jetting help for dummies....

[jhendr3702]

this is the plug on my 07 mc 250.. this was ggmans 250 from houston area. we are way different alt and temps..
i have scoured the jetting database and am running the same jetting here as my 01 300.. different needle..we are about 3500' and temps in the 80's right now..
i am running 40 pilot 170 main cek on 2 as 1 1/8 out per ron's rb mod sheet on as settings..pretty sure both bikes have 7 slides.. the bike runs great, starts easy, idles perfect, but i have spooge running all the down the tcII. same fuel mix i have always run also..
have tried a different mix, r50 at 40:1 with the same results..
any thoughts.. i know the picture is a little out of focus, but the color looks good to me.. i have basically 3 needles here..the cek, a ddk, and the n1ee in the 300.. the 300 spooges a little, but not bad..

 

[lankydoug]

Don't jet according to spooge. Is a matter of fact take comfort in knowing that the mix oil is still lubricating all the way to the tailpipe. Higher combustion temps will burn away spooge but running lean to achieve this is not the answer.

 

[jhendr3702]

Don't jet according to spooge. Is a matter of fact take comfort in knowing that the mix oil is still lubricating all the way to the tailpipe. Higher combustion temps will burn away spooge but running lean to achieve this is not the answer.

i kinda understand that.. just really trying to get in my head why with two bikes, same jetting,(differnt needles) both run great here, same fuel, and one runs spooge all the way down the silencer and one does not..

 

[Jakobi]

I agree and disagree..

Spooge is the result of 'excess' unburnt fuel/oil mix. Its a sure sign you are getting lube to the bottom end, but you're also getting it coming out the exhaust port, through the packing and right out the end.

High grade oils like Motul 800 etc etc will produce loads of spooge at anything more than 50:1. Thats why the brands of oil make recommendations on what to mix at. Otherwise its just too thick with too high a flash point to burn cleanly. Excess comes out the pipe.

The other thing is that the plug is only showing you a certain reading (which is when you killed the engine). You can run rich rich rich rich rich and have a lean main and still get a lean reading on the plug if you chop it at WOT. Another consideration is the riding you are doing and the loads you place on the engine. A bike thats hammered in the sand will require more lubrication than one that just chugs around off idle all day in the bush. Jetting is based on so many variables its no doubt we all have different results, even when using the same bikes and same jets.

Further more, once the exhaust packing is spooged up enough to come out the end, its pretty much done for and will continue spooging unless if you lean things right out. This is why its not a good idea to use spooge as a benchmark for jetting.

Right up if you want to get yourself a rock solid baseline ideally you'd have a fresh top end, fresh exhaust packing, fresh reeds, and a fresh plug, and then start playing.

FWW, I get no spooge dribble at all. Just a nice oily ring around the exhaust which the dirt likes to stick to!

 

[Jakobi]

i kinda understand that.. just really trying to get in my head why with two bikes, same jetting,(differnt needles) both run great here, same fuel, and one runs spooge all the way down the silencer and one does not..

Different needle = different jetting..

IMO, the needle covers the widest part of the jetting and is the most critical regarding 1) fuel consumption, 2) power delivery, 3) spoogeo.. Then you have the overlaps in the circuits where the needle and pilot are somewhat dependant on eachother..

Not sure if you're comparing a 250 to a 300 here either? Different years used different model carbs.. Squish band and compression also plays a part in jetting. You really can't compare 2 bikes with the same jetting, let alone one running a triple taper n1 needle and one with a straight taper CCK.

 

[jhendr3702]

i have new packing.. i will change that out and start over.. i am an old slow trail rider, so this bike gets lugged around most days, with a few good clean outs..
i dont mind a little spooge, it is a 2 stroke.. i have seen it on videos and it looks pretty good also (as far as smoke goes)

i pulled this plug after a normal trail ride end, normal speeds and terrain riding to the truck and shut if off..about 8 miles from start to the finish..
not really trying to get a wot chop, just to see how it would look normally riding..

 

[jhendr3702]

Different needle = different jetting..

IMO, the needle covers the widest part of the jetting and is the most critical regarding 1) fuel consumption, 2) power delivery, 3) spoogeo.. Then you have the overlaps in the circuits where the needle and pilot are somewhat dependant on eachother..

Not sure if you're comparing a 250 to a 300 here either? Different years used different model carbs.. Squish band and compression also plays a part in jetting. You really can't compare 2 bikes with the same jetting, let alone one running a triple taper n1 needle and one with a straight taper CCK.

you are correct.. one bike is an 01 300..it still has the n1ee..
other is an 07 mc250 with the cek.. same carbs..

jakobi.. i have read volumes of your jetting threads..

 

[Bailey28]

I can't resist here! Straight diameter, Straight diameter Straight diameter!! I can't say enough on how the straight portion of the needle affects how the bike runs from idle to 1/3 throttle.

