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New Top End Needed. Valves And All. What Would You Do?

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I have CRF450R that I race cross country and Enduros on. I weigh 225 with gear on and am a B rider. I am 47 years old in good physical shape.

The engine on the 08 CRF450R started acting funny about 5 hours ago. Didn't start as easy as in the past. Now wont start at all. Checked valve clearances and intakes are Left, could not get a .03mm feeler gauge in. The Right .063mm gap. Exhaust left is .203 gap and right gap is .203.

So, looks like I am going to need to do a valve job. While I am in the engine, I want to replace the piston and rings.

My questions are:

1. Whose valve components would you use and who to do the work?
2. What piston would you use and would you stay with stock compression or go higher. (My piston is stock now)
3. Would you change cams?
4. Would you replace timing chain and gears?

I am open for all suggestions.

Thanks in advance for the help!

 

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If it were me. Id do it myself. Except for cleaning up the valve seats.. Pull it down put a new piston and rings in of your choice.. Go with a quality stainless valve and spring kit. replace the cam chain and quide and tensioner.  Change the cam if you desire? But how do you like the power it has now??   I do all my own work except the machine work, so its not that pricey etc..  Put it back togther and ride..   LOL..   Just my 2cs.

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I have CRF450R that I race cross country and Enduros on. I weigh 225 with gear on and am a B rider. I am 47 years old in good physical shape.

The engine on the 08 CRF450R started acting funny about 5 hours ago. Didn't start as easy as in the past. Now wont start at all. Checked valve clearances and intakes are Left, could not get a .03mm feeler gauge in. The Right .063mm gap. Exhaust left is .203 gap and right gap is .203.

So, looks like I am going to need to do a valve job. While I am in the engine, I want to replace the piston and rings.

My questions are:

1. Whose valve components would you use and who to do the work?

2. What piston would you use and would you stay with stock compression or go higher. (My piston is stock now)

3. Would you change cams?

4. Would you replace timing chain and gears?

I am open for all suggestions.

Thanks in advance for the help!

 

 

1) OEM Valves. (Most cost effective and durable solution.)

2) Wiseco 13:1 piston.

3) Yes - Stage 1 or Stage 2 Hotcams. 

4) Yes - Install new cam chain. "It's cheap insurance" ($40.00 for new OEM chain)

 

Suggestions:

1) ECU Remap. (Eddie Sisneros)

2) MRD Pro Comp pipe. ($460.00 shipped)

3) Hinson Clutch. (Bullet proof) "6 spring or BTL" - I have both..

 

Hope this helps.

 

JL

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1. Whose valve components would you use and who to do the work? OEM, OEM, OEM, BUT STAINLESS TRX VALVES AND COMPONENTS FOR ENDURO . AS RACING FOR THE HEAD WORK. 
2. What piston would you use and would you stay with stock compression or go higher. OEM OR JE OR COSWORTH. NO CHINESE WEISCO! GO TO 12.8 OR 13.0
3. Would you change cams?  NO! STOCK CAMS ARE PERFECT FOR OFF ROAD. HOT CAMS WILL GIVE YOU A POWER BAND SQUISH UNLESS YOU PORT.
4. Would you replace timing chain and gears? OEM CHAIN, MANUAL AFTERMARKET TENSIONER, OEM STRIP

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I have CRF450R that I race cross country and Enduros on. I weigh 225 with gear on and am a B rider. I am 47 years old in good physical shape.

The engine on the 08 CRF450R started acting funny about 5 hours ago. Didn't start as easy as in the past. Now wont start at all. Checked valve clearances and intakes are Left, could not get a .03mm feeler gauge in. The Right .063mm gap. Exhaust left is .203 gap and right gap is .203.

So, looks like I am going to need to do a valve job. While I am in the engine, I want to replace the piston and rings.

My questions are:

1. Whose valve components would you use and who to do the work?

2. What piston would you use and would you stay with stock compression or go higher. (My piston is stock now)

3. Would you change cams?

4. Would you replace timing chain and gears?

I am open for all suggestions.

Thanks in advance for the help!

 

 

 

For what you are doing, revving its brains out isnt needed

 

recut valve seats, stainless steel valves,

stock cam is decent, or talk to ron hamp, or hot cams stage 2

no matter what, forged 13.5:1 piston its cheap easy horsepower

and yes replace the timing chain they are dirt cheap

 

for the valve work i would talk to jeff @ www.bigborethumpers.com he can hook you up and hes on these forums often.  I had my head rebuilt by www.fastheads.com   These would be my top two choices if you cant do the work yourself.

Edited by adam8781

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1. Whose valve components would you use and who to do the work? OEM, OEM, OEM, BUT STAINLESS TRX VALVES AND COMPONENTS FOR ENDURO . AS RACING FOR THE HEAD WORK. 

2. What piston would you use and would you stay with stock compression or go higher. OEM OR JE OR COSWORTH. NO CHINESE WEISCO! GO TO 12.8 OR 13.0

3. Would you change cams?  NO! STOCK CAMS ARE PERFECT FOR OFF ROAD. HOT CAMS WILL GIVE YOU A POWER BAND SQUISH UNLESS YOU PORT.

4. Would you replace timing chain and gears? OEM CHAIN, MANUAL AFTERMARKET TENSIONER, OEM STRIP

 

 

Krannie,

 

Why no Wiseco piston?

 

Thanks!

Edited by cleaner1

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  1. had two heads done by racers ER - currently have a PC head from a pro national bike that brent put the valves in for sale in the classifieds section

Brent is the man with heads and nice guy to he did some extra work for me for free and said it was free merry Christmas....

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Krannie,

 

Why no Wiseco piston?

 

Thanks!

