278 replies to this topic

[JBX]

There is an atmospheric pressure sensor, located beside the main fuse, and the intake pressure sensor, located on the fuel pipe of the throttle bodies assy (near the fuel pressure regulator).

[frits44]

Yes i will try it when I get the chance Frits, the next time I remove the tank for maintenance probably

 

I think most of us have seen already many modifications to the airbox. Some of us have maybe had a vehicle which required that the original airbox be unmodified because alterations and changes caused worse performance.

 

However, i do also feel that our bikes, like many others, have the capacity to make a lot of noise and that is, as far as EU legislation goes not permissible. !  Hence why i think the airbox has such a massive volume of air inside and a relatively small air inlet.

 

But that also asks the question - why did Yamaha fit a restrictor in the airbox when they made the airbox flap. They say that it improves low speed running....but many of us disable it to get the bike to run better, so is the flap also there to act as a noise reduction device when driving at low to medium speeds in towns and cities ?

 

I suspect there may be benefits and disadvantages either way, and I have considered , many months ago, buying an airbox off ebay just for the purpose of modifying it and seeing if it made much difference.

 

Good morning fixitsan,

 

I did read your story again, and the noise in my filter now is very low only when I hit the throttle for full power I can hear it better.

 

I am sure that YAMAHA did make a construction failure with the design of the air box cover.

 

JBX air box mod we all did, after that we took out the air flap, and is was still not good.

 

So that also make me think that the cover of the air box is not good with the small inlet.

 

Do not forget that a TDM 900 engine needs a hole lot of air, and wen it needs air free airflow is the best way.

 

But thats the way I am thinking.

 

Have a nice day,

 

Greetings, Frits from Holland

[fixitsan]

Yes the way I see it is that we have one half of a 4-cylinder 1800cc engine, and that needs quite a large air intake. Partly due to having more frequent intake strokes, but partly due to the volume of air sucked in on each downward stroke.

 

At 3600 rpm that's 60 intake strokes per second (2-cylinder = 1 intake stroke per revolution), at 450cc of air for each intake stroke, is 27 litres per second at full throttle, through the available opening in the airbox cover.

[fixitsan]

So the airbox arrived..... I got to it, cutting out the flap mechanism and taking some of the top off....but then i tested the fit against the underside of the tank, and noticed that the foam seals all around the airbox under my tank fit very well to the airbox cover, so the only way for air to enter is towards the rear of the tank

 

To that end, there's no point taking plastic off the top, if you have a foam seal like mine, just cut the back wall off the cover and all is well.

 

So I have the top cover pictured, a K&N filter (didn't realise that till today) and 2 long snorkels, because I removed the short one from the existing airbox and fitted the long one which came with the new airbox.

 

Is it better ? I would say so, the roll-on feeling is smooth, the engine feels more responsive, and when I open up the throttle my butt dyno says it definitely goes better.

 

 

 

I turned the CO to 40/40, which was pretty good but still a bit uneven, so i restored the difference of 8 which i originally had and now have CO set to 40/32, which is smoother than 40/40

Edited by fixitsan, 18 December 2016 - 06:32 pm.

[muddy]

Interesting. My bike is getting on in years and has seen better days, so I'd be willing to hack at airbox if it means an improvement and as long as its not detrimental. A simple fix always appeals, I couldn't be doing with all Power Commanders and other electrickery.

[fixitsan]

Interesting. My bike is getting on in years and has seen better days, so I'd be willing to hack at airbox if it means an improvement and as long as its not detrimental. A simple fix always appeals, I couldn't be doing with all Power Commanders and other electrickery.

