400ex Motor tapping Please help!!!!!
#1
01-10-2005, 03:47 AM
Join Date: Jun 2000
Posts: 186
Likes: 0
Received 0 Likes
on
0 Posts
400ex Motor tapping Please help!!!!!
Ok, Here goes,
I just recently put a new top end on this 400ex. all was well, But now Im noticing that when I start it up before I go riding that Im hearing a tapping noise on the right side of the cylinder head. at fist I thought it was the valves so I adjusted them but Im still hearing the tapping. oh yea, the tapping stops when the motor warms up, this is only when its idling. when I hit the throttle i bit I can still here the tapping a little. when the top end was done the guys who did it removed the compression release do-dad. would that be whats making it tap or would it have to do with the timing chain. I m thinking that the timing chain may have streched and its slopping around in there.
Does anyone have any idea whats wrong? please help.
I just recently put a new top end on this 400ex. all was well, But now Im noticing that when I start it up before I go riding that Im hearing a tapping noise on the right side of the cylinder head. at fist I thought it was the valves so I adjusted them but Im still hearing the tapping. oh yea, the tapping stops when the motor warms up, this is only when its idling. when I hit the throttle i bit I can still here the tapping a little. when the top end was done the guys who did it removed the compression release do-dad. would that be whats making it tap or would it have to do with the timing chain. I m thinking that the timing chain may have streched and its slopping around in there.
Does anyone have any idea whats wrong? please help.
#2
01-10-2005, 02:42 PM
#3
01-10-2005, 04:41 PM
#4
01-10-2005, 04:52 PM
400ex Motor tapping Please help!!!!!
Originally posted by: cals400ex
why would they remove the decompression assembly on the stock cam????/
if the decompression assembly isn't used, the spring and plunger must be removed from the head or they could be floating around in there.
why would they remove the decompression assembly on the stock cam????/
if the decompression assembly isn't used, the spring and plunger must be removed from the head or they could be floating around in there.
Who did your work, a dealer or someone you know?
#6
01-10-2005, 10:59 PM
Join Date: Jun 2000
Posts: 186
Likes: 0
Received 0 Likes
on
0 Posts
400ex Motor tapping Please help!!!!!
I took it to a little famly owned shop. I usually take all my stuff there and have no problems. I havent taken the head off yet I was just wondering if I should get a new timing chain, I have spoken to a friend who knows two different people who have broken there timing chains on there 400exs.
I was wondering if it was a common thing that happens to 400s.
I have rebuilt a 300ex top end is the 400 pretty much the same thing inside?
I was wondering if it was a common thing that happens to 400s.
I have rebuilt a 300ex top end is the 400 pretty much the same thing inside?
#7
01-11-2005, 09:46 AM
Trending Topics
#8
01-11-2005, 01:10 PM
400ex Motor tapping Please help!!!!!
Originally posted by: PaulV
Ok, Here goes,
I just recently put a new top end on this 400ex. all was well, But now Im noticing that when I start it up before I go riding that Im hearing a tapping noise on the right side of the cylinder head. at fist I thought it was the valves so I adjusted them but Im still hearing the tapping. oh yea, the tapping stops when the motor warms up, this is only when its idling. when I hit the throttle i bit I can still here the tapping a little. when the top end was done the guys who did it removed the compression release do-dad. would that be whats making it tap or would it have to do with the timing chain. I m thinking that the timing chain may have streched and its slopping around in there.
Does anyone have any idea whats wrong? please help.
Ok, Here goes,
I just recently put a new top end on this 400ex. all was well, But now Im noticing that when I start it up before I go riding that Im hearing a tapping noise on the right side of the cylinder head. at fist I thought it was the valves so I adjusted them but Im still hearing the tapping. oh yea, the tapping stops when the motor warms up, this is only when its idling. when I hit the throttle i bit I can still here the tapping a little. when the top end was done the guys who did it removed the compression release do-dad. would that be whats making it tap or would it have to do with the timing chain. I m thinking that the timing chain may have streched and its slopping around in there.
Does anyone have any idea whats wrong? please help.
Then if for any reason you cant get it to them or they dont find anything I would recheck the valve settings, reset the timing chain tensioner, check the spart plug for jetting and any indications of pre ignition problems etc, check the exhaust gaskets where the header bolts to the head, and if you didnt find anything from these I would prepare to be learning a lot about this engine becaue the next steps get a little involved.
One question I do have for you is what mods have been done to the engine both internal and external and this is very important if you cant find the cause from the few things listed above.
So check the easy stuff first (if your not sure how etc post about it and I will help with what I can etc) and dont assume that because work was just done they couldnt have forgotten or missed something etc.
And dont get frustrated cause that only makes it worse
#9
01-11-2005, 03:53 PM
#10
01-11-2005, 06:30 PM
400ex Motor tapping Please help!!!!!
Originally posted by: cals400ex
are you using a stock cam?
i run a crf450 dirtbike timing chain. it is thicker than the stock one. get yourself an owners manual for this bike before you go diving in. it will make things easier.
are you using a stock cam?
i run a crf450 dirtbike timing chain. it is thicker than the stock one. get yourself an owners manual for this bike before you go diving in. it will make things easier.
Agree on the manual as its a must.
Curious what you think about running that timing chain. I have heard it works fine, and also that it rides too high due to actually having a different pitch (how a chain is measured from pin to pin of its links) and that if true isnt a good thing.