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TMC Customs

Crash Investigation

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First of all, it was great meeting some of you at Mid-o on Tuesday and I definitely appreciate the offer to ride the mini's but unfortunately I did not fair well on my last session.  Going into the carousel, something happened with the bike or I made a mistake.  I am really not sure what happened so I figured some of the folks on here would have some thoughts.  At first I thought one of my front shocks gave out, torqued my wheel and pressed the brake pad to the rotor harder than I intended.  This could still be the case and one of the instructors and I were messing with the front suspension 5 laps prior and he said they were in bad shape (definitely should have done some maintenance).  When looking at the video, I am not sure it looks like a front tire skid, it almost looks like a rear tire skid.  I ended up saving it and standing it up but by that time I was headed straight while I was in a curve and tried to keep it as upright as possible in the grass, heading for the barrier, I figured it was better to ditch in the grass than hit the tire wall.  Unfortunately, the pegs, frame slider, handlebars, etc dug and stopped the bike quicker than by body stopped and my thumb got caught up on the bars so I am out for the season with surgery on Monday.

So, if anyone is interested, lets see if we can figure out what happened.  Video is at the following link: https://youtu.be/bVKemjhj6vk

I uploaded the entire lap so you can see if there are issues elsewhere.  It actually looks like I may have had some front slip at around the 1 minute mark.  I am very serious about figuring this out, I don't really want to get back on and repeat the same mistake or have the same failure

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Looks to me like the back slid out first. Did you get on the back brake there? It sure looks like it.

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Going into the carousel you didn't rev match and caught 2 downshifts from 3rd to 1st. Not sure if you hit a false neutral and then tried to get it back into any gear you could (which happened to be first gear according to your gear indicator, I can hear the "clunk" of going into first) and then you let the clutch out pretty quick, your motor wasn't going as fast as your rear wheel at that point and the motor slowed your rear wheel so abruptly it caused a slide (nice save btw).

Rev-matching will help get the motor up to the speed that the rear wheel is going when you downshift and will help prevent slides. However I think most of the issue in this incident is that you went all the way down into 1st gear and let the clutch out quickly.

Edited by TimTheAzn

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1) Slipper Clutch

2) The carousel is tricky and is usually a throwaway turn. There’s only one good line thru there and one so so line. 

As Tim said, that shift sounds wrong and with the bump there in the carousel it’ll bounce you and traction is gone

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6 minutes ago, MidgetTodd said:

1) Slipper Clutch

When I was thinking of getting serious on the track and getting a bike for it, that was mandatory requirement of any of the bikes I looked at.

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25 minutes ago, MidgetTodd said:

It’s great even for street riding. 

Totally agree. The Wing has it.

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Rear wheel locked from downshifting it seems, as said above.

 

Was good meeting you, bummer about the trip to the farm at the end of the day. Your bike looked fine for the most part so I was hoping you got through unscathed as well but it sounds like that wasn't the case. I hope the surgery gets things sorted out and it heals up fast! 

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Thanks for the replies. It looks like the majority believe it was driver error with a downshift and I think you could be right. Some things to consider: the bike has a yoyodyne slipper that I typically use to go from top gear down to second on the back straight I a never get wheel hop or lock up and that is with full braking in front. Also, I just installed the gear indicator and it doesn’t appear to be working correctly. Seems like it is meant to determine gear with rpm and speed but doesnt know what to do with high revs and high speeds. I am guessing the slipper also throws it off

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Have you had a chance to see if the bike runs/shifts through gears normally after the incident? Could be a clutch issue?

I think @blue03636 got thrown on his head into china beach due to a clutch issue?

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When is the last time the clutch has been pulled? Mine was toast and when the slipper caught it was like dumping the clutch. It could also be from going in to first gear, not sure why that was done. It also appears that you are very jerky with inputs and the bike just moves a ton. Might need to work on being super smooth with any input.

Pull the clutch cover and look at the steels to see how they look. If they are fine I would guess it's just from dropping in to first and the inputs not being smooth.

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Like others have pointed out, looks like you locked the rear up momentarily downshifting which upset the bike and caused you to go off track. You pulled the clutch in and let the revs drop down to like 4-5k then let it out too fast. Try not to let the bike free roll like that, get your downshift done quickly blipping the throttle to reduce shock to the chassis. 

 

  • Beer 1

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nothing to add they all hit it on the head... sadly driver input error... just work on being smooth.. and  rev matching it will save you some pain now and as you increase pace

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Oh man!  It was good to meet you, real sorry to hear about the injury.  No need to beat the "reason for the crash" horse to death.  Heal up soon and we'll see you out there again.

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I guess the verdict is driver error which I am actually glad to hear. I can always get better and if I loose confidence in my equipment, I won't feel comfortable out there.  Most seem to say I need to rev match, do you all still rev match with a slipper?

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If that thing has a slipper, it's not working right.

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Also, I don't use the slipper. It's a backup of I screw up.

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It has a yoyodyne slipper with the OEM equivalent clutch plates. This is the first season I have used a slipper so I figured I was doing something wrong. Coming off the back straight, I pulled the clutch, dropped two gears and dropped the clutch...all seemed fine

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On 7/12/2019 at 1:45 PM, TimTheAzn said:

Have you had a chance to see if the bike runs/shifts through gears normally after the incident? Could be a clutch issue?

I think @blue03636 got thrown on his head into china beach due to a clutch issue?

I have not had the chance. Someone at the track started it up, put it in first and pulled it onto my trailer for me. It is still sitting on my trailer. 

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3 hours ago, TMC Customs said:

Most seem to say I need to rev match, do you all still rev match with a slipper?

Absolutely. It’s mechanical, it can fail. 

A slipper is not your go to, it’s your safety net. 

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