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YZ 450 CAM SET UP

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Hi, so i have just bought a YZ 450 inlet and exhaust cam, ( as they were sold as a pair ) to fit to my 1998 WR 400,so my first question is, is it just the exhaust cam or can the inlet be fitted as well ?

Second question is how do i go about setting the cam timing, i guess i would use the YZ timing but not sure how to go about it ? Any help is much appreciated ?

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I would only use the exhaust cam as you need to use the original inlet cam for ease of timing up again. 

14 cam chain pins between the '12 o'clock' cam timing punch marks is the way to time the exhaust cam relative to the bikes original '98 inlet cam as the YZ450F exhaust cam timing punch marks don't work with older cylinder heads.

I ran a 2003 YZ450F exhaust cam in my 2002 WR426F and it was a great upgrade all round! You will be on 'YZ timing' by the nature of the cam you have bought but it works just fine!

Read the .jpg info sheet posted on page 2 of this thread:

https://thumpertalk.com/forums/topic/264516-450-cam-mod-on-wr426-how-many-pins/?page=2

Edited by foggy3061

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Thanks foggy, your a star mate, its nice to hear from someone that's actually done this mod, cant wait to get it all back together and see what she,s like ?

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43 minutes ago, Bad-Boy said:

Thanks foggy, your a star mate, its nice to hear from someone that's actually done this mod, cant wait to get it all back together and see what she,s like ?

Not many have in the UK have!

Most reach for hot cams in order to gain the auto decompressor function but I found the hot cams ruined bottom end performance in favour of top end - not what I wanted!

The cam chain won't sit perfectly on the 450 cam sproket compared the the original but mine never gave issue with jumping teeth or accelerated wear.

As far as I know my old bike is still running that cam somewhere (MOT history check shows it was on the road last Oct)!

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Yeah i did look at Hot Cams but decided to go the 450 cam route as i like doing things a bit different, currently doing a complete ground up resto on this 98 WR400 to use on the road next year, just hope it turns out to be reliable.

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9 hours ago, Bad-Boy said:

Yeah i did look at Hot Cams but decided to go the 450 cam route as i like doing things a bit different, currently doing a complete ground up resto on this 98 WR400 to use on the road next year, just hope it turns out to be reliable.

No reason why it shouldn't if you rebuild to spec with good quality parts.

Might be worth upgrading the carb to a newer FCR from a 450 too.

7 hours ago, StevetheSnake said:

Yes Hot cams ruin the bottom end even in the 07-15 bikes. ?

Yeah I can imagine! ?

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On the subject of carbs i have a 2005 Honda CRF450 carb that i,ve been told should work well, and yes, trying to get the best parts i can find for it.

20181214_2135014.jpg

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On 12/14/2018 at 9:41 PM, Bad-Boy said:

On the subject of carbs i have a 2005 Honda CRF450 carb that i,ve been told should work well, and yes, trying to get the best parts i can find for it.

20181214_2135014.jpg

Do yourself a favour and invest in an upgraded AP spring and you'll avoid the dreaded bog! ?

https://www.frankmxparts.com/epages/62910900.mobile/en_US/?ObjectID=22261015

An easily adjustable mixture screw will help too. The one KTM offer is far better than most about as it's stainless steel and the tip profile is an accurate match for the original keihin screw. Far better than the cheap alloy versions flooding the market!

https://otwpowerstore.co.uk/ktm-powerparts-factory-mixture-control-screw-59031017300.html?gclid=CjwKCAiAjNjgBRAgEiwAGLlf2qOYT9S-geZxUuGuRIH-f1tjnb3mNGovhO1RhM1GiLIPgz5FVwA0pxoCoPsQAvD_BwE

Edited by foggy3061

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1 hour ago, foggy3061 said:

Do yourself a favour and invest in an upgraded AP spring and you'll avoid the dreaded bog! ?

https://www.frankmxparts.com/epages/62910900.mobile/en_US/?ObjectID=22261015

An easily adjustable mixture screw will help too. The one KTM offer is far better than most about as it's stainless steel and the tip profile is an accurate match for the original keihin screw. Far better than the cheap alloy versions flooding the market!

https://otwpowerstore.co.uk/ktm-powerparts-factory-mixture-control-screw-59031017300.html?gclid=CjwKCAiAjNjgBRAgEiwAGLlf2qOYT9S-geZxUuGuRIH-f1tjnb3mNGovhO1RhM1GiLIPgz5FVwA0pxoCoPsQAvD_BwE

Great info foggy, thanks, im guessing the AP spring does away with the need to do the o ring mod ?

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1 hour ago, Bad-Boy said:

Great info foggy, thanks, im guessing the AP spring does away with the need to do the o ring mod ?

Yes it does. Think of it as a permanent 'O ring mod', no stretching or perishing! ?

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