I heard that the 2002 grizzlys had soft valve srings that cause valves and valve seats to wear out? Is it true? Has anyone see it? what is the fix for it? Where could I buy a set of valve springs to fix the problem? Is yamaha doing any thing about it?

Four Stroke Tech has HD springs for $100, am trying to find out if Yamaha is paying for any, so far no luck, probably should call them.
www.fourstroketech.com

IF YOU HAVE SOFT VALVE SPRINGS..THEN WHY IS IT HARD ON THE VALVE SEATS AND VALVE FACES....THIS IS A CONTRADICTION OF THE PROBLEM....
I HAVE PERSONALL TALKED TO ROBERT, FRED, AND LARRY AT TECH SERVICE....THERE IS NO RECORDINGS OF ANY VALVE TRAIN PROBLEM ON THE 660 GRIZZLY...THEY ARE THE SAME AS THE RAPTOR...WHY ISNT THE RAPTOR HAVING PROBLEMS???? I THINK YOU GUYS ARE HEARING A FEW RUMORS THAT ARE FLOATING AROUND....DONT BE ALARMEND BY EVERYTHING YOU HEAR....

According to Mickey Dunlap owner of Four Stroke Tech, one of the best fourstroke atv engine men around, I believe, the weak valve springs are causing the valves to bounce off of the seat causing valve seat damage. He says that the damage can be seen in as little as ten hours. Maybe Mickey will jump in as he is on here occasionally. I also hear that if you want new valves from Yamaha that they are back ordered. I have not confirmed that. Also two heavier springs will fix the problem, so not every spring is weak, not sure if we are talking about the intake or exhaust, I think it's the exhaust.

[ 03-10-2002: Message edited by: GrizRodder ]

Hey GrizRodder do you know if this valve spring trouble is only with the 02 Griz or is it affecting all the 660's? (eg: 01 Raptors)

The raptor and the grizzly have different valve springs part numbers on the fich. It is hard on the valve and seats because soft springs allow the valve to float or bounce thats why the grizzly valve have been tighten up. The valves are not on back order because I order 3 intake valve and they will be here monday.

Rad-Man, I am told that it is all Griz 660's according to Mickey Dunlap at www.fourstroketech.com ,not sure about the Raptors, do not know really what going on here as Alcohol Burner has not had any problems with the 660's he services. Maybe it takes a lot of miles before the engine head is damaged enough to decrease performence. I will e-mail Mickey Dunlap and see if he will jump in here, as I respect Alcohol Burner for all the help he is giving us on this forum and his efforts to give out the best of information.

[ 03-16-2002: Message edited by: GrizRodder ]

Thanks for looking into this, I will keep watching here to see if anyone finds out more info on this.

Both the Grizzly 660 and the Raptor 660 have the same problem. With 10 hours or more, depending on how you ride it, your intake valves will start to suck up into the head causing your valves to go closed. Valves bounce on the seats causing them to "mushroom" the 45 degree angle on the valve. I have had reports of over 60 hours on motors with my valve springs without having to adjust the valves on both Grizzly's and Raptor's. The intake valves have just come off backorder with the past week. This is the 2nd time they have been on backorder in the past 6 months. I also sell stainless steel intake valves for $60 each but in my opinion they are not necessary. Some people want the extra security of a harder valve. Valve springs for both intake and exhaust that I sell have increased seat pressure and nose pressure for higher lift cams. Valve springs sell for $100 a set.

Thanks for jumping in Micky, with about 100 hours on my 660 Griz, are the stock intake valves salvageble, or should I replace them, from your post it looks like this is the case. Can the stock valves be ordered from you or do I have to go thru Yamaha? Thanks

[ 03-20-2002: Message edited by: GrizRodder ]

Just get them from your dealer.

I have about 100 hours on my Grizzly and I have adjusted the valves 3 times, should I be concerned on anything?

Glenn

Thanks Micky, I will get the valves from the dealer and order the springs from you. Sounds like the valves will always need adjusting with the stock springs.

Have been doing more researh on the weak valve spring problem with the Raptor and Grizzly 660. A lot of the dealers are saying that they do have a problem, but I think it depends on how hard the bike is ridden, the majority of us do more putting around on our new Grizzlys, so I believe with that kind of riding you may never see a problem. On another forum a Griz 660 owner had been ridding his bike wide open a lot and the valves were ruined. So in my opinion if you are easy on the machine you may not have a problem for quite awhile, if at all. More then normal valve adjustments needed indicate that you probabley need to replace the valve springs and valves if they cannot be saved.

[ 03-26-2002: Message edited by: Griz660Rodder ]

The thing that has me PO'ed is if this is a problem then why hasn't Yamaha issued a recall. I mean if there is a real problem they as a good corporate citizen should replace all the valve spring and any damaged valves, NO CHARGE. If you want to keep loyal customers in your good books then step up to the plate and fix your mistake. You don’t make these machines to be ridden like a little schoolgirls, if that were the case you wouldn't need 660cc's. So far I haven’t had any trouble, YET!!

You are right, does not make for very good public relations.

did anyone die or get seriously injured because the valve clearance on their raptor/grizzly660 went to zero?i doubt it,that's why there isn't a recall.if you want to hammer the crap out of something you best know how to take care of it.how often did you guys check the condition of your machine before you rode it?

I check my quad out every time I ride, go over everything. But the last time I checked I couldn't see through metal to inspect my valves.
I doesn’t matter if check you quad or not if these valves are going to fail due to weak springs, they will. No amount of maintenance is going to prevent this type of failure.