Cam tapping sound at idle

[rebeltaz83]

Yeah, another thread on engine sound:bang head: noticed a very noticeable tapping sound from the right front cylinder can't tell if it's the the intake cam or the exhaust cam making it. Sounds like a lifter tap. If any expiernced mechanics know what I'm talking about. It's a 97 max with 18,000 miles. Gets louder as the oil warms and thins out. Time for valve adjustment? Or is it a worn out lifter?? It just started this after a ride. No other noises, and it gave no warning. Also from a cold over night start I notice this cylinder gets hot faster the the other 3. I know I need a set carbs as the pilot screws are stripped and corroded in the holes. Found a good set of carbs off a running 87 for 250. But I have other major things to spend my money on at the time. Like 1300 dollars worth of tires for my truck............ I don't think it's the timing chain as I only hear this sound from the right front cam cover the left side and both rears are silent. Thanks for any help and or ideas.

 

[Traumahawk]

Sean is probably a good one to answer that. I know that it has been said before that sometimes you hear some noise from the wrist pin that gets louder as the bike warms up.....but isn't really an issue...well the bike is OK for 10s of thousands of miles.

Sent from my SCH-R890 using Tapatalk

 

[Fire-medic]

Hydraulic lifters which are collapsed can cause insufficient lift to open a valve. We have solid shim over bucket cam followers. No loss of oil to fail to 'pump-up' the lifter.

Use a HFTools stethoscope to try and locate the source of the sound, top end, bottom end, cam chain. Sean has recently written about engine noises, you might try searching. The RF cyl is the one that often has given owners problems on the big end of the rod. The crank & block thrust surface too if you're unlucky.

Yeah, another thread on engine sound:bang head: noticed a very noticeable tapping sound from the right front cylinder can't tell if it's the the intake cam or the exhaust cam making it. Sounds like a lifter tap. If any expiernced mechanics know what I'm talking about. It's a 97 max with 18,000 miles. Gets louder as the oil warms and thins out. Time for valve adjustment? Or is it a worn out lifter?? It just started this after a ride. No other noises, and it gave no warning. Also from a cold over night start I notice this cylinder gets hot faster the the other 3. I know I need a set carbs as the pilot screws are stripped and corroded in the holes. Found a good set of carbs off a running 87 for 250. But I have other major things to spend my money on at the time. Like 1300 dollars worth of tires for my truck............ I don't think it's the timing chain as I only hear this sound from the right front cam cover the left side and both rears are silent. Thanks for any help and or ideas.

 

[rebeltaz83]

I seen this on a fotd engine. Pump is at the back, spun a bearing on the very front crank/rod connector. Toasted the motor. It may be the wrist pin, in all my years of mechanic work a knocking on the bottom end usually has expensive consequences. My guess is the right front is the last rod to get oil from the pump resulting in extra wear and tear.

 

[thor_eyerdhal]

Don't run it at idle on sidestand too long..

 

[scuff]

Doubt it's a lifter, like Firemedic said it's not really possible, wrist pin is possible but like Trauma said Sean Morley has stated it's not a really big worry, Let me put out a 3rd and easy to fix possibility, do you have a stock exhaust ? If so the head pipes are double walled and can crack on the inside this noise sounds just like a lifter or wristpin and does get louder when it warms up due to the pipes heating up and making the crack worse also the crack would let exhaust gases escape in between the pipes and thus heating the outer one faster, take a rubber mallet and bang on your exhaust pipes see if you hear a rattle or better yet get one of those inspection scopes unbolt your exhaust and look, Hopefully that's it, it's an easy cheap fix,

 

[rebeltaz83]

Doubt it's a lifter, like Firemedic said it's not really possible, wrist pin is possible but like Trauma said Sean Morley has stated it's not a really big worry, Let me put out a 3rd and easy to fix possibility, do you have a stock exhaust ? If so the head pipes are double walled and can crack on the inside this noise sounds just like a lifter or wristpin and does get louder when it warms up due to the pipes heating up and making the crack worse also the crack would let exhaust gases escape in between the pipes and thus heating the outer one faster, take a rubber mallet and bang on your exhaust pipes see if you hear a rattle or better yet get one of those inspection scopes unbolt your exhaust and look, Hopefully that's it, it's an easy cheap fix,

I'll check that just to be sure. But when I found that jug gets hot faster than the other three I put on hand on the jug itself not the exhaust. But I will check just to be sure, because the other wall did get hit extremely fast as well. But it never made this before. Got back home from a ride and all of a sudden it had a slight tapping noise, or a knock coming from the right front cylinder. I'll try to get a video or a sound clip and see if I can post them up. I'll get one cold, and one hot. Maybe I'll take a trip to the parts store and buy a 5 dollar stethoscope so I better determine where the song is originating. Thanks guys. I know where there is a motor, but it lost 2nd gear. Might take two and make one lol.

 

[leroycp]

Mine has always had that "sound" It got louder when I changed to a modified water pump. Runs great. I've written mine off to "the nature of the beast"

 

[rebeltaz83]

Well no sound clip or video. But exhaust is good. Narrowed it down to starter clutch cover. It's more of a chatter than a knock. And another sound I hear is the cam shafts from all four corners. Think I got paronoid and made the sound sound much worse than it was, lol. Of course I am used to riding it with open trapps, and I dropped to 5 discs on each side so I can hear my intercom when I ride with my wife, and also so I can listen to the radio as well. Is it common for the starter clutch to chatter like that?? I did pull the clutch lever, no change in the noise. Just relieved its not a wrist pin, or spun bearing.

 

[Fire-medic]

If it's a spun bearing, you'll soon know, as the power will go to the level of a 400 twin, and it will overheat, smoke, and eventually stop running.

 

[rebeltaz83]

If it's a spun bearing, you'll soon know, as the power will go to the level of a 400 twin, and it will overheat, smoke, and eventually stop running.

I've seen a spun bearing, not pretty. I had a Dodge Dakota once had a 4 cylinder. Oil pump went. I drove it home on 0 oil pressure has no choice sadly. Got another motor, had to use old oil pan. Dropped it, full of metal. It spun all 4 bearings, and still ran on all 4 cylinders. Each rod had at least a half inch gap between the rod and the crank. Same truck a few months earlier it had an overhead cam, it spit out a follower. Hydraulic lifter lost oil pressure wouldn't pump up. Spun bearing was what happened on that Ford motor, stacked the bearings on top of each other.