(Ready to) Race Against The Machine

[chevaliernoir]

Today; I took engine head and cylinder at work to measure how flat is the gasket surface.
That was interesting. KTM write that the maximum allowable flatness deviation (sorry, I do not know the exact wording, but I'm quite sure it is understandable)
is 0.1 mm on the cylinder head, and also 0.1 mm on the cylinder.

I checked first the cylinder head.
I found that it's quite flat except a kind of "hole" of 0.04 mm deep, exactly where was the leakage, a a kind a "bump" of 0.02 mm nearby.
So flatness is 0.06 mm wish is considered acceptable by KTM, but the relation with my head gasket blown is quite obvious at is was less pressure on that area.

The cylinder side was better with a flatness around 0.02 mm

So my understanding is that the issue does not really come from the gasket (even if I imagine there are many different qualities) but the cylinder head flatness.
Thin gasket would not solve it.

So I decided to make it flat by myself (It is the first time I do this for a cylinder head)
I install grinding paper on a glass table (to be sure it is well flat, and spend time in moving the cylinder head on this making "8" movements... during a long long time..

[video]

[/video]

By the way, I finally decided to start by "500" paper in order to really remove material, then "800", then "1000" then "2000" then "5000" to have a mirror state.
Tomorrow, I will measure again the flatness, and see how it is improved or not.

 

[chevaliernoir]

Oh, One thing more I want to share with you.

I discovered that the piston shaft clips were not in the correct orientation (made in India...) as the open side of the clip should be downward.

I removed the clip on the right side. The shaft was free to move on 1 or 2 mm but no more.
I removed the clip on the left side. The shaft went out easily on this left side.
Strange, no?

 

[chevaliernoir]

You know what? I'm happy today.
I measured the cylinder head and cylinder flatness.
The result is 0.01 mm (maximum allowed by KTM is 0.1 mm)
There is no more low point where the gasket blew, and the rest is perfectly flat (I'm not able to measure less than 0.01 mm.
So my technique worked well. I recomand this to anyone that have a blown gasket in order to secure the new setup.

So I'm ready for rebuild!

 

[OpusNectar]

Nice work. Hope reassembly goes without a hitch.

 

[chevaliernoir]

Oh, by the way, I found a note from Wednesday, where I weight the bike before dismounting :
Complete, in full condition to run, with fuel in the tank at the threshold to inform the "Low Level".

In "Road street legal" version (with all lights, licence plate, mirrors...
I found out :
68.6 kg on front wheel
63.8 kg on rear wheel
(so total 131.4 kg)

This means between 130 kg and 140 kg, depending of fuel level in the tank

OK, I was probably missing some cooling liquid in the white smoke). But the battery was fully charged. Does it compensate?

 

[Lima6]

Awesome DIY work and solution for flattening the head.

Keep us updated

 

[chevaliernoir]

I rebuilding the engine and want to share a "detail" as I lost half day on that so it could be useful for other

My issue was to insert piston (and rings) in cylinder.

KTM uses a special tool, and insert the piston from the top.

I have almost the same toll, but did not succeed to keep the piston rings in place while compressing with the tool, or did not succeed to insert in the cylinder.
The issue is with the bottom ring. It consist of :
- a ring with a U shape,
- a kind of spring.
You can see these two parts while I was dismounting the engine the first time

The spring fits perfectly inside the U ring. That is the way I tried to insert it during half a day....

But this is NOT the way to mount it.
The "spring" must be BEHIND the U ring, like this ::

I hope it will helps.
In any case, I will make a dedicated post about how to solve the blown head gasket, with tips and trick not present in workshop manual, when I will confirm my bike runs again properly.

 

[chevaliernoir]

Today a great pleasure : check the gap on valve, with the cylinder head on the kitchen table.
By the way, all measurement are OK, so tomorrow I can re assemble the cylinder head!

I used this free time to evaluate the variation of volumetric ratio caused by the flatness work on cylinder and cylinder head plans. I estimate to have removed about 0.6 mm material, so the volumetric ratio moved from 12.9:1 to 13.04:1
Not a dramatic change but it goes in the good direction to improve power/torque as long as there is no knock
In any case I still have to perform the complete fuel and ignition tuning.

