The TRX900 Project kicks off

[coxylaad]

Cheers Al, I don't see the point in doing something just to be different, but if there are alternative methods of achieving the same goal (cheaper) I like to explore them!

Croft is expensive because of the noise regulations. they basically have to pay off the locals to keep them happy.
peak season its 175 quid for a week day and 195 on a weekend.

There's a day coming up on the 22nd or 23rd and that's 89 quid.

The TRX belongs on the track - its so much fun.

[Silver]

The TRX belongs on the track - its so much fun.

I'll second that, Doing Bedford autodrome tomorrow. Might be the last one this year for me.

[coxylaad]

We need to have another TRX get together, there's 2 on the road in our group now, with a potential third one in the making

[Silver]

I'll look forward to that.
All the best , Dave

[coxylaad]

Update:

The last track day of the year (i think) happened on Monday, it was cold, and sometimes spitting on to rain, but an awesome time was had by all.

The usual video if anyone is interested:

https://www.youtube.com/watch?v=cz1O_4A ... e=youtu.be


The quick shifter has worked flawlessly since i originally installed it with no further adjustment required. very impressed, I dont believe its a gimmick, when I am blasting out of a high speed corner and I need to hook another gear the last thing I need is to have to be thinking of something other than where the bike is going. with the quick shifter I just pull the level and click the next gear in straight away.

Once again I took the Aprilia Mille with me, this time I told myself I am definitely going to use it this time. I got it out the van and put it along side the TRX in the garage. I never used it. there was some small issue to solve but to be honest it didn't stop me using it. I am just having too much fun on the TRX. Its light its nimble, brakes are excellent, its comfortable, and I feel I can really push the bike.

I am starting to think the Mille is a waste of time. The only critisism I have of the TRX is its a bit down on straight line speed. Everything else is just spot on.

With that in mind I am considering getting rid of the mille, and putting some of that money in the engine on the TRX.

Its currently a stock engine running an open (removed) airbox and big headers.

I am thinking instead of having 2 bikes to play with lets just consolidate and improve the one I love.
There is not a great deal available on tuning a TDM900 as they are just not that type of bike, but I am thinking along the lines of:

937cc JE piston kit
increased compression ratio
carillo rods??
big valve ported head.
cams

I already have a set of 45mm throttle bodies to go on. That little lot should be the pinnacle of what you can do with the 900 engine.

It has to be reliable, as its used as a track bike to its full potential, and seeing the state of engine of the guy who was racing his after it let go makes me think I would like the carillo rods!

The aim here is not really to be massively fast. If I wanted that I could just use the Mille. I want to be able to limit the losses on the long straights to the supersports 600 bikes that knock out 120bhp. At the moment they just disappear in front on my eyes on the straights - check the vid.

This is all dependent on money however. Its a new step for me as I generally always run a stock engine. that way I if anything goes wrong I just have to find another stock engine.

Edit: the video has just uploaded and is processing. will be available in about 20 mins from now (14:45)

[cobbadiggabuddyblooo]

why not look at gear ratios as another option...

THE TDM900 yzf750 TRX850
1st 2.75 2.571 2.571
2nd 1.9474 1.941 1.85
3rd 1.5455 1.556 1.4286
4th 1.24 1.368 1.1739
5th 1.04 1.217 1.03
6th 0.9231 1.083

I'm 90% sure the gears from a yzf750 will fit onto the tdm shafts from all the reseach I've done.
The step from 3rd,4th and 5th on the tdm box is a larger than the yzf gear ratios and 1st is lower than both the trx and yzf so not really as linear as the yzf gears.
A little tweaking on your front/rear sprockets you may find yourself a little closer to them down the straight without compromising your lower gear punch out of the corners.
Lighter weight wheels and some headwork , power commander and larger valves and throttle bodies as you mentioned would compliment things greatly without too much extra strain with oversize piston. The tdm rods are touted by yamaha to be lighter and stronger too by around 20%..
The fun never stops just the cash flow...

[coxylaad]

Hi Cobba,

I already have lighter weight wheels and a power commander on the bike.

Regarding gear ratios, I have altered the final drive ratio and I think its absolutely spot on to be honest.

I think I may just look at the head for now, keep the standard block (and save a pot of cash in the process)
Yeah I seen the Yamaha gumff about the tdm900 rods being lighter and stronger.

If I can limit the loss on the straights to around 10 to 15 meters I am still on for the almost patented 'Coxylaad Block Pass (TM)' on the brakes

[coxylaad]

on a side note - why do these engines not rev to 10k? if its still producing power at 10k then it would be flying

[dandywarhol]

If they breathe better then they'll rev better. The Mille is the same stroke (67.5) so the piston speed will be the same and the Mille will rev over 10,000 so with the right breathing (intake/cam timing/exhaust) then they could be producing more power. Power is directionally proportional to torque, torque done in a shorter time i.e. higher revs will produce more power. Get that thinking cap on, your 45mm bodies will be a starting point, although I would be looking at Carrillo rods for the kind of abuse you're looking at.

[cobbadiggabuddyblooo]

Good video of the track day
Nice open field with plenty of run off..
So was that 5th gear around 190k's down the straight????

[trixynut]

Pretty sure if you do the TPS bypass wiring mod it raided the red line to 10k too.
Motors more than good for it, but it only really benefits a tuned engine.
Search if you need more info: I posted pics of the mod when I eventually figured out how to do it.

[dandywarhol]

You remembering its a 900 with injection Trixy?

[coxylaad]

Yeah its a completely different wiring and ECU setup I have, its running the full 900 ecu injection systems.

Croft is a good circuit Cobba, its been around for a long time, used to host a BSB round until the locals lodged complaints about the noise (don't move next to a race circuit A holes). Yes it was 5th gear, not sure what the speed was I only look at the rev counter. I still have another gear to go, hopefully the increase in power will help me get into 6th

Yes Al that's what I was thinking, the easiest way to make more power is through revs. I know an engine tuner who may be able to help me out with the head work.
Question is, do I go for bigger valves in the head or are the stock valves sufficient?

where can you get carrilo rods from?

[dandywarhol]

I'd say if you want more gas in then bigger valves and porting is the way to go. Might sacrifice some bottom end but if it's horsepower you want then get it in faster and out faster (f'nar, f'nar).

Sandune (Mark) is probably the man to ask. I got a set of his 2mm bigger inlets - waiting for bigger exhausts before I start any port work. Got to say the new valves look the part. I'd be interested to hear from anyone who's fitted a set of his valves to comment on how long the valve clearances stay put.....................

From memory 6th is more an overdrive on the 900 box, meaning you'll lose engine torque, so you might not be able to push through the air as well at speed. You might be better sticking with 5th and raising the overall gearing when you get more power. You'll only really need 1st on the 900 box for moving off I guess. It varies from track to track -some tracks demand a certain gearing to get drive out of a particular corner (especially a quick one with a longish straight after it) to get to the next corner quicker. You looked like you were getting quicker through Clark Esses later in the session, barely knocking off through them.

Reckoned I've got Croft sussed just watching your vids

[coxylaad]

Cheers Al. Clarke Esses and Barcroft are my favourite part of the track. mega fast corners and it takes some stones to keep the throttle wide up.

Although I think its possible on my bike, my right hand refused to comply

still umming an ahhing about what to do. Maybes I should give the Mille a chance. Its not that heavy I suppose, it just feels massive compared to the slim TRX