engine knock when engine is hot

[Drichey]

I have a 1982 XJ 1100 that I bought with 3rd gear issues I removed the oil pan to find the countershaft bolt in the pan. I replaced the bolt and the countershaft from a parts bike. I now have a light knock when the bike is hot. I have heard others with 2nd gear issues that said there main bearings were trashed. Has anybody run to this on these bikes?

bearings come in colors such as brown and green what does that mean?

Does anyone know if I can use the crank from the parts bike (1980 xs1100 special) in the XJ

[TopCatGr58]

Hey David,

An Engine KNOCK and the tranny are not necessarily linked in cause/effect!

Okay, you say you hear this knock after the bike warms up! The engine gets leaner as it warms up. When do you hear this knock, under load, or just idling or revving in neutral? Also, where exactly is the knock? You can take a piece of broomstick or such and use as a stethoscope and put it against the engine and your ear and check to see IF you hear if more from the top end or the bottom end!

What mods if any have been done to the bike, like intake/filters or exhaust? Same question for carbs? Have you checked your compression? What do the plugs look like? How many miles on the engine? Could be piston slap, low octane ping/knock.

The XJ got rid of the mechanical cent. and vacuum advance units/components of the ignition, so it's just a timing plate/pickup rotor under the timing cover. MORE DETAILS PLEASE!
T.C.

[Drichey]

no mods

I have not done any mods to this bike yet. I have a XS850 final drive to put on but have not done it yet.

It is not spark knock/low octane ping

The noise is mostly at idle, coming from lower end. although when I run throught the gears I hear some noise at one point during the rpms. But only when the bike is good and hot on 90+ days. The bike has 45,000 on it and it runs really well.

I am pretty sure its the lower end so I haven't checked compression and or plugs.

[trbig]

I don't want to alarm you, but I had a knock in my XJ, although it was an XS motor at the time. I continued riding it and it never got really bad, but I started getting oil seeping out the crank seals.. even though I replaced them. The bearings were out and it ended up spinning a bearing on the left side. This ruined the crank AND the block of the motor.

These cranks all interchange, You will have to have someone better than me explain the bearing color thing, but I'll try. Your crank will have a number stamped on it (I think on the end of the weighted part of one lobe on the crank... EX. 55555. This will be the number associated with each race in order on the crank. I don't remember where on the block, but it's somewhere on the bottom half front of the motor, you will find a similar set of numbers stamped.. ex 22222. This is the journals in your head measurement. Each color of bearing is numbered 1-5.. each represented by a different color. You subtract the two numbers... 5-2=3)equaling 33333, so you would need 5 (I think a 3 is green) bearings for the crank.. one of them a thrust bearing. The crank has 5, the rod bearings have 4.

It may not be this simple (Mine was) and it may take a different color at each journal. I hope I didn't confuse you more.

Tod