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scottzx7rr

Dang These Motors are tough

10 posts in this topic

Well I got to find out this past weekend how tough these motors are. I had a race Sunday at the local track, mind you I race Harescrambles. I was working on the bike Saturday night and have a local neighbor kid(about 10yrs old) that loves to help me. With winter here I was changing out the water/antifreeze out and placing new in. So I drained it, and explained how fill it up and put the cap back on to him. Leaving him to do it while I was doing something else. So I get to the race ran practice and instead of doing my normal checks before the race I relaxed a little.

The course was almost 6 miles long. It was a great course. Race starts and with a first turn crash in front of me I am relegated to last place, my buddy is in front of me. So we hook up and start working our way through the class. We work our way up to front(so I have been told top 5) when on the fifth lap I started to notice a little chugging at times. It only got worse as the next two laps wore on. I was going from 3/4 gear to 1/2 and no power. Well I am about half way into my 8th lap when I had to stop. Big ball of smoke coming out of the exhaust. I sit for about 10 minutes fire her up and ride it back to the pits. I crack open the radiator to find her dry. I added engine ice and water. Made a call to the neighbor to find out he didn't put anything in the engine. When she got filled up there was oil or something else that came out, so I am pretty sure the head gasket is shot, but will know more when I pull the head. But she ran a total of 50 miles without a drop of coolant at race pace(average speed was 22mph, gotta love those trailtech computers, LOL)

On that note anyone know of a good place beside Eric Gore for top end work? As I know I will need to replace atleast the valve springs and seals for the head.

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It is amaizing that it went that far! You may want to replace the rings and inspect the piston, cylinder and wristpin as well. Sometimes the rings will loose their springiness when they overheat (I don't know if the rings in this bike will or not) and if the piston and/or wristpin is blued then you may want to replace them for fear of them being weak from the heat. Good excuse to redo the top end though! :)

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I am going to go through the motor this winter, just not this early. LOL I am replacing all the bearings also.

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Scott, just for the record...what oil were you running? Bonus question... are you still gonna let that kid help you work on your bike???

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I only run Mobil 1 15W-50 in all my bikes. When I checked the fluid level I also checked the oil, and looked just like new. Very little contaimination. And yes I will still have him help me. I can't or willn't be mad at him. In the end it is my responsibility to check the bike and I didn't. I was going to rebuilt the bike anyway this year so it just moved up the schedule a little. LOL Besides it is probably payback for all the pain that I caused my dad on his race cars when I was younger. LOL

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Scott; I commend you on your patience with the 10 year old kid. Without realizing it, you've probably made a big difference in that kid's life. Not long ago I also had a teenaged kid stop by my garage one evening to ask for assistance with his YT180. The kid only had his mom and needed help with his bike. I spent nearly a whole Saturday going over his bike and getting it to run well. He started hanging around anytime he saw me working in the garage and learned alot about working on his own machine. His mom called me a couple of weeks later and thanked me through her tears about how much of a difference I had made in his life. She said he had turned from being an angry and cynical young man into a happy and optimistic one. He simply needed someone who cared enough to give him some time.

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I appreciate the words. Thanks.

I agree with you about the youth of today needing someone that is a mentor/role model. If more youths had them there might not be as much craziness going on right now.

Besides he is my excuse for rebuilding the bike. LOL So I told him that he did me a favor. It allowed me to have a excuse for spending all the money with the wife getting upset. LOL

I agree also about that is what motorcycling is all about. Great friends, great riding, and great clean(maybe not so clean on a hot dusty day, LOL) fun.

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Hey Scott,

Why do you want someone beside Eric Gorr to do the head? He is by far one of the best motor guys around.

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Hey MXTuner,

It wasn't that I wanted someone else to do the work as I agree he did several of my Two-Strokes and I was very pleased. I was just looking for some others to compare.

Motor Update:

Well I got lucky, the only damage that I have found on the motor was a cracked head gasket. I tore down the motor this weekend and the only damage was the gasket. There was no scoring or damage anywhere, gotta love that Mobil 1 Oil. Heck the cross-hatch from the 420 bore job was still present. The rings were still within spec(.001 wear) but I am going to replace anyway. I should have the girl back and running within two weeks. I am going to replace the valve springs and anything that needs to be replaced when I start doing the head work next weekend and then assemble the next week.

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