TOPIC:

IM NOW AT THE POINT I VE NO CHOICE BUT TO PULL THE ENGINE OUT OF FRAME AND SPLIT IT.THe HEAD HAS 3 BENT VALVES AND THE END GROUND OF ONE SO I AM WORRIED ABOUT THE CRANKSHAFT IT HAD NO OIL LIGHT ON BUT YOU ALL SEEN THE PICK UP I HOPE THESE CRANKS ARE STRONG SO MUCH FOR THE SELLER SAYING IT WAS THE BEST HE EVER RODE HE HAD OWNED 6

Oh dear , not so good. The crank is pretty robust -but- you found Tertius Buys there in South Africa and there is lots for sale eveyrwhere. Just not cheap to send where you are. Fix it yourself if needed.

thanks and yes freight is a big cost over here.Can any one tell me what limits the crank end float the manual says bearings and crank case .A car engine has thrust washers i don't see any of the mains for sale with side thrush washers.I have a mate who is a engineer and between us im sure we can fix it with the help from this site and the people selling parts thanks Graham

Sorry to hear of your problems. It would really help us if you would keep your bike on a single topic and just add new posts. I'm struggling here trying to understand what started this problem and where you are at. I tried to find previous posts regarding you finding bent valves or .....

In regards to your question, the crankshaft side thrust is accommodated by number 4 mainbearing just like in cars. The #4 main bearing has side faces that keep the crank centered. Side play is .50mm or .020" which is generous from what I'm used to seeing in most engines. Usually side thrust is down around .005"-.008". Reference page 189 of the shop maanual.
Most crankshafts can be saved unless debris has been pumped through the oil system and the debris got stuck in the babbitt bearings and then chewed up the journals. Your crank should be fine. The worst I've seen is when the oil system is not pressureized and the engine is run to the point where the babbitt melts and plates out on the journals. Usually you can polish the babbitt off of the crank and replace the bearing shells. The babbitt bearing act as a sacrificial component.
If you suffered a timing chain jump and bent valves, then the motor would stop and I doubt that you have any bearing issues but I say this because I can't find the whole story here.

Thanks that's good to hear that there is a thrust washer .The bike never stopped except for the first ride when the timing rotor came away from the advance weights because some one left out the retaining washer.Its always idled bad when hot and i was always chasing a miss just off idle but if i opened up the idle mixture it went away?There was never a oil light on but i posted that photo of the nearly blocked oil pick up i never expected bent valves only pulled the head because some nice person took to number 1 inlet shim with a grinder.Also found a plastic gear broken in halve sitting next to the cam chain its from the ignition pick up but one part of the gear is missing so they replaced it but of coarse they cant get to the broken gear so they left it there nice and in doing this they left the washer out for the rotor .I never wanted to split the cases but once that's done i can rebuild it and know exactly what i vie got and then i can only blame myself but i can see its going to be expensive.There is no wear that i can see in the cylinder bores but a score mark down number two looks like a sharp edge of a ring has done it and there is still hone marks on cylinder walls.Do these re ring OK or is it better to re bore it its still on standard pistons.Sorry about the mess of my posts

kiwirider wrote: Thanks that's good to hear that there is a thrust washer .The bike never stopped except for the first ride when the timing rotor came away from the advance weights because some one left out the retaining washer.Its always idled bad when hot and i was always chasing a miss just off idle but if i opened up the idle mixture it went away?There was never a oil light on but i posted that photo of the nearly blocked oil pick up i never expected bent valves only pulled the head because some nice person took to number 1 inlet shim with a grinder.Also found a plastic gear broken in halve sitting next to the cam chain its from the ignition pick up but one part of the gear is missing so they replaced it but of coarse they cant get to the broken gear so they left it there nice and in doing this they left the washer out for the rotor .I never wanted to split the cases but once that's done i can rebuild it and know exactly what i vie got and then i can only blame myself but i can see its going to be expensive.There is no wear that i can see in the cylinder bores but a score mark down number two looks like a sharp edge of a ring has done it and there is still hone marks on cylinder walls.Do these re ring OK or is it better to re bore it its still on standard pistons.Sorry about the mess of my posts

Ok Graham, first we're here for you. It would really help if you started a new post and maybe call it "Kiwirider's Rebuild of 79 KZK1300" and then when you want to post just keep going back to that topic and add a post. That way when we need to see pics from prevous posts we can go back through the posts in the same topic. This just keeps everything together so we can follow along.

I'm going to answer your post line by line because there is a lot of information here and questions.

You wrote ".Its always idled bad when hot and i was always chasing a miss just off idle but if i opened up the idle mixture it went away?" That sounds like a transition port in one of the carbs blocked. The idle transiston ports are in the carb bore right where the brass butterfly valve is. If one or two of those ports are blocked, you get a misfire at idle and then it will smooth out just off idle, so that's something you can look at later on.

You wrote "There was never a oil light on but i posted that photo of the nearly blocked oil pick up" so you took my advice and found the blocked oil pick up. That's really good to find before a real problem. If you didn't see any damage on the camshafts or ccamshaft bearings then I would think you'll be ok.

You wrote " i never expected bent valves only pulled the head because some nice person took to number 1 inlet shim with a grinder." So I'll assume that the previous owner didn't go and gert a smaller shim and elected to just grind a shim? And based on this you decided to pull the head? And then found 3 bent valves? Could you post pics of this ground shim and was the ground side up or down?

You werote "Also found a plastic gear broken in halve sitting next to the cam chain its from the ignition pick up " I'm struggling to understand. Was the broken gear on the timing advancer shaft? If so it's not next to the camshaft drive chain. That gear would be next to the timing chain which is a different chain. Now if the plastic gear was on the camshaft chain on the back side of the engine, then the broken gear would account for the 3 bent valves. Maybe you could post a picture of this broken gear.

If you want to split the motor and go through it from one end to the other and make it right, that's fine. I'm not sure I would go that far unless after you had the oil pan off, you checked the slack in the primary and secondary chains and found a problem or if you found broken pieces gears or otherwise in the bottom of the oil pan.

You wrote" There is no wear that i can see in the cylinder bores but a score mark down number two looks like a sharp edge of a ring has done it and there is still hone marks on cylinder walls.Do these re ring OK or is it better to re bore it its still on standard pistons." It's not likely that a vertical score was caused by a sharp edge on a ring. It could have been caused by a piece of carbon breaking away from the piston or head and getting trapped between the piston and cylinder wall causing the score. It could have been debris sucked in past the air filter or during a time when no air filter was in place and the engine was run. In any case a light hone and re-ring would be fine. I might just leave it if its a light score. If you can get your fingernail to fel it out it might be deep or wide enough to have to hone out.

You're in this bike way too deep to just walk away from it. $20,000 NZ dollars should have bought you a pristine immaculate example of a KZ1300 not a bag of trouble. Hang in there.

Hope these thoughts help,
KB