Track day on standard NX4

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Racer-unk
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Re: Track day on standard NX4

Post by Racer-unk » Wed Mar 14, 2018 7:10 am

Track is Aldo Scribante in Port Elizabeth. Not resurfaced in years and the track surface is quite abrasive?

I do agree that consistency beats wild riding any day, but you must learn the limits before you can become consistent.
I am improving....(know this by having less off track excursions) but have room for improvement. Changing the gearing to suit the track will certainly help.
That's on the cards when I do the wheels.

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Re: Track day on standard NX4

Post by cobbadiggabuddyblooo » Thu Mar 15, 2018 1:53 pm

One of the lads posted a good video on one of the TRX Facebook sites of a small tight curcuit ( 3 sisters?? In the UK ) and perfect to show limitations as he was going really well, found the next guy to overtake in his sights and the next couple of corners you can see him pushing harder and the way it was impacting on drive out of corners and under steer until he overstepped the limit of the rear suspension and low sided the front out of a corner when the arse end squatted. It was one of the faster corners on the curcuit so bike would have been close to peak torque.
Trx was std suspension just 5mm shorter dog bones.
Good video to watch as a learning tool.
Moral of the story, suspension is the key .

Be mindful too lower gearing = a little more acceleration and further stress in the rear suspension.
I'd suggest taking a few shorter dogbones sets in your next track day ( 10mm and 12mm ) as a cheap simple easy mod to feel how it impacts on limitations and handling.

What sort of top speeds are you making fown the straight???
You want to look for close to peak HP ( 7500 ) in top gear by the end of the straight.
My local curcuit is about 3km long and 220kph down the main straight . 1St time out I ran 17/40 but never used top gear so went down to 16/41.

You see so many people get close to the limit and blame tyres and think , I'll fork out $500 for a set of Pirelli supacorsas. Spend $500 on the suspension and see just how much further you can push your old tyres first. Bridge stones and dunlops give great feedback through the tyres so you can feel when your getting close to the edge. Michelins and Pirelli not so much feedback and will let you know when they have had enough so you need to read the tyres once off the bike each session.
Pretty well all sports tyres now can be pushed pretty hard and sort your suspension you'll get much better wear from whatever tyre you choose so it will only save you money.
laughter is the best medicine

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Re: Track day on standard NX4

Post by cobbadiggabuddyblooo » Thu Mar 15, 2018 2:44 pm

laughter is the best medicine

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Racer-unk
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Re: Track day on standard NX4

Post by Racer-unk » Thu Mar 15, 2018 3:02 pm

currently 22,5mm dropped front
170mm dogbones
slow rebound on rear
Front-end done as well as I can....pretty please with it, bar the outstanding fork brace. (springs, emulator, drilled, my custom original rebound adjuster and 20W oil)
Still travels all the way....

Currently have 16 x 39 gearing and want to go to 16 x 41 gearing as I change to 5th too late on the straight.
Power is standard till I can get a spare head to up Comp and flow a bit.
Maybe later this year look for secondhand FCR or equiv.

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Re: Track day on standard NX4

Post by cobbadiggabuddyblooo » Fri Mar 16, 2018 6:50 am

With the rebuilt rear shock that should compliment things well and look forward to hearing how things go.
If your still finding limitations, look at trying a few different riding styles as perviously suggested to find that extra couple of %.
I did a similar thing about 4 yr ago after the major chassis changes. ( late brake, vs corner speed. Up against the tank compared to against the tail, etc )
I know now when I do my track days I usually focus on 1 item. Footwork or body position for example to find that happy medium on performance, handling and comfort, longevity.
That's the fun I find in my trackdays now, just that fine tuning to find that little more in certain sections and not about going hard looking for consistant fast times. I'll slow down too just so I can overtake where I want and pounce instead of fighting for the apex... :lol:
Following a Tz250 or similar through corners is a perfect way to get a handle on corner speed. :wink:
Maybe that's my body just telling me something... :lol:
Like you said earlier sometimes you have to push to the boundary to see if it will move but I think I've set mine. :) . I'm happy with the fast 1.06 time around Lakeside and Averaging 1.09's. There is no hope in hell I'll get close to 10 seconds faster with the likes Mick Doohan , Troy Bayliss around Lakeside. :riding: :riding: :r1p: :riding: :nakedbike:
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Re: Track day on standard NX4

Post by Racer-unk » Fri Mar 16, 2018 7:43 am

Cobba...what is your take on going 180 on the rear. I have not ridden a TRX with a 180 fitted, so dont know the difference.
I personally dont think the bike has enough power to worry about traction on a 160 rear. Will a 180 on a 5.5 rim make the turn in tardier?