 

if you have access to a hole saw you could probably drill three large holes in the area marked with green dots. If you dont like it then the discs which were removed could easily be fixed back with some ABS cement

 

 

I'll run it like this for a while, to get used to it, then change to a pair of shorter snorkels to see if it matters, or how.  Traditionally shorter stacks are better for peak power, longer ones better for torque....but in this case the shorter ones  have a straighter path for inlet flow too, so it could be interesting

[frits44]

So the airbox arrived..... I got to it, cutting out the flap mechanism and taking some of the top off....but then i tested the fit against the underside of the tank, and noticed that the foam seals all around the airbox under my tank fit very well to the airbox cover, so the only way for air to enter is towards the rear of the tank

 

To that end, there's no point taking plastic off the top, if you have a foam seal like mine, just cut the back wall off the cover and all is well.

 

So I have the top cover pictured, a K&N filter (didn't realise that till today) and 2 long snorkels, because I removed the short one from the existing airbox and fitted the long one which came with the new airbox.

 

Is it better ? I would say so, the roll-on feeling is smooth, the engine feels more responsive, and when I open up the throttle my butt dyno says it definitely goes better.

 

airbox1.jpg

 

airbox foam.jpg

 

 

I turned the CO to 40/40, which was pretty good but still a bit uneven, so i restored the difference of 8 which i originally had and now have CO set to 40/32, which is smoother than 40/40

 

Good morning fixitsan,

 

So you did it too, I told you if you give your TDM 900 more free airflow so it can breath better and easier  he would run better.

 

Many people in my country remove the foam at the bottom of the fuel tank  I think it does not help enough.( without cover mod.)

 

My CO has now 50/50, I measure it in my end exhaust value is 4.75 %.

 

Here in my country the value for CO goes from 3.5%  too 6%, lower than 3.5% co is too lean 

 

 

I can use my rpm from 1500 rpm too max rpm without problems. no jerkey no nothing I am still very glad with this mod.

 

Nice too see that you are doing it too .

 

Look out that you do not make the inlet too big it is very noisy with a big inlet you have now when you hit the throttle.

 

I know because I did test ride without the cover too try.

 

Greetings, Frits from Holland

[Catteeclan]

I was thinking of using a hole saw as that's what I've used on car air boxes. Glad to here you think it's smoother, the extra mid range boost which I was sure would come is just a bonus.

 

As those unifilters seem to be hard to get here I was also planning a couple of pod filters. I'll wait till the spare box arrives before buying anything else.

Edited by Catteeclan, 15 May 2016 - 08:29 am.

[fixitsan]

 

Good morning fixitsan,

 

So you did it too, I told you if you give your TDM 900 more free airflow so it can breath better and easier  he would run better.

 

Many people in my country remove the foam at the bottom of the fuel tank  I think it does not help enough.( without cover mod.)

 

My CO has now 50/50, I measure it in my end exhaust value is 4.75 %.

 

Here in my country the value for CO goes from 3.5%  too 6%, lower than 3.5% co is too lean 

 

 

I can use my rpm from 1500 rpm too max rpm without problems. no jerkey no nothing I am still very glad with this mod.

 

Nice too see that you are doing it too .

 

Look out that you do not make the inlet too big it is very noisy with a big inlet you have now when you hit the throttle.

 

I know because I did test ride without the cover too try.

 

Greetings, Frits from Holland

 

 

Noise ?  I wear earplugs. I prefer the safety aspects....

 

Yes it is noisier, but then I removed too much, but also I left all the foam around the tank so it helps keep it from being too loud.

 

I didn't realise I already had a K&N filter in the airbox, so the intake system was breathing better, which explains maybe why disabling the flap didn't seem to make too much difference.

 

Next for you Frits, advance the ignition timing a few degrees, you will enjoy that just as much.

I was thinking of using a hole saw as that's what I've used on car air boxes. Glad to here you think it's smoother, the extra mid range boost which I was sure would come is just a bonus.

 

As those unifilters seem to be hard to get here I was also planning a couple of pod filters. I'll wait till the spare box arrives before buying anything else.

 

 

I'm sure you'll figure it out.

 

I want to try this setup using both shorter snorkels next, but I need a few more miles first. I'll keep you posted with that because I think there will (should be) a difference

[frits44]

Oke fixitsan,

 

It is good too hear you like it.

 

The K&N filter I do not use  I find it too noisy and the price is not good € 90,00 in my town.

