engine rattle

my wr400 seems to have a bit of a rattle that wasn't there 100k's (70 miles) ago when i bought it. bike has about 2700k's, (1500 miles) on it.

when i got it, it had a nice tight sound, a bit of a mechanical whine to it.

just a faint tapping. now it sounds like an xt250 thats done 20,000k's, no whine and a little bit more chatter than when i bought it.

it does slightly feel like its not as crisp when you are on the throttle.

as far as i know the valves were done before i got the bike, and it seemed like

they were.

they have no adjustment at all? just shims?

could the clearance be out of spec from running rich and lugging it around (and a few short sprints here and there)?

or could the cam chain/tensioner be stretched? it has stalled with a bit of a weird

'pop' witch i just assumed because it was so rich/cold couldnt burn all the fuel,

and also sounds like a 'tick' noise from the bottom end/cam chain when it happens.

i did post on that problem originally but didnt get many answers and gave up,

and just assumed it was normal.

any ideas? thanks.

Easiest thing to check first would be the valve clearances. My guess is that you have a tight Intake valve. And if it's not that, the 400's were known to have top-end bearing problems. That's one reason why Yamaha enlarged it for the 426's/450's. Hope this helps. And let us know what you find. Maniac

Easiest thing to check first would be the valve clearances. My guess is that you have a tight Intake valve. And if it's not that, the 400's were known to have top-end bearing problems. That's one reason why Yamaha enlarged it for the 426's/450's. Hope this helps. And let us know what you find. Maniac

i would have thought that a rattle would indicate a lose valve.

the rattle does seem to follow down the left side of the engine.

when i got it, it was real tight, would make a mechanical sorta whine like a new bike.

less than 100 miles later.. i have no idea why but its gone and replaced with a light rattle.

it sort of lags on instant throttle response off idle and feels a bit soft/hollow

like its going to stall.. and it does, when it does the motor goes 'tick' and sorta pops/coughs once out the airbox/exhaust.

edit: its not jetting, its running just a bit rich.. maybe thats causing stress on the valve seats etc,

especially with the heat. the muffler gets hot enough to melt the plastics due to unburnt fuel, but the header never glows.

Like Maniac says...check the obvious (cheapest) solutions first, before tearing into any serious stuff.

well its a serious noise. and it seriously wasn't there 100 miles ago.

can lugging around on a bike thats jetted overly rich cause excessive valve

wear?

the pipe doesn't glow, but its a bills pipe (double walled header) and the end

can heats up enough to melt the side plastic and toast the heatproof tape on it.

i really cant make it any clearer. the bike seems soft and missing that crisp snap

off idle, feels soft and floaty. its also missing that new bike 'whine'.

im only asking because i dont have feeler guages, tools or cash etc.

i have a bike. if it blows up, i will have no bike. last 2 times i asked people about

a specific problem and put up enough info for it to be correctly diagnosed (not on tt)

people just asked me stupid questions and i keep giving the same answers.

then my bike blew up, because i listen to the 'armchair experts' and then i have no

way to fix it... so i end up with no bike for a year. i have a bike license, and no car license,

so a bike is a necessity for me. its not just a toy that i take out on the holidays.

anyway... so it will make noise when the valves tighten?

rather than make noise when they tighten?

if its a valve (AS WELL) then it will be the left exhaust valve.

edit: i can rule out a top end bearing.

I don't know what you want us to do, fly over there with our feeler gauges and measure your valves for you? Look. We're trying to help you, but your going to have to do some of the work we recommend. Feeler gauges cost all of $5.00 over here, which means $20.00 down in Australia, but you've got to have them! And yes, if the Intake valves get tight, then it will seem like exactly like you said, "soft & hollow" like. Does the bike start hard? This also is a sign that the valves are out of spec. And I've got to ask, without any tools, how we're you able to rule out the top-end bearing? I don't think it's your top-end bearing either, but I do think your valves are out of spec with the limited information you've provided so far. If your not willing to try any of the ideas us "armchair experts" recommend, then why would we continue to try to help? Maniac

To echo Mainiac's statements as well, iIf you think you've put up enough info for us to diagnose a "possible" noise 5000 miles away your nuts. And also stupid for buying a motorcycle and not having any tools/money/etc. to maintain it. Sorry to say but your in this pickle by your own doing because you bought a motorcycle and have no way able to maintain it. Maybe you should have bought a 2 stroke instead. Or a Honda XR.

