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Discussion Starter #1
heah guys i was checkin my compression on the bike tonight its an 05.. its only going to 25psi.. the intakes are inspec and the exhaust and the decomp was readin in spec to the book before had i have found just as i finished ridin the bike on sat it was hard to start... it has a hot cam to and 12.0.1 piston

i think the compression is way to low!?

cheers Andrew
 

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Thats way to low. The compression is suppose to be about 108 psi. Are you holding your throttle open while you kick it? I would try again and double check all your clearances then fiddle with the decomp clearance. Also make sure that the compression tester had a good seal into the spark plug threads.
 

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Thats way to low. The compression is suppose to be about 108 psi. Are you holding your throttle open while you kick it? I would try again and double check all your clearances then fiddle with the decomp clearance. Also make sure that the compression tester had a good seal into the spark plug threads.[/b]

yeah the bike will fire with that after alot of kicks !!and i did that with my carb off maybe where am getting the wrong reading??... i went over all the clearences it even does feel very easy kicked over when its up and running it idles very rough bt runs well like to ride

its is making a good seal as i put it on and yanked it with a spanner its a snap on blue point tester only got it last month before she used to read 60psi

but i willl test it again with the carb on...
 

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the carb OFF allows even more air to flow than just holding the carb at WOT... .which really does not matter much anyways and is NOT the way you would normally start your machine....

remember.... you are not checking for overall compression of the engine... only CRANKING/KICKING compression... so test it the same way you would start it.....rarely is there more than 5psi difference on most machines anyways....

25 is way too low....... book calls for 108.... most people settle for about 80-90 psi... makes it easier to kick and starts up just fine......

good luck.....g
 

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the carb OFF allows even more air to flow than just holding the carb at WOT... .which really does not matter much anyways and is NOT the way you would normally start your machine....

remember.... you are not checking for overall compression of the engine... only CRANKING/KICKING compression... so test it the same way you would start it.....rarely is there more than 5psi difference on most machines anyways....

25 is way too low....... book calls for 108.... most people settle for about 80-90 psi... makes it easier to kick and starts up just fine......

good luck.....g[/b]
cheers man i noticed the barrell was a little shiny when i put it together i gave it a little hone with a very fine hone i have... it was a very tight fit the piston it has done 6hrs and run like a dream and when it goes it pulls so well just hard to start evrything in the head is in spec..

i never replaced the base gasket as it had only 2 hrs on it this is possibly the problem!?! the head gasket is a brand new cometric one i had... it idles rough which is leading me to think it is a cylnder leakage piston problem possibly a broken compression ring!?!?! :(

many thanks andrew
 

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well i went into the garage again found my valve was stuck open on the tester i replaced it like a car tyre valve core goes in it!! when kicking i got 65psi this is wat i had b4..

so i went about changing plug checking spark ok
then i stripped carb double checked everything no dirt nothing onto ward ok
then i cleaned checked hot start and checked all ok


what i noticed is i have to give the quad gas to get it to start i screwed up the tick over finally after a 50 kicks it fired with a little throttle screwed the idle toget it to tick over it revs okay. but will only tick over high and very rough!?!?!? then i stopped it tried again barely fired up it sounds like it is tickin over too slow then if i rev it it will run at a very high rough tick over but it will rev out really well...

does this sound like a possibly hot start issue or carb jetting issue?? or possibly a stator issue?? it has a good bright spark tho!!


thanks Andrew
 

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Yeah, i'd try with the carb on, not sure if it would make a difference but it wouldn't hurt to try![/b]
what do you mean on? im assuming you 2 are talking about the fuel valve. and also is this 110, what ive read most places, while kicking with the decomprssor acting like normal or what?
 

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heah guys i was checkin my compression on the bike tonight its an 05.. its only going to 25psi.. the intakes are inspec and the exhaust and the decomp was readin in spec to the book before had i have found just as i finished ridin the bike on sat it was hard to start... it has a hot cam to and 12.0.1 piston

i think the compression is way to low!?

cheers Andrew[/b]
ummm, 25psi, a lawn mower will make more than that.lol. i dont compression check stuff much, i just run pistons about 20-40hr, rings at 20hr, and cometic gaskets along with a JE or CP forged piston. if the piston is farly new then i bet it is the valves not seating correctly. check the carberator, tear it down and see if there is any exhasut resido in it. if it is you need new valves, if there steel or all ti with copper seats, get them reseated/lapped if steel. it was a slight problem with the hard seats on the early heads
 

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My service manual says to put it in neutral then hold the throttle open all the way and forcefully kick it several times. Didn't realize that with the carb off it is basically the same until after i posted. Just went through the manual and it said to have the engine warmed up...i didn't when i checked mine and my compression was at 109-110 psi. Anybody think i should re-check with the engine hot?
 

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i honestly don`t know whats wrong :(

the head had new valves seats guides on the intake and exhaust.. plus where cut in professionally...

i actually got it to start up tonight after 50 kicks srew the idle!! it only idle high and rough it will idle low bt stop... it revs out so nice and sharp and crisp...

anyway now that she was warm i tried a compression test anc got 80 which is good

is there a poossibilty its a carb issue?!?!? i just don`t have many people in northern ireland to take it to that you can trust!!
 

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Any luck
i honestly don`t know whats wrong :(

the head had new valves seats guides on the intake and exhaust.. plus where cut in professionally...

i actually got it to start up tonight after 50 kicks srew the idle!! it only idle high and rough it will idle low bt stop... it revs out so nice and sharp and crisp...

anyway now that she was warm i tried a compression test anc got 80 which is good

is there a poossibilty its a carb issue?!?!? i just don`t have many people in northern ireland to take it to that you can tru
 
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