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Raptor smoking and milky oil

2K views 8 replies 6 participants last post by  eddiefromcali 
#1 ·
Well today I thought I finally fixed ALL of my raptors issues.
Heres a rundown of what happened...
Bought it last summer, rode it one night, smoked bad, got the engine fully rebuilt (bored, new piston, new crank, new connecting rod, bought a head off of Cuztom Racing on here, new cam, basically new everything minus valves)
Got the engine back in February, put it in, oil galley was stripped, took the raptor to the shop, they put a helicoil in and it was good to go.
Rode it most I could, which wasnt much due to a long winter. Replaced wheel bearings, starter solenoid, battery, patched the radiator pinhole with jb weld.
I have maybe 5-8 hours of ride time on it since I got it back in February, oil has been changed twice and is always full. Never smoked, nothing. Went to go riding tonight, fired right up. Took off, I noticed it popped alittle under deceleration and didn't want to idle. I adjusted the screw on the throttle cover on the left side of the carbs (where the throttle cable goes in) and fixed the idle, but still popped a little under decel. Well I got to a clearing, stopped because I needed to call a friend. Went to start back up and it was really hard to start and blowing blue smoke. I got it started by dropping clutch down a hill and rode back to my place (<5 minute ride). It died as I was coming down the hill at my place. Couldnt get it started. My dad pulled me and I got it started, but same thing. Pulled it into the garage... dipstick showed full all the way up to the top of the dipstick by the threads. Took out the resevoir drain plug... nothing but milky oil came out and the radiator was super low on water (so Im assuming the coolant is getting into the crank and thats why its showing so high on the dipstick) What would cause this? Bad headgasket, shot rings? Like I said, since the engine got fully rebuilt, it doesnt even have 10 hours on it.
 
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#2 ·
head gasket would be first place to look
 
#3 ·
Definitely head gasket, when you dismantle make sure the head gasket area of the head and cylinder are flat, it is best to resurface both surfaces very lightly to remove any imperfections...........
 
#4 ·
alright, since its a 101mm bore, dont gaskets come in stock 100 and then 102mm? what size gasket will i need and which is the best brand to buy? i think when the shop did it they used moose gaskets
 
#6 ·
dropped the raptor off at the shop saturday, im hoping its just the head gasket.
the one they put on it during the rebuild was moose, any known issues with those, like poor quality or anything that would be to blame for the blown gasket?
 
#7 ·
Also, clean the carbs - the popping you describe is most likely due to dirty pilot jets, a common occurrence when leaving the bike sitting for some time. I won't say that the lean operation led to the head gasket damage, but, if it did, you sure don't want a repeat right after replacing the head gasket.

To prevent the pilots from plugging you need to empty the float bowls if the bike is going to sit for more than a few days - just close the petcock and idle till the bike dies.
 
#8 ·
talked to the shop today, they checked it over and couldnt see anything visually wrong. gaskets looked like they were ok, didnt see any cracks anywhere in the head or jug. they have new yamaha gaskets on the way (mightve came after i talked to them) and theyre gonna put it back together and see what they come up with
 
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