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12 Posts
Discussion Starter #1
i am a proud owner of an hornet 900 2002
( engine based on the 900RR 99 engine + injection )

Wich i modified the engine head some this winter

what was done as info :

99 900RR cams + soldered cam pulse on intake cam
TB and head ported and matched
shaved head 0.7mm ( ~ 0.030" )

So now i am up to the fire it up time ..
after a week of testing and thinking,
i'm up to nothing good

compression is between 130 and 150 on all 4 cylinders
( wich is way not enough :p )

no idle ( could be because compression is too low )

but once it fires up, i can go up to 4000-5000 easily, but runs extremely rich and goes on like if 1-2 cylinders were completly off

so tonight i am wondering ..

Could timing of cams, talking in single digit degres here, alter the compression that much ?

I know that when i timed the cams, there wasn't big choice there
since i don't have adjustable cam gears, the IN on the intake was a bit below the head line while the EX on the exhast cam was a bit up
so i know that milling the head modified the timing a bit, i'd say 2-4 degrees

could that be my problem??

have you guys ever had this type of problem ?

i don't think i could be off by 1 chain link on the timing, because that would make it go really passed the marks on the crank ( 1 link looks to be more in the 10-20 degres range ?? )

Please anybody that knows much about that ..what should i test, do now ?

i know that it's not a valve/seat/seal related problems, cause it's on all 4 cy.inders, and i didn't touche the base of the engine at all ..

engine fires up but runs rich and rough idle

please need help, i've had lots of problems with that buildup, and i'm getting over head with all the time i'm putting on it

thanks all :)

12 Posts
Discussion Starter #2
The more i read out on the net, and in the shop manual,
the more i think that cam timing may be the big problem here

i'll order cam gears and degree wheel tomorrow

please ADVICE ME mr PROS :p
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