Hi all,

the other weekend i installed a DNA filter in my tenere. All went well and i can feel the bike breathing much better. I'm also running an iridum plpug.

But i am now 3 tanks of fuel into the new filter and my f-trip now comes on at 210 miles where is was coming on at 250 miles before hte DNA was instelled.

I ride the same router everyday to work...same rider...same roads...same fuel..nothing has changed.

The idle has not chnaged in any way either.

So is this normal? Should i expect such a drop in MPG?

i will get a kev mod soon but need to do xmas first.

Any ideas please?

Mike

There was a thread about the bike's not running so good on the iridium plug's, i've not fitted mine yet so cannot comment, but might be worth a search

Good point, I would go back to the original plug and try 3 tankfulls as if you make only 1 change at a time you have a chance of understanding the changes.....I found a slight increase in fuel consumtion when I fitted the Stage 2 DNA filter but I think that this was down to a new er even-open throttle hehehe.....

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(Now sold on, sob) 2011 Blue XT660X with gold wheels, was 26,500 km.
Engine mods: K&N Stage 1 filter, DNA Stage 2 filter, snorkel removed, Kev fuel mod fitted.
Plus: smoked Puig screen, Yam aluminium sump guard, Yamaha / Acerbis handguards, Givi Trekker aluminium side cases, Leo Vince X3 cans plus Kev front fork mod and Fender Xtender. Just fitted Michelin Road Pilot 3 tyres.

SOLD the XTX for a Super Ten 1200. And just bought a Raptor 700 so staying on here for some tips....

I forget to mention that i fitted the plug a couple of months ago and didn't notice a change in anything.

It's only since putting in the DNA stage 1 that i've seen such a drop in MPG.

Mike

I notice a drop in mpg once it gets colder, maybe its that?

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check out www.redbikejohn.com for all the latest race reports from the CHEC and enduroland.

A change from 250 to 210 miles before the F-Trip is almost a 20% drop in fuel economy – which is quite a lot! I very much doubt that a change to a DNA stage 1 filter will have caused this all on its own?

Has the filter been over-oiled? Brakes binding due to the salty roads? Chain deteriorated? Are you being more throttle-happy? As you said, you can “feel the bike breathing better.” I’d guess the ambient temperature is also a lot lower on your commute recently, more so than when you had the OE filter in? Is it a short commute? That’ll make the negative effects of cold weather on fuel economy more pronounced.

I’m with RBJ on the cold weather conspiracy.

All engines have an optimum operating temperature, and the colder it is, the longer it takes to get there. Although the sensors and ECU take account of a lot of variables, the essential fact is that the fuel injection system is only fully efficient when the engine is at full operating temperature. When the ambient temperature is low, the motor requires a longer period of time to reach full operating temperature (and efficiency) —and it’s in that warm-up period that a lot of fuel efficiency is lost.

Colder weather increases friction too. The oil is thicker and more resistant to flowing when cold, so it’s harder to pump, which means more work for the engine. Rolling resistance also increases with a drop in ambient temperature, which isn’t what we naturally assume – usually we think of dry hot days as good for high friction (grip). Tyres, for example lose approximately 2psi for every drop of 10C, which increases rolling resistance and hurts economy.

Also, add to the above the fact the battery takes longer to recover from starting, so causes more drag from the alternator as it tries to get the battery voltage back to where it should be.

Having said all of that, I tend to get more mpg in the winter! However, I definitely know I ride less enthusiastically in the colder months, which kind of cancels things out.

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