My poorly ZX6R....

[byke95]

Hello!

I'm looking for some advice on what could be going on with my 1995 ZX6R. I've recently changed to exhaust system, stainless steel downpipes replacing the originals, with the same Micron Race can at the end.

The problem is that my Mid Range seems to have become sloppy (between 4000-9000). Nothing drastic but if I'm going at about 40-50mph and want to give it some beans a flick of the wrist results in slow progressive acceleration rather than it 'pulling' quickly .

Anyone have any suggestion, has the new downpipes somehow messed up the mid range (effected the air/fuel mix) or is it something else, the bike is due for a damn good service!

Many thanks...

[kev]

In a word Micron downpipes are shit.

You would need to get the bike rejetted to set them up but you will find that nobody with a dyno will tell you that you will get a power gain with them and you will find it hard to find one who will be able to tell you that they can set up you bike to run properly with them.

You best bet is to put the standard ones back on or buy a decent system.
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20:02:36 Jammy-R6: any holes a goal
20:02:48 kev: even if its a hairy mans arse
20:02:56 Jammy-R6: hell yes

[byke95]

Cheers for the reply Kev,

Thing is, they're not Micron downpipes, I got them off the net from Track and Race in Nottingham (basically their copy of the original). It's just the end can that is Micron.

Still the same story? If so, bollox , they cost me loads!

[kev]

Micron downpipes tend to be generally pants but the cans are ok.

All you really need to do then is just get the bike jetted and set up on a dyno.
____________________
20:02:36 Jammy-R6: any holes a goal
20:02:48 kev: even if its a hairy mans arse
20:02:56 Jammy-R6: hell yes

[byke95]

Phew

Is dyno time expensive?

Thanks for the help Kev!

[kev]

Your probably talking around £100 for the kit, £40 for a filter and about £150 fitting and setting up.
____________________
20:02:36 Jammy-R6: any holes a goal
20:02:48 kev: even if its a hairy mans arse
20:02:56 Jammy-R6: hell yes

[byke95]

mmmm, near on £300 plus the service it needs, gonna need to get hold of some money!

...now where's my ski mask and water pistol.....

[Zx6man]

worth checking your bike on a dyno for any can change. Worst case it can burn your valves causing mucho expensivo damage.

[kev]

[Zx6man]

I said worst case....A can that runs lean can burn the valves....or should I have put.....

the race can which was put on my zzr600 ended up burning the vales out, costing over 400 notes to sort out, engine out and the works

now you have heard of it

[Kickstart]

Hi

Wonder how good a copy of the original pipes these ones are?

It is very easy to screw up the performance of an engine by fitting an aftermarket exhaust.

To go with what Kev says I had a Micron 4>1 system on the FZ750. This gave it a very nasty flat spot between 3000 and 4000rpm, so bad that on larger throttle openings it would barely pull through it.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[byke95]

I'm thinking you might have hit the nail on the head there kickstart ; the copies gave me loads of hastle when i was fitting them - had to send them back once due to poor workmanship.

Will dyno sort this out or is it just a case of crap pipes crap performance?

[loply]

Personally if I was buying a new exhaust (or any new major component), I would have the bike dyno'ed before and after.

It might cost £50 or whatever to dyno the bike twice, but at least if it turned out the new exhaust reduced peak power by 4bhp and lowered the entire midrange by 20% you could take the useless lump back!

I bet loads of people have bikes running significantly under their normal power because of aftermarket exhausts which are coincidentally the wrong length for the engine. And the thing is - These people will fool themselves into believing its faster, because its louder!

[Kickstart]

Hi

The lengths of the individual pipes and how they join together is very important.

I would say get the bike on a dyno. It might well be able to sort out the fueling and improve performance.

Loosing a load of low down power and then having the top end power come in with a bang can make a bike feel faster, even if it has lost top end power at well.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing