Jump to content
Sign in to follow this  

What's the best fix for 2005 crf450 valve issues

Recommended Posts

My 05 CRF 450R eats valves every 15 hours and its rediculous!

I change the oil and clean the air filter religiously and its still happening.

BIg bore thumpers offer new heads with stainless steel valves that they claim offers more reliability. Apparently the 08 model heads would fit the 05 aswell.

I have read that stainless steel valves are great, but the 05 model CRF's have a soft seat material, which would cause the hard valves to beat themselves in and lose clearance anyways. So the problem might not be the valves themselves, but the seats they sit in. Do they 08 models have a better seat material?

Im wondering what is the best way to fix this at a reasonable price.... or else it might be time to trade-in for a newer model!

Share this post


Link to post
Share on other sites
My 05 CRF 450R eats valves every 15 hours and its rediculous!

I change the oil and clean the air filter religiously and its still happening.

BIg bore thumpers offer new heads with stainless steel valves that they claim offers more reliability. Apparently the 08 model heads would fit the 05 aswell.

I have read that stainless steel valves are great, but the 05 model CRF's have a soft seat material, which would cause the hard valves to beat themselves in and lose clearance anyways. So the problem might not be the valves themselves, but the seats they sit in. Do they 08 models have a better seat material?

Im wondering what is the best way to fix this at a reasonable price.... or else it might be time to trade-in for a newer model!

In my 05 crf450 I put the kibblewhite stainless intake valve kit w/ springs and retainers after the right oem intake valve closes.I did not do any valve seat refacing I just lap the valves lightly with the finest grinding compound I could find.

Guess what that was already 3 years ago and I just shimmed the valves latey with only the next size smaller shim.

I could not remember how many times I race the bike but I ride it pretty hard my guess would be 80 hrs already w/ ss valves I wouid say there is stiil plenty of life left in the valves.

Do it you wont regret it!!!!

  • Like 1

Share this post


Link to post
Share on other sites

I think Honda changed the valve seats in '06, so ya an 08 would have better seat material.

  • Like 1

Share this post


Link to post
Share on other sites

Try using a new OEM stock filter with a petroleum based filter oil. There are known issues regarding aftermarket air filters (too porous) and bio-degradeable filter oils (not sticky enough to trap and hold dust).

Hope this helps!

Edited by jleblanc321
typo

Share this post


Link to post
Share on other sites

15 hours? I would take the airboot off the airbox and reseal it first.

the BBT heads are a great deal. the 07-08 heads have the smaller valves for better velocity, basically a bit more bottom end.

  • Like 1

Share this post


Link to post
Share on other sites

I talked to some people from the local track and the kibblewhites seem to work really well!

I'm definitely thinking the 08 head from BBT. A little more bottom end won't hurt either.

I never thought of using the stock air filters and resealing the boot... i'm gonna get right on that, thanks for the ideas!

Share this post


Link to post
Share on other sites

+1 for checking your airbox for sealing and keeping your filter clean every ride. Probably a main reason for valves needing adjusting and replacing. Frequent oil changes help too. I know a guy with an 08 and is a freak about keeping his airbox immaculate and changing his oil (rotella) every ride. He rides almost every weekend and has never touched his valves. Thing runs great with no starting issues.

Share this post


Link to post
Share on other sites
+1 for checking your airbox for sealing and keeping your filter clean every ride. Probably a main reason for valves needing adjusting and replacing. Frequent oil changes help too. I know a guy with an 08 and is a freak about keeping his airbox immaculate and changing his oil (rotella) every ride. He rides almost every weekend and has never touched his valves. Thing runs great with no starting issues.

Although frequent oil changes are a good thing and contribute to overall crank and engine health, They don't affect valve wear as the sealing surface of the valve that wears isn't lubricated by oil.

  • Like 2

Share this post


Link to post
Share on other sites

It sounds like your guides are worn out and or your seats may need to be cut. There is a few pictures on how to measure the contact area of the valve to the seat. I would inspect that and the guides before installing a new valve.

seatface2.jpg

seatface.jpg

valveguide.jpg

  • Like 1

Share this post


Link to post
Share on other sites

The Stock titanium valves are too hard they beat the valve seats up bc they are made of softer metal. the Simple fix is to just put a set of SS Valves in the bike it doesn't matter which kind but kibble white is pretty good. this should eliminate any valve issues

Share this post


Link to post
Share on other sites

titanium harder than steel? not! thats why the sealing surface of the valve get chewed up by the seat once the coating is gone. titanium valves with copper seats is the only way to go, makes both components last much longer.

Share this post


Link to post
Share on other sites

When I rebuilt my 05 motor I found a 06 head on ebay for $200. It was kind of a risky move but a year and a half later the valves have not moved. I don't race the bike, but I do a fair amount of sand dune riding. The other option of stainless steal is what I put in my 03. I had good results with that too.

