can not figure out what is causing this sound

[kindest]

first time you can hear it is @ 16s then again 27,30,40,46,1.00,1.05,1.08,1.10,1.19,1.21,1.24 etc

When the bike is on the center stand in gear it makes that sound randomly it seems and the bike shakes (rocks on the stand and the chain dances weird). When in neutral or any gear w/ clutch is pulled in there is no weird sounds or "shaking".

Ive tried pulling the plugs put it every gear spin the tire to try to find out if there's a broken gear tooth but I don't find anything weird going on there. I thought it might be the chain hitting on something but I can't see it hitting anything.

When I'm riding I don't notice anything and everything seems in perfect working condition. Anyone ran into this before?

 

[JARichmond]

How old is the chain? You may have developed a stretch in the rungs and thus created a heavy side and light side. The rocking may be a frequency issue where the weight transfer of the chain happens with another natural weight transfer such as the firing of a cylinder.

 

[kindest]

I just replaced the chain today cause my old chain was shot. It was doing the same thing before as well as with the new chain. Didn't even think about the frequency issue that is good thinking. I'm just terrified there is something wrong with the engine/transmission or something.

well i think im crazy cause afer riding for a while and attempting to re-create the problem I can't. Appears to only happen when the engine is cold so I guess its self fixing.

 

[JARichmond]

I would look for heavy spots in the chain and on the sprockets caused by grease and dirt. If the chain is new, it's not likely that it's worn out already (or you may have just got boned). Best of luck

 

[xschris]

I would have replaced your sprockets as well. A worn chain could have messed them up too. Bad idea to put the bike in gear while its on the center stand you can just role the tire with your hand. The chain could be too tight.

 

[HoughMade]

I don't think anything's wrong. You have a bike sitting on the center stand, clutch out in first. Every once in a while the engine bogs momentarily....no big deal. Maybe I'm not hearing what you are hearing, but it just doesn't seem like much to me.

As for changing sprockets and chains together, it can't hurt, but on these bikes, it's not necessary. First of all, the sprockets on XS400s are steel. Most modern performance bikes use aluminum today. From the use of relatively soft aluminum comes the recommendation to change chain and sprockets together. Chains are steel and will wear on aluminum sprockets quite a bit. When the sprockets are steel, they can take a lot more use before they start to get hooked teeth...and I mean a lot. The chain, on the other hand, has a lot of moving parts and can be expected to wear out before steel sprockets, even if properly lubricated, but especially if not.

In other words, "change the sprockets and chain at the same time" is advice for different bikes, with more than 38hp (tops) with different sprockets from a different era.

 

[drewpy]

chain looks a bit tight to me. it is also in a non riding position so the rear swing arm is low causing the chain to run and hit on the pivot.

 

[kindest]

thanks guys.

I think your right HoughMade somehow my subconscious is looking for an excuse to tear the engine apart. I did replace the rear sprocket.... was going to replace the front sprocket but I couldn't get that nut off. Tried with a breaker bar and a 2ft pipe extension thing would not budge.

Don't fix it its not broken and ride it till it breaks. Just gotta continue telling myself that.