Another Project and Possible conversation with God about my wrenching choices.

GF's Son's Friend has a 200(?) Yamaha Raptor, I think a 600cc.

Water Pump Cover weep hole started leaking consistently, told him not to keep riding it until fixed, kid didn't listen and only added water as a fix, don't know if he ran it dry though?

Kid mentions something about driving through a big puddle WFO where his problems began, thinks he blew it up?

Bike will start and idle apparently however when he goes to give it any amount of throttle it will bog out, not accelerate and he thinks it's popping through the exhaust. I asked about smoke, either White or Blue coming out the exhaust and he's unsure if any.

I've never worked on a 4 Stroke Bike/Quad, plenty of experience with 2 Smokes and Auto stuff though.

Is the Raptor motor an interference type fit meaning if he did blow something up wouldn't the Valve be smacking the Piston?

To me the popping / backfiring through the exhaust, the inability to rev out, the W.P. Impeller Shaft Seal Issue along with taking a overheating (I would assume it was) motor through an instant cooling puddle, leads me to thinking it's a possible Blown Head Gasket.

Once I get the bike I am going to check all the electrical, see what it does and sounds like upon start up and look it over carefully before agreeing on taking the job as I'm a little elary of taking on a 4 Stk. motor job, if it requires that.

If you don't agree with the H.G. diagnosis what are your thoughts on what it could be?

If it needs an entire top end and piston kit, how hard of a job is it to install?

Rough price of parts?

Is getting the Valve Train in an all timed up a .....?

If the Valve seats need replacing what do machine shops charge for this type of job?

How much compression, roughly should this motor have?

Thanks for any advice you can give.

easy to work on  , depending on price though can be a bit pricey as well. first things first, check the oil, see if the antifreeze has mixed with it 

FYI Size on that motor is a 660 ran that up until 2007 when the 700 was released fuel injected.

Saw this Happen with a YZF426 a few Years Ago.Brand new Bike,Guy rides thru Puddle,Water gets into the Cylinder and does over $2000 in Damage.After the Rebuild it still wouldn't run.They finally junked the whole bike out before the 5th Payment was made on it.

ive puddled a quad before, many times its unavoidable. when that happens, dont run it, and change/flush the oil , or what jug said, is a very REAL possibility

Turns out, it was as simple as Unplugging the Parking Brake Connector behind the Radiator.

On these bikes the have a few Switches, One for the Parking Brake, and One for the Reverse Selector. When either one of these devices are activated the CDI senses it and puts an automatic Rev Limiter on, figuring you don't want full revs while either one is being operated.

So when I got the bike I started it, and to me if it starts and can idle more than likely the motor wasn't blown, so I started looking at wiring as being an issue thinking it was a short or something. A few minutes in I tried unplugging the PB connections and the bike perked to life and full revs.

$50.00 bucks in my pocket, the kid thinks I'm a genius, he was resigned to the fact he needed a top end. He forked over another $50.00 for me to do the Water Pump seals, just waiting on parts for that now...

Thanks for the help.

cheap and easy fixes are the best.

yup i love those. they keep food on my table