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Discussion Starter · #1 ·
Hard starting after Cam Chain Tensioner replacement -- Video Inside -----------------
Hello guys, I have a problem with my 2005 CBR1000rr. 15k miles.

Here is what happened, cliff-notes style

Pre teardown
- Noise was coming from cam chain
- Determined the Cam chain tensioner went out

- Did not put in Top Dead Center
- Pulled back tank, removed airbox, secondary injectors
- Got down to the throttle body, but decided to leave those in
- Was able to replace the Cam chain tensioner with OEM unit

After repair
- Bike usually starts after a few turn overs, now it takes 10 seconds.
- Sometimes it just turns over but never starts at all
- If I manipulate the throttle, I can hear it turn over faster, and that sometimes makes it start
- If I open the throttle all the way for a few seconds, and then close it, that will also make it start sometimes
- Besides starting it, it runs good once it's going

Do you guys have any ideas why it's giving me so much trouble now?

Here's my ideas
- Cam timing got thrown off, Here's a quote from another site "
With the piston at TDC the valves will all be closed and there will be no chance of tension on the cam chain. If the piston is not at TDC of the compression stroke there is a chance, a chance, that one of the rocker arms will be positioned just so on the cam that the valve spring tension will "squirt" the cam to a different position when you remove the cam chain tensioner, allowing the cam chain to jump on the sprocket."

- Maybe I damaged a sensor when I removed the airbox?

Here's a video of me trying to start the bike. It didn't start until I gave it some throttle.
Youtube video here

If you have any ideas please shoot them my way! I would love to get this fixed by the community.

2,274 Posts
My first question is why a cam chain tensioner replacment at 15k miles ?? Was the one you removed faulty ? And if so what had happened to it ? Replacing one of those on a bike with 15k on the clock is feeling all wrong to start with .. the most I would expect if any cam noise is maybe maaaybe the auto tension mech needed a reset as it was just on the cusp of a turn, and I would only do that after serious badgering from a customer and would never bother on my own bikes .
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