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Discussion Starter · #1 ·
Ok my problem is I have everything to specifications, and I can only get 65psi decompression and it won't start,bike has 10mm Athena Cylinder with CP Carillo piston, Stock Ferrea Valves and springs kit,Hotcams stage 2,hotcams timing chain,for jetting I have alot of oem keihin jets,from 165 main to 185main, pilot 42 to 50,leak jet 35 to 55 now I was getting more compression before,I was at 105psi now it won't go past 65 psi could this be the piston rings? I check the head and did the water test on the valves they don't leak,so that's eliminated, Any other thoughts???? I read some abnormal numbers on the stator could that be an issue of not starting? But it doesn't have to do with compression, I'm about to tear it down to the piston again and start from scratch..... Anyone please share some knowledge on this!!!!
 

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Increase the decomp gap until you reach about 100-110psi kicking/cranking compression....

Make SURE your not actually activating the decompressor lever during your valve clearance adjustment......at TDC.....the decomp divot on the cam comes VERY close to engaging the decompressor.... move the cam to make sure your not activating the decompressor.....then try again....
 

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Discussion Starter · #3 ·
Increase the decomp gap until you reach about 100-110psi kicking/cranking compression....

Make SURE your not actually activating the decompressor lever during your valve clearance adjustment......at TDC.....the decomp divot on the cam comes VERY close to engaging the decompressor.... move the cam to make sure your not activating the decompressor.....then try again....
06 trx450er, electric start brother,per manual50- 55psi but with my mods 100mm Cylinder with CP Carillo piston, Stock Ferrea Valves and springs, Hotcams stage 2,Barkers exhaust system, no lid ,keihin jets I have from 165 main to 185main, pilot 42,45,48,50,leak jet 55,40,35 aftermarket a/f screw T shaped with numbers....I'm trying to get it to 75psi ,but I may have to go back to the rings again, because I've got it to 100psi,then it looses it to 50psi,it's got me lost,it doesn't have no riding time,and now I believe I have to buy a new stator and battery, what jetting you think I need for this set up?
 

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When you say, "then it looses it to 50psi" If I remember correctly I dont believe these motors will HOLD pressure because the intake/exhaust valves overlap slightly at TDC. Also for the compression test your cranking with the throttle wide open right? As far as jetting 55 pilot and 185 main should be fine.
 

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Need to be feeler gauging the decomp clearance and appropriate valve clearance to stock specs. Crank it at WOT till you get your highest PSI reading and thats the number you roll with. If the decomp clearance is off or needs to be adjusted it will effect ease/hardness of starting.
 

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Discussion Starter · #6 ·
When you say, "then it looses it to 50psi" If I remember correctly I dont believe these motors will HOLD pressure because the intake/exhaust valves overlap slightly at TDC. Also for the compression test your cranking with the throttle wide open right? As far as jetting 55 pilot and 185 main should be fine.
Thanks for your time and help,No I didn't do WOT compression check,I didn't even had a clue that the wa is done,so I will do that,I just started buying some parts again,I also need a new stator for sure and battery,I already bought a new spark plug boot and the starter reduction gear and new gasket kit just in case,so a few more parts and I will try your suggestion for sure,now about the jetting I noticed you say 55 and 185 main,what do you think for pilot? 45 or 48? Thanks for your time first and foremost, and also thanks for helping me!!! I really appreciate it, you have no idea!!!
 

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Discussion Starter · #7 ·
When you say, "then it looses it to 50psi" If I remember correctly I dont believe these motors will HOLD pressure because the intake/exhaust valves overlap slightly at TDC. Also for the compression test your cranking with the throttle wide open right? As far as jetting 55 pilot and 185 main should be fine.
Also I have the NCYQ needle on my carburetor....I took of the oem none adjustable needle.
 

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No problem for helping....As far as compression testing, thats mostly used to find worn parts, yours are new so as long as pumping the motor up to 100 psi didn't hurt anything during your initial testing (one-way valve or reed) then just use feeler gauge as directed in manual to get valve clearances shimmed and decomp in spec and try to start her. On jetting I'm not the best, depends where your are elevation wise but, 48 pilot and 3rd clip on the needle, 2.5 turns out on A.F. screw should work. I know if the decopmp is out of spec then it will next to impossible to start, worse than valves being too tight as far as start-ability.
 
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