please tell me i dont need a new engine

[franky_402]

so today reached 90 for the first time this year. Me an my buddy were driving around and were stopping and parking the bikes a few times throughout the day. Later on in the day i started hearing a sound that is worrying me. History on the bike first

Bike has 14k miles 1996 (although speedo cable was broke when i bought the bike)
It has autolite spark plugs
carbs are bench synced, and a/f is set out 2.5 and fully cleaned
stock exhaust and airbox.
fresh oil change with shell rotella t (diesel oil rated jaso-ma

So im riding and i start to hear like a knocking/pinging/type of noise. Kinda sounds like when a car has a hole in the exhaust flexpipe. No loss of power what-so-ever. No noise at idle or when holding a steady speed. Only audible when accelerating medium, or decelerating. When i WOT in a lower gear i dont hear it. When i started noticing it today i checked the oil and noticed it was on the low mark but the oil light didnt illuminate. I went and filled it back up to full. The reason the bike was low on oil is because the starter cover has 2 stripped bolts and is leaking which i am going to be fixing here soon but dont want to deal with that if my engine is blown. The PO didnt know anything about the bike and he bought it not running right. Carbs were really dirty he said he could only run it on choke wouldnt do anything else.

So is this an exhaust leak or valves. If its valves is it bent or just need to be adjusted. Im confused as to exactly what it is. Im thinking if its anything main in the engine then it would always be audible and i would think even worse at WOT but thats not the case

[steves]

First off, chuck those auto-lite plugs in the trash because they aren't worth anything and get some NGK's.

Then look into doing a valve adjustment.

[franky_402]

sounds good the plugs will have to wait for tomorrow as im broke until i get paid. I am going to pull the plugs and see what they look like. Just curious, are you thinking the problem lies in the plugs (the noise) I didnt even really think about it but maybe since the noise isnt always audible it is just the plugs or something, i hope its an easy fix. BTW the reason i put the autolites in the bike to begin with is because when i got the bike it didnt run, i didnt want to buy $40 plugs and it not solve the problem so i went the cheap route.

[5forty2]

I would check you header mounting bolts, maybe they are slightly loose and you have an exhaust leak when the engine torques just right.

[Black_peter]

BTW the reason i put the autolites in the bike to begin with is because when i got the bike it didnt run, i didnt want to buy $40 plugs and it not solve the problem so i went the cheap route.

$40?? Where are you buying plugs? Most I have ever paid is $5 each.
If you have a 750 (you didn't say) I'll throw you a set cheap.

[steves]

The CR9Ek's are expensive, but the Pre doesn't use them unless you've swapped motors to 98+

[whitecl0ver]

You dont need a new motor!

[suzukiray]

If I remember correctly, the D9EA NGKs are the same size & only 2-3 bucks each. Ray.

[franky_402]

when i bought my bike it had the cr9ek's in there and it wasnt running right so i cross referenced them to the autolites 4302 to make sure the engine was sound. suzuki wants 10.50 a plug and the autozone around here wants $9 a plug. I was thinking of getting the nkg cr9e's since they are around 2.50 a plug since most of my rides are longer than 10 minutes so fouling shouldnt be a problem. I have a 96 600 so im not sure why my bike takes the cr9ek's but they do apparently. Any way to tell what year my motor is from??

[steves]

If the motor is BLACK it's a Pre98. If it's silver, it's not.

for the pre98 600 that should be a DR8ES which is a single electrode plug, and they are usually cheap.

The CR9EK's are dual electrode, and usually expensive.

[akarob]

I'd do a compression test to make sure it was healthy.

[franky_402]

If the motor is BLACK it's a Pre98. If it's silver, it's not.

for the pre98 600 that should be a DR8ES which is a single electrode plug, and they are usually cheap.

The CR9EK's are dual electrode, and usually expensive.

Well my engine is black and it takes the cr9ek's no problem are they the same thread that they will fit. If i put in the dr8es will they thread in still and maybe run better??

And for the compression test i forget exactly but there are supposed to be within ten percent of each other...

[Kat750_1126]

so today reached 90 for the first time this year. Me an my buddy were driving around and were stopping and parking the bikes a few times throughout the day. Later on in the day i started hearing a sound that is worrying me. History on the bike first

Bike has 14k miles 1996 (although speedo cable was broke when i bought the bike)
It has autolite spark plugs
carbs are bench synced, and a/f is set out 2.5 and fully cleaned
stock exhaust and airbox.
fresh oil change with shell rotella t (diesel oil rated jaso-ma

So im riding and i start to hear like a knocking/pinging/type of noise. Kinda sounds like when a car has a hole in the exhaust flexpipe. No loss of power what-so-ever. No noise at idle or when holding a steady speed. Only audible when accelerating medium, or decelerating. When i WOT in a lower gear i dont hear it. When i started noticing it today i checked the oil and noticed it was on the low mark but the oil light didnt illuminate. I went and filled it back up to full. The reason the bike was low on oil is because the starter cover has 2 stripped bolts and is leaking which i am going to be fixing here soon but dont want to deal with that if my engine is blown. The PO didnt know anything about the bike and he bought it not running right. Carbs were really dirty he said he could only run it on choke wouldnt do anything else.

So is this an exhaust leak or valves. If its valves is it bent or just need to be adjusted. Im confused as to exactly what it is. Im thinking if its anything main in the engine then it would always be audible and i would think even worse at WOT but thats not the case

If the oil pressure light isnt going on your moter is still good for the most part. It shows all theb (oil) bearings are holding pressure, however valves could still be off

[akarob]

When I checked mine they were 140 - 155 psi. The manual says +/- 20 between any two I think. If you see one much below the others, there is a problem.

It's probably not a compression problem, its just nice to know for sure.

[franky_402]

I am hopefully doing the compression test today as well as changing the plugs, should I get the cr9e's or the dr8es??