Just if you are interested in increasing volumetric ration, with the think cylinder head gasket proposed by Chad, for example, of by working on cylinder head flatness, here is my calculation of the volumetric ratio depending of the with reduction you performed :

 

[John390]

stock is only 12.6:1, so if your math tells you its now 13.04:1 that is a decent bump!

 

[chevaliernoir]

stock is only 12.6:1, so if your math tells you its now 13.04:1 that is a decent bump!

Hummm... from your message I realize I maybe did a mistake. Not on calculation, but on stock compression ratio value.

All websites write the standard engine is 12.6:1, as you said.
I took the 12.9 from the workshop manual that states 12.9 (at least in french version. I need to check other versions)

That's why on my calculation, I considered 12.9 as starting point.

So if stock is 12.9, I imagine I reached 13.04
If stock is 12.6, I reach 12.75

So in any case, a nice to have but not a dramatic increase.

 

[John390]

well, 12.6:1, bumped up to 13.0:1 is an appreciable bump.

12.9:1 is not much, no

 

[chevaliernoir]

I forgot to tell you...

when I opened the engine, I found a damaged part :

It is not critical by itself, but it could have been bad if the cracked part felt in the engine.

I decided to mount the same part on the engine (just removing the small broken part)

So have a look, the next time you access the timing chain!

 

[John390]

while I agree that it is probably ok, I would DEFINITELY change that part.

 

[ReidMcT]

I install grinding paper on a glass table (to be sure it is well flat, and spend time in moving the cylinder head on this making "8" movements... during a long long time..

Very nice! It looks as if you put something between the paper and the glass, to keep the paper from moving. What is it?

 

[boogieman065]

I would not install that top chain guide. It cracked in the first place from heat/stress. Installing a half way broken part to your higher compression build seems like you're willing to accept it as a weak point.

Excited to see your final build numbers!

 

[=maz=]

I would replace the broken part...why not, you're already elbows deep in there and it's not an expensive part.

 

[chevaliernoir]

Very nice! It looks as if you put something between the paper and the glass, to keep the paper from moving. What is it?

Hi
There is nothing between the paper and the glass.
It is even important to have nothing soft in between in order to force the flatness.
I simply use tape on each border to maintain the paper not moving.

 

[chevaliernoir]

I would replace the broken part...why not, you're already elbows deep in there and it's not an expensive part.

I understand your concern, and I would also recommend anyone to change it.
If I was close to my dealer and if it had the part available, no doubt that I would have changed it.

I took and accepted this kind of "risk" because :
The screw is (or should) press the metalic part, not the plastic. So in my case it does not change the pressure and anything about the screw.
I think the plastic part was slightly to high on that point, so the screw pressed it, and it cracked when mounting at KTM factory, then the broken plastic part moved when I disassembled.
So my configuration now is better than the original one, as I do not have the risk anymore to lose this plastic part inside the engine.
So what could happen? The only failure mode I imagine now is that the plastic part split from the metal. Then the "guide" would turn around the other fixing screw. No dramatic effect and no short term engine break to be expected.
By the way, I do not consider this part as a guide, as it does not touch the chain, but a protection, in case cam chain tensioner break, to limit the risk to jump cam teeth. But maybe I'm wrong.

Anyway, thank you for your advise, and fore sure, next time I check the valves gaps, I will change the part.

 

[chevaliernoir]

I'm happy. It works !

As I already wrote, I installed, in addition to standard O2 sensor a linear O2 sensor (Bosch LSU 4.9)...



and Innovate LC-2 interface to get the AFR.

I have an AFR gauge at the dashboard,...

but tuning the bike just with this is not convenient at all. also because the tachometer is really hard to read.

I finally mounted a PCV, and modified the harness in order to have accessible TPS signal, Ignition signal (between ECU and PCV, so without the coil high voltage), and AFR from LC-2 interface

I connected these 3 plugs to a data logger I have at work : Vector GL1010

Initially I was expecting to find on CAN the TPS and RPM value, but there is no free running frame with this data. So the GL1010 uses the analog signals.
I configure to measure AFR and TPS every 10ms, and to have a timestamp a each Ignition transition from 0 to 1, so I have a time stamp at each engine cycle and can evaluate RPM.

