What did you do today? Cobba's rebuild

[cobbadiggabuddyblooo]

Next task out of the way and fitted the quickshifter switch. I used an old vacuum line I had lying around and slipped the 2 switch cables inside the vacuum line for added protection and used a 2 pole water resistant connector to patch it into the ignition adapter loom.
This way I can easily isolate the switch without going into the program to turn it off .
I can alway plug in an Unterminated female connector so there are no active pins open to free air to earth out and cut the ignition signal
I mounted the speedo sensor on the forward caliper mount too and that tidied up the rear caliper tucking it out of view under the swing arm.

[cobbadiggabuddyblooo]

I dropped the motor out of the bike once again and removed that pesky copper head gasket for the last time..
STUPID IDEA using a copper head gasket on a water cooled motorcycle as I could never get a good seal no matter what I tried short of o ringing it.
So should have gone with my own original idea right from the start and saved all the dramas so this arvo I removed the motor to make things easier and took the head off again.
I used 2 copper head gaskets as a jig with the std MLS gasket between them with showed the 0.25mm radially I needed to remove.
I used a flapper to take the material from the std gasket and all turned out good. Measuring the bore size of the gasket I now have 0.1-0.2mm larger than the cylinder bore so all good.

[alextrx850]

I've seen those talented lads doing time trials competition on V8 engine building, clearly they know what they are doing and have done it a few times..

[cobbadiggabuddyblooo]

Very happy with changes made over the last couple of days and no fluid leaks to date... time for an early morning run up the mountains tomorrow to put it through its paces.
Revised the ignition map once again with more advance from 60% throttle sorted the huge fueling / torque dip from 4000 to 6000rpm on my dyno run the other day.
A little homework on the structure of the Std 100 point TRX map opened my eyes to a simple mistake.
I'm sure those with Std motor / pipes / FCR's would benifit from a little more advance on 60-80% throttle from 4,000 to 6000rpm.
Right where you twist the throttle to 100% and coming into peak torque. But the std trx curve on 100 point mapping with its advance peak is only at 100% because of the CV carbies. The TPS is reading 100% but they still rely on vacuum so they are not instantainent like FCR's. TPS reads 100% but the slide is still rising via vacuum.
That's why you need to advance 60 and 80% for FCR's in incriments up to 100% in that midrange peak area.

O2 sensor put back on today and was pretty close with the 162.5 mains at WOT from 4500rpm to 9000rpm it's sitting pretty at 12.5 slowly rising to 13.0 at 8500 onwards.
I just had to move the clip from the centre position with it reading high 10's -11's on partial openings. I settled on 3rd from the top (12-13 AFR) as 2nd from the top found it hunting for fuel.
Look forward to the dyno day read out as I'm keen to try an A-B test with the 2 cans I have.

What put me onto this was the map I put in the ignition had a different TPS calibration so partial throttle gave me a more advanced timing than what was programmed.
Just before going for the dyno run, I re calibrated it to the correct voltage readings and riding to the dyno, I noticed I'd lost a lot of response.

[cobbadiggabuddyblooo]

A good 160km travelled today with a healthy sports riding session up to the top of Mt Mee and back again . No weeps from the head gasket and the motor performed finally to my expectations.
I'm keen to do an A-B run next with the current ignition setting compared to using the Std TRX map just at -4 on the correction.
This will give me an idea if I can run a little more advance down low or if I need to run more advance on the lower valued TPS settings in this area...
I just want to find a little more response between 2000-4000rpm.
It makes it so much easier having the 2 ignition units as I can swap them around while out riding to see if I'm barking barking up the right tree.

[Kevtrx849]

A good 160km travelled today with a healthy sports riding session up to the top of Mt Mee and back again ..

I was wondering why all the helicopters were focused on Mt Mee yesterday morning. You must be pleased now that it's all back together. Great riding weather at the moment.

[cobbadiggabuddyblooo]

Too fast for em now Kev...
Get a sore neck when riding now looking up and above...
Yes more than happy with the bike now , it's no longer letting me down, just my back is now...
Next project soon is the Nomad.. The grey one...

[cobbadiggabuddyblooo]

Good article on swing arm bracing and chassis flex...

http://motodna.net/motogp-tech-talk-swingarms/

[cobbadiggabuddyblooo]

Latest edition to add in the coming weeks is a Scotts steering damper to fit above the steering stem on the top tree.
Ohlins where producing the same item under licence a few years back.

Plenty of options on settings allowing a 25 point low speed damping/resistance plus a high speed valve for those sharp spikes and a sweep motion setting which allows your damping to work within whatever angle from the centreline you want. So you can set in a narrow sweep that still allows you to move freely when negotiating traffic or tight u turns.
I won't need to dial in much, if any low speed but the hi speed is perfect to keep things tracking a little better when opening the throttle especially 2nd and 3rd gear out of corners.
The sports bike version (which have R stamped in on the top plate) also has a rebound circuit built in too compared to the dirt bike version.



Perfect explanation of all the functions on the U tube site below..
Hi speed circuit is a set n forget and the low speed can be dialled on the fly. The little rubber pointer lifts off the knob so once you set a base setting, you can lift off the rubber pointer and set it to 12 o'clock so if you change it at all while riding you always know where your base setting is as a reference...

https://www.youtube.com/watch?v=yq690nLCjIs

.

