Valve seat cut

I'm Upgrading to kibblewhite valves and spings, how important is it to cut the valve seats?

Very important. Usually after the stock valves go bad, they distort the valve seats. You won't get a good seal between the valve and the seat.

You'll be replacing your new valves in no time if you don't cut the seats.

Absolutely mandatory.

I decided to replace my valves the first time they needed adjusted. My ucle said that since I had such low hours on it that I could probably lap them in. He gave me some lapping compound and away I went. I have had continued to have troubles but I also hear that the '05 CRF250s are known for having bad valves/heads. I have a buddy that had the same bike and had his head done at Vance and Hines who hasn't had any problems ($135.99) http://www.vhmotorsports.com/services-swf/services.html. Also, you could just get a new head off of ebay. Just some options and advice from someone who has been there.

I decided to replace my valves the first time they needed adjusted. My ucle said that since I had such low hours on it that I could probably lap them in. He gave me some lapping compound and away I went. I have had continued to have troubles but I also hear that the '05 CRF250s are known for having bad valves/heads. I have a buddy that had the same bike and had his head done at Vance and Hines who hasn't had any problems ($135.99) http://www.vhmotorsports.com/services-swf/services.html. Also, you could just get a new head off of ebay. Just some options and advice from someone who has been there.

You never ever lap stock intake valves. You can lap steel or stainless steel valves. Stock valves are coated titanium. If you lap them, it takes the coating right off of them and you won't get any time out of them at all.

I decided to replace my valves the first time they needed adjusted. My ucle said that since I had such low hours on it that I could probably lap them in. He gave me some lapping compound and away I went. I have had continued to have troubles but I also hear that the '05 CRF250s are known for having bad valves/heads. I have a buddy that had the same bike and had his head done at Vance and Hines who hasn't had any problems ($135.99) http://www.vhmotorsports.com/services-swf/services.html. Also, you could just get a new head off of ebay. Just some options and advice from someone who has been there.

you cant lap TI valves because you will ruin the hard coating and they will fail in short order

listen to Charlie C :smirk:

You never ever lap stock intake valves. You can lap steel or stainless steel valves. Stock valves are coated titanium. If you lap them, it takes the coating right off of them and you won't get any time out of them at all.

Sorry. I forgot to mention that I went ahead and got some new stainless valves from Faction.

If that was the first time you lapped them in, you were ok. If I was guessing right, you used the stock valves and tried to lap them in?

The first time I needed to adjust my valves I went ahead and changed my valves to some sturdier ones and got a Hot Cam, so yes, I went from stock valves and to the stainless valves. this is when I lapped them.

That's not a problem. If you didn't have the seats cut, the valves never seat right. The seats have to match the valve angles and after they've been distorted by the old valve, they're ususally not right.

After my seats are cut I'm not going to need to lap the valves am I?

After my seats are cut I'm not going to need to lap the valves am I?

No, just have them cut by a reputable shop.

Ti valves aren't the only valve material to use coatings. When in doubt, do NOT lap until you get the OK/recommendation from the manufacturer of the valve.

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