Yamaha TRX850 Enthusiasts Forum

bike has been great for last 6000 klm,
did the second oil/filter change since putting the iridium plugs ,and would not idle,or rev, running on one pot.Pulled the plugs and the left one was sparking weakly out the side from the start off the isolater.
Went to auto barn after checking this forum for the right ngk old fashioned plug $6 each and it is running well again

You actually get a slightly stronger spark from your $6 plug but don't have the longevity.
The thing that sells the iridium plugs is they are supose to last 50,000km+ and set and forget right from the box and should not be altered. I had 1 fail at 500KM from new and have heard of others suffering a similar fate to you and I.

Me too. Lasted about 5000 or so, then both died within a week of each other.

I think I put my iridiums in six years ago or something ...
Still in there last I looked.
Fuel mixture (running rich )..building carbon on the electrode would be the one to watch for.

My bike is running a bit rich,the chap that sold the spark plugs said in turbo cars they[iridiums] don't like carbon when they run rich.A yamaha trained mechanic in Perth told me they are rubbish but I had already ordered them,so gave them a crack
So that was interesting,I was worried i might be running lean with over exhaust and k&n filter
Hoping to put the fcr's on soon now I have a TPS kit from germany that killerwhale suggested have to get the little shaft turned down to 7 mm with a slot for the spring,fortunately my mate has returned who has both a lathe and knowledge!

Just stick with the stock 142 mains on the std carb as the Trx run rich anyhow.
138-140 mains are a common choice for the Trx.

Can everyone say what brand of iridium plugs they have tried? When they first appeared the general consensus was the Denso ones were pretty good, but the NGKs were rubbish. But the Densos cost more, so hardly anyone bothers with them..

Also, I'm running 136 mains with the clip at the top of the needle. 50-70MPG has been achieved, but by gum it's lean. Cannot recommend, if only for the peace of mind

alextrx850 wrote:I think I put my iridiums in six years ago or something ...
Still in there last I looked.

We must have bought the same ones…i replaced mine years ago, because they looked old.

Snod Blatter wrote:Can everyone say what brand of iridium plugs they have tried? When they first appeared the general consensus was the Denso ones were pretty good, but the NGKs were rubbish. But the Densos cost more, so hardly anyone bothers with

I've also NGKs.
I tried a Denso plug in my Tricker but after ordering it took forever to arrive.

Rod.s wrote:

alextrx850 wrote:I think I put my iridiums in six years ago or something ...
Still in there last I looked.

We must have bought the same ones…i replaced mine years ago, because they looked old.

Same here!