[ace.cafe]

I´ve tried a flat top piston with the ACE head and would recommend it for street use only with hessitations because it did affect the idle rather negativelly. I would need to let it idle above 1500rpm to have an stable idle and it would be very temperature sensitive, meaning the idle would rise by 500rpm or so with hot engine. The benefit was marginally better torque in midrange and about 0.2-0.5hp more power output. With the dished stock piston however the engine idles rock stable under all conditions.

It probably will behave differently when the flat top piston is used togeather with the modded stock head.

You might try retarding the ignition a couple of degrees. It might help that.

[Taurim]

Now that everything is working correctly I have to experiment different intake tract lengths.

In my previous installation I was concerned about the velocity stack being in the way of the air filter intake which may (or may not...) create turbulence.
So this time I tried a shorter configuration : 43mm less than before. The velocity stack length in the airbox is now 40mm.



Weather outside is cold, windy and rainy so I will test that later

I'm curious to see if the autotune will create a very different injection map and if it feels different when riding !

[Guaire]

Now that everything is working correctly I have to experiment different intake tract lengths.

In my previous installation I was concerned about the velocity stack being in the way of the air filter intake which may (or may not...) create turbulence.
So this time I tried a shorter configuration : 43mm less than before. The velocity stack length in the airbox is now 40mm.



Weather outside is cold, windy and rainy so I will test that later

I'm curious to see if the autotune will create a very different injection map and if it feels different when riding !

Very interesting. We'll wait to hear what Mr. AutoTune says!

[Taurim]

Today I tried the shorter air horn.

I started with this map as a baseline. It was correct for the long aluminum horn :



Here is the variation found by Mr Autotune after a 70 Km ride :



More losses than gains... BUT the engine feel sluggish everywhere ! If there is an improvement around 3250/3500 RPM I did not felt it.

I reinstalled the long steel horn you sent me Guaire and reverted to the injection map optimized for the long aluminum horn (length is the same).

Variations after a 20 Km ride are very limited :



There is no doubt about the fact that the engine works a lot better from 4500 RPM with the long horn. Especially since I tried both in the same hour.
I'm not able to tell if there is any difference between the long steel horn and the long aluminium horn.

Now I should try an even longer air horn but the space is very limited at the back of the airbox.

[dexterkane]

Hi guys,

I'm new in this forum and I did not find a dedicated subject to post a first presentation message. So I will start here with a presentation of my "slightly modified" 535 GT 
I own it since  May 2020. This is not my only bike (I also own a Monster 1100s) but fell in love with the look of this retro new bike.
I bought it specifically to modify it to my taste and also as a past time during confinement days here in France  And I had a lot of time to do that so there is a huge number of modifications 
The base is a 2017 Euro 4 model.

Some pictures will be more useful than a long boring text. You will probably guess what I am doing 

This is the July version of my 535 :












And what I removed from the bike at that time



This summer I did a few thousands kilometers. It was great fun but I'm still searching for an engine with more character.

With the new confinement this winter it's time to work on that 

Some before / after pictures :

Intake :




Exhaust :




Combustion chamber :





1.15 mm less height on the cylinder to have 1 mm squish band and a better CR :



As I don't have yet H's performance cam, did Mr Henshaw's trick to the intake camshaft :



And the mandatory Carberry plate :



Reassembly with a modified exhaust tube built from H's Inox exhaust pipe :



And the interesting detail welded on the tube behind the brake pedal 



I used a cheap endoscope to check and adjust intake tract alignment :



It's alive and (not !) clicking  Work remain to be done on the ECU.



That's a lot of wires to install under the seat !



Done ! I added a switch to the right handle bar to command some feature on the PC5 (at the moment : Autotune On/Off)



Compression ratio looks good 
(not sure if the reading is correct, CR looks suspiciously high given what I have done to the cylinder. I thought it would be 9.3 bars and it is a little more than 10.5 bars...)



Time to ride the thing to check everything is OK (it was 4 days ago)... Yes it's good to ride again ! And the GT is pulling better than before 



After the short run, check the spark plug which shows a nice color (not too visible on this picture).



PC5 is starting to generate the Trims from the Autotune/Wideband sensor. It's a really clever thing 
I started with some conservative target AFR (13.6 to 13.2).



What remains to be done :
- I just received my ACE.derottone airbox kit (Yes I was reading this forum long before today  ). The idea is really great But I will probably install a different velocity stack as the one I received is different from 2016 model.
- I think I have found a Performance cam kit in a French RE forum 
- riding the bike to set up a good PC5 map.

That was a long first post 

Hey Taurim, quick question for you if that's OK? Did removing the handle bar counterweights increase vibrations? And where did you get those mirrors from? Thanks!

[Guaire]

Hi Taurim - ACE tells us the velocity stack helps intake at wide open throttle.
  I'll be installing an AutoTune on mine. Is that your AutoTune mounted at the end of the header pipe near the union with the muffler? Dynojet support document shows the AT sensor within a few inches of the exhaust port. I haven't mounted mine yet.
BG

"If your exhaust has an o2 bung (18mm x 1.5), go ahead and screw the included Wideband Oxygen Sensor into this location. If you have to drill a hole for a new bung (mild steel bung included), we recommend doing so before the catalytic converter (if applicable)."

