Yamaha TRX850 Enthusiasts Forum

I was having a bit of a ferret about under the tank on the bike and saw the intake trumpety thing on the top of the airbox. That can't be good for power, or is it? Has anyone opened up the airbox on the 'dirty' side of the air filter to loosen things up a bit? I don't mind cutting stuff up

if you want to open it up a bit best bet is to fit K&N style pod filters
dont forget to factor in a dyno run&rejetting into the cost tho

AFAIR there has been some discussion before about removing the snorkel or drilling holes but no one ever proved any power increase.

The TRX ain't known for having restricted breathing, and there's a lot of science behind airbox designs.

As the seagull sez, a K&N or similar panel filter to replace the original will let more air in, but not much point just doing that alone really.

Easiest BHP gain is cans.

trixynut wrote:AFAIR there has been some discussion before about removing the snorkel or drilling holes but no one ever proved any power increase.

The TRX ain't known for having restricted breathing, and there's a lot of science behind airbox designs....

Are you sure? My airbox ended up with no snorkel, holes all over the front as well as a lifted tank and foam removed....

Mind you the engine and carbs are far from standard....

Mind you the engine and carbs are far from standard....

...think thats the thing: yep, big fat FCR carbs need more air, whether it's via mods like yours or no airbox/pod filters like mine, but for standard carbs, messing with the airbox don't do owt, even if you've got a set of cans on.

I could be talking rubbish though, as usual...!

The bike had open pipes on it when I bought it so no worries there.

I decided to have a go anyway, given that araldite and gaffa tape is cheap enough It certainly sounds faster, ha ha. I cut the trumpety bit away and cut some holes in the front of the box. I took it for a quick blast around our local test circuit and it didn't feel any worse. I'll leave it as it is, just for the sound more than anything else

Kayla wrote:The bike had open pipes on it when I bought it so no worries there.

I decided to have a go anyway, given that araldite and gaffa tape is cheap enough It certainly sounds faster, ha ha. I cut the trumpety bit away and cut some holes in the front of the box. I took it for a quick blast around our local test circuit and it didn't feel any worse. I'll leave it as it is, just for the sound more than anything else

AFAIK, people have tried this in the past and it really doesn't make much difference on the TRX, unless perhaps you have honkin' great FCRs on it. Depending where you cut the holes, be careful during wet cleaning!

I could be wrong, but I would suggest that if you don't need to rejet, it's probably not doing anything meaningful. Take the airbox cover off my (soon to be ex) Duke, for example, and you have to go way up on MJ or the bike will just stop when you open the throttle. But perhaps that's just singles?

Oh, and as far as K&N, I have one myself, but I do remember (I think it was) PB doing some tests on them years ago and finding that mostly what they did was bugger up the power curve. Perhaps someone else here remembers that article?

I took it for a quick blast around our local test circuit and it didn't feel any worse

..that'll be a result then!

trixynut wrote:

I took it for a quick blast around our local test circuit and it didn't feel any worse

..that'll be a result then!

Yes, very clever, smart *rse. Obviously if it had been worse I'd have put stuff back to standard, or at least used lots of araldite and gaffa tape on it

I used to work for K&n in nz, there are a few interesting thing i lernt. honda airboxes, dont pull them out like most boy racers as they lose horse power when this is done.
But i dont see how this kind of thing would effect the trx, at the end of the day they are carbs.any thing you can do to give them more COLD air will help.

But i do imagine the induction noise would be magnificint.!!

If it sounds faster it must be!

CV carbs can be very sensitive to air flow changes. Things may be great on calm days, but if strong cross winds or the like are around, Kayla's TRX may start acting strangely.Be prepared for the tape and araldite, just in case. Flat slides however; love the extra cold air, so pod filters, stacks, extra holes in the airbox etc can be advantageous.
Terry

As twolfe said when I had the standard carbs and filter I drilled as most others do and found that if I rode with a cross wind the bike would sometimes start to hunt like running out of gas , the remedy was to open the legs away from the tank , changing the air flow to the airbox , that made the bike run ok . I think I covered the holes in the end . Even tried to air ram into the air box with tubes from the front of the fairing . bike ran like poo so maybe still air is best . Don't let that stop you from playing kayla . The best thing about Rex's is the sounds they make and the fun it gives

or stop smoking, drinking ,,eating,, o and using gas and electricity,,and buy some FCR,s

I have a drilled airbox taking up space in my garage. If anyone is interested PM me.