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38mm or 40mm carbs for gsxr1127 motor


MooreMatthew

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I’ve both sets of carbs but been told that factory pro do conversion for the 38mm 750 carbs to suit 1127 Or use the 40mm that are from the 1127 motor originally 

which has people used 

they will be fitted to a slabby project so will end up having to run filters for them to fit anyone got pics of what filters there running in slabby frames 

Thanks 

 

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If you're going to use filters the 38's will be better - the 40's need an airbox to work well, you get dips in the delivery without the airbox, I tried for a while with the Factory kit. The 40's work really well with the airbox and free flowing filter, then jetted to suit. The 38's work well with or without an airbox, still need to put a bit of work in to make them work nicely, but it's far easier.

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4 hours ago, nopokewithoutsmoke said:

I wouldn't use Pipercross - many years ago I took a 38mm carbed 1052 to the dyno...to cut a long story short, swapping the new Pipercross filters for some 'slightly squashed to fit 'K and N's' that I had spare gained 5hp at peak.

I wouldn't class that as a reason not use pipercross. The installed jetting might have been better suited to a slightly less air flowing filter.

As dyno time is expensive, it's quicker to swap filters to suit jetting than changing jets to suit filters. But that doesn't mean you can't get more bhp from the pipercross with suitable jetting.

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I'd go for the 38mm carbs all day, the 40mm I've heard are a real pain to set up, if you ever can get them to run right.

I've get a set of 38mm on my bike (1127) and they did not take to much to set up.

The 38mm gives you good top end with good power all the way through the rev range, the 40mm from what I'm told are good for top end but shit for anything else.

Someone will tell me that's not right xD

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35 minutes ago, Jaydee said:

I wouldn't class that as a reason not use pipercross. The installed jetting might have been better suited to a slightly less air flowing filter.

As dyno time is expensive, it's quicker to swap filters to suit jetting than changing jets to suit filters. But that doesn't mean you can't get more bhp from the pipercross with suitable jetting.

Fair comment about the jetting, but the Pipercross filters were the first thing Russ at Torque Tune, Ollerton commented on before he put the bike on the dyno.

 

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47 minutes ago, wraith said:

I'd go for the 38mm carbs all day, the 40mm I've heard are a real pain to set up, if you ever can get them to run right.

I've get a set of 38mm on my bike (1127) and they did not take to much to set up.

The 38mm gives you good top end with good power all the way through the rev range, the 40mm from what I'm told are good for top end but shit for anything else.

Someone will tell me that's not right xD

Did you also use the factory pro kit or did you just take it to dyno and let them set it up 

looks like it will have the 38mm

ill keep the 40mm for my Slingshot that will have the airbox on 

as the ones I’ve got with that are seized so can sort them at a later date 

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I put b12 pilot jets in them and then contacted Dyna and got them to send me a Dyno jet kit.

pilots set at 2 1/2 turns out.

150 main jets.

I think I set the needles in the third groove.

running with K&N filters, gsxr1000k2 down pipes with open can.

runs clean all the way through the rev range and just keeps pulling, till my neck can't take anymore xD

Never had it in a Dyno as it's running well so never needed too and I know how big my dick is so don't need to brag ;)

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On 10/29/2018 at 8:49 PM, wraith said:

I put b12 pilot jets in them and then contacted Dyna and got them to send me a Dyno jet kit.

pilots set at 2 1/2 turns out.

150 main jets.

I think I set the needles in the third groove.

running with K&N filters, gsxr1000k2 down pipes with open can.

runs clean all the way through the rev range and just keeps pulling, till my neck can't take anymore xD

Never had it in a Dyno as it's running well so never needed too and I know how big my dick is so don't need to brag ;)

40 mains?

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On 10/29/2018 at 6:45 PM, wraith said:

I'd go for the 38mm carbs all day, the 40mm I've heard are a real pain to set up, if you ever can get them to run right.

I've get a set of 38mm on my bike (1127) and they did not take to much to set up.

The 38mm gives you good top end with good power all the way through the rev range, the 40mm from what I'm told are good for top end but shit for anything else.

Someone will tell me that's not right xD

(y)

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On 10/29/2018 at 7:49 PM, wraith said:

I put b12 pilot jets in them and then contacted Dyna and got them to send me a Dyno jet kit.

pilots set at 2 1/2 turns out.

150 main jets.

I think I set the needles in the third groove.

running with K&N filters, gsxr1000k2 down pipes with open can.

runs clean all the way through the rev range and just keeps pulling, till my neck can't take anymore xD

Never had it in a Dyno as it's running well so never needed too and I know how big my dick is so don't need to brag ;)

@wraith do you have a pic of your exhaust set up ???

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12 hours ago, Rossco(Iceman Josros) said:

What’s it look alike with the belly pan off ???

Have a look at my gsx1157et project same zorst fitted to a b12 motor in a ET frame and with no belly pan, as like I said above I HAVE NO PICS OF THE KAT WITH OUT THE BELLY PAN.

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