Replacing Top End

Hey guys I have a 2008 CRF450r and I'm at about 90 hours and ready to replace the top end. The reason I'm posting here is because I want to know if there's anything else that I should be replacing in the engine while I have it apart and is there any special tools I should invest in before taking this project on. Please let me know if you have any suggestions or advice.

I been thinking I might so the same lately. Is the cam chain a must? Any point in getting a wiseco cam chain? Any way to tell if it's beat?

Take it to AS Racing in Canyon Country, as they are the best in CA I believe:

asracinginc.com

Take it to AS Racing in Canyon Country, as they are the best in CA I believe:

asracinginc.com

 

AS Racing has my 08 CRF450R head at this time doing a valve job, port and polish job. Going to replace piston with JE piston kit and replace timing chain and timing chain tensioner as well. Will let you know how it turns out if interested. 

I just did my '08. JE 13.5:1 piston, HotCams stage 2 cam, FastHeads Extreme duty head package, cam chain and tensioner.

Came out great - I got the same great powerband with more juice everywhere, couldn't be more pleased.

AS Racing has my 08 CRF450R head at this time doing a valve job, port and polish job. Going to replace piston with JE piston kit and replace timing chain and timing chain tensioner as well. Will let you know how it turns out if interested. 

How much did all that run ya price wise?

I just did my '08. JE 13.5:1 piston, HotCams stage 2 cam, FastHeads Extreme duty head package, cam chain and tensioner.

Came out great - I got the same great powerband with more juice everywhere, couldn't be more pleased.

piston and cam looks like $300 in parts, cam chain/tensioner another $150, plus head work. sounds a like $700-800 otd

Bigborethumpers.com has everything for you to do the job. Check them out. We have new heads for your bike done up with stainless steel valves ready to bolt on and go for $575. 

$85 bucks OEM chain and tensioner - partzilla - cheapest place I've found for OEM stuff. I would have gone to BigBore, but I wanted to stick with the Ti valves and BeCu seats - sorry Jeff, but I didn't want to do anything that I thought might make the motor rev any slower than it already does.

hey guys just wondering if you can tell me abit on how to replace the top end of my crf450r 09 please

hey guys just wondering if you can tell me abit on how to replace the top end of my crf450r 09 please

Piston and gasket kit, preferably off of eBay with a 13.1 high comp piston (to stay running on 91 octane) New can chain, a mechanical cam chain tensioner(the automatic ones that come on the bike are known for failing) if your valves are fine and wanna not waste money then leave em be. and a SERVICE manual for 60 buck on eBay that breaks to down how to do the job.

Get a manual. The only special tool needed is a flywheel remover which is only needed if you replace the timing chain. I replaced mine, but it looked fine. My piston and cylinder looked pretty good too. I used fastheads for my parts. New 08 head with upgraded titanium valves. Weisco high comp piston, all gaskets, tchain and tool was around 900.

Get a manual. The only special tool needed is a flywheel remover which is only needed if you replace the timing chain. I replaced mine, but it looked fine. My piston and cylinder looked pretty good too. I used fastheads for my parts. New 08 head with upgraded titanium valves. Weisco high comp piston, all gaskets, tchain and tool was around 900.

Piston n g 200

Timing chain 60

Tool 15

900-275

So you got a brand new head with titanium valves for 625?

How much did all that run ya price wise?

JE forged Piston kit, valve job, stage 3 porting, timing chain, timing chain tensioner, and all gaskets. $1050.

Porting was $400. Glad I spent the $400 on porting. Smoothed out the power delivery and added some extra punch.

Edited by cleaner1

$85 bucks OEM chain and tensioner - partzilla - cheapest place I've found for OEM stuff. I would have gone to BigBore, but I wanted to stick with the Ti valves and BeCu seats - sorry Jeff, but I didn't want to do anything that I thought might make the motor rev any slower than it already does.

 

 

Whatever you do, dont buy one of those god damned POS OEM chain tensioners. I believe that they are quite possibly the worst device ever to leave a Honda factory. Spend some money on a manual tensioner and never have to even think about it again. Ive seen so many OEM tensioners fail that I cant hardly believe that the entire device hasnt been recalled. The redesigned one is supposed to be better, but Ive seen more of the "new, good ones" fail than the 02-03 model, but thats probably due to shear numbers in service.

Whatever you do, dont buy one of those god damned POS OEM chain tensioners. I believe that they are quite possibly the worst device ever to leave a Honda factory. Spend some money on a manual tensioner and never have to even think about it again. Ive seen so many OEM tensioners fail that I cant hardly believe that the entire device hasnt been recalled. The redesigned one is supposed to be better, but Ive seen more of the "new, good ones" fail than the 02-03 model, but thats probably due to shear numbers in service.

Do you think that the failures could be due to owners not replacing the tensioner at proper time intervals?

Do you think that the failures could be due to owners not replacing the tensioner at proper time intervals?

 

 

Could be, but there isnt a replacement schedule for that part (that I recall) and I've seen almost brand new ones fail. I trust my lying, cheating, drunken, bi-polar ex-wife more than one of those OEM tensioners.

Piston n g 200

Timing chain 60

Tool 15

900-275

So you got a brand new head with titanium valves for 625?

They sell a brand new head with kibble white upgrade for 675. I called them. Was originally going to get upgraded seats and ti valves on my head. Talked to the main guy. I didnt want to wait due to an upcoming weekend. Bought newhead 08 head, coated ti valves with stock seats. He said I'd get great life out of it. They'd give me core value if i sent my old head in. It was six something before core.

They sell a brand new head with kibble white upgrade for 675. I called them. Was originally going to get upgraded seats and ti valves on my head. Talked to the main guy. I didnt want to wait due to an upcoming weekend. Bought newhead 08 head, coated ti valves with stock seats. He said I'd get great life out of it. They'd give me core value if i sent my old head in. It was six something before core.

Their doing my head right now with ti valves porting and polishing it for 899... Wtf

Actually it's in its way back and it's only took a month out of my riding schedule... Yeah not too thrilled. Hopefully I Atleast got a better port job OR SOMETHIN jeez

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