Went to a nice track in W. PA yesterday. Although it rained for most of the morning we had 2 or 3 nice sessions during the day. SLF 951 from here was there again and this time brought his NSR so I could see it. He didn't take it on track though for fear of scaring some of the beginners, at least that's how I understand it. I just wish one of us had thought to take some pictures of the 2 bikes together - they definitely looked like long lost brothers.

Because of the rain I didn't wear my original Rothmans leathers most of the day, but did during the last 2 sessions. The track photog quit before I went out so there's no really good shots. Maybe next time.

At the end of the day I ran into some trouble with the bike unfortunately. When I got off the gas at the end of the front straight (full throttle through all gears), the rear tire was locked up. I managed to grab the clutch and coast to the side of the track where I thought I would find the engine seized solid. It turned over with the kickstarter and I told the cornerworker I wasn't sure what happened. He and I talked for a minute and I said that I must have accidentally kicked it down more than one gear and slowed the tire down, locking it up. I started the bike, which ran completely normal, and ran 2 more laps. At the end of the front straight on the second lap, it did the same thing. This time the kick lever wouldn't move and I got a ride back to the trailer on the "crash truck". After a brief cool-down, we put the transmission in 3rd gear and bumped the engine backwards. It turned over easily.

I haven't tried to start it but the plugs both looked normal. Not sure what happened but I'm going to take it down and check unless I discover something else.

Here's some pics:













I'm uploading videos now (nothing spectacular) and will post the links later.

Craig
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Craig
MC21 SP Rothmans
MC21 R fake Rothmans - track bike
MC21 SE R9N

End of a long straight, rear wheel lock up, sounds like a sieze to me.

I don't think you have enough lower gears to lock up the wheel, but it sure would make the motor sing.

You haven't been inside the top end yet so before it spits you off in a turn a tear down is in order I'd say. Hopefully you didn't hurt it too bad and a hone and clean up might be all that's needed. A carb tear down and clean wouldn't hurt either.

Rear wheel locking up twice - that sounds like the piston seizeing and then freeing off, possibly caused by a weak mixture. My advice would be to get the cylinders of ASAP to see what has been happening.

Remember you must identify the reason for the fault, and rectify that.
If you just repair the fault (new piston for example), the same thing will likely happen again.
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Rich
MC21 Track Bike / RS250 NF5 'Spencer', NX5 'Cadalora' & NXA 'Aoyama' / RS500 / Two Brothers Racing RC30

My bike did exactly the same thing in a clubmans race, cracking along end of a long straight lockup in top nearly flat out jumped on the clutch. Freed up after but seized later that day again, freed up again after cooling but needs to be stripped down to see whats up before it grenades.

I did find that my water pump impeller was old and missing a blade - so potentially inline with overheating caused mine. Check the plastic water pump drive gear too they're prone to cracking and failing from what I saw of mine and a spare one. I've since replaced it but ive not had a thorough look at the top end - altho bike starts first kick i'm not going to run it properly until i've checked it out.

I was running premix Castrol TTS 35:1 standard carbs & airbox

Castrol TTS is primarily an injector oil, which is a bit lower viscosity.
If you are on pre-mix with unleaded fuel, Castrol XR-77 is a better choice.
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Rich
MC21 Track Bike / RS250 NF5 'Spencer', NX5 'Cadalora' & NXA 'Aoyama' / RS500 / Two Brothers Racing RC30

craigsutton wrote: When I got off the gas at the end of the front straight (full throttle through all gears), the rear tire was locked up. I managed to grab the clutch and coast to the side of the track where I thought I would find the engine seized solid. It turned over with the kickstarter and I told the cornerworker I wasn't sure what happened. He and I talked for a minute and I said that I must have accidentally kicked it down more than one gear and slowed the tire down, locking it up. I started the bike, which ran completely normal, and ran 2 more laps. At the end of the front straight on the second lap, it did the same thing. This time the kick lever wouldn't move and I got a ride back to the trailer on the "crash truck". After a brief cool-down, we put the transmission in 3rd gear and bumped the engine backwards. It turned over easily.

Craig

You might want to have a look inside that there motor...

After the second time, I was terrified because I knew what happened. If I hadn't been able to grab the clutch both times or if it did it in the middle of a turn, I would have probably gotten a free ride in the meatwagon.

Please keep the discussion to our trackday - I'll start a thread in the appropriate forum for talking about my engine issues. Thanks!

No comments on my matching leathers?
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Craig
MC21 SP Rothmans
MC21 R fake Rothmans - track bike
MC21 SE R9N

Although your Rothmans Leathers look great, they would be the last thing on my mind if my engine had nipped up twice in one track day
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Rich
MC21 Track Bike / RS250 NF5 'Spencer', NX5 'Cadalora' & NXA 'Aoyama' / RS500 / Two Brothers Racing RC30

got to agree with rich,get your spanners out and check your cylinders for damage mate.leathers look good but i would be getting a better helmet
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ive seen more tarts than mr kipling

Yea leathers look great, bike looks great now back to keeping both those things looking great, tear that engine down and see what's up.

lol At the helmet comment.

I'm suprised you can see with what looks like stickers and tape over half the visor.

Nice clean bike though. As everyone else says I think I'd be in there rather sharp ish to see whats going on before you get bitten.
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If I have to take the carbs off once more...

The Rothmans leathers looked the business! The helmet...not so much.

I thought about that picture thing to Craig.... Just a bit to late as well.

Scare the beginers... I think more like scare my wallet!!!

Was a good track day once the rain cleared up and we could get the tires warm.... Craig was really running that thing hard too... And in the Rothmans leathers, to cool, had to follow him a few laps. I did consider bringing one of my extra helmets for him , maybe next time.
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MC21
04 NSR50R
93 CBR F2
98 CBR F3 track bike
95 VFR750
89 FL400R Pilot
90 FZR 4/600

Guys, what's up with my helmet???? That was a Christmas present from my parents after I got my first bike in '91. The day after Senna died I repainted it like his. Does it look like a too-old model, or is it something else I'm not noticing? My wife thinks the yellow should match the bike but that's it. I always have my dad's white Shoei there in case the tech guys want to see a Snell sticker but I think it looks too plain so I always wear mine.

And you'd be surprised how well I can see out of it - I see what I need to and that's it. Ever see a F1 visor? I think they have 1/2 inch of clear visor! haha

The bike won't come apart until I have an entire evening to do it right. I don't want to be doing one thing a day and losing parts and/or my way. There's enough stuff torn apart around here that may never get put back together and this bike won't be one of them! And don't worry, no more running until I'm looking at both pistons and cylinders to find out what's wrong.

Craig

1991!

Dude tell me you're kidding. That helmet should have been put on the shelf by 1996 as it's no longer safe to use 5 years after it's born on date.