So I have all data available,

but analyze is not obvious just looking at this :

So I implemented some data filter. for exemple, to analyze the richness in Full load, I filter TPS around 100%, and I obtain a graph of richness Full Load, depending on RPM. Then I know what to adjust.

As I was targeting 12.7 full load, I'm satisfied.
As I use O2 optimizer, the richness in closed loop area is around 14, so it is OK too

Now I want to adjust ignition timing.
I will do it at dyno, in order to add advance full load only if it bring more torque. So it is still untouched for the moment.
I use also ignition for drivability.

Yesterday I was on track. It's a small track, very slow, with only a very short straight line, used also for karting.

I practice here, and stay 95% of the time in 3rd gear. 4th gear only 2 times a lap during 1 second)
There is an effect I do not like, even on standard bike, it is the roughness of throttle response at low rpm, when you are in a curve, and you slightly want to produce a little bit of torque. In such condition I feel uncomfortable, because the engine response is to strong to small grip variation..
So I use the record of yesterday track session, ...

... and select 1 lap only, in order to recognize each curve or straight line.
I highlight here in yellow the conditions when the throttle response is too harsh for me :

I see it is always in the same TPS range, between 6.5 an 13%
In this condition RPM is between 3900 rpm and 6500 rpm
So I will remove ignition advance in this zone, and will test again on track next time if the improvement is enough or not.
Here is my last calibration, then :

It cannot be reused as it is for you because of my custom exhaust and Intake. I still did not tested the long intake that I expect to provide high torque at 7000rpm...

 

[Icehax]

Hello from France.
Sorry for my French accent ("but it's so cute!")
I plan to describe here the motivation, evolutions, and feedback about my RC390.
I will try to update this first post with the complete list of changes done, and link to individual description and feedback (or at least a picture).

So, I'm now 47; long distance rider over the world (on 640 Adventure, then 990 Adventure), and for the first time on modern sport bike (Yes, I exclude my T100R Daytona).
I spend a lot of time in the workshop to build, modify and maintain motorcycle, mainly old ones.
I work in engine management system for motorcycle. It could be usefull!
My motivation for RC390 was to have a bike "Ready To race", where I would save time in the workshop.
Let's face it : I completely failed on this point : I can't resist to modify the bike.

All modifications are lead by the same motivation :
I want the bike optimized for track, but still usable on the road, on a low budget.

I'm not a racer, and my laps time are not competitive, but this is like my school track bike. (I go 5 to 10 times a year on track)
As I want to keep it usable on the road, I have to keep somehow the legal equipment.

So the bike is RC390 from 2015, bought 2nd hand, 7000km, 3700€
It was already equipped with :
- tank grip (from ktm powerparts)
- front/back crash pads
Modification I did :
- Sticker removal
- custom rear light/licence plate/turn indicators
- KTM racing windshield (finally I removed it while going to Tyga front fairing)
- Tyga racing seat
- Tyga belly pan
- passenger footpegs removal
- chain protection removal
- Chinese low cost rear set
- low stroke grip
- Tyres Dunlop Alpha 13
- R6 schock absorber
- "prepared" fork
- Front brake pads
- cylinder head exhaust port rework
- custom exhaust line
- Termignoni muffler
- Power Commander V
- Lithium battery
- Tyga front fairing
- light LED lense headlight "999" style
- custom 3D printed intake
- oversized air filter
- Linear O2 sensor + display

Could come later on :
- smartphone holder integrated in battery cover and fast Bluetooth GPS, for track recording.
- ABS removal
- Radiator change

The nickname of the bike is : "(Ready to) Race against the Machine"
Let's go!

Wow i finally found another crazy guy like me lol. I have a couple of questions for you! Hopefully you'll read this, it would help me quite a bit in my own project. First question, how are you getting all of your data? Im especially interested in the rpm as i cant seem to find the right cable in the diagrams... also how is your afr gauge mounted in the place it is? Id love to borrow the design lol. And last what material is your custom 3d printed intake made of? I'm currently trying to do something similar (without removing the airbox, just a new intake runner like the rc390R one but homemade )