TRX 916

Post by **Max** » Fri Sep 07, 2007 3:13 am

I think the TRX is limited to around 100hp simply because it cannot rev higher. If you try, you better have a one piece machined titanium crank and wear a titanium cup.

Six speed boxes can be made from YZF750 parts, I looked into it a long time ago, major headache and expensive. I've always wanted an extra gear between third and fourth.

Quan-Time · Post by **Quan-Time** » Fri Sep 07, 2007 5:38 am

you sure that the crank wont handle more power ?

you would be surprised.. I suspect its quite capable of more. But the inherent design of a V-twin, or rather a 270deg crank requires too much overhead power.. such as balance shafts.

Also the 5v adds more strain on the drive line because of extra resistance on the cam.. thus 4v is a very good balance.

I do strongly believe with some mods and what not (internally) it is quite possible to hit more than 100hp, YES you need to free up some rev, and there in lies teh problem..
I read somewhere that someone took out both balance shafts to get extra RPM.. it worked.. at the cost of the bike making your hands numb from the vibrations.

there HAS to be a way to make it spin more freely..

6spd from a yzf ? wouldnt a TDM 6spd be more... effective ? since its the same case ? should be VERY close to fitting.. once again, ill have to have a look at it... if i get some time..

cheers.

Killerwhale · Post by **Killerwhale** » Fri Sep 07, 2007 5:57 am

Quan-Time wrote:you sure that the crank wont handle more power ?

you would be surprised.. I suspect its quite capable of more. But the inherent design of a V-twin, or rather a 270deg crank requires too much overhead power.. such as balance shafts.

Also the 5v adds more strain on the drive line because of extra resistance on the cam.. thus 4v is a very good balance.

I do strongly believe with some mods and what not (internally) it is quite possible to hit more than 100hp, YES you need to free up some rev, and there in lies teh problem..
I read somewhere that someone took out both balance shafts to get extra RPM.. it worked.. at the cost of the bike making your hands numb from the vibrations.

there HAS to be a way to make it spin more freely..

6spd from a yzf ? wouldnt a TDM 6spd be more... effective ? since its the same case ? should be VERY close to fitting.. once again, ill have to have a look at it... if i get some time..

cheers.

We will see, a Swedish guy is building a turbo kit on his and aiming for 160hp

Post by **Max** » Fri Sep 07, 2007 6:11 am

I checked the ratios of the TDM six speed a couple years back, not what I needed for the track. What's needed is a closer top three gears to keep it in the torque curve. I ran longer gearing so I wouldn't over rev too much in 5th at the end of the straight but paid for it by widening the gap between third and fourth.

HP figures do come more from RPMs. The only way to match figures with a low reving engine is more displacement and compression, but then you are stressing the bottom end.

At least, that's my take on it.

And another thing. It ain't all about numbers. If you want to go really fast in a straight line, buy yourself one of those ugly Hayabusas or something.

Post by **phuk72** » Fri Sep 07, 2007 7:53 am

Max wrote:I checked the ratios of the TDM six speed a couple years back, not what I needed for the track. What's needed is a closer top three gears to keep it in the torque curve. I ran longer gearing so I wouldn't over rev too much in 5th at the end of the straight but paid for it by widening the gap between third and fourth.

HP figures do come more from RPMs. The only way to match figures with a low reving engine is more displacement and compression, but then you are stressing the bottom end.

At least, that's my take on it.

And another thing. It ain't all about numbers. If you want to go really fast in a straight line, buy yourself one of those ugly Hayabusas or something.

I agree with all of that

kebab19 · Post by **kebab19** » Fri Sep 07, 2007 8:57 am

Maybe 120 @ the crank instead of rear wheel? Sounds more plausible....

Sp!ke · Post by **Sp!ke** » Fri Sep 07, 2007 1:09 pm

I'm not so sure...Yamaha were claiming 115rwhp on the Sonauto Dakar YZE850 bikes (where the trx engine was developed).

That said, the engines were swapped every night so longevity wasnt really an issue.

