Yamaha TRX850 Enthusiasts Forum

Found time earlier this week to get the bike onto a rolling road dyno. I asked for just a single run to establish a baseline for my planned engine mods over the coming months. Very pleased with the price at an inclusive £20.

I chatted at some length to the owner,Paul. It turns out he raced a Trx around a decade or more ago, he showed me his dyno charts all kept neatly in a binder with other details.
His produced 90bhp on this same dyno when it was fully developed,so it will be interesting to overlay our respective power and torque curves when I have modified my engine. His spec was;878cc,ported head,FCR's and Akra 2 into 1. I didn't ask about it but he mentioned that he felt the breather mod was worth almost 2 horsepower.
As I will be aiming for a stronger midrange rather than outright power at the top I think 90 horsepower on this dyno with my planned mods may be more than I'll manage.Anyway,it'll be good to have targets to aim for.

The power and torque curves below are for a well used 1996 850 with 38000 miles.It is presently standard except for ART cans fitted with dB killers.

It made; 56 lb-ft @ 5898 rpm
72.78 bhp @ 7924 rpm








Mark

mine was 82 hp with a set of crumby harpoon cans, and a k and panel filter theres a dyno print out somewhere on here....with like 10,000 miles..


oopssss 77.6 bhp at wheel.... heres the post from a few years ago.. i never did post the print out dunno where its gone now though...

viewtopic.php?f=27&t=4855&hilit=+dyno

My `stock` and a little tired motor was logging 88.1 at the last check, dynoed in 2010, with just mini cans on stock headers and the FCR`s Mark. You SHOULD see in excess of 90.

Mark

Can you confirn that Tagg are at the following address please?

Tagg Racing
Unit 11, Old Surrenden Manor
Old Surrenden Manor Road
Ashford
Kent
TN26 3DL
Tel: 01233 820601

The Tagg website appeared to only detail kart stuff, not bikes?

I am looking for a recommended local (ish) dyno where I can get my TRX set up once Santa has delivered my FCR's.

I will post the BHP and Nm plots once they are done; JE878cc, Akro headers, Devil end can.

Many thanks

Phil

Interesting and healthy chart. Always worth noting where max power and max torque are so you can ride accordingly.
Just a freeflowing pipe with cans, fcr41s and pod filters showed 89.5 on my otherwise standard motor.

Phil,

Yes,the address and phone number are correct. I would recommend without hesitation, I only had the one dyno run but I liked the proprieter and got along well with him. I understand he is an ex-BSB mechanic and having raced a Trx he knows where we are coming from .

My "almost" 73 horsepower sounds a little low,but,I'm not at all disappointed.It's just a number and at the moment is not really relative to anything.Perhaps the dyno is a little stingy,maybe it's ultra accurate,but if I keep using it, I'll be able to measure real gains(or losses ) Riding home from the test I was changing up at 6 and it felt plenty fast enough for the conditions.It has confimed to me that I am looking to produce a broad range of torque that can be accessed every time I ride without spinning the motor up to 8000. The sort of torque that Dandyworhol's bike is producing is very impressive and is the type of delivery that I need to aim for.
Thanks for all your comments.

Mark.

sanddune51 wrote:Phil,

It's just a number and at the moment is not really relative to anything.Perhaps the dyno is a little stingy,maybe it's ultra accurate,but if I keep using it, I'll be able to measure real gains.

Mark.

So true, all Dyno's vary and the figures quoted are as you say "just a number". I am looking forward to the progress you make, well done

Mine was much the same when stock .. Coming in at 70,8 then after after a little work getting 73 and finishing off back at 76.74hp at 7200rpm and 59.86 ft/lb at 6200rpm.. At 80,000 km and just staintunes with no baffles n K@N filter in the air box .. Like you say it gave me a starting point .. With the FCR's n 2 into 1 system and bell mouths I'm up to 86.71hp and 62.16 ft/lb Oddly enough producing 73hp at peak torque . The main difference I noticed was the difference with the rear tea strainer in the can between 2500 and 4000 rpm could be up to 10 hp with only 1 hp difference ultimately to top end readings

I had mine done when I fitted my new ( ish ) engine

73.26 hp @ 8600 revs 50.5 ft/lbs @ 6400 revs .........

Have a look at some of my older posts. When the bike was first dynoed, it was showing less than 70bhp through crappy jetting - making just under 80 when the Akra was added.

In the end, I got it up to 102.3 - all done on the same dyno.

That's why mine started at 70.. Crappy jetting and new needles n tubes ... If I can get the laptop running again I'll try to post the results

This discussion prompted me to contact a local dyno operator to indicate the likely cost of set up for my 878 TRX with FCR's.

He simply suggested that the TRX was alright in its day, that it is 'old school' and that I should buy a TL or an SV unless I want to get eaten by everything else thats out on track????

Not quite the response I was hoping for; think I'll take my cash elsewhere...................

Told him I've already got an SP1 and that to me, the TRX is more fun than the Honda on track. Will be even better with an extra 10hp..................

Takes all sorts.

How strange,I've also got an SP1 Looking to get bar risers for it as the riding position on the road at legal speeds is murdering my neck and wrists ,but would be fine on the track. The thing is, it's a bit minty and I'd surely cry if I binned it . I've done track days with the Trx and have no such qualms. As far as dyno time goes, I'd be taking my money else where.

If Ashford isn't too much of a treck,I'd be happy to meet you there to see your bike being dynoed? Let me know.






Mark

Crikey, I got a castrol painted honda too. Must be catching!
Dave

Hope you guys aren't using Yamalube!