[cobbadiggabuddyblooo]

http://motorcycleinfo.calsci.com/Airboxes.html

I think I may have added this link on a previous thread but it probably explains why so many found a dip in their torque curve around the same RPM range with the FCR's .

I'm hoping to sneak in another dyno run next week before the dyno day to get a reading on the new mapping.
O2 readings show good improvements around that 5000rpm zone from last months dyno result so if I find gains I'll be happy.
That will allow me to explore on the dyno day the influence from the tray/air box I made up so I'll be keen to run with the tray/airbox removed and just the open bell mouths under the tank to see how that influences things.
In the mean time I'll take some air temperature readings under the tank with and without as a comparison too.

[craybait]

The airbox is very interesting when you read the article, The chap in Melbourne whose name you gave me that has a motorbike shop and used to race a TRX said the airbox he built for his made a huge difference but was difficult and time consuming to make. He used more colourful language.[Have lost the note with his name] I did not ask if he had a template unfortunately

[cobbadiggabuddyblooo]

Last week I was just running the bell mouths no filters or box and could smell fuel when I opened up the throttle in the 2000rpm to 5000rpm area.
Found plenty more power over the last week adjusting timing in that RPM zone and I can't smell fuel when I crack the throttle open now.. .
So be interesting to see if I can feel any restriction again in that 4-5000rpm area with the cobba box back on.

With the box back in place I'll take a few air temp readings of with and without the box.
The air box all be it a little rough at present is made from an aluminium base and 2mm rubber sides re enforced with aluminium.
Doesn't give 100% seal but it's pretty close and a prototype.
What it does though is it gives me an idea on volume and how to incorporate the snorkel to give me the velocity and neutral pressure in the overlap/rpm zone.
I just set the 2nd ignition unit up with a little less advance in that area so I can do an A-B test tomorrow.

[Killerwhale]

Last week I was just running the bell mouths no filters or box and could smell fuel when I opened up the throttle in the 2000rpm to 5000rpm area.
Found plenty more power over the last week adjusting timing in that RPM zone and I can't smell fuel when I crack the throttle open now.. .
So be interesting to see if I can feel any restriction again in that 4-5000rpm area with the cobba box back on.

With the box back in place I'll take a few air temp readings of with and without the box.
The air box all be it a little rough at present is made from an aluminium base and 2mm rubber sides re enforced with aluminium.
Doesn't give 100% seal but it's pretty close and a prototype.
What it does though is it gives me an idea on volume and how to incorporate the snorkel to give me the velocity and neutral pressure in the overlap/rpm zone.
I just set the 2nd ignition unit up with a little less advance in that area so I can do an A-B test tomorrow.

If success post the numbers up and i´ll try em out on my old TCIP

[cobbadiggabuddyblooo]

Intake air temperature readings...
Ambient air temp 20*c and cloudy weather conditions the same over the last 2 days...

Today....
Cobbabox with bell mouths / no filter
Air intake Temps average between 28-30*c through traffic and while spirited riding up Mt Nebo (445m) and Mt Glorious.(599m).
( water temps 75-80*c / oil temps 65-70*c) and would max at 32*c when back in traffic and stuck at lights for a couple of minutes ... Water temps would rise to 92*c.

Yesterday..
No Cobbabox just bell mouths / no filter under open tank.
Air intake temp average between 38-42*c with same water / oil temps as above and would rise to 45*c + when stuck in traffic as above.

So The Cobbabox is giving me much cooler air feed into the carbies.
Cooler air is denser in oxygen than warmer air so more fuel/air can atomize together = more power.

Quickshifter really came into it's own especially into those tighter 2nd gear corners exiting running up to 4500rpm and short shift into 3rd doesn't unsettle the bike on the exit ...

Still finding gains with the programming. I can run down to 1500rpm in traffic and roll on the throttle with a smooth acceleration and no need to feather the clutch or stammering for that couple of seconds until you got over 2500rpm like before.

Next I'll check the O2 readings again to see if my a/f reading have leaned up a touch in the lower and mid rpm range.
Good thing being winter here now means come summer the mix will only get richer so if I find a base now once the programming is done. I can take air temp and O2 readings again come spring/summer and change my jetting accordingly.

[cobbadiggabuddyblooo]

The airbox is very interesting when you read the article, The chap in Melbourne whose name you gave me that has a motorbike shop and used to race a TRX said the airbox he built for his made a huge difference but was difficult and time consuming to make. He used more colourful language.[Have lost the note with his name] I did not ask if he had a template unfortunately

Don Stafford
He had a pretty competitive 110+ HP TRX and having the OVER dealership here in Oz, the world was his oyster on performance parts...

With only the bell mouths under the tank and no Cobbabox, it seems a lot of that cool air coming in from under the tank is being sucked straight out the sides of the tank via Venturi effect with the air rushing past the bike.( the window down in the car trick to draw out the stink when someone farts )
So to balance things, it draws the hotter air from below and around the motor to fill the void and ultimately feed the carbies..