Valve/Head work - Yamaha Grizzly Forum : GrizzlyOwners.Com Yamaha Grizzly Forums

mbudzynowski · 01-22-2012, 05:36 PM

I'm in the middle of doing a go-through-and-fix-what-I-find-wrong with my grizzly, I pulled the top end of the engine apart yesterday, the exhaust valves don't look too bad but the intake valves and their seats are pretty beat up. I know I need new intake valves (there is no margin left on mine) but I think the seats would need to be machined too far back to use stock valves. Does anyone know a good place to get oversize valves? And will I need to put reliefs in the top of the piston for oversize valves? Any input is appreciated.

rbdenman · 01-23-2012, 02:36 PM

You might be better off just cleaning up what's there and maybe pitching a Raptor cam on the pile to make for some better breathing...
(Unless you need to go oversized to straighen up a problem...

)

mbudzynowski · 01-23-2012, 04:28 PM

I took the head in to the local shop and the seats weren't as bad as I thought they were, the mechanic said he'll clean them all up and grind my exhaust valve faces because they're still good. Ordered 3 wiseco stainless one piece intake valves (only $2 more each than OEM). While I was there I had him measure my bore and found it quite a bit out of round. If I had the funding I'd be putting in a 686BBK...but the boring for that costs more as well as the piston kit. Since I just spent all my money on head work I have to save some up for the piston/jug, but I'm having it bored 1mm over (673cc) and getting a 101mm 11:1 piston kit. I'd like to go with JE pistons, but again my funding won't let me. I'm looking at a Namura kit, which the mechanic said he hasn't had any problems with them. And I was looking on ebay today and picked up a raptor cam for $36 shipped, I couldn't pass that up. With the cam do I need to replace all my valve springs with raptor springs or can I get away with just replacing the center intake spring?

mbudzynowski · 01-23-2012, 04:41 PM

Another question, will I need to put a jet kit in the carb for the cam/hc piston? it has stock intake and exhaust and it will probably stay that way for a while while I'm on my college student budget.

rbdenman · 01-24-2012, 12:35 PM

Jetting will be affected...

I stuffed a 10:1 102mm JE in mine with the Raptor cam and all of the valvesprings replaced.... I had to lean it out quite a bit right up to the very top end...
I'm not sure what the 11:1 Namura's going to do though...

mbudzynowski · 01-24-2012, 05:59 PM

Looks like it'll be trial and error, I'll talk to the mechanic and see what he recommends

mbudzynowski · 01-24-2012, 09:40 PM

Sorry I keep thinking of questions after I post lol, I was checking the decompression cam on my grizzly cam and the decompression pin is normally sticking out and when I turn the decompression cam plates the pin goes in, when I let them spring back the pin sticks out. Is this right or is it normally supposed to be in and when you turn the cam plates it comes out? Also when I put in raptor valve springs do I also need raptor spring seats, retainers and keepers as well or will these work from the grizzly? Sorry, just want to make sure I get it all together right the first time

rbdenman · 01-30-2012, 09:44 AM

I know that the springs are a direct replacement.
The decompressor stuff though... I'm guessing that when you turn things manually; you of course don't have enbgine compression doing its thing to push stuff back into their origianl positioning... (Just a guess!)

mbudzynowski · 01-30-2012, 12:13 PM

Thanks, the mechanic said he may have an extra set of raptor springs laying around from when he put a hot cam and springs in his raptor, hopefully he can find them for me, that'll save me $35 (every dollar counts!). I'll have to look at the decompressor stuff more in depth and see if I can figure it out. nothing should've changed since it worked before I took the cam out and I havent taken the sprocket/decompressor off yet, but it seems to me like it's different from what the manual shows. I could just be reading it wrong though

haha thanks for the help. Right now I can't wait for it to be done. Just dropped off the jug on saturday to get punched out to 101mm and ordered the piston kit. Now it's just a matter of gettin money!

01-23-2012, 02:36 PM	#2 (permalink)
rbdenman Senior Member Join Date: Apr 2006 Location: Grahamsville Posts: 7,435	You might be better off just cleaning up what's there and maybe pitching a Raptor cam on the pile to make for some better breathing... (Unless you need to go oversized to straighen up a problem... ) __________________ SOLD!! 2004 Grizzly: Way too many modifications to try and list them all here...

01-24-2012, 12:35 PM	#5 (permalink)
rbdenman Senior Member Join Date: Apr 2006 Location: Grahamsville Posts: 7,435	Jetting will be affected... I stuffed a 10:1 102mm JE in mine with the Raptor cam and all of the valvesprings replaced.... I had to lean it out quite a bit right up to the very top end... I'm not sure what the 11:1 Namura's going to do though... __________________ SOLD!! 2004 Grizzly: Way too many modifications to try and list them all here...

01-30-2012, 09:44 AM	#8 (permalink)
rbdenman Senior Member Join Date: Apr 2006 Location: Grahamsville Posts: 7,435	I know that the springs are a direct replacement. The decompressor stuff though... I'm guessing that when you turn things manually; you of course don't have enbgine compression doing its thing to push stuff back into their origianl positioning... (Just a guess!) __________________ SOLD!! 2004 Grizzly: Way too many modifications to try and list them all here...