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Re: Track day on standard NX4

Post by cobbadiggabuddyblooo » Fri Mar 16, 2018 12:38 pm

160/170 works quite fine and it's not until you start pushing well over 90hp plus that you need to even think about a wider rim and 180 tyre.

Simple little things like getting an intereference fit on the bolts that hold the rear shock and dog bones Inplace in the relay arm will help those 1 or 2% your chasing to help prevent the manifestation of rear wheel chatter hard under brakes when on the edge. I used some 0.002" shim plate cut and rolled to tighten the pin fittment in the sleeve that runs in the shock/dog bone bearings. Previously with the rear wheel in the air, I could grab the swing arm and get close to 5mm movement up and down and all was coming from the sloppy bolt fittment in the bushes and that was with new bearings, bolts and bushes. Yamaha models through the 90's where notorious for this from factory even when replaced.

There are a few excellent sites that show how to read tyre wear with photos for reference on setting compression, rebound, geometry and how that impacts on tyre degradation and pressures with hot and cold tear. You'll definately find different settings from previous with the new rear shock so monitor the true each session. Just be mindful , Too slow on rebound in the rear will only keep the rear squatting longer out of corners and aid in under steer and running wide out of corners too.
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Re: Track day on standard NX4

Post by dandywarhol » Sat Mar 17, 2018 2:10 pm

Strange one - didn't sound like he was on power when it happened.
1996 TRX 850, blue, Ohlins 46HRCLS, Race Tech Gold Valves, 0.90 springs, Venom pipes, R6 brakes............
1974 Yamaha RD250A, Candy Blue
1998 Yamaha SZR660, blue of course
1967 Yamaha TD1C 250, Blue and white

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Re: Track day on standard NX4

Post by cobbadiggabuddyblooo » Sat Mar 17, 2018 3:07 pm

Split second just before the front end lets go you can hear he just starts to roll on the throttle.
Because he's just carrying speed through the corner and suspension has settled, there's no real braking compression on the front end to counteract the transfer of weight to the rear and enough to unweighted the front end.
40kph 2nd gear around 4000rpm so obviously geared down possibly 1 on the front up 2 on the rear so plenty of acceleration. Looks like that long double apex corner he came down in just trying to sneak a little more between the 2 apexes but was already carrying enough speed to catch the next rider... You could see in the last lap especially he stepped up from 9/10ths to 10/10ths.
Looks like a really fun track and be a good work out and take a lot of concentration especially 10 minutes into it with no real time to just rest for a couple of seconds.
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Re: Track day on standard NX4

Post by Racer-unk » Tue Apr 10, 2018 9:56 am

Went for official race practice past Saturday.....crapped myself when i loaded the bike afterwards. Rear tyre had cracked almost all the way around on the one side.
Same tyre that lost air on the previous outing....and again this time.
I fitted a new tyre yesterday,for this coming Saturday (race day), and read the warning sticker on the new tyre for the first time.
Now, I know not to re-use an old tyre if it has been lying around for a year or more. (no blueing or any other bad signs)

Some people use Supercorsas on their road bikes, but surely it is not a good idea unless you live in a warm climate and ride the bike constantly.

Anyway, i had a decent practice day, but have become very wary of the squatting issue with the old un-serviced rear shock.
I have become very conscience of the bike settling after heavy braking, before i tip the bike into the corner. Just be patient getting onto the power early.
Practice mate said he could see the bike squat in certain corners....although it feels more evident to me in other corners.
Best I take it easy Saturday, and.....maybe I get a nice surprise when I get the shock serviced.... :D

I an desperate effort I contacted a local gent who serviced our Enduro bike suspensions, but he has unfortunately retired permanently.
Will have to wait till after Saturday to send the unit away for service.


All's well that ends well...... :!:

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Re: Track day on standard NX4

Post by cobbadiggabuddyblooo » Tue Apr 10, 2018 2:25 pm

Just a change of riding style to suit the needs, brake just a little earlier and carry a bit more corner speed instead. Lorenzo was a master of this when racing his Yamaha.
I changed from point and shoot to corner speed and decided to stck behind a compeditive Tz250 on a practice session and followed the line. Doesn't feel as aggressive and flows a lot easier with confidence and so much easier to focus on other things like foot and body position.

Hope things go well with your next session, just don't get too greedy on the throttle out of corners ... :lol: :lol: you can alway change just the spring rate through your suspension mate until you find someone to rebuild it.
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Re: Track day on standard NX4

Post by Racer-unk » Mon Apr 16, 2018 12:59 pm

First Race day for the year has come and gone. Could not believe it had been 6 months since my last race. ridden the bike on 4 occasions this year, but a race is different. The start and first three corners are hectic and dangerous.
Considering the state of my rear shock and the fact I have to fly away for business on Thursday, I approached the race-day with caution.

