GPz engine in J frame - Airbox problem. SORTED!

[Big Fluff]

Got a bit of a problem here lads.

After fitting a GPz1100B1 engine in place of the stock 1000J motor, and fitting the standard 1000J airbox, there is next to no gap left between the back of the carbs and the airbox.

The standard 1000J air box rubbers are twice as long as what’s required.
The only thing I can think of is that the casting of the GPz head is different to the J head in that the mounting faces for the throttle body rubbers is about 1 inch further back that of the J head, leaving a gap of approximately 15mm between the airbox and back of the carbs.
The rubbers however are twice that length at least, so there’s no way I can get them to fit.

Has anyone on this forum done this conversion before (I would think so) and what did they do to overcome the problem.
I really don’t want to fit pod filters either.

I’ll post some pics tonight.

Thanks, Will

[zed1015]

The problem is as you have mentioned, the B1 intake runners are longer due to the integral injector ports.
I would presume you either need the b1 air box or the connecting rubbers as one or both of those must be slightly shorter than the 'J's

[z1bman]

the problem is with the inlet ports they are longer. also the the throttle body's are shorter in width than the carburettors & the b1 air box is longer in width & you would have even less clearance than you have at the moment

[Big Fluff]

Rob
I would imagine the airbox is the same physical size and that the throttle bodies are shorter than the CV carbs on the J.
I would also imagine that a GPz B1 airbox would be of no use due to the flow meter and different volume in there...
The GPz connecting rubbers are far too small too.

Didn't really want to use pod filters, but if I have to, I suppose I could cut recess holes in the standard airbox for the individual filters to go into. That would hide them.

[Big Fluff]

Ah... just seen Z1b's response.... Looks like I'll have to get busy with the hole cutter then

[z1bman]

take a look at these katana inlet rubbers they only protrude about 20mm from the air box not sure on the outer diameter though?

http://www.ebay.com/itm/New-Suzuki-GSX- ... 3cce4fd264

[Big Fluff]

Thanks for that. However, the two outer ones need to crank outwards by about 14mm and I'm pretty sure I won't be able to find any that will suffice. i.e. protrude 13mm but crank 14mm.

I will probably look at 4 x foam filer pods, cutting the existing 4 holes in the airbox to match just under the outside diameter of the filters.
This way I can still have the airbox fitted so aesthetically it’ll look standard plus the filters will be out of reach of rain and when washing bike etc.

I'll obviously remove the filter and the carrier from the airbox and hope it'll flow enough air.

[Pasc]

You could probably cut away a great deal of the air box behind the panels and top and bottom so air flow shouldn't be a problem I'd say.

[big green bus]

I had this problem you will have to chop the airbox to bits, fit filters or put a B2 head on. the air box will also hit the battery box and front mounting plate where the fuel pump goes is nutshell it is a nightmare

[Big Fluff]

Cheers Steve - That's exactly what I thought.

I have measured the carb inlet OD (55mm), the airbox inlet diameter ID (55mm) and the approximate length required (30mm).

Today I had a quick look around in my workshop at Bentley where I have several engines lying around. My 'beady' eye spotted some potential hoses on a 6.75l V8 twin turbo engine. Well would you believe it, 55mm ID and 55mm in length. They'll do then!
All I will have to do is slightly enlarge the airbox holes to suit just under the OD of the Bentley hoses which measure 63mm. Thst means I'll make the holes 61mm to ensure a good snug fit.

This is really good news, as I wanted to retain the look of the stock airbox anyway.

The only question hanging over my head now is about the fact that the new hoses will have no 'trumpet' shaped tracts on the inlet side (inside the airbox). Does anyone think this will make a big difference

[Big Fluff]

I had this problem you will have to chop the airbox to bits, fit filters or put a B2 head on. the air box will also hit the battery box and front mounting plate where the fuel pump goes is nutshell it is a nightmare

Well I came up with an idea on how to keep the standard Z1000J air box and carbs on a GPz1100B1 head.
If anyone needs to know I shall put this in the "How To" section.
I also have a spare set of 4 'special' hoses to give away FOC if anyone else wants to do this conversion.
http://z1ownersclub.co.uk/forum/viewtopic.php?t=28714
Regards, Will