[Taurim]

Hi Taurim - ACE tells us the velocity stack helps intake at wide open throttle.
  I'll be installing an AutoTune on mine. Is that your AutoTune mounted at the end of the header pipe near the union with the muffler? Dynojet support document shows the AT sensor within a few inches of the exhaust port. I haven't mounted mine yet.
BG

"If your exhaust has an o2 bung (18mm x 1.5), go ahead and screw the included Wideband Oxygen Sensor into this location. If you have to drill a hole for a new bung (mild steel bung included), we recommend doing so before the catalytic converter (if applicable)."

A wideband sensor is more fragile than a stock O2 sensor. Especially the one used with the Dynojet Autotune module which is a first generation Bosch LSU 4.2.

MOTEC installation instructions about this sensor for a car : https://www.motec.com.au/filedownload.php/?docid=3524
All the instructions are not easy to follow for a bike !

- Place the sensor at least 1 meter from the exhaust ports to avoid excessive heat (recommended).
- Place the sensor at least 1 meter from the open end of the exhaust system to avoid incorrect readings due to outside oxygen (recommended).
- Place the sensor away from the flame front coming out of the cylinder head and away from areas where one cylinder may have more effect than another.
- If possible, do not place the sensor near exhaust slip joints; some designs allow air to enter resulting in incorrect readings.

...

Sensor Lifetime

Sensor lifetimes are highly dependent on application for example the type of fuel used and the volume of gas flow over the sensor.
Some factors that reduce sensor lifetime are:

...

- Incorrect placement in the exhaust that can overheat the sensor

You can also find some informations here : https://www.wbo2.com/lsu/LsuInstal.pdf


That's the reason why I installed it where it is : no too close from the head.
I'm not using an open end muffler but a muffler with a dB Killer.
The sensor is installed before the joint between the header and the muffler.

The M18x1.5 inox bung is welded with the correct angle (10° min away from horizontal, 15° min away from vertical) and not too much protrusion of the sensor in the tube (aprox 12mm).

You can see it behind the front of the brake pedal.



A welder custom modified my H's inox header to include a bend to have the muffler in the correct position and weld the bung in this portion.


(bung not welded yet)

[Taurim]

Hey Taurim, quick question for you if that's OK? Did removing the handle bar counterweights increase vibrations? And where did you get those mirrors from? Thanks!

The installation is OK, the mirrors are probably as heavy as stock counterweights.

The mirrors are Halcyon 835 : https://classicpartsltd.com/835-streetfighter-bar-end-mirror.html
Small mirrors (7.5cm diameter) with a convex mirror providing a good enough rear view.

You also have the 830 with a slightly bigger 10 cm mirror : https://classicpartsltd.com/830-halcyon-bar-end-mirror.html

[dexterkane]

Thank you, think I may have to get some of these for mine!

Prefer them to the RE ones.

[Arschloch]

The Halcyon stuff is good. I have one of those goggles, first worn by Biggles time proven piece. Nothing can beat it when it comes to riding experience. I know I´ll get stoned now by the FF helmet proponents. 

https://classicpartsltd.com/halcyon-mark-9-vintage-flying-goggles-brown.html

[dexterkane]

The Halcyon stuff is good. I have one of those goggles, first worn by Biggles time proven piece. Nothing can beat it when it comes to riding experience. I know I´ll get stoned now by the FF helmet proponents. 

https://classicpartsltd.com/halcyon-mark-9-vintage-flying-goggles-brown.html

Looks great quality!

[gizzo]

The Halcyon stuff is good. I have one of those goggles, first worn by Biggles time proven piece. Nothing can beat it when it comes to riding experience. I know I´ll get stoned now by the FF helmet proponents. 

Only if you pipe up on the 650 int/GT forum 😉. Don't tell anyone, I get around in halcyon goggles and a black Shorty....

[Arschloch]

Only if you pipe up on the 650 int/GT forum 😉. Don't tell anyone, I get around in halcyon goggles and a black Shorty....

I can't help but it feels like having stuffed your head in a car when riding with the FF helmet around the hills on a RE.

[Arschloch]

Today I tried the shorter air horn.

I started with this map as a baseline. It was correct for the long aluminum horn :



Here is the variation found by Mr Autotune after a 70 Km ride :



More losses than gains... BUT the engine feel sluggish everywhere ! If there is an improvement around 3250/3500 RPM I did not felt it.

I reinstalled the long steel horn you sent me Guaire and reverted to the injection map optimized for the long aluminum horn (length is the same).

Variations after a 20 Km ride are very limited :



There is no doubt about the fact that the engine works a lot better from 4500 RPM with the long horn. Especially since I tried both in the same hour.
I'm not able to tell if there is any difference between the long steel horn and the long aluminium horn.

Now I should try an even longer air horn but the space is very limited at the back of the airbox.

I've extended mine again and there's something to it. I should have trusted my own theory. One horse for sure.

[Taurim]

I've ordered a 1m long 45mm diameter aluminum tube to experiment a little more