low side crash and throttle response. - Triumph675.Net Forums
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post #1 of 20 Old 08-19-19, 20:57 Thread Starter
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low side crash and throttle response.

Hoping to get some help breaking down a lowside crash at the track.

TLDR: I lost rear traction on my first lap in the first corner and I really don't think it was all me. Throttle response is funny and previous owner crashed it in the same way when he bought it.

So I bought I a 13' 675r track bike to move into the 600 class for racing. I've been riding for 8 years on the street, track days and racing in the 300 class for about a year now. I came across a deal for a 675R and thought it would be a good machine to move up to middleweight. Everyone online raves about this machine, but no one in the paddock in the mid-Atlantic knows anything about them, and they're a rare sight in my short experience. Anyways, my first time on the bike on track the rear lost traction - on my first practice session lap in a hairpin exit corner, and I'm kinda stumped as to why. I'm by no means an expert but I'm not exactly new to this either. I'm usually pretty hyper critical of myself and know when I make a mistake but i'm not convinced this one was all me. Needless to say I was pretty shocked, embarrassed, frustrated and retired for the weekend as my confidence was pretty rattled and I dint need to put anyone else at risk if I couldn't keep it together at pace. Heres the details:

1. First time at Summit Main. Watched a lot of video and did some track walks on a bicycle. Not my first time showing up and racing at a track I don't know. Crashed at turn 1.
2. First time on track with a 600 but by no means my first time on a 600. First time with brembos and Ohlins though ;)
3. Bike is mostly stock minus ergos, crash protection, and a werkes exhaust that is now nicely rashed. 5k miles on the motor.
4. Fresh dunlop Q3+s. Stock sizing. rear was 29psi. This is the setup I've always run on track to start out the day, rain or shine, 40 degress through 100 degrees f outside temps. it was about 80 on track at the time. No warmers for testing purposes.
5. Crash speed was no more than 35mph, inside line. I slid like 2 yards and my bike maybe 8? I'm lucky no one was behind me and didn't take it back out because of it.
6. Tire marks show it lost traction an inch of the center of the tire, so, hardly leaned over. No tire noise what so ever. No warning. No slide. Bike was pitched head on and not turned back towards me like the front lost traction, but it didn't. I felt like I was hanging off a bit, mainly trying to keep the bike as upright as a could while warming up. Honestly, I don't think I could have gone any slower or more cautiously without being borderline dangerous.
7. Bike was in second gear, I was off the front brake and rear, and I felt like I had just flipped my wrist forward and onto the accelerator and it let go, like I hit an ice patch. My plan was to just neutral throttle it late through that corner before joining the race line at turn 2 through turn 3.

Now for the interesting bits. After cleaning up the bar ends in the paddock, my coach noticed that the engine spurts from 0-5% throttle as we took it around the paddock. It sounds like the auto shifter when upshifting, honestly. It feels like you cant tighten up the top part of the chain without disrupting the chasis. like "brarahhhhhh". Almost like a tiny blip and go. There also appears to be a throttle response lag. This old thread describes exactly what I felt happened. https://www.triumph675.net/forum/sho...d.php?t=103010

I also contacted the guy who sold me the bike, turns out he crashed in the same exact way, same corner, same scenario right after he bought it from a Brit who shipped it here, then said f*** it, and sold it to me. Another motoamerica guy mentioned that he was all over the place on the corner, so track conditions could have been at play.

So, looking for thoughts and suggestions. If you think I just suck and pinned the throttle, hey, its possible, but I'm just looking for ideas. I'm still new to the sport, but also have had a lot of different track experience in my first year. I know what it's like to go out in the cold rain on stock tires and keep it upright. I know what its like to lose front and the rear, and also regain it. I was shocked at how fast I was down. The stigma that I'm just not used to the power of a 600 definitely has some merit, and I could have been harder on it than I thought, but I'm wondering if something else here is at play. I've decided to hang it up this season until I figure out what went wrong as my confidence is definitely shaken. My coach seems to think it wasn't all me, but I don't need to be back out there wadding this machine up and taking people out if I can't keep the rubber side down. I'm gonna hop back on an sv650 in the spring until I'm confident I've worked out any issues with this thing.
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post #2 of 20 Old 08-19-19, 23:46
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Did you ham fist it coming out of a corner? If so, welcome to torque!



On a dyno. The 2013+ Daytona makes 40 lbs of torque at 3,000 rpm!
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post #3 of 20 Old 08-20-19, 00:29
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Quote:
Originally Posted by Shamrock View Post
Did you ham fist it coming out of a corner? If so, welcome to torque!



