Adapting throttle bodies to fit...What would you do?
Posted: Tue Oct 23, 2007 12:04 am
I have an '83 Suzuki GS1100GL that I'm hoping to get Megasquirted eventually. The first step for me was to get throttle bodies, get them mounted and make sure everything's right along those lines. I figured I'd start with the '01-'03 GSXR 600 throttle bodies, since they're somewhat close in size to the carbs I have on the bike now and the GPZ1100 TBs (which are the closest fit spacing-wise) seem to be impossible to find these days.
I obtained a set of GSXR 600 TBs this morning for $51. I brought them home, pulled the injectors/fuel rail off, removed the computer-controlled butterflies and control mechanism and generally got them down to a good "starting point." My problem is getting them on the engine.
The GSXR 600 TBs have center spacing of 80-80-80. The GS is spaced 77-93-77. My first thought was to take them all apart, cut the bodies down so they're spaced properly for the outside pairs and add some space for the central pair and then have a new fuel rail built. After looking at some of the numbers, I thought about leaving the outer pair spacing alone and just offsetting the outer pairs 1.5mm "to the outside" of the outer pairs, which would require me to add 10mm to the space between the center two throttle bodies. Finally, I thought about obtaining some silicone hoses that neck down in size, stabbing those hoses inside the carb boots, butting them up against the TBs and throwing another hose to hold the inner one against the TB around the TB and the hose. This would give me some flexibility in positioning, plus not require me to do any hacking on the fuel rail or TBs themselves, but I'm unsure of the adverse effects of lengthening the intake "runner" by an inch or two, depending on how much room I need to make the size and angle transition.
The bike is pretty much all stock except for Dyna coils and (eventually) a Vance & Hines four-into-one exhaust.
Which method would be the easiest? Which method would be the best? What method would you all recommend? Is there anything I've overlooked?
I obtained a set of GSXR 600 TBs this morning for $51. I brought them home, pulled the injectors/fuel rail off, removed the computer-controlled butterflies and control mechanism and generally got them down to a good "starting point." My problem is getting them on the engine.
The GSXR 600 TBs have center spacing of 80-80-80. The GS is spaced 77-93-77. My first thought was to take them all apart, cut the bodies down so they're spaced properly for the outside pairs and add some space for the central pair and then have a new fuel rail built. After looking at some of the numbers, I thought about leaving the outer pair spacing alone and just offsetting the outer pairs 1.5mm "to the outside" of the outer pairs, which would require me to add 10mm to the space between the center two throttle bodies. Finally, I thought about obtaining some silicone hoses that neck down in size, stabbing those hoses inside the carb boots, butting them up against the TBs and throwing another hose to hold the inner one against the TB around the TB and the hose. This would give me some flexibility in positioning, plus not require me to do any hacking on the fuel rail or TBs themselves, but I'm unsure of the adverse effects of lengthening the intake "runner" by an inch or two, depending on how much room I need to make the size and angle transition.
The bike is pretty much all stock except for Dyna coils and (eventually) a Vance & Hines four-into-one exhaust.
Which method would be the easiest? Which method would be the best? What method would you all recommend? Is there anything I've overlooked?