H1 · Post by H1 » Fri Sep 07, 2007 5:52 pm

Hi!

120HP (crank) at the laaks is correct... the video tells about proved HP!
6Speed: As i told a year ago... my german friend Huby is still trying to build it up... YZF doesnÃƒâ€šÃ‚Â´t compare, R6 nearly but doesnÃƒâ€šÃ‚Â´t TDM doesnÃƒâ€šÃ‚Â´t ... so he is on the way to build an own with some helping hands

we will see ... also under construction is 878 cc and cam shafts... but at the moment the project waits for some parts (6-Speed)... i will tell you if there are reults

One of our TRX has 97 HP standard! Modification only TDMR40 and BoS-Racing

The Laaks 916cc dontÃƒâ€šÃ‚Â´t work a longtime the engine crashed often! Only for race Version! The man behind (Idea) to build it up was "Klacks" Leverkus a crazy

german guy who loves such experiences... The video is such a one of "to must have"

Ciao!

Heinz

devlin · Post by **devlin** » Sat Sep 08, 2007 12:21 am

If you went back to a balanced 180 degree crankshaft, wouldn't you be able to get rid of the balanace shafts. Obviously then you would have to get a whole new came shaft set up to match the phasing. I know it wouldn'y have the 'V twin' feel or sound but it would aloow the crank to spin up faster. How much money would it all take though?

Greg · Post by **Greg** » Sat Sep 08, 2007 8:49 am

devlin wrote:If you went back to a balanced 180 degree crankshaft, wouldn't you be able to get rid of the balanace shafts. Obviously then you would have to get a whole new came shaft set up to match the phasing. I know it wouldn'y have the 'V twin' feel or sound but it would aloow the crank to spin up faster. How much money would it all take though?

So there might still be some use

for the 180 deg TDM crank and cams I bought 3 years ago then lol...

Actually, one of the guys at Poole Motorcycles remembers someone racing a TRX years ago - apparently whipping out the balance shafts is worth some HP as well as (I assume) helping the motor spin more freely as a result of less rotational mass.

Greg

Post by **Kevtrx849** » Sat Sep 08, 2007 3:08 pm

Don Stafford of Staffords motorcycles in Victoria done the full Over conversion on his TRX which included taking out the balance shafts. Made it spin up quickly but made it unusable on the street. The article is posted on this site under "TRX ARTICLES."

TRXHooL · Post by **TRXHooL** » Sat Sep 08, 2007 7:01 pm

Quan-Time · Post by **Quan-Time** » Mon Sep 10, 2007 3:28 am

Its possible to take out the balance shafts, but it does have a tendancy to make your arms numb after a short time (so im told) but obviously does allow the motor to spin up more freely.

You gotta remember what the engine was originally designed for. Its not a flat out performance motor.. Sure we would like it to be, but you should know that a good ol TRX can equal, in some cases beat a R6 around the track. Yes R6 has more hp, but it has way less torque which you can use to your advantage. On a race track the trx is quite lacking in many aspects, but its the thrill of the ride.

After saying all this, 160hp is possible with a turbo, hell, i suspect 200hp is possible before something goes bang.. I suspect it will be the piston melting or possibly the rods bending. Dunno how the stock head bolts will hold up.. MIght wanna get some high tensile ones incase they stretch too much. Actually, dont do it to a stock motor.. get some uber parts.

devlin · Post by **devlin** » Mon Sep 10, 2007 4:06 am

TRXHooL wrote:Above magazine article

Roughly translated as?

CULater · Post by **CULater** » Mon Sep 10, 2007 9:15 pm

We have several members who race (or raced) their TRX (and TDM)
The engine don't like reving over 10.000 tpm.
It also break down when the balance shafts are removed.

The BotT (Battle of the Twins) championship winning TRX back in '97 had 105 Bhp. (had lots over OVER parts in it and was blueprinted by a Yamaha technician) It lasted the complete season, the

biggest problem they had during the season were the rearaxle bearings
they couldn't handle the power.

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