On a dyno. The 2013+ Daytona makes 40 lbs of torque at 3,000 rpm!


Exactly what I was thinking
It may not have been your first time on a 600, but if itís your first time on a triple, itís all the same. Japanese in line 4s donít come close in terms of low end torque and our bikes are more like 1000s in that range.
I have experience riding R6 and recently the ďsupposedlyĒ more torquey ZX6R 636 but itís like riding a 250 until you get to the high end of the rev range, literally.

Iím thinking either that, or a patch of oil/dirt on the track. Thatíll spin the rear or slide the front and give you that feeling of zero resistance and instant sliding youíre describing. Been there and itís no fun at all!

Iím leaning towards the extra torque and maybe a bit twitchier response in on / off throttle scenarios.
A good dyno tune can help that even without significant modding.



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post #4 of 20 Old 08-20-19, 00:32
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P.S.
You say it was your first lap?
Cold tires maybe?


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post #5 of 20 Old 08-20-19, 01:46
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New Dunlops in my opinion are some of the slickest tires you'll ever ride on. However that said have you tightened up your chain slack towards the tight end of spec and the throttle play the same? Even on warm slicks I break it loose exiting a corner in second. So this bike will be a different beast from what you are use to. Again thought there are things to do to smooth out the off/on throttle condition. I mentioned the two biggest the next one that is an absolute must as far as I'm concerned even with a stock bike is a proper custom dyne tune.
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post #6 of 20 Old 08-20-19, 06:55
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Dunlops?


Here's a warming-up lap on Dunlops.



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post #7 of 20 Old 08-20-19, 21:03
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post #8 of 20 Old 08-20-19, 21:48
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I can see it and it works right now. Do you have a blocker?
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post #9 of 20 Old 08-20-19, 22:48
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I can't read Greek so no clue what it said at the end of the video, but, I don't see how that was the fault of the tires. You can see that the front of the bike was in the air just as the rider was coming out of a lean. Too much throttle caused that slide.

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post #10 of 20 Old 08-20-19, 23:39 Thread Starter
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Quote:
Originally Posted by Shamrock View Post
Did you ham fist it coming out of a corner? If so, welcome to torque!



On a dyno. The 2013+ Daytona makes 40 lbs of torque at 3,000 rpm!
Quote:
Originally Posted by ramnakhle View Post
Exactly what I was thinking
It may not have been your first time on a 600, but if itís your first time on a triple, itís all the same. Japanese in line 4s donít come close in terms of low end torque and our bikes are more like 1000s in that range.
I have experience riding R6 and recently the ďsupposedlyĒ more torquey ZX6R 636 but itís like riding a 250 until you get to the high end of the rev range, literally.

Iím thinking either that, or a patch of oil/dirt on the track. Thatíll spin the rear or slide the front and give you that feeling of zero resistance and instant sliding youíre describing. Been there and itís no fun at all!

Iím leaning towards the extra torque and maybe a bit twitchier response in on / off throttle scenarios.
A good dyno tune can help that even without significant modding.



Sent from my iPhone using Tapatalk
Damn I'm embarrassed to say I didn't research torque charts but I'm glad you said something. Found this gem of an chart comparing the 675r to everything else: https://images.app.goo.gl/nBPcs9LWVZ1dDx259

So my mapped r6 essentially was a shit baseline to go off of and doodoo compared the the triple which acts more like a 750 or an 848 evo. +1 for hamfisting it then. That being said shes getting a PCV and map as soon as I find a shop that's worth a damn. I'll play with the chain tension and throttle tensions as well though they pass all the basic tests. One of the drills I work on in the neighborhood and at the dirt track is applying just enough throttle to tighten the top chain line while effecting the chasis is little as possible. I feel that amount of fidelity just isn't there right now and it's way harder than it needs to be on this beast. My brothers 1198 doesn't even punch like this.

+1 for cold tires and shit track conditions. Bunch of offs there all weekend, and the track safety guy "thought" an oil spill was "hopefully" cleaned up there during the riders meeting....like, what? Also should have thrown on the tire warmers when offered but I've never used em before and wanted to get a gauge on pressure changes hot off the track. This is the first crowd i've seen hate on dunlops. Q3+s are all I know and I can get sets for under $200. But like the r6 comparison maybe they're not a good enough tire for the torque? What do 675rs like for rubber?
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