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LC4 400 spewing oil, overheating, too lean??

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Recently I discovered white milky oil spewing from my LC4 400 and noticed my coolant levels running very low. After researching, I rebuilt the water pump and discovered what looked like a bad seal, replaced it and changed the oil 5 times until it ran clear. I did not adjust the valves when I did the repair b/c I did not have the proper gauges (they do make noise, but the same noise before and after the repair).

After the repair, the bike seemed great, so I went on to fine tune the aftermarket FCR carb to my 7000 foot elevation. I replaced the stock 170 main jet with a 162 and changed the pilot from a 48 to a 45. The bike ran pretty good with a much better low end and not necessarily any difference in the high end. I also added stainless oil filters to the bike at this time. The air box is open and it has a Big Gun exhaust.

I loaned it to a friend to ride on an 80 mile dual sport ride yesterday and as he was nearing completion of the ride on a long 60mph street uphill in 80 degree heat the bike just stopped running and spewed out most of its oil (everything still turns fine - no seizing). The seals on the engine seem intact and the clear plastic tube that drains from the frame got blown off causing oil to cover the engine suspension, etc... the oil is fairly brown and clear and does not look like the milky mess I experienced before the water pump fix. There is little or no coolant in my radiator, however, I cant find any obvious leaks in the cooling system. Argh!

Suggestions?

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I have heard of this before on KTM, sounds normal... enjoy!

Recently I discovered white milky oil spewing from my LC4 400 and noticed my coolant levels running very low. After researching, I rebuilt the water pump and discovered what looked like a bad seal, replaced it and changed the oil 5 times until it ran clear. I did not adjust the valves when I did the repair b/c I did not have the proper gauges (they do make noise, but the same noise before and after the repair).

After the repair, the bike seemed great, so I went on to fine tune the aftermarket FCR carb to my 7000 foot elevation. I replaced the stock 170 main jet with a 162 and changed the pilot from a 48 to a 45. The bike ran pretty good with a much better low end and not necessarily any difference in the high end. I also added stainless oil filters to the bike at this time. The air box is open and it has a Big Gun exhaust.

I loaned it to a friend to ride on an 80 mile dual sport ride yesterday and as he was nearing completion of the ride on a long 60mph street uphill in 80 degree heat the bike just stopped running and spewed out most of its oil (everything still turns fine - no seizing). The seals on the engine seem intact and the clear plastic tube that drains from the frame got blown off causing oil to cover the engine suspension, etc... the oil is fairly brown and clear and does not look like the milky mess I experienced before the water pump fix. There is little or no coolant in my radiator, however, I cant find any obvious leaks in the cooling system. Argh!

Suggestions?

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dude, many scenarios here. But they're characteristc of overheating caused by the following

a) cracked head unit

open up the head of the block and check for cracks in the head on the side where the piston should be. Where I come from it's boiling hot and a cracked block head is a common fault on the LC4s especially the 2nd generation ones. all it takes is a very small crack so look carefully. You might have to force in water at high pressure where the water pump inlet is to see this.

The oil does not necessarily have to look milky to discern if water has been mixing in the oil. It takes a lot of water and a good mixing for that to happen

Check if your radiator has oily sludge. It won't be distinguishable from just looking in so take a dip and feel the sides with your finger. It's one of the signs of a cracked head. Don't forget to flush the radiator after you've replaced the head of the block. dropping the whole engine and cleaning it out is a must. don't compromise by simply doing a couple of oil changes. while you're at it change the timing chain as well... The head will cost you quite a bit if you can find it that is. You can try fitting a SuperCompetition block if you like. I find that they're more bulletproof.

:thumbsup: Faulty water pump

Another common fault on the LCs. start up the bike when cold and see how fast the water pump heats up. It should heat up really fast like in a couple of seconds. If it takes longer than 5 minutes or so, than you've got a faulty pump causing the problem. replace it.

c) First parade task!!!

Always check the radiator and engine oil before every ride! this thing sucks them up like a drain pipe especially in hot weather. Top up before you start up the bike. 10w40 mineral base engine oil is my recommendation. don't compromise wth cheap 20w50.

Enjoy!

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