Bike not running right

[cheese]

My bike was not running quite right and felt a bit sluggish the other weekend, so I thought I'll repack the pipe and check the plug and if I can be bothered a recon.

I found the plug quite black and quite alot of carbon build up. The muffler has a bit of oil over it at teh end of each ride too so I think its running a bit rich.

[jimmy 2006]

probably a silly query, but have you just tried cleaning the plug?

[Mulisha_troop]

My bike was not running quite right and felt a bit sluggish the other weekend, so I thought I'll repack the pipe and check the plug and if I can be bothered a recon.

I found the plug quite black and quite alot of carbon build up. The muffler has a bit of oil over it at teh end of each ride too so I think its running a bit rich.

i had a rm125 that did this a few times and kept fouling the plug ,only thing i can think off is check your mix ratio,try a hotter burning plug to

[cheese]

probably a silly query, but have you just tried cleaning the plug?

LOL yeah, I was trying to get a diagnosis from the plug condition. I'll probably put a new plug in.

[Rupe]

My bike was not running quite right and felt a bit sluggish the other weekend.

Maybe you've put weight on:girlfight:

[vr4king]

Well from the looks of that plug id say its just old and used if it was running fine before then maybe you have lost some compression and could be a sign to give the top end a birthday.............And bang a new plug in it at the same time

Just my 2cents so dont take it as gospel:msn-wink:

[-df-]

My bike was not running quite right and felt a bit sluggish the other weekend, so I thought I'll repack the pipe and check the plug and if I can be bothered a recon.

I found the plug quite black and quite alot of carbon build up. The muffler has a bit of oil over it at teh end of each ride too so I think its running a bit rich.

My plugs look like that after 1-2hours riding...damn its getting expensive, might have to talk to a shop as $7 a plug adds up after a while.

[Danger]

Have you leaned of the jetting for summer riding? Your bike runs richer in the heat.:doh:

[B0000M]

[QUOTE=-df-;1363565]My plugs look like that after 1-2hours riding...damn its getting expensive, might have to talk to a shop as $7 a plug adds up after a while.[/QUOTE

wow, you're getting a cheap deal on plugs!

[-df-]

My plugs look like that after 1-2hours riding...damn its getting expensive, might have to talk to a shop as $7 a plug adds up after a while.

wow, you're getting a cheap deal on plugs!

presuming thats a pisstake? if so, where do you get yours?

[B0000M]

no, not a pisstake, i went to cyclespot on barrys pt rd - takapuna, they charged me $20

[Danger]

BR8EG is about $20.00
BR8ES is about $7.00

[barty5]

no, not a pisstake, i went to cyclespot on barrys pt rd - takapuna, they charged me $20

ill price en up tomorrow and let you know what i can do i get around 50% off most stuff including plugs

[Lion]

My plugs look like that after 1-2hours riding...damn its getting expensive, might have to talk to a shop as $7 a plug adds up after a while.

rejet your bike mine was doing the same so i spent some time reading up on the internet and got my bike running way better. my bike used to destroy a new plug in half an hour. gets expensive over time

[mxracer_nz]

just sounds like a case of right hand no turney far enough! open that thing up man or get a 4 stroke!

[k14]

My plugs look like that after 1-2hours riding...damn its getting expensive, might have to talk to a shop as $7 a plug adds up after a while.
Geez $7?? Plugs cost me $120 a pop for the RS. Too cheap to change them too often.

[-df-]

Sorry for the thread hi-jack.

I'm just getting plugs from REPCO (BR8ES), $7 for them there...tried the $20 once (platnium or what ever)...lasted just as long so didn't do that again.