Your CCK, N1EE, DDK all have very rich straight diameters which allows a lot of fuel to pass at the idle to 1/3 throttle area.

If you like how the bike responds above idle, and want to minimize spooge, especially at 3500', then go with a CCN, CEP, or DEN, DEP, N1EH, or NOZH, NOZI..

I feel that these bikes run better with a richer pilot jet, (42-45ish) and a lean straight diameter. Your K and E diameters (2.695") are eating up your fuel and spooging up your pipe.

http://www.sudco.com/vol33/135-136.pdf

 

[lankydoug]

Jakobi has pretty much nailed what I wanted to say but was too lazy to write it all down.

Jet your bike to run good bottom to top. If it still spooges too much maybe your top end is tired or the squish in your engine is too big of a gap.(low compression)

My GasGas 200 has a fresh top end but I suspect the squish gap is big. It runs great at high rpm and will run on cheap pump gas with no complaints. If you pudder around on it the spooge will oil the chain. If you keep it revved up where it likes it, it won't even drip down the silencer. On the other hand my WR250 Husky will break your foot if you try to start it without good boots on. It will ping unless it is running on race fuel and makes gobs of mid range power. I suspect the squish is very tight but haven't freshened it yet so I don't know for sure. The Husky won't drip spooge even at 32:1 and goof off riding.

I bet if you did a head mod to the spooging bike you would raise the combustion temps enough to stop the spooging (or you could seek out the magic needle).

 

[jhendr3702]

Jakobi has pretty much nailed what I wanted to say but was too lazy to write it all down.

Jet your bike to run good bottom to top. If it still spooges too much maybe your top end is tired or the squish in your engine is too big of a gap.(low compression)

My GasGas 200 has a fresh top end but I suspect the squish gap is big. It runs great at high rpm and will run on cheap pump gas with no complaints. If you pudder around on it the spooge will oil the chain. If you keep it revved up where it likes it, it won't even drip down the silencer. On the other hand my WR250 Husky will break your foot if you try to start it without good boots on. It will ping unless it is running on race fuel and makes gobs of mid range power. I suspect the squish is very tight but haven't freshened it yet so I don't know for sure. The Husky won't drip spooge even at 32:1 and goof off riding.

I bet if you did a head mod to the spooging bike you would raise the combustion temps enough to stop the spooging (or you could seek out the magic needle).

i hear ya.. this was gasgasmans 250.. the top end is fresh.. it is more than likely i am not riding this bike anywhere near where he used to..
the ride before this one, i really tried to ring it out more and the spooge was only half of the silencer.. on this ride, well... that did not happen..

 

[jhendr3702]

I can't resist here! Straight diameter, Straight diameter Straight diameter!! I can't say enough on how the straight portion of the needle affects how the bike runs from idle to 1/3 throttle.

Your CCK, N1EE, DDK all have very rich straight diameters which allows a lot of fuel to pass at the idle to 1/3 throttle area.

If you like how the bike responds above idle, and want to minimize spooge, especially at 3500', then go with a CCN, CEP, or DEN, DEP, N1EH, or NOZH, NOZI..

I feel that these bikes run better with a richer pilot jet, (42-45ish) and a lean straight diameter. Your K and E diameters (2.695") are eating up your fuel and spooging up your pipe.

http://www.sudco.com/vol33/135-136.pdf

that 1/3 throttle is probably 90 % of our trail rides... are you sure on the straight diameter ????? lol...
thanks

 

[Jakobi]

I haven't watched your video but I have to agree with Bailey on this aswell. The thick needle diameter is what causes everyone to turn the idle screw in a long way to get a sustainable idle. Its what causes the burbling at light throttle openings, and what this is is essentially fuel passing through unburnt.

N1EF my bike ran strong but spooged alot. It would load up the plug a bit if lugged, and clear out when hammered. I'd get 70km to a tank.

NEDW is leaner off the bottom and into the mid. Throttle response is better. Only a light burble right off idle. Its easier to ride fast as you don't have the rich to lean transition on the bottom end. And I get 100km to a tank.

 

[jhendr3702]

awesome.. thanks everyone..

 

[Jakobi]

Hope you have sucess! Watched your vid. Wasn't boring at all. Not sure which bike was yours but the one with the helmet cam sounded good! Looked like some nice trails too. Those open fields.. We don't see that kind of stuff where I live.

 

[jhendr3702]

Hope you have sucess! Watched your vid. Wasn't boring at all. Not sure which bike was yours but the one with the helmet cam sounded good! Looked like some nice trails too. Those open fields.. We don't see that kind of stuff where I live.

i was in front of him.on the black 250 gg
.that is one of the few other gg's here..
it is an 02 300 and it runs great.. he has no idea what is in the carb... go figure.. but he says it wont idle at all... he is a very good rider..
this particular day, there were more gg's than anything else..(2)
have needles ordered.. have packing..i will get it..

thanks again

jay