My Raptor blows blue smoke when you pin in 2nd gear and sometimes when I let off the thottle in any gear it will blow blue smoke out of the pipe and also when I have false netuarl and I didn't mean to hit the gas and when I let it off it will blow pretty much of blue smoke! so What's up with that? Any thought of it?! If you know what's wrong let me know! I don't feel any power loss still strong like new! My Raptor has over 3000 miles or more. I also have Pro Flow Air Filter Kit. Is my head gasket bad or what? Thank you for your help!! Was I suspose to rejett for this air filter or not?

Have a great day!
Dusty
01 Raptor with some mods

 

I have been telling people about this problem with the Raptor head for ages.

Yamaha produced a number of early 660 engines that had too much valve stem to guide clearance. As a result, oil is sucked into the combustion chamber through the intake ports. With three intake valves, you have a real oil problem.

To check for this condition, simply remove the carbs and rubber manifolds. Look inside the intake ports for oil film. Take a white towel and run it in the intake ports. If the visual or towel test shows oil, you have the problem. I suggest you then take it to Yamaha and raise Hell. It is a defect in the manufacturing process.

Oh, one more thing, although you think there is no power loss, I know that there is about a 5 bike distance on a hill between a oil leaker and a clean burner.

 

Wolverine 16, your Raptor is smoking because one time or another, you sucked dirt through or past the air filter and your oil ring is sanded down. The power will remain same because the compression rings are still holding good seal.

The symptom you described is caused by the rings because the oil gets pulled up past the rings under high vacuum condition such as decel or off throttle from rpm.

Engineer Raptor720 is on a tangent. There was no defective valve guides. Even if the guide clearance is out of spec, it would be difficult to consume oil because there is a spring loaded valve seal (race engine style) to prevent oil getting past the guides/stem. If valve guides were the cause, it will smoke more so during engine start up (due to oil seeping past the guides) and not so much during high vacuum conditions or normal running.

You will need to ring your engine. Depending on how much wear, your cylinder may need to be bored to next over. Why did you install aftermarket air filter - did you suck dirt with the original? I'm sure this question will open up a can of worms.

 

Get ready to R U U U U M B L E! It's a cage match between raptor720 and RapTech. One man will be the victor, the other the vanquished. Come on guys, you both have great info for us, so come to conclusion on this. Is it possible that you could both be correct in that what RapTech explains is the usual and what raptor720 explains is the exception (which would be easy to believe considering yamaha's numerous hic-cups with the Raptor) ?

Keep the info coming guys, I like it!

 

Rap Tech is a wealth of knowledge and I don't oppose his conclusion -- it is possible. HOWEVER, on decel, there is a major amount of vac that can pull oil past the intake guides -- and there are 3 of those pesky guides. Oil can also go past the rings as stated by Tech but it is highly unlikely unless you really messed up the stock filter. I have seen the valve guide problem first hand on 5-7 660's not including some old MZ's.

As for the "race" valve stem seal, it is the same part number used on the Warrior -- a real high performance sport quad NOT. A race seal is usually teflon-- is can withstand heat better than rubber and has less friction than rubber -- here we have rubber -- it does have a spring to help control oil leakage but if the guide clearance is too large, you have oil problems.

On the dirt past the air filter thing ---- Sure, I agree, that is possible. In fact, I noticed the problem on one of my 102 builds when it was torn down for inspection. What happened was the UNI filters (not stock filter) did not hold back the dirt and the cylinder was worn. Even so, there was no oil consumption and a leak down test did not reveal a problem.

Sure, Yamaha is going to send out letters to all 660 owners and say that 1. The trans may fail; 2. The valve guide clearance is too big on some engines; 3. The rear axle is junk; 4. The carbs will usually blow off miles from home and there is no allen wrench in the tool bag----- I DON'T THINK SO.

NOW, on the to R U U U U M B L E issue, Wolverine16, please take off the carbs and check for oil. If it is not there, I will buy my friend Rap Tech a beer at Glamis and tell Knutz (the DS650 lover) that the DS is better than the Raptor [I better be right -- those DS's stink]

 

Well, raptech may be on to something. I just did my first service on my raptor, I have had it about a month and a half and probably about 10-12 hours. I also, added the big gun exhaust, dynojet kit and a k&n filter. I runs much better now. I don't think the carbs were seated all the way in thier boots when they came from the factory. I noticed some dirt around the carb where it is supposed to be in the boots.

When I reinstalled my carbs, I made absolutely sure that they are seated all the way and plan to check them every time I ride to make sure they remain seated. I think I caught it before any problem occured,because there was no dirt inside the carb or boots.

I am not sure on the valve guide thing, except to say that what raptech says is true about how it works.

My 2 cents
Paul

 

Unfortunately Bat, your response does not qualify for the R U U U U M B L E bet -- and your carb problem was not a real problem.

 

raptor720: rear axle is junk?
I always stay to the right on the trails. Now when I am on the highway in my Z-28 thats a different story. With all the things that I have heard on the Raptor what is wrong with the rear axle and is it truly junk. Chet

 

For the wife, it is ok -- for mild trail riding it is ok -- for anything else, it is too weak

 

raptor720,
I just saw on another post where you state that the axle flexes 1.5 inches under acceleration. Is this on both sides or just the chain side? How can I see this happening? Should I let someone else ride the Raptor and watch this occurring. Chet