Yamaha Raptor 660 valves adjustment
Tools you need:
Breaker Bar (optional)
3" Extension (not shown)
4MM Hex Key
5MM Hex Key
Needle Nose Pliers
Yamaha Spark plug socket (not shown)
Philip Screw Driver (or socket like on the picture)
Service Manual for Torque Specs and Valves Clearance
AND A STONE COLD ENGINE!!!!! best way to do it is if the engine hasn't run overnight!
First you need to remove the front plastics.
Use the 10MM socket to remove the bolts (displayed with red arrows).
Use the 10MM socket and phillip screw driver to remove the screw and nut (blue arrow)
Remove the hood with the 4MM HEX key (yellow arrow)
Once the hood is removed, remove the last 10MM bolt that holds the front plastic (red arrow)
Now remove the plastic tank cover (cannot remove the front plastic with it in place). It's holding with plastic clips, only ~1/2 turn with a screw driver will allow you to remove them. (red arrow)
You might want to clean the plastic cover before you remove it as you have to remove the gas cap to take it off. You don't want any dirt in your gas tank!!!!!
OK now you're ready to remove the front plastics.
it can be a little tricky when it's the first time you take them off.
You have to pry a little on those tabs to lift the plastic as they're holding by that little bump where you removed the bolts.
Now that the front plastic is free to move, lift it ~4-5" but be careful! the reverse knob might hold it a little. You don't want to break it.
Now pry the back of the plastic so both sides will go around the wire and cables on each side of the steering (pink arrows) and pull it toward you.
Now with the plastic off
Now you have to remove the 2 remaining 10MM bolts on the gas tank (red arrow)
Turn off the petcock (green arrow) and remove the gas line (blue arrow)
Now put the gas tank where the petcock will not touch anything, a milk crate if perfect for this task!
Now you have access to a rubber hood that covers the intake valve tappet cover. You have to remove it by "fighting" those 2 reusable tie wraps (green arrow).
Since you'll be turning over the engine manually, remove the spark plug with the Yamaha spark plug socket. You'll need your ratchet and the 17MM socket.
Again you might want to wipe off the dirt before you remove the spark plug cap.
*no pics of this step*
Once the plug is removed you need to take off the covers for the timing and crank bolt (red arrow). A large flat blade screw driver will fit perfectly to remove your covers but be careful as those covers are plastic.
Here are the 2 covers. Watch those little O-rings!!! They might stick on the engine and fall off. It's better to remove them and keep them on the covers. Clean them up too! (green arrows)
This is what you'll see once the covers are off.
I always wipe off the oil in the thread with a rag and then use it to remove the dirt around the hole (green arrow).
Now take the ratchet (or breaker bar), 3" extension and 19MM socket (3/4 will work too but it`s a little too big) and turn the engine COUNTER CLOCKWISE
(yellow arrow). Align the I mark (not the I-I) with the grove (red arrow)
Once they're aligned, take off the intake valves tappet cover, you might want to clean it before with a rag as you don't want any dirt in your engine!!! It's held on with 4 5MM hex screws (blue arrow)
Clean up the mating surface of the cover and the O-ring (green arrow)
Now you have access to the intake valves (red arrow) and clean the surface on the engine (green arrow). Be careful with the cleaning!!! Again you don't want any dirt in your engine!
Now to find out if you're at TOP DEAD CENTER (or TDC) I always use a smaller feeler, if it's not going in, your most likely 180 degrees off (which means you're not at TDC). You can also turn the crank bolt back and fourth 1/4 turn and see if the intake valves move at all. If they don't then you ARE at TDC.
As stated in the service manual, if there's no clearance, you're not there yet (need to do another turn).
See the picture, the .076 isn't going (I use the .076MM feeler because I know my valves wont out of spec that bad).
I did another counter clock wise turn and now it's freely going in!
Now the clearance specs for the stock cam are .100MM to .150MM .
I always use the feeler the closest to the average which is .125MM (with my feeler the closest is .127MM)
It has to be a snug fit! not too loose and not too tight.
If the valves are within specs the .100MM feeler will go in freely and the .150MM will not fit in!!!
If the .100MM is tight or .150MM is loose it's time to adjust the valves.
The way I do it is, I loosen up the lock nut with the 10MM wrench (red arrow), take the needle nose pliers and turn the tappet with the needle nose pliers (yellow arrow). Fit in the .127MM feeler, tighten the adjuster back a little and tighten the lock nut! Do this for all 3 intake valves.
Once it's done I do 4 or 6 COUNTER CLOCKWISE turns on the engine with the ratchet (or breaker bar).
Recheck the valves! If within Specs, put back the tappet cover! YOU'RE DONE for the INTAKE!
Now it's time for the exhaust valves! They're a little tricky to do because the space is LIMITED!!!
Take off the 2 exhaust valves tappet covers with the 17MM socket (yellow arrow).
See there's not much space to play around
See where you have to squeeze in the feeler
To do the exhaust it's easier with a bent feeler, I bent mine with a custom angle where it fits quite easily.
I also go with an average to adjust the exhaust valves.
Specs with the stock cam are .150MM to .200MM. Myself I go with the closest I have which is .176MM.
To insert the feeler easily, I slide from left to right!
Again for the specs if the .200MM doesn't fit and the .150MM is loose, you OK. If the .200MM fits, even snug, I'll tight them a little.
If the .150MM is snug, I'll try to loose them up to .176MM. Do that for both exhaust valves.
Once adjusted, I'll turn again the engine 4 or 6 turns COUNTER CLOCKWISE and recheck. If they're not within specs, do it again!. If they're within specs. Put back the tappet covers, YOU'RE DONE!!!!