Yamaha TRX850 Enthusiasts Forum

I've just fitted the Ignitech I purchased from Overlord Neil and everything is fine apart from small throttle openings. I've set the TPS and I'm using the standard TDM850 map and all seems good except when opening from a closed throttle where I get a hesitation and a small backfire. Once on the move it all appears good but this backfire and what feels like a slight misfire keeps happening even when up to temperature. The carbs are rebuilt with standard airbox and venom cans and the problem does not occur with the stock ECU......any ideas folks please.
Cheers Rich

Coils, maybe?

It sounds similar to the problem I was getting a week or so back. Replaced the coils and it's running like a new bike.

Are you sure the TPS works properly?
With TDMR40's carbs, it was the other way around; fully opened was registered as closed and vice versa.

Tarwetijger wrote:Are you sure the TPS works properly?
With TDMR40's carbs, it was the other way around; fully opened was registered as closed and vice versa.

I assume it is, I got 0.64v at 0% and 4.13v at 100% readings when I set it up.
Just seemed odd that there is no hint at any problem with the standard ECU fitted.

I am interested in what transpires with this topic.
For reference, my setup (from ignitech) is very different from the standard TDM graph. Mine has a bump max at 37 and drops again as revs go higher.
TDM stays flat at 32 if i remember correctly.
My main upgrades on which my setup is based are airfilter, exhaust and 6 Sigma jetting. Maybe send the factory a mail and ask them for a setup. (worth a try - maybe Cobba will know if they will oblige)

Just been out to have another look. Changed the TPS for a spare I had (just in case) re-fitted the Ignitech and went through the set-up process again.....still the same problem, it's almost like it doesn't want to run properly until the revs increase to over about 1750, before that it's like it picks up on one cylinder and then the other one chimes in just after with a little backfire, from about 2000 rpm onwards it's fine.....any ideas?
I've re-fitted the stock ECU and it runs ok now

What RON fuel are you using..91 The IGNITECH map runs best with 95-99 RON.
Std TDM/TRX 850 IGNITECH map has the 37* midrange hump AND drops back to 35*.

cobbadiggabuddyblooo wrote:What RON fuel are you using..91 The IGNITECH map runs best with 95-99 RON.
Std TDM/TRX 850 IGNITECH map has the 37* midrange hump AND drops back to 35*.

Hi cobba, last time I filled up it was Shell V-Power which I believe has the higher RON rating. It's almost like the right hand cylinder is cutting in a split second after the left followed by a pop from the exhaust but it revs cleanly from 1100rpm with the stock ECU.
Cheers
Rich

Try looking at your throttle % 0n the program when connected to your PC , Look at where and when you have the misfire.
EG.... 30% throttle at 2000rpm
Go to your 100 point map and retard the timing at and either side of 30% throttle 2000rpm point to create a smooth transition and see how you go.

cobbadiggabuddyblooo wrote:Try looking at your throttle % 0n the program when connected to your PC , Look at where and when you have the misfire.
EG.... 30% throttle at 2000rpm
Go to your 100 point map and retard the timing at and either side of 30% throttle 2000rpm point to create a smooth transition and see how you go.

Cheers cobba I'll give it a go at the weekend.

By either side I mean 20% and 40% throttle.
If no luck try a little advance..

Problem solved I downloaded the programme from the Ignitech site to my other laptop, plugged into the box and went through the set up process again, read, verified and programmed and it works fine, no more misfire low down and runs a treat......happy days

all's well that ends well....