Well then, that raises suspicion. I too, drove for years on a broken transmission. I finally replaced it last winter.
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What have you done to your XS today?
- Thread starter I am Carbon
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Well then, that raises suspicion. I too, drove for years on a broken transmission. I finally replaced it last winter.
I removed the rocker cover, head and cylinders and didn't find any thing damaged or worn severely to indicate the loud rattle it was making other than the score marks on each side of the back of the pistons and the rear of the cylinders??.the front cam chain guide looks untouched after 4000klm. Only thing so far is a piece of high tensile wire/clip i found in the bottom of the clutch case. It almost looks like a gudgeon pin clip torn in half??.
Are score marks like that common at 4000km?
No, they're not. Cylinder scoring usually increases as the piston to cylinder wall clearance increases. More clearance allows the piston to rock back and forth on the pin as it's thrust up and down, rubbing the skirts on the cylinder wall.
Did I maybe read it wrong. The camchain guide has 4k km but the rest of the motor is older?
(edited,spellcheck changed camchain to catching}
(edited,spellcheck changed camchain to catching}
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Bob Wegman
XS650 Enthusiast
Could that metal piece be from one of the springs on the back of the clutch basket? Might explain the rattle noise too.
Its the original engine with exchange head and cylinders, new pistons, rings, cam chain and both guides fitted 4000klms ago. Still ran good just very rattley lately.
The scoring and heat discoloration on the sides of the pistons looks to me like there wasn't enough clearance between the pistons and the cylinders. Were they bored oversize?
The rocker cover, head, cylinders and pistons, rings and gaskets came as a kit from Geoffs xs. I don't have any callipers/ vernier to take precise measurements and trusted all was correct as 1 thou oversize. Think I will take the cylinders and pistons to a engine machine shop for their input.
Found this.... talks about seizure, but it's basically the same thing. Score marks 45° from the pin.... not enough clearance.
I was going to say something positive about having the rest of the winter to deal with repairs but then connected the name and the continent. Bummer.
When I rebuilt the engine and first went to kick it over to pump some oil up i was surprised how much compression it had but figured it was because how worn out it was previously.
2 guys in my neighborhood and I acqired a 80cc suzuki, '66 or '67 model. Our youthfull hormones were enraptured with flying down the highway on that magnificent beast, it was 30cc's bigger than a lot of bikes in the area.
On buddy's dad ran a foundry and the bore and piston were shot. We bought an oversized piston and said dad got the barrel bored. Mind you we did this all with crescent wrenches, maybe an open end wrench or two and pliers and vice grips. The first assembly was snug but we figured kick it a few times and it will wear in. First kick spit ring parts out the exhaust. We didn't want to go to the well to often (dad at foundry) so we started honing. Lots of honing. We got new rings, got a lot less resistance, and reassembled. Spit rings out again. I have no idea where that bike ended up.
You nailed it Bob, checked the clutch basket and sure enough there's a broken spring. Might be why I couldn't find the rattle with the stethoscope but the wire/ clip type parts I have found are 2mm diameter and the clutch basket springs are 4mm diameter plus there is the piece of thread and the chunk of alloy that I can't explain.
I refreshed mine with new rings and a honing, machine shop supervised. It was all I could do to kick it. You didn't miss anything there.
My leg got sore just watching you on the kickstarter. Lol. Looks like it’s running well.
Yes. After a couple shakedown rides, I took it on a 700 mile weekend trip.
I need to step away from you folks and get out into the garage. The front end is off the bike and needs reassembly.