 

Thats why I use the NIPPARTS filter J1321029, less noisy much better than the stock filter and only € 15,00 in my town and it fits perfect.

 

I do not know how too, advance the ignition timing a few degrees ????

 

Greetings, Frits from holland.

[fixitsan]

The ignition timing can only be moved by modifying the pickup coil mounting, which is located above the alternator inside the left side engine cover. The sensor needs to be moved towards the rear of the bike.

 

I have cut slots in the pickup coil mounting holes on my bike. like this

http://www.carpe-tdm...=32724&p=330529

 

When the bike leaves the factory it is set up to run on the worst available type of fuel without suffering from preignition, or 'knocking' ...generally this is retarded ignition for good quality fuel.

[frits44]

THANKS I will look in too it.

 

Greetings Frits

[frits44]

Look what I found.

 

Programmable ignition or injection.

 

http://www.ignitech.cz/en/

 

I do not no It.  

 

Maybe you do

 

Greetings, frits

[fixitsan]

Yes. Programmable ignition units cannot be installed on the 900 (but can the 850) because all ignition is controlled by the combined injection/ignition ecu.

The best and cheapest replacement ecu is called 'microsquirt'.

[frits44]

How do you disable the air induction system from a TDM 900????

 

You do not need it wen you have half open or open exhaust.

 

If you shot it down you will have less air in your exhaust and less gas explosions 

 

Good for stock exhaust not good for open exhaust.

 

I did read this:

 

http://www.fjrforum....howtopic=106119

 

I can not find it for TDM 900 .

 

Greetings, Frits from Holland

[fixitsan]

[attachment=8050:AISpipe.jpg]

 

[attachment=8051:AISfull.jpg]

 

 

I just blocked the pipe, with thick piece of plastic film....easy to fit and remove (just for testing) no need to remove the airbox

 

The exhaust gasses pull fresh air into the exhaust through the AIS system.....in older times we would prefer to use all the exhaust gas 'momentum' to empty the cylinders and draw in fresh intake mixture - just another way to think about it

AIS is very good for catalytic convertor efficiency, without it I think the catalyst could more easily be poisoned

Edited by fixitsan, 18 December 2016 - 06:33 pm.

[frits44]

AISpipe.jpg

 

AISfull.jpg

 

 

I just blocked the pipe, with thick piece of plastic film....easy to fit and remove (just for testing) no need to remove the airbox

 

The exhaust gasses pull fresh air into the exhaust through the AIS system.....in older times we would prefer to use all the exhaust gas 'momentum' to empty the cylinders and draw in fresh intake mixture - just another way to think about it

AIS is very good for catalytic convertor efficiency, without it I think the catalyst could more easily be poisoned

Thanks for your answer,

 

I will block the pipe too or take it of complete.

 

Many thanks.

 

greetings, Frits from holland

[frits44]

So I did the job today,

 

I took of the air induction system, because I do not need it.

 

I have half open exhaust without catalytic converter, there for it is useless.

 

I only gives you  fresh air in your exhaust that you do not need with open exhaust

 

and it creates gas explosions in your exhaust.

 

So I believe that it is better for my system, and now I also can measure my CO much better.

 

Here are some pics:

 

http://s1175.photobu...html?sort=3&o=0

 

Tomorrow I go for a test ride.

 

Greetings, Frits from Holland

[frits44]

Today I did a test ride,

 

Yesterday I took of the complete air induction system because I do not need it on my bike.

 

I have half open exhaust without catalytic converter.

 

Before I took it of  there was sometimes a little explosion in my exhaust.

 

Now its gone.

 

You can also fix it by blocking the pipe in your air box like fixitsan did above this message.

 

Greetings, Frits from holland

[frits44]

I forgot to say,

 

If you block the air induction system, you now can measure your CO in your exhaust pipe very easy 

 

With the air induction system on and with open exhaust, there will be to much air in your exhaust

 

and that is not good to measure your CO.

 

Greetings, Frits