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?
Adapting throttle bodies to fit...What would you do?
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Read the manual to see if your question is answered there before posting. Many users will not reply if the answer is already available in the manual.
If your question is about troubleshooting, configuration, or tuning, you MUST include your processor type (MS-I or MS-II) and code version in your post. If your question is about PCB assembly or modifications, you must also include the main board version number (1.01, 2.2 or 3.0).
If you have questions about MS1/Extra or MS2/Extra code configuration or tuning, please post them at www.msextra.com Such questions posted here will be moved to: a temporary MSextra sub-forum, where they will be removed after 7 days
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mjheathcote
- MegaSquirt Newbie
- Posts: 4
- Joined: Sun Oct 08, 2006 11:51 am
- Location: England UK
Thanks for the reply. Turns out my original idea of spacing the TBs out 10mm in the center while leaving the outer TB spacing alone was pretty spot-on. The other night I separated the throttle bodies, stuck all four on the engine, measured the space between the center TBs and was surprised to find that it matched my calculated space increase (10mm) exactly. You can see my ghetto-spacer test setup if you'd like.
Now, the hunt is on to find some replacement bolts. Since the TB setup is now 10mm wider, the original M6-1.0x250mm, cad-plated, partially-threaded, socket-head cap screw only engages three or four revolutions of threads in the outer TB, which doesn't sit very well with me. I'm shopping for a replacement screw that's 10mm longer, but I'll probably end up hacking something together out of allthread or the like.
For spacers I'm just going to get some 1/2" (or 13mm or so) diameter, round, aluminum rod, cut it to length and drill through the centerline.
For the fuel rail I'll probably just buy extrusions and drill them myself or just take the rack of TBs somewhere and have a rail made.
Thanks again.
Now, the hunt is on to find some replacement bolts. Since the TB setup is now 10mm wider, the original M6-1.0x250mm, cad-plated, partially-threaded, socket-head cap screw only engages three or four revolutions of threads in the outer TB, which doesn't sit very well with me. I'm shopping for a replacement screw that's 10mm longer, but I'll probably end up hacking something together out of allthread or the like.
For spacers I'm just going to get some 1/2" (or 13mm or so) diameter, round, aluminum rod, cut it to length and drill through the centerline.
For the fuel rail I'll probably just buy extrusions and drill them myself or just take the rack of TBs somewhere and have a rail made.
Thanks again.