ZXR 400 Rough below 5-6k boggy + backfire any ideas?

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reggie1324
Posts: 6
Joined: Mon Jun 19, 2017 7:33 pm
My Bike: zxr 400 l9

ZXR 400 Rough below 5-6k boggy + backfire any ideas?

Post by reggie1324 » Mon Jun 19, 2017 7:46 pm

Hi All just new to ZXR'S and this forum :)

So I have bought a ZXR 400 L9 with 531 miles on the clock, It has been sitting in the showroom of a racepaint company for 16 years and hasn't been ridden in that time.

So about me, I do most jobs on my bikes the only thing i won't touch is gearboxes :)

The last carb bike I had was a Honda Nc29 years ago.

So far I have

cleaned inside of the tank
cleaned carbs ( air compressor and brake cleaner )
set idle to 2.5 turns out ( same as it was )
new plugs
new oil
new coolant
new air filter


The bike struggles up until about 5-6k then comes to life, and if you take it to redline it with backfire.

Now im not familiar with these bikes atall so if there any common symptoms I have mentioned? If so any help would be much appreciated.

Thanks all

Reggie

reggie1324
Posts: 6
Joined: Mon Jun 19, 2017 7:33 pm
My Bike: zxr 400 l9

Re: ZXR 400 Rough below 5-6k boggy + backfire any ideas?

Post by reggie1324 » Mon Jun 19, 2017 7:52 pm

to add to this sorry

I can't seem to get the choke to work properly, if I put it full on the bike will cut out.

Also sometimes the revs will hang around 2.5k then drop back down

Thanks

bendog66
L-plate hell
L-plate hell
Posts: 479
Joined: Sun Oct 12, 2008 11:12 am
My Bike: ZXR400 L4, ZX6R F1 track
Location: Chesterfield

Re: ZXR 400 Rough below 5-6k boggy + backfire any ideas?

Post by bendog66 » Tue Jun 20, 2017 12:28 am

When you say set idle do you mean the idle mixture screws?

If so, the original settings for these were 1.75 turns out so try that and see if it helps

reggie1324
Posts: 6
Joined: Mon Jun 19, 2017 7:33 pm
My Bike: zxr 400 l9

Re: ZXR 400 Rough below 5-6k boggy + backfire any ideas?

Post by reggie1324 » Wed Jun 21, 2017 8:42 am

:smt010 LP
bendog66 wrote:
Tue Jun 20, 2017 12:28 am
When you say set idle do you mean the idle mixture screws?

If so, the original settings for these were 1.75 turns out so try that and see if it helps
Thanks will give that ago. If that don't work I will have to have the carbs off again I think and double check​ everything

reggie1324
Posts: 6
Joined: Mon Jun 19, 2017 7:33 pm
My Bike: zxr 400 l9

Re: ZXR 400 Rough below 5-6k boggy + backfire any ideas?

Post by reggie1324 » Wed Jun 21, 2017 7:17 pm

Tried 1.75turns still the same. It's almost like it's running on 3 untill 6k+rpm

You guys think carbs or coils?

bendog66
L-plate hell
L-plate hell
Posts: 479
Joined: Sun Oct 12, 2008 11:12 am
My Bike: ZXR400 L4, ZX6R F1 track
Location: Chesterfield

Re: ZXR 400 Rough below 5-6k boggy + backfire any ideas?

Post by bendog66 » Wed Jun 21, 2017 10:38 pm

Blocked pilot jet?

reggie1324
Posts: 6
Joined: Mon Jun 19, 2017 7:33 pm
My Bike: zxr 400 l9

Re: ZXR 400 Rough below 5-6k boggy + backfire any ideas?

Post by reggie1324 » Thu Jun 22, 2017 7:33 pm

bendog66 wrote:
Wed Jun 21, 2017 10:38 pm
Blocked pilot jet?
so nearly sorted it :excited

These carbs have been sitting so long I think the o rings on the pilot screws are done.

Also a pilot screw is bent as well as a needle having bad corrosion.

Where is the best place to buy rebuild kits and jets etc?

Thanks guys

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Miles
zxr400 oc member
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Posts: 466
Joined: Wed Apr 30, 2008 11:00 pm
My Bike: ZXR 400 L3
Location: Bangor, Northern Ireland

Re: ZXR 400 Rough below 5-6k boggy + backfire any ideas?

Post by Miles » Thu Jun 22, 2017 9:42 pm

I would say your carb o-rings have dried out from lack of use.

I'd recommend a seal kit from lite tek and new needles from kwak

reggie1324
Posts: 6
Joined: Mon Jun 19, 2017 7:33 pm
My Bike: zxr 400 l9

Re: ZXR 400 Rough below 5-6k boggy + backfire any ideas?

Post by reggie1324 » Thu Jun 22, 2017 10:32 pm

Miles wrote:
Thu Jun 22, 2017 9:42 pm
I would say your carb o-rings have dried out from lack of use.

I'd recommend a seal kit from lite tek and new needles from kwak
Thanks just ordered the kit from lite tek, bike is rideable atm so will go and enjoy it while I wait for its parts to come biggrin

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