[B0000M]

ill price en up tomorrow and let you know what i can do i get around 50% off most stuff including plugs

ordinaryly i source my own bits like plugs thru either my old man's work or thru the mrs's old work, i know br8ev? i think it was for the jetskis were costing like $4

[soundbeltfarm]

i was looking for an answer for a similar problem on thumper talk and just searched pre mix and found an awesome post.
you dont go to a hotter plug or adjust the mix you adjust brass.
heres what i read on thumper talk.
Motu would love reading this stuff











Any of you that believe that spooge is caused by too much oil in the mix are flat out wrong. If you know how to jet, you can run any amount of oil you choose, and have absolutely zero spooge.

Looks like it's time for a little pre-mix 101. I don't usually get into ratio discussions, because mix ratios are like religions to most people, and they tend to be closed-minded and hard-headed on the subject, but I'll put in my $.02 here anyway.

There is a prevailing myth that less oil is better, and that the oil in the fuel is what lubricates the engine. And there is also a very common belief that spooge is caused by too much oil in the fuel mix. Both are wrong. The engine is lubricated by the residual oil that builds up in the crankcase. All the oil in the fuel does is replenish this oil. And spooge is caused by rich jetting.

When an engine is jetted too rich, the excess fuel leeches heat from the combustion process, causing the combustion chamber temperatures to be too low to effectively burn the oil, or even completely burn all of the fuel. The result is spooge and deposits. The spooge is nothing more than unburned fuel and oil passing out the exhaust.

If you have a spooge problem, you have a jetting problem. You don't get rid of the spooge by reducing the oil, you get rid of it by fixing the jetting. Correct jetting will produce an air/fuel ratio of about 14:1, which will produce combustion temperatures in the 1200 degree range. This will provide sufficient heat to consume the premix oil.

You don't choose a mix ratio based on "spooge", you choose the ratio based on the amount of oil your engine needs to provide sufficient protection and adequate ring seal. The common misconception is that mix ratios are "one-size-fits-all", when in fact nothing could be frther from the truth.The amount of oil that is correct for one rider on his bike may not be enough oil for another rider/bike, or it may be too much oil. It all depends on engine displacement, riding style, and how hard you push the engine.

The best way to determine if you are running enough oil is to check the level of the residual oil in the crankcase. If the ratio you run leaves enough residual oil in the crankcase to cover about 1/8" of the bottom of the crank wheels, then you are fine. If you don't have that much residual oil in your crankcase when you pull the top-end off, you aren't running enough oil for your riding style and conditions.

With that said, to have that amount of residual oil in the crankcase at 50:1 (a ratio made popular by magazines and oil bottles), you can't be riding very hard, or your bike is jetted richer than necessary simply to deliver enough oil. I arrived at 26:1 for my bike with my riding style because that is the amount that gives me the proper amount of residual build-up. Small-bore engines require greater oil concentrations than larger engines to achieve the proper amount of residual build-up, because they rev higher and have higher intake velocities. Along the same lines, someone that pushes the engine harder, and keeps the revs higher, also needs to use higher oil concentrations to achieve the proper residual build-up.

To understand why the residual oil is so important, you have to understand what happens to the oil in your fuel when it goes into the engine. While the oil is still suspended in the liquid gasoline, it can not lubricate anything. It has about as much lubricity at that point as straight gasoline. When the gasoline enters the engine, it evaporates, dropping the oil out of suspension. Now that the oil is free, it can lubricate the engine, but it must get to the parts to lubricate them. The way it gets to the bearings and onto the cylinder is by being thrown around by the spinning crankshaft, and being distributed through the engine by the air currents moving through the crankcase. The main bearings are lubed by some of this oil dripping down through tiny "drip passages" in the cases above the bearing pockets.

People believe that the oil just rushes right through a two-stroke along with the fuel, but that just isn't so. It can take 90 minutes or more for the oil migration through a two-stroke to result in a complete oil exchange.

