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Cam issue

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I have been beating myself up re checking the timing on my 2005 CRF 450 r. Every one I can get to try to start has said it is the hardest to start 450 they have ever kicked. the only way to start it was to push the kicker just past TDC and kick like Bruce Lee. This weekend my friend purchased a 2007 CRF 450 r and asked me to help him check the valve lash, this bike started as easy as any I had seen and the pryor owner said it had a 13 to 1 piston, after determining that his left intake had less than .003 clearance I asked if we could install complete cam cradel on my bike and see if that would change how hard mine was to start. Wow mine is just as easy to start as his with his cam assembly. Removed his cam reluctently and changed his shims to get proper lash and reassembled my bike. while plug was out on both bikes verified cam timing marks were right on, then on my bike with a long screwdriver I checked and marked with black fine sharpie marker where BDC was where decompression opend in up stroke where it closed also where TDC was. then I checked the same on his bike using red fine sharpie. my decompression opened about 1/8" off BDC and closed around mid stroke where his opened around mid stroke and closed just a little over 1/8" before TDC. put both bikes back to TDC on crank and cam marks and I could tell that intake lobes were not in the exact same location both were angled up tword rear, mine was rotated a little higher up. is there any way the cam could have twisted where cam gear bolts up? I bought this bike from a guy that sold it to me after buying an X model because it was so hard to start, so I dont know the pryor history on the bike. the bike is in great shape execpt for the kicker that is worn out.(probably from this issue thats been there for a long time)

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First off, the 05 and the 07 use a different decompression system. The 07 is non adjustable. The 05 you have to adjust the rocker arm for the decompression.

So go back to the main thread, hit up the sticky there with pics. Notice the arrows, hash marks and triangles. Get get all lined up, measure your valve clearances and then when they are spot on, then adjust the decompression arm clearance.

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what jj said, very good sticky on cam timing. BUT, to answer your ? on if the cam can move in the sprocket holder.. YES, it can and did on my 04 but that bike had literally over 850 hrs at the time. We now tack weld the sprocket holder to the cam on all my bikes. Is that what occured on yours? don't know and it is pretty rare, but in a thread i started awhile back a couple others posted it did happen to them too. Remember that if your checking your timing marks with the cctensioner loose, the marks will be OFF when you release the cct (will retard timing a bit as you take up slack in the front side of the chain).

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yes I am well aware that the decompression is totally different and yes the timing marks are both bikes are spot on with tenisioner installed. and I have a .011 feeler gague under rocker and a.014 under de compress rocker at TDC on the 05. that being said the de compressor opening and closing on the bottom half of the stroke is not releasing any compression to speak of and the fact that my bike has had less bottom end than the other three CRF 450 I have ridden and its so hard to kick tells me somthing is wrong . my other friend has a 03 and his intake lobes are in a slightly different spot than than mine at TDC. I plan on moving the cam gear till the de compression closes more tward TDC and check for piston to valve clearence tonight. that being said would I be better off finding another stock cam or going with a aftermarket cam. The bike has DR.D full Exauast and I weigh 225# and I use to race Novice on a 125 several years back . Which Cam would you suggest

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Did you inspect the spring for the decomp mechanism to be sure it returns the arm back? Also, check the roller actuator on the decomp mechanism, It has ahalf moon shape.

If the compression is to high close the gap on the lash adjustment to reduce the cranking compression.

It doesn't sound like you are checking the timing right. Look at the left side cover inspection hole and align the second mark to the slash on the cover. Rotate only coutercockwise from the left side or clockwise from the right. Then check the timing mark.

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Advanced the cam two teeth on cam gear tonight now de compression is close to where the 07 was as far as the marks i made on the screwdriver shaft and the intake lobes look to be in the same location as the 07. bike kickes through very easy and no interferance with valve to piston. Mark on cam gear is way above triangle infact triangle pointer is behind cam gear spoke, even though it starts i think i will try to find another cam that is not off on timing before I ride it. anyone have a cam they want to get rid of or any sugestions on what to buy?

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So now retard the cam one tooth! And youll be where it should be!! Sounds to me like it need a new cam chain??

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I put a new chain on less than 5 hours back and ive read the forms and verified timing no less than five times using the sticky on this site. been trying to figure this out since i bought the bike last year. It sounds good and starts as well as others I have started now, the cam has definatly slipped timing not sure how it happend or when but it was pryor to me owning it im just glad to know what it is, and if its the only one that anyone has ever heard of that makes sence as im quite use to Murphy's Law! I do not know exactly where nor trust where timing is at so before I go out riding it will have a new cam. im afraid if timing on cam slipped once it could do it again and have piston to valve crash, and that would be alot more expensive than then the cost of a new cam.

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I did a quick look on ebay for an 05 stock cam used but didn't find anything that was a great value. I would get a hotcams cam. I put a stage 2 on my 05 because I thought the off idle response of the 05 was too violent for my taste. The Stage 2 hotcam mellowed that out a bit and added a bunch of top end power (which I didn't really need but it does feel good to have the front end come off the ground during accelleration on long straights). I like the way it feels better on trails because it doesn't rip your arms off when you are in low rpm rolling on the throttle. Anyway, just a thought. The stage 1 is supposed to add a bunch more low end torque if you would like that better. You can get one for around $170 instead of over $200 for a stock one. The used stock 05 cams on ebay weren't much less than the hotcams cam new.

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Ive got a cam/cam carrier and decompression assembly that came off an 05 450. When I bought it I didnt know the decompression was different from the 05 to 07. I couldnt use it on my 07 so Im needing to sell it. Let me know if youre interested.

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Ive got a cam/cam carrier and decompression assembly that came off an 05 450. When I bought it I didnt know the decompression was different from the 05 to 07. I couldnt use it on my 07 so Im needing to sell it. Let me know if youre interested.

yes I am interested what do you need out of it?

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thanks new to posting on forms, i had to figure it out but i did PM Red

Rider501. but have been looking on here for a while TT is a lot of help.

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