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I installed the TB cam on my 2015 OG a couple weeks ago and at high RPMs the motor don't sound right to me.. Valves making a slight noise as the RPMs increase. Not noticeable at idle.
At first I went with the recommended I.004 & E.007 valve clearance.. That didn't sound right so I called Hard Racing and they said to try I.004 & E.006.
This sounded better but I can still hear the cam/valves tapping at high RPMs... Its like I can hear the cam spinning and hitting the rockers... Has anyone else experienced this? I have checked the clearances after a few days of riding and they have not changed..
What valve clearance settings have worked for you guys?

Also do I need to (or should I) get stiffer valve springs to accommodate the steeper cam slope?

Chimera Intake
M4 Exhaust
TB Cam
PCV
Stock piston
5,000 miles on the motor.
 

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This has been discussed over and over. Valves should be set to .003/.004. The fact that hard racing doesnt know that disturbs me.


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FWIW I run mine at .003 / .003 same cam
 

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As per DHM, I'm also running my TB Cam at .003 / .003
 

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.003 on the exhaust is damn tight. Id rather have a lil noisy of a valve train than a hot exhaust valve that cant fully close.

I have said it before and will say it again, Stock head with stock valves (or anything close to a stock head, including big valve heads with valves in the stock locations ... aka anything thats not a 4v head or 2v Neo head), the lash's should remain stock .004 and .007.



The reason why the TB cam is so noisy is its based on a regrind cam (DCR)... as such it has a small base circle (probably why you had to screw in your valve tappets quite a bit to get right clearances). The small base circle makes the clearances more pronounced in the form of noise.
 

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agreed. .003" on the exhaust is too small IMHO. the exhaust valve gets hotter and expands more, also along the axis. I run mine at .006 (ex) and .004 (in) on the koso 4v and its quiet. Cam doesn't dictate lash, head /rocker/and valve combo do. The speed of the lift on the cam can however make one noisy.
 

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Maybe the noise is coming from your cam chain area.

I set my Takegawa 181-4v valve lash at .003 intake .004 exhaust and adjust it the next morning where the engine is stone cold and the timing mark is set at Zero "0" on the cam sprocket mark and TDC on the flywheel.

Good luck
 

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Discussion Starter #11
Thanks for all the input.. The users in this forum are awesome and and very helpful..
I'm going to try .003 intake .004 exhaust. I'll let you guys know how it goes.... :encouragement:

I'm also trying to decide my next upgrade.. debating on either a fimbro big valve head or a 143 big bore.. I also need to add an Autotune/WB2 soon.
 

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Pard, Its very well known for years that, that is incorrect. Tbolt cam is supposed to be .003/.004. Its based off the DCR cam which at one point was also labeled incorrectly for the valve spec.
 

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Pard, Its very well known for years that, that is incorrect. Tbolt cam is supposed to be .003/.004. Its based off the DCR cam which at one point was also labeled incorrectly for the valve spec.
Thanks. Rather odd that this has not been corrected by the manufacturer.
 

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.003 on the exhaust is damn tight. Id rather have a lil noisy of a valve train than a hot exhaust valve that cant fully close.

I have said it before and will say it again, Stock head with stock valves (or anything close to a stock head, including big valve heads with valves in the stock locations ... aka anything thats not a 4v head or 2v Neo head), the lash's should remain stock .004 and .007.



The reason why the TB cam is so noisy is its based on a regrind cam (DCR)... as such it has a small base circle (probably why you had to screw in your valve tappets quite a bit to get right clearances). The small base circle makes the clearances more pronounced in the form of noise.
Because the reground base circle of a TB cam is so small, does it cause any issues with the rocker screws needing to be screwed in so far? Seems like it would put the screws at more of an extreme angle in relation to the top of the valve stem.
 

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I have been running the TB cam for a while and when it was first installed I was worried about the way the valves were making noise. However I have had two different shops check their clearance and everything was in spec. If I am not mistaken those specs were the .003 and .004. Honestly its been a while though and havent had any issues ...
 

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Installed and tested the TB Cam. Nice mod indeed. Hitting rev limiter in situations that previously could not, such as up some steepish hills in 2nd gear.

I did not notice any changes at lower RPMs. In any case, I pretty much ride the Grom WOT at all times.
 

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BTW, the TB cam came with a new set of tappet adjustable pushrods and lock nuts.

The stock rods needed to be adjusted in so much that barely any thread remained for the lock nut. I did not realize that issue until I had already sealed everything up so I left it as is. Marginal, but I will keep a eye on it. I tried to remove the stock threaded pushrod from the rocker arm but it would not fully unscrew.

The rods that came with the TB cam are probably longer for the reason mentioned above, but I can't seem to remove the stock rods from the rockers.

Anyone else have this issue?



86349
 

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I
BTW, the TB cam came with a new set of tappet adjustable pushrods and lock nuts.

The stock rods needed to be adjusted in so much that barely any thread remained for the lock nut. I did not realize that issue until I had already sealed everything up so I left it as is. Marginal, but I will keep a eye on it. I tried to remove the stock threaded pushrod from the rocker arm but it would not fully unscrew.

The rods that came with the TB cam are probably longer for the reason mentioned above, but I can't seem to remove the stock rods from the rockers.

Anyone else have this issue?



View attachment 86349
Had the same issue. Was able to spin them all the way through instead of backing them out. Took me a while to figure that out...
 
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