Posts
2334
Joined
7/31/2010
Location
Merritt Island, FL, USA
Edited Date/Time
2/12/2012 9:52am
For me it was 1980 at a track called Burnt Hickory in Dallas GA.
I was racing my 1980 YZ 125G and as I was running down a longer straight, the engine bogged and died as I was WFO. I kicked and kicked and couldn't get it to start. My Dad came over and helped me push it back to the pits. We kicked and kicked with no results. We pushed it down the pit road trying to bump start it with no success.
We packed up and went home. I checked spark - Good. I checked fuel - Good. WTH?! I pulled the head off and didn't see anything. I rotated the engine and as the piston went down, I saw a grove in the cylinder. Huh?
Pulled the jug off and found a perfect grove in the piston and cylinder with no other signs of damage.
Well, I took the cylinder in to be bored - honing wasn't enough - and ordered the next over sized piston and rings.
A few days later I put it all back together again and it starts on the first kick. I'm smiling to myself as it idles while warming up when all of a sudden - it locks up solid! SHIT! What's going on?
I pull out the kick starter and I can't push it down. The beast is locked up big time.
I pull the head - nothing.
I pull the cylinder - nothing.
What is going on here?
The crank won't rotate and there is no damage to the head or cylinder...
I get out the magnifying glass and see something wedged between the crank and the case. I take a small drift and I'm able to tap it loose and it falls into the bottom end.
Now, I've had to pull the engine from the frame and I can hear the metal something rolling around in the bottom end. I turn the engine upside down and a piece of metal falls out.
It was the head of one of the screws for the reeds! The damn head had broken off, gone through the reeds and caused the initial damage to the piston and cylinder. It must have fallen down into the bottom end and been bouncing around when I started the bike after the new bore and top end.
I was really lucky that I didn't have a repeat of the first failure. After removing the screw head, I put it back together and everything was fine.
I've never seen or heard of anything like this before or since...
I was racing my 1980 YZ 125G and as I was running down a longer straight, the engine bogged and died as I was WFO. I kicked and kicked and couldn't get it to start. My Dad came over and helped me push it back to the pits. We kicked and kicked with no results. We pushed it down the pit road trying to bump start it with no success.
We packed up and went home. I checked spark - Good. I checked fuel - Good. WTH?! I pulled the head off and didn't see anything. I rotated the engine and as the piston went down, I saw a grove in the cylinder. Huh?
Pulled the jug off and found a perfect grove in the piston and cylinder with no other signs of damage.
Well, I took the cylinder in to be bored - honing wasn't enough - and ordered the next over sized piston and rings.
A few days later I put it all back together again and it starts on the first kick. I'm smiling to myself as it idles while warming up when all of a sudden - it locks up solid! SHIT! What's going on?
I pull out the kick starter and I can't push it down. The beast is locked up big time.
I pull the head - nothing.
I pull the cylinder - nothing.
What is going on here?
The crank won't rotate and there is no damage to the head or cylinder...
I get out the magnifying glass and see something wedged between the crank and the case. I take a small drift and I'm able to tap it loose and it falls into the bottom end.
Now, I've had to pull the engine from the frame and I can hear the metal something rolling around in the bottom end. I turn the engine upside down and a piece of metal falls out.
It was the head of one of the screws for the reeds! The damn head had broken off, gone through the reeds and caused the initial damage to the piston and cylinder. It must have fallen down into the bottom end and been bouncing around when I started the bike after the new bore and top end.
I was really lucky that I didn't have a repeat of the first failure. After removing the screw head, I put it back together and everything was fine.
I've never seen or heard of anything like this before or since...
Oldest kids 04 CRF250 shredded the cam chain tensioner and plugged the oil filter. Topend ran dry welded everything together. Never seen such a disaster althought the repair bill appeared all too familiar from when my 01 YZ250F dropped a valve at speed.
Snapped the powervalve link, that little flat bar type connector to open the powervalve. Snapped in half, inside the case.
Push rod connector plate for the clutch, where it runs along the side of the case bent....twice. Had to have a piece fabbed in to keep it from bending out.
