Engine problem- cam sprocket & dowel pin(keyway)

[jmd599]

Hey everyone I just bought a 2000 warrior 350. I've been riding for all my life but finally decided to finally buy my own! The previous owner claims it has the following modifications: hot cam (do not know the lift/duration), hot rod, vertex piston, rings, and bored over one size (do not know how much).

Of course when I bought it, I rode it and it broke within the first 10 minutes.

So here's my problem I need help figuring out what exactly is wrong and why before I go fixing anything of course. My friend says the dowel pin(keyway) came out and hit the cam sprocket. And now it does not start. Thats my first problem/question. How&why & how to prevent it. What will I need to order?

Secondly, considering its bored over "one size" if I buy a head gasket can it be a stock head gasket or at least stock size. I know some gaskets have a little more clearance just in case. Just making sure before I go ordering things. Thanks in advance!

 

[Warrior1996]

Is the bolt that holds the cam sprocket on still tight? Behind that bolt, there is a dowel pin that locates the sprocket to the camshaft. It's a semi-common problem for the bolt on the end of the cam (the one that holds the sprocket on) to back off, and then tear the dowel pin out of the cam. This ruins your cam, possibly the sprocket, and can easily send metal pieces into your case. Pull the bolt off the end of the cam and have a look. If it's broken, it'll look something like this (see pic below). As for the the head gasket, you should be fine with just a stock gasket.

 

[jmd599]

Yes! I just took off the sprocket that is exactly what was wrong. If I'm going to replace the sprocket and camshaft I may as well do everything else though right? valves, springs, etc.

Or should I just buy this whole assembly and save some time? Whats the smartest way of fixing this problem.

- http://www.ebay.com/itm/YAMAHA-WARR...ash=item3a8c3f83e4:g:X5YAAOSwq5lTqu4o&vxp=mtr

 

[lbjamm]

I'd just slap another cam in, locktite the bolt, retime it and ride. Unless of course the piston and valves met. Then it's time to rebuild.

 

[Warrior1996]

I would go about the problem exactly how lbjamm said to. However, to add to it, if you lost the broken pieces of the cam and the dowel pin inside of the case, I would recommend flushing your case a few times to try and get those pieces out.

 

[lbjamm]

I would go about the problem exactly how lbjamm said to. However, to add to it, if you lost the broken pieces of the cam and the dowel pin inside of the case, I would recommend flushing your case a few times to try and get those pieces out.

Good idea.