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I think its time for a new top end :'(

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ok, so I have a 2005 crf 450r that is stock top end, stage 2 cam, about 150 hard hours on it. always clean a/f, change the oil every 2-3 hours. I ride it pretty hard, but dont ride track.

I have shimmed the valves 3 times now. now they are starting to make a weird knocking sound. the bike is also hard to start for the first time of the day. gotta be the intakes, which I just shimmed. its time to change them. this is where I get lost.

what is the best choice here?

1. buy new intake valves, exhaust valves and springs off ebay, tools needed and do them myself for like 2-400$?

is my head going to need to be shaved? how do I tell if it needs it or not? what kind of valve springs am I going to want to put in?

2. send my whole head into ron hamp or someone on TT and get them to completely service it for around 5-600$?

3. buy a brand new bolt on head with everything brand new and ready t go from ron hamp or another good seller, for about 600-800$

more questions:

is a new top end going to give me more power? I hate to say it but I think the bike is a little little weaker than when I bought it, still very very strong though. change the piston too or what guys? is that another big job?

I would like to keep this engine rebuild project under 800$ canadian if possible.

any input would be appreciated

thanks guys.

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Hi, after shimming the first time, the hard coating on the stock titanium valves is worn through so they continue to wear very quickly. This causes the seating surfaces to be distorted so they will need to be redone. The cheapest fix is new stainless valves, the appropriate springs to handle the additional weight of the valves (unfortunately the most expensive part of this process) and having the seats resurfaced. Some claim to notice the steel valves vrs ti. I have not, but I'm not an expert or pro. Going for the ti replacement valves may not cause this percieved performance loss but doesn't really create any gains. Getting an '06 head has a performance advantage of better flow through the ports (I read on TT) and a harder seating surface. The seats themselves can be replaced at a pretty high cost but may be worth it if you've put money into having the head ported. I hope this helps you in your decision.

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Hey,

I'm from MB and my intakes went on my '05 a couple Summers ago, I did almost all of the work myself and the whole job cost me $600 Cdn.

I paid $60 to have the valve seats cut in my head to match the new stainless valves and I paid another $60 to have the head set up. I would have set the head up myself but didn't have the time or a shim kit. I put an aftermarket valve set in (Kibblewhite) with their spring kit - I haven't noticed any performance loss btw. I also put a new OEM piston/rings/pin back in it too. I've since put 75 hours on the bike and it's running great.

I bought all of the parts out of the US, as you know the Cdn shops prices are 35% more than those out of the US :) . Even now with the exchange it's still usually a deal.

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Hi, after shimming the first time, the hard coating on the stock titanium valves is worn through so they continue to wear very quickly. This causes the seating surfaces to be distorted so they will need to be redone. The cheapest fix is new stainless valves, the appropriate springs to handle the additional weight of the valves (unfortunately the most expensive part of this process) and having the seats resurfaced. Some claim to notice the steel valves vrs ti. I have not, but I'm not an expert or pro. Going for the ti replacement valves may not cause this percieved performance loss but doesn't really create any gains. Getting an '06 head has a performance advantage of better flow through the ports (I read on TT) and a harder seating surface. The seats themselves can be replaced at a pretty high cost but may be worth it if you've put money into having the head ported. I hope this helps you in your decision.

oh ok, thats nice to know. I think Ill get SS intake SS exhaust and new springs then.

Hey,

I'm from MB and my intakes went on my '05 a couple Summers ago, I did almost all of the work myself and the whole job cost me $600 Cdn.

I paid $60 to have the valve seats cut in my head to match the new stainless valves and I paid another $60 to have the head set up. I would have set the head up myself but didn't have the time or a shim kit. I put an aftermarket valve set in (Kibblewhite) with their spring kit - I haven't noticed any performance loss btw. I also put a new OEM piston/rings/pin back in it too. I've since put 75 hours on the bike and it's running great.

I bought all of the parts out of the US, as you know the Cdn shops prices are 35% more than those out of the US :) . Even now with the exchange it's still usually a deal.

yeah I was expecting to spend nearly 600$.

I think im just gonna send the whole head into someone on TT, I will get them to replace the valves, and everything, and re do the seats. im expecting to spend around 800$ on it :'(

now, should I get OEM valves, or kibblewhite SS valves?

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You're definately going to want stainless valves.

What I have done in the past is buy a Faction MX stainless intake valve kit, new guides and seals from Service Honda and send the head to mxtime.com. He'll re-cut the seats, check the guides and install the new valve for about $65. My last valve job cost me about $300.

If I didn't want to deal with any downtime, I'd buy a new assembled head for $575 from these guys: http://bigborethumpers.com/crfheadkits.html

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You're definately going to want stainless valves.

What I have done in the past is buy a Faction MX stainless intake valve kit, new guides and seals from Service Honda and send the head to mxtime.com. He'll re-cut the seats, check the guides and install the new valve for about $65. My last valve job cost me about $300.

If I didn't want to deal with any downtime, I'd buy a new assembled head for $575 from these guys: http://bigborethumpers.com/crfheadkits.html

yes Ive seen that site, actually have them bookmarked.

now this is where I need to do some pricing.

either I can send my whole head in, get it all redone, for around 5-600$ im guessing.

or I can buy a bolt on, ready to go head for 800$ from that site. its 575 US, so after shipping im guessing 650$ US, which is 812$ canadian!

the bolt on is faster, but im spending another 200$ for the head, which I dont need. mine will still work fine after a 60$ valve cut job.

but now is it worth it to send in my old head, 50$ shipping, 60$ to get them cut, then 50$ shipping back??

this is a hard one.. im gonna need to talk to some guys on here and find out what their price is if I sent them my head and got them to work on it. otherwise I will buy a new bolt on head for an 07 (my bikes an 05 but I was told that 07 heads are better)

im gonna message ron hamp right now. anyone else I should ask? any specific usernames here on TT?

thanks.

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The '07 head used smaller valves. I think it took some of the hit out of the earlier engines. I though there was also somthing different about the cam tower (part that holds the cam) so you'd have to check with Ron if you could just switch over.

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I'd send a PM to Agent Smith, he can set you up with everything you need, and cut the seats.

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I'd send a PM to Agent Smith, he can set you up with everything you need, and cut the seats.

lol dude, hes been perma banned/IP banned from this site for like 6 months now. I heard he was the best though, and from reading a few of his posts (which I believe are now all erased) I believe hes one of the best.

I guess he advertised too much, TT told him stop, he said no and kept doing it, they banned him. he went onto his wifes TT and advertised more. then they perma banned him.

AGENT SMITH: IF YOURE STILL OUT THERE, PM ME PLEASE!!!!

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Oh, I had no idea about that. I thought he was a TT sponsor. I think he's over at crfsonly.com. Or at least he was in the past.

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