Or maybe spent $100 less on a bike and visited Walmart for some cheap tools and a meter. If you don't maintain something IT WILL FAIL!!! End of story. No matter what it is. You either pay to fix or get tools and learn to do it yourself, there are no other choices.

It's not like we are telling you to spend big money on anything here and at this point not much we can do other than suggest the obvious by checking the valves. How is it you think it's the left exhaust as well?

Mike

I don't know what you want us to do, fly over there with our feeler gauges and measure your valves for you? Look. We're trying to help you, but your going to have to do some of the work we recommend. Feeler gauges cost all of $5.00 over here, which means $20.00 down in Australia, but you've got to have them! And yes, if the Intake valves get tight, then it will seem like exactly like you said, "soft & hollow" like. Does the bike start hard? This also is a sign that the valves are out of spec. And I've got to ask, without any tools, how we're you able to rule out the top-end bearing? I don't think it's your top-end bearing either, but I do think your valves are out of spec with the limited information you've provided so far. If your not willing to try any of the ideas us "armchair experts" recommend, then why would we continue to try to help? Maniac

no offense i do know you are just trying to be helpful but i personally would not trust a $5 feeler guage for the life of my bike.

a good set would probably cost around $80 here.

you dont have to pull a bike down to check if you have a big/small end problem.

if you are mechanically minded, and have a good feel for engines,, it can be diagnosed buy putting it in gear and moving it/kickstarter.

chances are it is the valve clearance (and timing chain/tensioner because thats the path most of the noise follows)

still does not answer the question of why it has happened if the bikes

just been serviced.

can a bike thats over jetted and running rich put excess strain on valve seats etc.. enough to put the valves out after 100 miles of riding?

it has been lugged half the time (as low as it goes without getting any feedback from the bottom end) and run as hard as it will go the other half (on/off.. riding in traffic). thanks again.

And also stupid for buying a motorcycle and not having any tools/money/etc. Maybe you should have bought a 2 stroke instead. Or a Honda XR.

You either pay to fix or get tools and learn to do it yourself, there are no other choices.

Mike

the bike was just serviced when i got it, maintenance was not scheduled for another 2 months/ 500miles.

unexpected bills and the likes took more than i had. an XR400/600 was my choice,

but people ask too much money for them.. who wants to pay 5,000$ for a 2002 xr600?? the catch is, i needed a bike with registration, otherwise i wouldn't have been so limited to choice.

logic says, the wr is an enduro bike, it should be able to run all day.

i did my research, and these and all the other forums have guys who swear their WR is ultra-reliable. i actually did a lot of research. even found a post somewhere that claimed a WR to have 20,000 miles on the original eng.

its not like i dont have any mechanical knowledge, theres not much i cant do.

i have basic tools but im lacking a few things i really need. if it was an old xr or a 2 stroke i wouldnt be so worried, i've rebuilt bikes with a shifter, a screwdriver and a 10 & 12mm socket. i know this bike will be a lot more temperamental with head bolt specs and the likes.

i will maintain it, i do not want to have to replace anything because of cutting corners.

i owned a 2 stroke, i got rid of it because, a. too much trouble, i pulled the engine down 4 times in 6 months. b. too much trouble. c. see answers a and b.

i dont know anything about wr400's and what is normal for them.

i really hate shimmed valves.

one last question.. if the valves were tight enough they arent sealing effeciently could that also cause the 'rich' popping on decel to be worse?

I know things are more expensive in Australia, but you certainly don't need to spend $80.00 on feeler guages. $5 here in the states, and I'll guarantee that there just as good as any $80.00 ones you put up against them. I promise! As for your bike, my guess would be that when (if) they checked the valves during the service, they were just barely in spec, so they left them alone. Then when you were riding it, they tightened up slightly, causing your problem. I would not believe that your jetting issue had anything to do with them tightening up. They tighten up due to wear, which usually is a slow process, but can be sped up with excessive blasting down a high-speed straightaway and then "chopping" the throttle shut. This tends to "slam" the valves home onto there seats, which wears either the valve or the seat or both, tightening up the clearance. And yes, if the valves are tight, then your bike will tend to pop on decel, most noticeable thru the intake if those are the tight valves. Maniac

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now