The oil eventually makes it into the combustion chamber, where it is either burned, or passes out the exhaust. If the combustion chamber temps are too low, such as in an engine that is jetted too rich, the oil doesn't burn completely. Instead, some of it hardens into deposits in the combustion chamber, on the piston, and on the power valve assembly. The rest becomes the dreaded "spooge". The key to all of this working in harmony is to jet the bike lean enough to achieve a high enough combustion chamber temperature to burn the oil, but also still be able to supply enough oil to protect the engine. If you use enough oil, you can jet the bike at it's optimum without starving the engine of oil, and have excellent power, with minimal deposits and spooge. At 50:1, you simply can't jet very lean without risking a seized engine due to oil starvation.

With the high oil concentrations that I use, I tend to get far more life from my cranks and rings than most of my friends that run leaner oil ratios. The high oil content also produces better ring sealing, so more of the combustion pressure is retained.

One small point. No one ever broke an engine by using too much oil.

Now we come to the issue of ring seal. Simply put, the rings alone can not effectively seal the cylinder. They also need oil to provide a complete seal against the bore surface. And up to a point, more oil will provide a better seal.

I have run Dyno tests on this subject, as a school project in Tech School. We used a Dynojet dynamometer, and used a fresh, broken in top-end for each test. We used specially calibrated jets to ensure the fuel flow was identical with each different ratio, and warmed the engine at 3000 rpm for 3 minutes before each run. Our tests were performed in the rpm range of 2500 to 9000 rpm, with the power peak of our test bike (an '86 YZ 250) occuring at 8750 rpm. We tested at 76 degrees F, at 65% relative humidity. We started at 10:1, and went to 100:1. Our results showed that a two-stroke engine makes its best power at 18:1. Any more oil than that, and the engine ran poorly, because we didn't have any jets rich enough to compensate for that much oil in the fuel. The power loss from 18:1 to 32:1 was approximately 2 percent. The loss from 18:1 to 50:1 was nearly 9 percent. On a modern 250, that can be as much as 4 horsepower. The loss from 18:1 to 100:1 was nearly 18 percent. The reason for the difference in output is simple. More oil provides a better seal between the ring and the cylinder wall.

Now, I realize that 18:1 is impractical unless you ride your engine all-out, keeping it pinned at all times. But running reasonable ratios no less than 32:1 will produce more power, and give your engine better protection, thus making it perform better for longer.

[cheese]

Will try 32:1 then.

[clmintie]

Kawasaki recommend 32:1 for the KDX... I don't know enough to argue with them.......I'm presuming (cause I never asked) that when Mr Motorcycles fitted the after market pipe and muffler, they jetted it to suit. It runs sweet, with just a little residue on the rear mudguard. After nearly 700 miles, plugs still good...and at my speed, thats got to be hundreds, if not thousands of hours..... :rolleyes:

[dammad1]

Kawasaki recommend 32:1 for the KDX... I don't know enough to argue with them.......I'm presuming (cause I never asked) that when Mr Motorcycles fitted the after market pipe and muffler, they jetted it to suit. It runs sweet, with just a little residue on the rear mudguard. After nearly 700 miles, plugs still good...and at my speed, thats got to be hundreds, if not thousands of hours..... :rolleyes:

Yeah always ran my old KDX at 32:1 and never had a problem, its all down to the way its jetted.

[cheese]

Ok so went to kimmys today. and all I've done is fit a new plug and put a new seal on the pipe (from the cylinder). Now the bike was going Very well today so I guess the old plug was just past it. BTW the plug I got I got it from a local BNT and it was $12 (or something) instead of $35!!! I really rate those Iridium plugs!!

ANyway when I'd stopped it was oil city! and there was fuel leaking so maybe my problem is a stick float??? I'll check my jets though.

[vr4king]

Ok so went to kimmys today. and all I've done is fit a new plug and put a new seal on the pipe (from the cylinder). Now the bike was going Very well today so I guess the old plug was just past it. BTW the plug I got I got it from a local BNT and it was $12 (or something) instead of $35!!! I really rate those Iridium plugs!!

ANyway when I'd stopped it was oil city! and there was fuel leaking so maybe my problem is a stick float??? I'll check my jets though.


Please do im keen as to know why so much oil/spooge