Broke the airbox boot right off where it goes into the engine intake.........sucked in dirt and sand for 2 laps and grenaded, crank, bottom end....the works
Had a lead this big still on the 1st lap
Lap 3 i was pinned WFO down a straight, coming into a corner hit a breaking bump and she locked up solid. Got home and tore it apart and not only did it blow the lower rod bearing, but the rod actually stretched and ovalized the bottom bearing hole so bad that the piston hit the head and fully locked it up. Ended up also having to replace the whole crank.
@EastFlorida: I also had something similar to you on my Pilot, screw came out of the reed block and got sucked through the motor, the screw left a perfect indentation on the top of the piston. never seized or locked up, and i actually was able to nurse it through the 1st moto, but anytime i went past 3/4 throttle it would garble, piss and moan, that was one frustrating moto!!
Luckily i had TONS of spares and was able to put in my spare cylinder and new top end in between motos, came back and won moto 2, went 4-1 for 2nd o/a and that ended up probably saving my title run that season.
The Shop
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
Luxon 4-Post Bar Mounts
$189.95 - $239.95
Oddest for me has to be my front brake locking up. Roost created a hole in the res on my bars, and my front brake keep going in and out. After noticing it was fading I pulled a hand full of front brake and my front brake actually worked for a brief moment. However that brief moment sent me into a endo because I slammed on them so hard. To this day I'm still unsure of what happened mechanically, but after the crash the front brakes were gone for good.
Thankfully no fires, but no gas either, so the race was done.
Turns out his choke had unscrewed from the carb. A Keihin flat-slide carb. So weird, I'd never touched it or unscrewed it ever. Just backed out and cost him a good finish. After that, I always put a wrench on them to check.
Pit Row
over causing me to wad up. I wearing sweats that day and they naturally follow my leg tumbling
down the track leaving my ass naked in the dirt..literally since I don't wear underwear. Scared the
shit out of the enter too...the leg, not my huge appendage.
Got towed all the way back to the pits by an ATV and figured the engine was toast. After cussing for a bit, look things over and notice the spark plug had backed out and fallen out.
Screw in new spark plug, race the second moto. Crazy thing was first moto was 9 am and second moto 4 pm. Lotta sittin round that day.
Several weeks before I had put one of those new snake pipes on, it dumped the exhaust straight into the ground in front of the rear brake pedal and as I stared at the belly of that beast laying on its side I saw that the exhaust was jammed with dirt! Fred frantically dove for a screw driver and started gouging the dirt out of that stinger/silencer, several others ran to the line to try and hold the race as I pulled a Dungee and tried to gather my attitude and get into race mode. Of course that smoker was loaded up and once she fired from another push it smoked out the pits as I raced to the line. This was a flag start and I was also friends with the starter Bob Bell. He gave me more than the 2 minute limit holding up the start and from the far outside as soon as the CZ cleaned her guts out Bob finally threw the flag. Me and my adrenaline pulled a huge holey and I never looked back. I got that trophy, the trophy girl and possibly the best night of my life!
In 2009 when Ryan pounded his own dirt plug into his 450's silencer (at Atlanta?) from a wreck I knew immidiately what his problem was and was screaming at RV & Williamson threw the TV, a personal flash back of 1976... somewhat ironic.
Well I cased it really hard two or three laps in a row. The right hander after it had a longer down hill double that is kind of flat on the landing.
I land off of that thing and my bike makes a weird noise, the engine seemed like it was revving more then it should have been.
I hit the whoops right after that and it does the same thing. So a turn later there is this big table top that launches you pretty high but has a pretty steep transition on the face. I hit the face of it and almost fall off the back of the bike.
The damn frame broke right underneath the steering stem!!!! Antifreeze was pouring out and it was a big smoke trap. I hop off and the bike is wide open since the throttle cable got stretched and luckily I shut it off before the thing blew up.
Got a brand new frame from Yamaha. And sold it right after that.
Ryan crushed everyone like he normal did but rode by to see if I was alright after the moto.
Racing a LACR GP I went in hard in a bowl turn the front end locked up sending me over the bars when I picked up the bike the front tire had rolled off the rim and the tube was still Inflated!! it looked like a cartoon wheel had to pop the tube to move the bike!
Post a reply to: What was the oddest mechanical failure you've had during a race?