THAR SHE BLOWS!

Maintenance, repair, troubleshooting, etc.
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Unit562
Lookin' Around
Lookin' Around
Posts: 23
Joined: Mon Aug 07, 2017 11:18 pm
Region:: Seattle, Washington
Motorcycles:: 1993 Yamaha XJ600 SECA II, 1984 Honda Magna V30
Location: Seattle, Washington
United States of America

Sun Sep 10, 2017 8:33 pm

A little backstory first, I traded this bike for a Buell Blast I dropped, this bike wasn't running. The previous owner took it to a service shop that double filled the oil, guy rode it a mile down the block and it stopped running. It sat for 2 years before I got my hands on it. (insert epiphany moment here) I got the bike running again, rode it a good 200 or so miles, and then yesterday happened.

While riding home from work yesterday, the bike started making really weird noises and was behaving odd. I figured the clutch was going out, as it's sounded horrible and the engagement moved to the very end of the lever, so I figured I'd just take the freeway all the way home and go as fast as I could per traffic conditions. (Which was probably 90-100mph.) This morning, I go out to start it, and it would only idle if I had the throttle pinned at full. It also sounded like a parallel twin.

I'll be honest, I got a little pissed off...

2 hours later, the head is off of the motorcycle.

The head gasket was in really bad shape... the right side of the gasket was separated into individual layers and the packing used in between steel sheet layers was totally gone on both sides. This explains why it sounded like a P-twin, only 2 cylinders had any compression. Today I went down and poked a bit at the parts and pieces of the bike, thinking I needed to check spacing between the pistons and cylinder walls... Here's where I lose it... Cyl 2 and 4 have enough play to grab the valve reliefs and wiggle the piston around, a lot. I walked out of the garage at that point. 1 and 3 feel great, look great, and are probably the two that were working until the right side of the head gasket blew out. This also explains the small clicking I was hearing with the clutch in at idle on the right side of the crankcase.

After looking at the price of parts, I'm just gonna buy a complete engine off of eBay with lower miles, which should be cake as mine has 48k on it...

I'll post pictures when lightnings better.
One bad idea fuels most Bike Nights.
My Civic isn't a lawnmower, it's a weed whacker. Get it right, gosh.
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radare
Site Founder
Site Founder
Posts: 8568
Joined: Mon Nov 07, 2011 12:42 pm
Region:: Rocky Mountains
Motorcycles:: '92 XJR600, '92 Seca II
Location: Denver, CO
Contact:
United States of America

Mon Jan 29, 2018 11:22 am

Unit562 wrote:
Sun Sep 10, 2017 8:33 pm
The head gasket was in really bad shape... the right side of the gasket was separated into individual layers and the packing used in between steel sheet layers was totally gone on both sides. This explains why it sounded like a P-twin, only 2 cylinders had any compression. Today I went down and poked a bit at the parts and pieces of the bike, thinking I needed to check spacing between the pistons and cylinder walls... Here's where I lose it... Cyl 2 and 4 have enough play to grab the valve reliefs and wiggle the piston around, a lot. I walked out of the garage at that point. 1 and 3 feel great, look great, and are probably the two that were working until the right side of the head gasket blew out. This also explains the small clicking I was hearing with the clutch in at idle on the right side of the crankcase.

After looking at the price of parts, I'm just gonna buy a complete engine off of eBay with lower miles, which should be cake as mine has 48k on it...

I'll post pictures when lightnings better.
Are you certain a new engine will fix your problem? I've seen head gaskets go on engines as young as 10k. Usually the high-pressure oil galley seal on the righthand side fails and they leak oil.

Carburetors that suck tank junk can also cause a host of problems off-idle. I've had bikes with needles gummed up which idle well but die the moment you turn the throttle. Problem is, the needle won't rise, the mix goes way lean, and they die. A new engine won't fix a problem with an ancillary system.

But looking forward to photos!
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