Share this post


Link to post
Share on other sites

Are you cutting the valve seats when you replace the valves? If not, I see the reason for the failure. It could be the valve guides, but that's not super common.

I rarely hear of a bike that has Kibblewhite valves needing further repair. It is usually a "fix it once" deal.

Share this post


Link to post
Share on other sites
titanium harder than steel? not! thats why the sealing surface of the valve get chewed up by the seat once the coating is gone. titanium valves with copper seats is the only way to go, makes both components last much longer.

Titianum is much harder than regular steel even stainless steel.. check you info an then do a search on the SS valve conversion for the CRF bikes and see what everyone has to say

Share this post


Link to post
Share on other sites

I'm pretty new to 4 strokes, but the seats where machined when the valves were last done. I'm not sure if this was done properly or not.

My intakes lost all clearance and my exhaust valves lost half the recommended clearance in about 15 hours since the valves were done by a well known shop.

I'm on the smallest shim and its still running fine, but im walking on egg shells everytime I ride!! (I've put 6 hours on the bike since the shim).

I've heard nothing but good things with kibble whites, but if the seat material is in fact soft, maybe going to a 06 head will be worth it... Riding season is coming to an end here in Ontario so I've got a loonnnng winter to think about my options!

Share this post


Link to post
Share on other sites
Titianum is much harder than regular steel even stainless steel.. check you info an then do a search on the SS valve conversion for the CRF bikes and see what everyone has to say

i happen to build motors for a living. theres a reson they have to put a hard coat on the Ti valves, once the hard coat is gone, the valves cup out and sometimes chip. stainless valves almost never wear out but actually pound out the seats. ive done plenty of the conversions but for pure performance purposes i stick with xceldyne valves, Bronze beryllium seats and guides with a nice concentric cut on the seats, reducing low pressure cavitation around the valve head and thus producing higher combustion chamber velocity, fuel atomization and more power. need i say more?

  • Like 3

Share this post


Link to post
Share on other sites

Hardness is measured on the rockwell scale. Depending on the grade of material Titanium can be harder than some grades of steel. Hardness is not the only consideration when determining why one component wears faster than the other.

It is very odd that your seats are wearing on the exhaust side. They are not Titanium from the factory. I have heard they are Inconel but I cannot find any data on it. If they are then factory exhaust valves would be my choice for the exhaust.

Like mentioned above you should have your seats cut or at least check the I.D. of the valve guides, concentricity of the guide to the seat and the seat width where the valve makes contact.

This issue is not the seat material or which year head to buy. They changed the seat surface finish (whether they used a different material or processed the seats differently) to reduce wear but it will not matter when using stainless steel.

Oil changes do help with valve wear believe it or not. Abrasion by oil can ruin valve guides. The valves are oiled from the top of the stem. This lubricates the guides. Microscopically oil enters the valleys and and pits in the metal and then passes seal. It's not enough oil to cause smoke until the seals are significantly worn.

Share this post


Link to post
Share on other sites

I bout a bigbore head , and valves last winter for my 450 , its a 06 head. Valves have not moved , i`m happy. Call them , and ask about thier heads , and valves set up , and why they think that they are better. I`v used k.w. valves too.

Share this post


Link to post
Share on other sites
The Stock titanium valves are too hard they beat the valve seats up bc they are made of softer metal. the Simple fix is to just put a set of SS Valves in the bike it doesn't matter which kind but kibble white is pretty good. this should eliminate any valve issues

It is just the opposite. Titanium valves are very soft and the seats beat the valve faces up easily.

That is why the stainless conversion works so well as the valves are harder and don't get the faces beat up like Ti.

We have the complete valve / springs / retainer kits for installing in low milage heads and help solve the clearance tightening up problem. If the head is worn enough enough to need new guides and seats remachined, then our new head is the best deal. Just bolt it on and go.

http://www.bigborethumpers.com/crfheadkits.html

http://www.bigborethumpers.com/newheads.html

  • Like 2

Share this post


Link to post
Share on other sites
It is just the opposite. Titanium valves are very soft and the seats beat the valve faces up easily.

That is why the stainless conversion works so well as the valves are harder and don't get the faces beat up like Ti.

We have the complete valve / springs / retainer kits for installing in low milage heads and help solve the clearance tightening up problem. If the head is worn enough enough to need new guides and seats remachined, then our new head is the best deal. Just bolt it on and go.

http://www.bigborethumpers.com/crfheadkits.html

http://www.bigborethumpers.com/newheads.html

THANK YOU!!! finally someone who knows what theyre talking about!

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×
×
  • Create New...