bh2285
05-26-2006, 08:31 PM
Ok, If you all would help me get this problem fixed that I cant seem to figure out I would be so happy...But anyway If you want to get the most detail search for my other posts. I have a noise that is only when I let off the throttle. Like for example when I rev it up and hold it everything sounds peachy but as soon as I let off the throttle I get this noise that sounds like a backfire to me. At first I told members here my problem and they told me to change the chain and guides... well I did that and I put in a CRF450 chain and and new front guide. My guide was destroyed had chucks missing and was just flat out beat so I thought for sure this new chain and guide would solve my problem. Well guess what all it did was make this noise louder.
So...My head and jug have each been decked .025 for a total of .050. When I had the old timing chain in there I could not get the marks to line up(it was in between a tooth) so I advanced it. Im guessing that this was because of my decking and chain strech. Now that I have the new chain in and new guide the mark line up pretty damn dead on. But my noise got loader with makes me belive that it is the timing and that the noise was never the chain is was my quad backing firing...But the backfiring was not coming out the tail pipe it was coming from the header/chain area which is what made me belive that it was my chain as people here stated. So my question is could this noise be that my exhaust valves are closing at the wrong time there for causing some kind of backfire that cant get out of the cyclinder? Would this all be caused by me not advanceing the timing. Or should the timing be advanced because of my decking and if so how much. Im so lost to what this noise could be?? Also why would it get louder if I have the timing marks dead on when before I had it advance probley a degree and it was not near as load as it is now. please ask questions Ill try to make this more clear if you dont understand what im saying I really need help and I have no idea what I should do next??
BTW: When I first got this motor it had a XR400 cam in it and it didnt make any noise it ran and sounded great...Then I got a stage 2 hotcam and installed it not thinking about how it was decked and tried to line the marks up but they would not line up so I put the as close as I could and ever since then ive had this nose..AHHH!
You can see my setup in my SIG ive got the stage 2 hotcam in there now and it is all adjusted to the spec card that came with it.
THANKS YOU GUYS FOR ANY HELP!
So...My head and jug have each been decked .025 for a total of .050. When I had the old timing chain in there I could not get the marks to line up(it was in between a tooth) so I advanced it. Im guessing that this was because of my decking and chain strech. Now that I have the new chain in and new guide the mark line up pretty damn dead on. But my noise got loader with makes me belive that it is the timing and that the noise was never the chain is was my quad backing firing...But the backfiring was not coming out the tail pipe it was coming from the header/chain area which is what made me belive that it was my chain as people here stated. So my question is could this noise be that my exhaust valves are closing at the wrong time there for causing some kind of backfire that cant get out of the cyclinder? Would this all be caused by me not advanceing the timing. Or should the timing be advanced because of my decking and if so how much. Im so lost to what this noise could be?? Also why would it get louder if I have the timing marks dead on when before I had it advance probley a degree and it was not near as load as it is now. please ask questions Ill try to make this more clear if you dont understand what im saying I really need help and I have no idea what I should do next??
BTW: When I first got this motor it had a XR400 cam in it and it didnt make any noise it ran and sounded great...Then I got a stage 2 hotcam and installed it not thinking about how it was decked and tried to line the marks up but they would not line up so I put the as close as I could and ever since then ive had this nose..AHHH!
You can see my setup in my SIG ive got the stage 2 hotcam in there now and it is all adjusted to the spec card that came with it.
THANKS YOU GUYS FOR ANY HELP!