knocking/rattle noise from cold/cool engine

[TheAudiDoc]

I started hearing this knocking noise from the engine about a year ago on a cold/cool motor and it is getting louder and taking longer to quiet down(engine needs to be hot before it goes away) if i very lightly accelerate(maybe1/8th throttle) in 1,2,3 0r 4th gear from 1600-2300rpms. it sounds like like a diesel engine. after 15 min of driving it quiets down enough where i cant hear it . any thoughts? i was thinking piston slap.

[David (N. Alabama)]

Hey Mike,

I recall mine doing that last year sometime. I put some seafoam in the oil for 100 miles and then changed the oil and it went away. I'm also thinking I had gotten gas at a different station around that time as well.

I am running Mobil 1 20w50 synthetic in the bike.

[TheAudiDoc]

well my old school kaw technician said the noise was valvetrain noise and told me to take out the mobil 1 synthetic and put in the stock kaw 10w40 conventional oil .... doing it tonight

[Turbo4x4]

Mike,
Sorry, but can't buy the tech's explanation. I'd trust Mobil 1 long before I would Kaw's oil. You need to ask for his backup.

[TheAudiDoc]

he claims to have has a dozen bikes with similar issues(kaw) and the oil fixed em...as soon as hurricane sandy is done having her way with us i'll go put some miles on

[Turbo4x4]

10-4. Not saying he's 100 percent wrong Mike, but never found oil to be the Culprit.

[Me Again]

first thing people tell a XII rider when they complain about valvetrain noise is 3 qt 22 oz of dino oil..
Oil does make a difference ,especially to much or wrong weight.
Some on this site say only motorcycle specific others swear it makes no difference.
listen to your tech.At the very least check the level and if all is ok change to a non synthetic for awhile .
I prefer a full synthetic because I don't have to change it as often.

[RodWestphal]

I am thinking it could be the hydraulic valves. Mine makes some valve noise every once in a while. Also hear this on the 1200 sometimes. Don't know the solution however.
Keep us posted.

[TheAudiDoc]

well I put a 100 very chilli miles on the bike since the oil change (kaw 10w40 conventional) IT'S 50-70% QUIETER!!!!!!!!!!!!!!!!!!!!!! I am gonna do another 200-300 miles this weekend and I am hoping it goes away completely

[gearheadfla]

A Kaw salesman told me last weekend as I was looking at a new 2013 1700 that during engine break in that the lifters will tap some when cold, maybe it last longer than the break in time. The 1200's due it do to the oil foaming when there is too much oil in the engine.

[kawasakigeoff]

My theory on the rattling, knocking noise is that the hydraulic lifters leak down a little when the motor is not running. On start up the lifters are slow to recover and they will cause valve clatter. If you just start it and let the engine warm up you don't get the noise. I always warm up well before riding and never hear the rattling but if I give it a little gas I know I will. Mine has been doing it for at least 2 years. I run on Amsoil 20-50, maybe synthetics leak down more readily than dinos, just a thought. The workshop manual does say even if you restart a hot motor to wait a minute before riding to make sure the oil is everywhere it should be. It is a tall engine. Just my thoughts, I may be full of it.

[Mr Jensee]

I would have to ask if you can tell where the knocking rattling sound is coming from. I ask because I once owned a GS Suzuki that had developed a ratting sound that I could not trace down. It was an air cooled engine so the sound was pronounced when it was cold. I eventually grew tired of pouring money into the bike and gave it away to a guy who lived in another city and was proficient in Suzuki engines. During a tear down he found out that the magneto on left drive shaft end had lost it's 3 supporting bolts and was beating around the engine casing. This may have nothing to do with your Voyager but if you got an engine stethoscope and narrowed down where the sound is most prominent you might go a long way toward figuring out what the problem is.

[Superdave54]

My 2012 did this for the first time a little while ago because it had been three months since I had started it. I knew it was dry lifters, so I kept the revs low and took it for a ride. In about 10 miles the lifters had purged themselves of air, and the engine was quiet again. I run Amsoil 10w-40. I agree with all those that say it's not the oil. Just sitting will do it. I won't let the bike sit that long again.