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Discussion Starter · #1 ·
I'm sure it's been covered somewhere, but I can't find anything on the issue I'm having adjusting my exhaust valves.
My tech manual only covers up to 06 and mine is an 08. Everything I find online about adjustment is for the 06 models with the nut decompression assembly. Mine is built into the cam gear and I can't seem to find much info on how it's done.
I did my intake side and they seem to be pretty good. I couldn't get any size feeler gauge in the exhaust side and it seems like there's pressure on it. I was told the wrong shims were probly put in before I got it and it's a guessing game to figure it out. I took out a 2.80 shim and even when I put the smallest shim in I can't get any gauges in. It ran before just seemed hard to keep started while warm and eventually stopped starting, so I figured it was time to check the valves. If it ran before, isn't it odd that it had such a large shim and even with the smallest I still can't get a reading? I'm guessing somehow I'm taking the measurement wrong. Any help would much appreciated.
Side note:. I notice when I pull the decompression/ spring arm up on the cam gear that the tension is released and I can get the feeler gauge in between and get a reading on the valves. Does this imply the tension has to be released in order to get and reading and I just haven't found that step written anywhere I've looked?
 

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To my knowledge there are only 2 setup types, the 04-05' and 06' and up. If your crank mark lines up and your cam tower marks line up, w/cam lobes facing back and up, and your not 180 off, then your measurements are ready to be taken. If you cant get a feeler in with 1.25 shim (smallest in HR kit) then i would say its time for a valve job. There are plenty of links on here. I use a template to keep it straight. Either way the procedures laid out in the manuals for cams w/ and w/out decompressor. I sent the template along, bare in mind that the tolerances are for an 04-05' setup.
 

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Discussion Starter · #5 ·
To my knowledge there are only 2 setup types, the 04-05' and 06' and up. If your crank mark lines up and your cam tower marks line up, w/cam lobes facing back and up, and your not 180 off, then your measurements are ready to be taken. If you cant get a feeler in with 1.25 shim (smallest in HR kit) then i would say its time for a valve job. There are plenty of links on here. I use a template to keep it straight. Either way the procedures laid out in the manuals for cams w/ and w/out decompressor. I sent the template along, bare in mind that the tolerances are for an 04-05' setup.
Here is a link to a simple valve shim calculator Shim calculator
My decompression setup on my 08 is not like either of the other 2. My tech manual only speaks of the setups with the lock nut type. Mine has no lock nut over the right exhaust valve or at all. No videos or anything I can find speaks of it, but I know it's not the same. My guess would be I'm supposed to release the tension on the cam gear to take the measurement.
Again, seems it wouldn't have ran if the shims were of that drastically. I was hoping not to have to spend $40 for a tech manual that covers 08+, but I'm out of ideas and all the shops around me say they can't take a look until sep.-oct.
 

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If you take the tension off the cam gear then the measurement could be as tight or loose as you want, meaning that when the feeler gauge makes contact with the cam lobe w/no tension, it will just push the lobe out of the way until the feeler gauge slides through. Also the timing of the motor to take the test has to have a standard TDC as I mentioned above with the cam tower marks and crank marks lining up, what good would valve shimming do if its not measured when the motor hits TDC? It wouldn't because your valve would never open or close fully in time with the rest of the motor. This is for an 08' TRX450R w/stock head?
 

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Discussion Starter · #8 ·
Yeah, it's an 08. As far as I know it's a stock head and thought I had it at tdc. Now that I looked at a couple more videos maybe I didn't. I guess the best thing to do now is put the old shims back, double check it's at tdc and try again. I guess maybe I had it on the wrong stroke. The video I saw first mentioned the lines on the shifter side to line up, but I'm just now seeing a video mentioning an arrow on the brake side. Never knew to check that
 

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Discussion Starter · #9 ·
Ok so it wasn't at top dead center. Now my question is, does it matter which way the decompression pin goes into the camshaft? Seems like it can go in two different ways, 180° from one another.
The way it's set now is to where as the intake valves are opening the center lobe pin slightly opens the exhaust side. Would that seem right?
 

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First of all, did you remove the cam gear? If so, did you fasten the cam chain to the cam gear together as they were before removing? Being a tooth or more off will advance/retard the opening/closing of the valves at TDC.

Idk what you mean by which way the pin goes but here is a pic of the assembly
 

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FYI, there are currently 473 entries on here under the search, "valve adjustment", it's also pinned in the engine section. Everything is in there.
 

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Discussion Starter · #14 ·
No, it's not off a tooth. I wondered that also. I didn't have it on the compression stroke and that's why I couldn't get a proper reading. I have it off and by the definition of how the decompression mechanism operates I'm pretty sure now that I have the pin correct. As the intake valves open the pin in the center lobe slightly opens the exhaust valves to relieve the compression. I searched the forum and everything I could think of before asking my question. That's why I apologized at the beginning if it had been covered, sorry. Thanks for your help
 

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Your good bro, and your welcome. Let us know if you get the shims measured and need to adjust the valve lash. Took me once or twice before it all clicked right in my head.
 

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Discussion Starter · #16 ·
It seems to be in spec other than the intake valves. I changed them and they seem to be ok. Hopefully this and the jetting I did will get me going.
 

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Your good bro, and your welcome. Let us know if you get the shims measured and need to adjust the valve lash. Took me once or twice before it all clicked right in my head.
Hi..... my first time doing my valve too....I have question ..... if I have a hrc kit and hcp 13.1 in my 2007 trx450er are the valves gapping same @ IN.0.16 Ex 0.28 I need some help?
Thank you
 
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