable about 2 stroke jetting and tuning when he started talking about squish band clearance. That's getting pretty technical in 2 stroke tuning there.

I've always either used 32:1 or 40:1 myself,...mostly because of the simple, idiot-proof mix formula: 32:1 is 16 oz. of oil in 4 gal. of gas,...and 40:1 is 16 oz. of oil in 5 gal. of gas.

That's just easy and simple for me. I pour off half a full bottle of Amsoil Dominator into an empty one, and I've got pre-measured oil for two cans of gas at the ready. I can then make it either 32:1 or 40:1 at the gas pump, depending on whether it's for my KTM or my Husky.

I'm probably going to try a 44:1 mix using Motorex and see if that reduces the spooge. If so, I'll stick with the slightly oil-rich mixture versus the 50:1.

Actually, the jetting was adjusted for the 32:1 mix and I realize I may have to go a bit leaner at 44:1, especially since the weather here in the southern USA will soon be 80-90 degrees F for several months. The beauty of the Husky 2 strokes is the 10 minute jet adjustments! I'm still painfully aware of the hours-long ordeals to adjust the jets in our (thankfully former) Honda CRF 250R!

Yeah I favor that school of thought on it too. In fact I think we've had this same discussion before. I've personally never had a 2 stroke that didn't spooge at least a little. My '06 KTM 300 XCW keeps it to a bare minimum,...but there's still a little black seepage on that silencer at the end of a long day's ride.

I have run various bikes at 50:1 for years and never had any issues that I'm aware of.

I run my trials bike at 80:1. Of course it isn't subjected to the sustained revving, as a regular dirt bike.

One thing to remember as well....if you changed jetting and or oils or ratio..you have to wait for some time before the results are seen with regards to spooge....as lots of oil hangs around in the bottom of that expansion chamber...

Question Why does my CR 125 run the same no matter where i ride it from below sea level or up to over 6000 feet. I have raced it from about 30 degrees up to over 100
Always stock settings and always 32 to 1 motorex 2t with 110 race gas I guest i am just lucky as i feel no need to ever change it.Plus the pipe and plug always look good to

Yep,...and the silencer packing gets saturated with it too.
When I finally got the jetting sorted on my KTM, I changed out the
packing.

I run all my 2 strokes at 32:1 with Klotz R50 and Chevron premium. None spooge once the jetting was situated. Jet for the mix and dont change the mix for the jets

The real issue is not the amount of oil your mixing with the gas. It's the combustion chamber is not getting hot enough to burn both the oil and the gas.... it's only burning the gas vapor and sending the unburnt oil down the exhaust.

By adding less oil to the gas you're actually richening the jetting. Less oil = more gas per molecule. More gas per molecule = richer jetting. It sounds wacky, but it makes sense if you think about it on a molecular level as only gas and air determine jetting. Oil is only for lubrication, but since it takes up space it has an effect on jetting. The extra fuel per molecule can make for a hotter burn I suppose, so in essence it can work but I'm guessing you'll still need to go leaner on the PJ and/or needle and you'll be reducing lubrication to your bottom end.

I dont race MX or scream my motors like a pro, but I still like the warm fuzzy feeling from running a quality oil at 32:1. More oil promotes better ring seal/life and keeps that lower end well lubed. That's worth jetting for IMO. Rule of thumb to test if your ratio and jetting are properly doing their job of lubricating is to pull the cylinder and stick a thin (clean) screwdriver between the crank halves to the bottom of the case. There should be 1/8" - 1/4" of residual buildup down there. Of course, this needs to be done on a motor with enough run-time to accumulate build up.

Troy and Rusty 2 touched on a good subject. If it's been spooging for a while then chances are 99.9% the silencer packing material is saturated and it's just blowing out old spooge that's been living and accumulating in the exhaust system. It will eventually clean out, but not immediately and you'll be chasing your tail in the meantime thinking it's still spooging when it's actually blowing out the old junk. You need clean packing to really know if your changes worked.

Think about at what throttle position you're in most often (and not RPM's) and then it's easy to jet. Some people even put little paint marks on their throttle at 0, 1/4, 1/2 and 3/4 throttle and then a matching mark at the 0 position on the throttle housing so they can have a visual aid to quickly tell what throttle position they frequently ride in.
This chart is a great resource:


On my 300, at the temps (50-60's) and elevation (1000-2000') I ride it only needed the needle raised one clip. It's now a little lean in the middle (I need the next richer tapered needle in slot #2 for perfection), but zero spooge. Even after raising the pilot one size.

If you like puzzles then 2 stroke jetting is right up your alley. If not, you need crazy friends like me. I love it!

After re-reading r's post, I'm a bit confused about the mixture's effect on jetting. I thought moving from more oil (32:1) to less oil (50:1) in the fuel would effectively allow more fuel to pass through the jet for a given volume of air, thus requiring a leaner jet to make up for the additional fuel mass flow

I really need to go to jetting college!

as motospotz says above, rich and lean refers to the fuel air mixture in all internal cumbustion engines. more fuel (ie 50:1) is actually a richer fuel air mix.
This is where so many 2stroke folks use the incorrect terminology,,,and call a higher oil quantity (ie 24:1) a rich mixture. If your 2 stroke jetting is perfect and you run your oil ratio per engineering (OEM) spec you will have a clean mostly dry exhaust pipe. To do this safely you will need to use high quality fuel (race gas) Like Ajax does. Then you can tune for a very clean (jet leaner) with race fuel and have burn consistency.

FYI most of the new tech Euro 2 strokes are engineered for lower oil ratios, I spoke with the technicians at the Fantic motor booth, they run all their factory bikes and reccommend all their 50cc motors to run at 2% oil to fuel ratios (50:1). I was amazed I figured 24:1 as they rev into the 5 digit level.
there is alot of great info out there on the 2 stroke mysteries from great techs like Eric Gorr and many others. When you buy Miscela (premix ) at the pump it is standard mix at 50:1,,,, It used to be adjustable I don't think it is any more with the new euro smog specs.

I take manufacturer's advice with a LARGE grain of salt. Not only are they in the bike business, they're also in the parts business too.

I'm old school though. I still change the oil in my truck every 3000 miles.