spent this weekend installing my 03 cam, when i was all done i tried to start it it was like kicking with no decompression at all! it flet like i should pull in the decop. lever to get passed top of center, but there is no decop. lever. when i did the installation every thing seemed to go in okay, the directions i got from tt seemed great, the only question i had is on the fly wheel is the tdc mark was not just a line but an "H 1" i lined up on the "1" mark. does everyone have same marks? need help before i tear it all apart again. p.s. do i need a new gasket if it has only been on for a day or so. mike
03 cam installation did not go right!
Started by BOWHUNTER, Feb 03 2003 08:27 AM
8 replies to this topic
Posted 03 February 2003 - 08:27 AM
spent this weekend installing my 03 cam, when i was all done i tried to start it it was like kicking with no decompression at all! it flet like i should pull in the decop. lever to get passed top of center, but there is no decop. lever. when i did the installation every thing seemed to go in okay, the directions i got from tt seemed great, the only question i had is on the fly wheel is the tdc mark was not just a line but an "H 1" i lined up on the "1" mark. does everyone have same marks? need help before i tear it all apart again. p.s. do i need a new gasket if it has only been on for a day or so. mike
Posted 03 February 2003 - 09:06 AM
There are two TDCs. One on the Exhaust Stroke and one on the compression stroke. Make sure you timed to the correct one. Just a suggestion. Go back and double check everything start to finish. That is the way I usually find my faux pas.
Posted 03 February 2003 - 09:23 AM
I had a similar problem after adjusting my valves on an 2002. Upon reassembly I alined the cams on the wrong punch mark (Bottom of the stroke instead of top) therefore my bike had no compression at all. When I reassembled the bike the second time I used a little trick with a the red straw from a can of WD-40. Once I had the bike at what I thought was TDC I put the straw in to see how far it would go before it would touch the piston. If it only went in a little, TDC. If it went in alot, BDC. One minute of checking saves 30 reassembling.
Posted 03 February 2003 - 09:31 AM
Quote
There are two TDCs. One on the Exhaust Stroke and one on the compression stroke.
on a 4strk that actually cares when it fires the spark plug, yes. on a 250F, no. see, the plug on a 250F fires each time it comes close to TDC. proved by the lack of a crank to cam to distributor alignment requirement normally found on 4strokes (ie your car) and the magnetic sensor on the flywheel.
as long as the cams match each other (the dots are where they are supposed to be) and the "H 1" (yes, i have that on my 01yz too) is in the window. all is good.
i put the 03 cam in mine a week ago. it was very simple and i've only had the top end apart twice now.
Posted 03 February 2003 - 09:59 AM
sunruh, when i look at the cams, the right one reads e-i with the dots lineing up, the exhaust cam only one dot lined up ant it was to the inside, with cam lobes pointing up to the inside at an angle of about 70 degrees. does this all sound right? and did you remove your decomp. lever? if so does the plug just push in? thanks mike
Posted 03 February 2003 - 10:21 AM
Looking at your cams from the cam-sprocket side, the exhaust cam lobe point should be pointing at approximately the 10-11 o'clock position and the intake cam lobe should be pointing at approximately the 1-2 o'clock position @ TDC
Posted 03 February 2003 - 10:40 AM
no, i did not remove the decomp lever.
what i did was compare the pic in the book to how i held it in my hand. you can always look at your original one and see how it goes. then hold up the 03 cam and make it the same. the dot lines up flush with the lip. just like the I-E does on the intake cam. i also had the crank on the "I" of the "H I". however, without the tensioner on, the is enough play in the chain that it only has to be close. double check again once the tensioner is in place and working. then it should be perfect. leave the spark plug out and kick it over several times to make sure nothing hits (ie valve to piston). then seal it good. bikedestroyer i think gives good advice in the post above.
what i did was compare the pic in the book to how i held it in my hand. you can always look at your original one and see how it goes. then hold up the 03 cam and make it the same. the dot lines up flush with the lip. just like the I-E does on the intake cam. i also had the crank on the "I" of the "H I". however, without the tensioner on, the is enough play in the chain that it only has to be close. double check again once the tensioner is in place and working. then it should be perfect. leave the spark plug out and kick it over several times to make sure nothing hits (ie valve to piston). then seal it good. bikedestroyer i think gives good advice in the post above.
Posted 03 February 2003 - 12:10 PM
Use the punch mark if your dealing with a YZ. If you look at the 03 E cam there are 2 punch marks on the cam wheel. one punch mark will line with the casting of the head the other punch marks is about 90 deg. straight up.
If you tear things down again start with placing a (I use 3/8)breaker bar on the flywheel nut. rotate the flywheel until your "I" mark lines up. Then place a block (of proper size)under the breaker bar handle and zip-tie or tape the bar to the peg. Things will not move now. You shouldn't had to remove the Intake cam so check to see that the E is on the left, I on the right and that the punch mark is lined up with the cast of the head. Next check the 03 E cam, there are 2 punch marks on the cam wheel, one lines up with the cast the other sit almost 90 deg. straight up, your lobes should be around 10 on exhaust side and 2 on intake side. As long as the punch marks are lined up and your still sitting on the "I" mark life is good.
PS if you want a picture of how the cam sits I can run out and take one. My motor is tore down but I could sit the cams in place snap one and e-mail it to you.
OPPPPSSSS No one caught that I had the E & I backwards
If you tear things down again start with placing a (I use 3/8)breaker bar on the flywheel nut. rotate the flywheel until your "I" mark lines up. Then place a block (of proper size)under the breaker bar handle and zip-tie or tape the bar to the peg. Things will not move now. You shouldn't had to remove the Intake cam so check to see that the E is on the left, I on the right and that the punch mark is lined up with the cast of the head. Next check the 03 E cam, there are 2 punch marks on the cam wheel, one lines up with the cast the other sit almost 90 deg. straight up, your lobes should be around 10 on exhaust side and 2 on intake side. As long as the punch marks are lined up and your still sitting on the "I" mark life is good.
PS if you want a picture of how the cam sits I can run out and take one. My motor is tore down but I could sit the cams in place snap one and e-mail it to you.
OPPPPSSSS No one caught that I had the E & I backwards
Posted 03 February 2003 - 12:29 PM
If you just need a visual check on the approx positions of the cam lobes, download the 450 cam swap PDF and have a look.
www.just-ride-it.com/450cam.pdf
The pictures will show how the cam lobes face away from one another. As long as you have the flywheel lined up properly and the cams lined up properly everything should be fine...
good luck,
David
www.just-ride-it.com/450cam.pdf
The pictures will show how the cam lobes face away from one another. As long as you have the flywheel lined up properly and the cams lined up properly everything should be fine...
good luck,
David
