Switch ratio because of fouling prob?

2001Rm125

Member
Jul 7, 2009
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0
I have a rm 125 and it keeps fouling plugs im using yamalube at a ratio of 32:1 should i try 50;1? Will this ruin the motor?
 

truckster225

Member
Jun 11, 2009
58
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Shouldn't hurt anything. At most, it will just smoke a lot. It will probably do the trick though. . . .

I had a DS 100 that was oil injected. I thought the oil pump was broke so I mixed the gas. Turns out the pump was just fine. So, for a full tank I was running nearly 70-1!! Smoked, ran kinda crappy, but it didn't hurt anything.
 

RM_guy

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Damn Yankees
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Nov 21, 2000
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You are fouling plugs because the jetting is too rich and it has nothing to do with the oil ratio. Stick with 32:1 and lean out the jetting. Going to 50:1 will actually make it run richer and make the plug fouling worse. Read the jetting link at the top of this forum.
 

2001Rm125

Member
Jul 7, 2009
77
0
ok ill stick to 32;1 wheres the jetting forum?
 

rmc_olderthandirt

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Apr 18, 2006
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Truckster: your math is backwards! If you normally ran 35:1 gas to oil mix, and doubled the amount of oil, you would be running a mix of 17:1, not 70 to 1!

2001rM125: Like RM_guy said. The plug isn't fouling because you have too much oil, the plug is fouling because the mixture isn't burning hot enough to heat the plug up enough to have it burn off the deposits.

If your air/fuel mixture is off then fixing that will not only help the plug fouling it will also make the bike run better. An all around win-win situation.

If you air/fuel mixture is proper and you are still fouling plugs then you can change the plug type to a "hotter" plug. For example, if you are currently running a BR8ES then go to a BR7ES. The lower number plug has more insulation between the plug tip and the threads so it doesn't conduct the heat out as easily and thus it runs hotter. The hotter plug will burn off the oil that deposits on it and keep it from fouling. Note that it is only the plug that runs hotter, not the engine.

Rod
 

whenfoxforks-ruled

Old MX Racer
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Oct 19, 2006
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If the jetting seemingly does not effect its running, you are overdue on some maintenance. You can not jet an engine with issues. Smokes a lot, spooge in the pipe, the right crank seal is the first suspect. 9 year old bike, whats the chances the carb float valve has been changed yearly? You can dive in and go through the top end, gaskets and a new set of rings, check the reeds and exhaust valve. The carb just needs to be done, especially when flooding issues arise. A leak down kit could help narrow down issues. Very nice try truckster, this is a NO GUY FIGURING ZONE! Might as well get out the tin foil hats, again.
 
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