Race 1,..... I had a great start only to back off and go wide into turn one as i watched two guys narrowly avoid taking us all out....lost many positions. Recovered, only to have a guy pass me on the inside of the first corner on lap two and go straight off the track. By now I am annoyed. Anyway I settled down and had a nice race with two other blokes. No great laps seeing I was been held up in certain areas. Big horsepower bikes can just pull a bit on the short stretches to make your late braking difficult. (well safely so)
A mate of mine lost his front brake lever on a pretty fast section approaching a tight turn...well he hit the tyres but walked away unhurt and hardly any damage to the bike. His pride...well that's another matter..... #-o

Race 2 ...not keen to ride seeing bike becomes loose-ish when rear shock warms up....anyway, real bad start due to too many revs and a bit of brain fade.....
First time I ever botched a start, but it had to happen sometime. (note to myself....... [-X )
Second last into turn one....then pass two more with aggressive dive into turn two....just had to get pass the slower riders otherwise I lose too much ground to the people i want to challenge. Chase down for a lap and half and then the fun started...three of us having a blast.
End the race with big smiles all around...just great fun.

Asked after the race, I was asked if i got tired, and I just responded...."I too much fun to think about getting tired"


Allswellthatendswell...............

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Re: Track day on standard NX4

Post by coxylaad » Mon Apr 16, 2018 1:56 pm

cobbadiggabuddyblooo wrote:Just a change of riding style to suit the needs, brake just a little earlier and carry a bit more corner speed instead. Lorenzo was a master of this when racing his Yamaha.
I changed from point and shoot to corner speed and decided to stck behind a compeditive Tz250 on a practice session and followed the line. Doesn't feel as aggressive and flows a lot easier with confidence and so much easier to focus on other things like foot and body position.
I found this out last year. Braking that touch earlier so you can let off the brakes earlier and glide through the corners makes everything seem much less rushed and intense. I will point out I am not racing, and you may get done on the brakes riding like this but I found it dramatically improved my lap times and general control of the bike.

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Re: Track day on standard NX4

Post by coxylaad » Mon Apr 16, 2018 2:17 pm

Racer-unk wrote:First Race day for the year has come and gone. Could not believe it had been 6 months since my last race. ridden the bike on 4 occasions this year, but a race is different. The start and first three corners are hectic and dangerous.
Considering the state of my rear shock and the fact I have to fly away for business on Thursday, I approached the race-day with caution.

Race 1,..... I had a great start only to back off and go wide into turn one as i watched two guys narrowly avoid taking us all out....lost many positions. Recovered, only to have a guy pass me on the inside of the first corner on lap two and go straight off the track. By now I am annoyed. Anyway I settled down and had a nice race with two other blokes. No great laps seeing I was been held up in certain areas. Big horsepower bikes can just pull a bit on the short stretches to make your late braking difficult. (well safely so)
A mate of mine lost his front brake lever on a pretty fast section approaching a tight turn...well he hit the tyres but walked away unhurt and hardly any damage to the bike. His pride...well that's another matter..... #-o

Race 2 ...not keen to ride seeing bike becomes loose-ish when rear shock warms up....anyway, real bad start due to too many revs and a bit of brain fade.....
First time I ever botched a start, but it had to happen sometime. (note to myself....... [-X )
Second last into turn one....then pass two more with aggressive dive into turn two....just had to get pass the slower riders otherwise I lose too much ground to the people i want to challenge. Chase down for a lap and half and then the fun started...three of us having a blast.
End the race with big smiles all around...just great fun.

Asked after the race, I was asked if i got tired, and I just responded...."I too much fun to think about getting tired"


Allswellthatendswell...............
Sounds like a mega adrenaline rush. I sometimes think I would like to race, but then think better of it :lol:

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Re: Track day on standard NX4

Post by Racer-unk » Mon May 28, 2018 3:10 pm

Well this past Saturday i had a terrible day at the track....long front wheel slide and left the track,then rear on two successive laps on an oil spill spread by overnight soft rain. that was qualifying which I and a few others just aborted.

Race one ....was OK, bar the numerous neutrals and failed shifts.
Race two ....I DNF-ed after leaving the track twice with the bike in neutral. (that after watching another rider's chain fly over my head on the first start)
Race three I ....tightened the entire shift mechanism and helalueyah....had no false neutrals......they were replaced by involuntary shifting of gears...the last down shift was when i dipped into a fast corner and not surprisingly left the track again after having to pick the bike up mid corner. I calmly rode back, loaded my bike and headed for the pub. Should have gone to play league bowls instead.

Anyway....now to make a longer gear lever and change to GP shift. Fortunately I can do this and retain my Push-type Quickshifter.


all's well that ends well..... :)

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