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Discussion Starter #1
First off, I'm new to quads, but fairly mechanical and understand general principles of repair and how they work. I'm not looking to break land speed records but I do like to go fast.

Long story short, I just bought a used 2001 Raptor 660 and it needs a new top end. It was ran without oil for unknown amount of time. The cylinder head was journals were basically melted and chewed up along with the cam.

So I purchased a cylinder head assembly from Partzilla.
1st question: do I need to have the cylinder head machined to put in new valves and springs in?
2nd question: is there anywhere to find a standard bore cylinder or should I just have the original one bored out?

I'm not looking to do 100mph on this thing. I'm just a weekend trail rider in Michigan.

Any advice is greatly appreciated!
 

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The new head is ready to go, just assemble and install.
As for the cylinder, there are a few options, I'll let others recommend which brand, but stock 660, or bored to 686 are both fine.
Stay at or under 11 to 1 compression(piston) if you want to run pump gas, 91-93 octane.
Stock is 10.1, and the 11.1 will give you a little more low rpm power.
 

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Discussion Starter #3
Thanks alot.

I have a little anxiety going forward. Never done this before. I am torn on whether or not I want to be basically stock or suped up. I dont have a endless cash supply. I dont want to have to change a million parts just to get it running.

If I change to a big bore cylinder. Will I have to change the Crankshaft.

Would I need new carbs or just jets?
Recommendations on cam, piston, valves, rockers.

I was definitely blinded by excitement for the purchase. And basically got screwed.
 

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If the stock crank is ok, there is no need to replace it.
If you have to buy a cylinder and piston, might as well go to 686cc and 11.1 piston.
Get rid of the airbox lid. The crankcase breather tube goes into it, so put a clamp-on K&N style autoparts store filter on that hose.
You will need an intake adapter for a new filter, either k&n style or Uni foam style is fine, and use a filter skin.
Search the 660 Stickie section for the 3mm Clear Tube Method, and related posts. That shows how to properly set carb floats' height, and how to trim the float stops so it doesn't starve for gas at high rpm.
Buy a DynoJet jet stage2 jet kit, the only way to buy their needles(start in 3rd or 4th needle clip position) use the 2 largest main jets in the kit(right carb main is always one size larger than the left).
Buy 2 pilot jets, both #25 or #27.5
www.jetsrus.com
Buy a pair of Vito's air screws, as they have adjustment knobs all machined as one piece. They will make life easy when it's time to adjust them(3 to 3.5 turns counter clockwise).
Buy a carb rebuild kit to replace all the rubber, and the needles and seats(don't use the jets or any other parts from the rebuild kit either).
Add a stage 2 or 3 cam if you want a little more mid to high rpm power.
If you trail ride, or like agressive throttle response, switch to a -1 front sprocket(12 teeth).
If you want to gain back a few mph on top end that you'll lose with that gearing change, then defeat the top speed limiter. Top rear of clutch cover, 2 wires go into a sensor. With the cover off, you'll see a gear with square teeth under the sensor, grind all but 4 teeth, evenly spaced, off of that gear/wheel.
Now the sensor counts less teeth at the same rpm, and will no longer pull timing in 5th gear high rpm(and if you just unplug the sensor, it'll retard the timing and you'll lose power).
The service manual is also in the Stickies. Follow it, torque, loctite, and anti-seize everything to spec, and make sure you install the timing chain tensioner by the instructions.
Finally, do not be intimidated.
The 660 is a great engine, is easy to work on, and the group here can answer all of your questions about it.
 

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I just noticed your "ran without oil" comment, sorry I missed that.
I would think the crank, bearings and transmission would now be toast.
That sucks, as it's more money, but still not a bad job.
 

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Discussion Starter #6
I just noticed your "ran without oil" comment, sorry I missed that.
I would think the crank, bearings and transmission would now be toast.
That sucks, as it's more money, but still not a bad job.
The crank freely rotates and doesn't twist or shake. It does show a small amount of discoloration. The trans felt fine when I rode it and went through the gears.

When i went to purchase from a younger kid. It started, rode it for like 5 mins. Trailered it home, started but was boggy, changed spark plug started great, sounded healthy. Made it 3/4 of the way around the block and died. Didnt start after that.

It was basically never taken care of and I bought a turd. But I will attempt this rebuild and hopefully it will be like new.

Things I discovered during teardown, bent center intake valve, worn piston, the cylinder wall was warped, the journals that the cam sit in ground up and cam ground up. Timing chain appeared to be off timing.

But hopefully I should be able to fix it.
 

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At this point, I would split the cases and measure the crank and at least replace the crank bearings, counterbalancer bearings, and transmission bearings.
Considering the damage you know about, there's no point hoping the bottom end is good, only to build on it and have to take it back apart.
 

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There was "NO" oil at all, either the motor or oil tank?? It doesn't take much to keep the crank and trans lubed.

Discoloration on the crank is normal from when it was assembled. Check the rod for up and down movement, some side to side is OK. If the crank spins freely, no rough spots in the rod or bearings, I would go for it.

Assemble the head as is, but lap in the valves. Factory rockers, valves, valve seals, springs, etc. If you get a Stage 2 or 3 cam, it will require stronger springs. For trail riding, a stock cam may work just fine. Get some assembly lube. The Raptor has a lot of torque and may be enough power for you.

Have the cylinder bored to the next oversize and a 11:1 piston, I like CP brand. New timing chain, and a "factory head" gasket.

"Factory carbs" are good, and in most cases just need new parts, "O" rings, gaskets, needle and seat. Don't use Chinese carbs or jets, carb jetting may not be needed unless you change the intake and/or the exhaust. But, #25 pilot jets are a good idea.

Read the manual, and ask questions if you need to. Last year, we rebuilt a motor in the UK from the US. He had more then his share of problems that we worked thru.
 

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Dont forget to check/replace the oil pump, pickup screen, and oil tank screen

Sent from my SM-G981U using Tapatalk
 

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Discussion Starter #11
There was "NO" oil at all, either the motor or oil tank?? It doesn't take much to keep the crank and trans lubed.

Discoloration on the crank is normal from when it was assembled. Check the rod for up and down movement, some side to side is OK. If the crank spins freely, no rough spots in the rod or bearings, I would go for it.

Assemble the head as is, but lap in the valves. Factory rockers, valves, valve seals, springs, etc. If you get a Stage 2 or 3 cam, it will require stronger springs. For trail riding, a stock cam may work just fine. Get some assembly lube. The Raptor has a lot of torque and may be enough power for you.

Have the cylinder bored to the next oversize and a 11:1 piston, I like CP brand. New timing chain, and a "factory head" gasket.

"Factory carbs" are good, and in most cases just need new parts, "O" rings, gaskets, needle and seat. Don't use Chinese carbs or jets, carb jetting may not be needed unless you change the intake and/or the exhaust. But, #25 pilot jets are a good idea.

Read the manual, and ask questions if you need to. Last year, we rebuilt a motor in the UK from the US. He had more then his share of problems that we worked thru.
Thanks for the encouragement and advice. The only oil I could find in that thing was in the oil filter. And that appeared to be full of oil. I only got a few drops out of the tank and a little bit out of the crank.
 

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Discussion Starter #12
139841



So this is what I bought now I need valves and springs. Any suggestions I've been buying things on ebay.
 
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