finally putting 810 motor back together

well after way to long without a rideable bike, and 2 topend rebuilds i am still clueless on why my bike has a loud knock. Fixing sometihng when you are unsure of the source of the problem is getting very aggrevating. The knock seems to be coming from the topend, when using a screwdriver to find the source of the noise. every motorcycle shop around my area said it was definately a bent valve, but i was unsure. the first rebuild i put on the kz head that was on my motor originally before i put on the gpz head. got it all back together and still the same annoying knock. second rebuild i dissassembled the topend adn checked everything for wear, used new shims, and checked the pistons for any damage. Then played with the advance/retard settings on my ignition. Still had the same annoying knock. The other thing that really bothers me about it is that it didnt seem to lose any power after it developed the knock. So now i am starting the final rebuild with a completely different bottom end (dont know why, but any change will make me feel better) my gpz head, and the kz cams(is it possible that my gpz cams could be bent?

right now i have both motors dowm to the bottom end, am putting the 810 pistons onto the other bottom end. i noticed that one piston pin was very hard to get out. I had to beat it out, and moves in and out VERY hard. could this cause any sort of knock?

It's not detonation is it? Are you running premium fuel? Ed

i dont believe so. i usually run 91, but have run 87 multiple times with no problems.

jordan wrote:

well after way to long without a rideable bike, and 2 topend rebuilds i am still clueless on why my bike has a loud knock. Fixing sometihng when you are unsure of the source of the problem is getting very aggrevating. The knock seems to be coming from the topend, when using a screwdriver to find the source of the noise. every motorcycle shop around my area said it was definately a bent valve, but i was unsure. the first rebuild i put on the kz head that was on my motor originally before i put on the gpz head. got it all back together and still the same annoying knock. second rebuild i dissassembled the topend adn checked everything for wear, used new shims, and checked the pistons for any damage. Then played with the advance/retard settings on my ignition. Still had the same annoying knock. The other thing that really bothers me about it is that it didnt seem to lose any power after it developed the knock. So now i am starting the final rebuild with a completely different bottom end (dont know why, but any change will make me feel better) my gpz head, and the kz cams(is it possible that my gpz cams could be bent?

right now i have both motors dowm to the bottom end, am putting the 810 pistons onto the other bottom end. i noticed that one piston pin was very hard to get out. I had to beat it out, and moves in and out VERY hard. could this cause any sort of knock?

was it sticking in the piston or the rod end? did you notice any slop in piston if you try twisting towards end of wristpin?

no slop at all, and it is sticking in the piston, not the rod which makes me think that this is not the issue as the piston moves freely on the rod. this is really bothering me, i dont know what i will do if it knocks after this rebuild.

ok,next question!when does it knock? hot/cold/idling when you hammer it or all of the above?

well. it seemed to tick louder once it warmed up, but was still noticeable right after startup. It seems to consistently increase rapidity as rpm increases. It definately sounds like a mechanical knock, but there is no noticeable wear on any of the parts. The kz head i tried came off of a perfectyl running bike, i just replaced it with the gpz head. As i mentioned before, it seemed to run fine, no cutting out or anything.

did you ever check the rod/main bearings to see what they loked like?how about pistons rocking in lose bore?

Jordan

What is the piston deck height?

never checked rod/main bearings or piston deck height, but the valves looked untouched by the pistons. The bike always ran great. took it to the dragstrip one weekend, ran fine all week, i put wiped down teh clutch disks with emery cloth, put it all back together, rode it a while, then the next weekend it started ticking. checked the clutch immediately, but evetything looked perfect

jordan wrote:

never checked rod/main bearings or piston deck height, but the valves looked untouched by the pistons. The bike always ran great. took it to the dragstrip one weekend, ran fine all week, i put wiped down teh clutch disks with emery cloth, put it all back together, rode it a while, then the next weekend it started ticking. checked the clutch immediately, but evetything looked perfect

So if I understand correctly, the noise stopped after you wiped down the clutch discs, then came back? If so I think you found the area of the noise.

Have you had the head or block surfaced? If there was too much taken off the edge of the piston can contact the head... even just a TINY TINY bit... I had a 4Wheeler engine do the same thing and gave me lot of headachs figuren it out.. just a thought. Also make sure you are using the 810 headgasket.