 

Because Weisco uses Chinese subcontractors for thier Cranks, Rods, wristpins, and some pistons.

You can buy a non-Chinese piston from them, but I refuse to support any business that relies on China to make a profit. 

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Krannie,

 

Why no Wiseco piston?

 

Thanks!

 

Cleaner,

 

Wiseco forged pistons are not made in China... they are made in the USA. I've used Wiseco pistons for years, (drag racing and mx) and they are very reliable pistons. I'm currently running a wiseco 13:1 forged piston, and plan to buy one again when I do the next top end build. I know lots of guys currently running wiseco pistons, and they are all happy with them. They produce great extra horse power, torque, and overall track speed.. if that's you're end goal.

 

At the end of the day, all I really care about is peak performance and reliability. I get both with wiseco pistons; and I bump the rev limiter a lot.

 

JL 

 

 

Powersports Forged Piston Advantage
PistonRings.jpg
Wiseco leads the performance aftermarket by producing the highest quality forged pistons for Dirt Bikes, ATV's, Snowmobiles, Outboard Marine, and Motorcycles right here in the USA. Wiseco is unique because we forge all of our own pistons in house, and produce all of our own forge tooling right here in the USA. This allows us to control all aspects of our manufacturing process from raw bar to skirt coating finished parts. 

In addition, in-house dyno testing gives Wiseco the ability to develop state-of-the-art technology such as new shapes, coatings, and components, and lead the industry through rigorous R&D. Linking all segments of Wiseco’s organization through design, testing, manufacturing, and distribution allows us to fulfill market needs with minimum lead-times. 

Extreme racing conditions demand the strength and toughness that only forged pistons can offer. Compared to cast pistons, forgings are tougher and more durable, and will stand up to the abuse that high performance motorsport applications require. Most castings are brittle, have no grain structure and tend to fail catastrophically when the material yield strength is exceeded. Forgings have condensed grain that is aligned to the features of the part, which produces higher mechanical properties, and resistance to impact and fatigue. Each forging is designed to optimize the strength-to-weight ratio, and maximize performance.

 

Link:

http://www.wiseco.com/Catalogs/DirtBike.aspx

0909131809.jpg

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Some of the pins Wiseco uses are Chinese, but you wont have problem. I've got one in my bike. 

 

If it were me, Id use all the ProX stuff for the head valve wise. A new manual tensioner is key to reliability. The OEM tensioner is a POS. Tokio Mods has a friggin nice one, the TT part is inexpensive and works great (got one on my bike) 

 

Krannie's opinion of Wiseco is more political than mechanical. Its not wrong, its just his view. 

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Cleaner,

 

Wiseco forged pistons are not made in China... they are made in the USA. I've used Wiseco pistons for years, (drag racing and mx) and they are very reliable pistons. I'm currently running a wiseco 13:1 forged piston, and plan to buy one again when I do the next top end build. I know lots of guys currently running wiseco pistons, and they are all happy with them. They produce great extra horse power, torque, and overall track speed.. if that's you're end goal.

 

At the end of the day, all I really care about is peak performance and reliability. I get both with wiseco pistons; and I bump the rev limiter a lot.

 

JL 

 

 

Powersports Forged Piston Advantage
PistonRings.jpg
Wiseco leads the performance aftermarket by producing the highest quality forged pistons for Dirt Bikes, ATV's, Snowmobiles, Outboard Marine, and Motorcycles right here in the USA. Wiseco is unique because we forge all of our own pistons in house, and produce all of our own forge tooling right here in the USA. This allows us to control all aspects of our manufacturing process from raw bar to skirt coating finished parts. 

In addition, in-house dyno testing gives Wiseco the ability to develop state-of-the-art technology such as new shapes, coatings, and components, and lead the industry through rigorous R&D. Linking all segments of Wiseco’s organization through design, testing, manufacturing, and distribution allows us to fulfill market needs with minimum lead-times. 

Extreme racing conditions demand the strength and toughness that only forged pistons can offer. Compared to cast pistons, forgings are tougher and more durable, and will stand up to the abuse that high performance motorsport applications require. Most castings are brittle, have no grain structure and tend to fail catastrophically when the material yield strength is exceeded. Forgings have condensed grain that is aligned to the features of the part, which produces higher mechanical properties, and resistance to impact and fatigue. Each forging is designed to optimize the strength-to-weight ratio, and maximize performance.

 

Link:

http://www.wiseco.com/Catalogs/DirtBike.aspx

 

 

I STAND CORRECTED.

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1. Whose valve components would you use and who to do the work? OEM, OEM, OEM, BUT STAINLESS TRX VALVES AND COMPONENTS FOR ENDURO . AS RACING FOR THE HEAD WORK. 

2. What piston would you use and would you stay with stock compression or go higher. OEM OR JE OR COSWORTH. NO CHINESE WEISCO! GO TO 12.8 OR 13.0

3. Would you change cams?  NO! STOCK CAMS ARE PERFECT FOR OFF ROAD. HOT CAMS WILL GIVE YOU A POWER BAND SQUISH UNLESS YOU PORT.

4. Would you replace timing chain and gears? OEM CHAIN, MANUAL AFTERMARKET TENSIONER, OEM STRIP

 

 

there are many great aftermarket valves that arent chinese and last far longer than oem, 

 

wiseco pistons are made in the USA, some of the best pistons ever made, wiseco cranks are made in asia.

 

 

Oem is not always best, On a crf250, the most durable valves you can get are aftermarket stainless steel (ape), or xcelidyne (spelling?) titanium vavles with copper vavle seats.   Oem intake valves would be a huge waste of money on the stock valve seats.

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Send the head off to a good machine shop to be worked. Choose a shop that has done this before. You will gain power and smiles. and your valves will last longer afterwards..

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