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Ok this is my first post so please give me a break if I am doing something wrong.

I have a 2009 Drz400sm I just picked up recently. It has fmf exhaust, big bore, hot cams, fcr carb, 3x3 mod, raptor petcock, and i'm sure a few other things. I was aware that the bike had a bad idle when I bought it and it would die if you didn't keep the revs up with the clutch in. I fixed the loose throttle cables and it seemed to clear the idle issue up for the first ride after that. Soon after that it started to have a bad idle again. Now the bike will not even start. It turns over but just will not start. I tried to hook up a battery box to the battery and that didn't help. The battery is charged, the spark plug is new and sparking, the air filter looks fine and it seems like it may actually be getting too much fuel because there was fuel on the plug. It was having some overheating issues when it was running and I checked the coolant to see there wasn't much in there. Filled it up with new coolant. I drained the oil the next day and it was creamy colored. I imagine that it was coolant in the oil because the coolant level dropped significantly in the radiator. I checked the valve clearance and intake are over spec slightly. It measured .18mm (.15mm is max spec for hot cam). The exhaust clearance is in spec. I know the intake is a bit out of spec but I don't think that is why the bike isn't starting. Between the milky oil, the rough idle, not starting, valves out of spec, i'm honestly not even sure where to start with finding the issue. I haven't torn apart the carb yet because the guy I got it from said he cleaned it but I am wondering about the jets that are being used. Please if anyone could help me out some it would be greatly appreciated. The starter will turn all day but the motor does not want to turn on. 

Edited by Singlecyl

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A proper leakdown test would tell for sure but this sounds like a blown head gasket to me.

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Thank you all for the answers. I will pick up some equipment today and try to do a leak down and compression test and see what I come up with 

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coolant in oil is usually head gasket, waterpump gasket or head welch plug...probably in that order

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6 hours ago, ohiodrz400sm said:

Hotcams used to not give spec's for the DRZ, only the recommended lash which was at the median of the stock range. That said, I wouldn't worry about that .0011", it isn't making any difference.

As others have said, it sounds as though you have a leaking head gasket.

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I guess since my issue is more than likely a leaking head gasket my next question would be how hard is it to change? I'll probably pull the motor and take a look but also is there a specific reason why it went bad? What should I be looking for when I pull the head off other than a bad gasket? Is this a costly repair if I do it myself? I'm no mechanic but it seems like I should be able to do this work in my garage rather than paying a shop to do it 

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You have a bigbore, it's possible the previous owner pinched the head gasket rivets between the mating surfaces of the head and cylinder. Other possibilities include not cleaning the surfaces sufficiently or under torquing the bolts.

If you get a service manual and have a socket set and a 3/8 drive 20-100lb torque wrench you'll be fine. The head can be removed with the motor in the frame

 

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Or the previous owner reused the old gaskets .  Best to have 1/4" torque wrench and 3/8 if at all possible for the lightly torqued bolts and the main head bolts.

 

 

.

Edited by jjktmrider
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9 hours ago, Singlecyl said:

Thank you all for the answers. I will pick up some equipment today and try to do a leak down and compression test and see what I come up with 

Harbor Freight makes an inexpensive leak-down compression test kit that works well. I usually use 80 psi as a reference pressure. For a cold engine anything above 72 psi is a good holding pressure. You may need a helper to keep the bike at TDC (bike in gear and foot on the brake) while you listen/feel for leaks. it's helpful to remove the carb from the boot if the intake valves are suspect (in this case they are not).

Edited by Gary in NJ

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So just to inform anyone, I ended up taking the head off today and sure enough the head gasket had failed. I am going to be ordering a new one either today or tomorrow. Anyone have any recommendations of which brand to get? At least I may have finally found my issue so i'm kind of happy about that. Thank you everyone who helped me on this issue! 

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