Author Topic: Will this be OK? Carb/tank/petcock, air filter clearance  (Read 141 times)

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Offline Scott S

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Will this be OK? Carb/tank/petcock, air filter clearance
« on: October 09, 2018, 12:06:46 pm »
Working on fitting a 2000 GSX750F engine with BST-36 carbs in a 1980 GS550E frame. The goal is to keep the stock GS550 bodywork, seat, etc.



 I'm running into some slight clearance issues with the tank to carb tops and the petcock to air filters. I swapped from K&N filters to RamAir and they're much more forgiving. After trying a few different brackets, etc., I think I have come to a solution that allows everything to clear and the seat to latch. However, the filter on the #1 throat is going to be mashed a little bit (actually, both outer throats will be mashed slightly, simply because of the frame).



 Is  this acceptable? It's pretty much gonna HAVE to be unless I throw out the stock bodywork. As you can see in one of the pics, I'm using Bandit 1200 air box rubbers, so they'll have an internal velocity stack. The stacks are clear by a mile and there's probably at least an inch of space from the end of the stack to the filter, even on the mashed areas.











 In this pic, there's a piece of fuel line to mock up where  it would run off the petcock. It will mash the foam on the #1 and #2 throats just slightly and run up to the center of the bike to a T-splitter (dual fuel inlets on these carbs).







 This pic shows a velocity stack on the #3 throat, to illustrate that even though the foam is mashed in spots, there's still plenty of space around the stacks inside the filters.



'73 CB500/550
'71 CT70
'14 Triumph Scrambler

 and too many projects...

Offline scottly

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Re: Will this be OK? Carb/tank/petcock, air filter clearance
« Reply #1 on: October 09, 2018, 09:23:50 pm »
Scott, it looks like there will be very little clearance from the back of the stacks to the inside of the filters; this would be my main concern. Can you fit shorter stacks, or shorten the ones you have?
Don't fix it if it ain't broke!
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Offline Scott S

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Re: Will this be OK? Carb/tank/petcock, air filter clearance
« Reply #2 on: October 10, 2018, 03:54:15 am »
 There's actually quite a lot of clearance from the end of the stacks to the rear of the filters. The filters don't slide all the way down on the stacks. In the last pic, see the groove in the stack, just over halfway down? That's where the filters fit.
 I'll try to get a side on shot and a measurement. There's quite a bit of room in real life.
'73 CB500/550
'71 CT70
'14 Triumph Scrambler

 and too many projects...

Offline Scott S

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Re: Will this be OK? Carb/tank/petcock, air filter clearance
« Reply #3 on: October 10, 2018, 04:42:23 am »
Here's a side view showing the intake rubber on the carbs.



 My finger is on the end of the bell mouth.



 And another pic to show the fitment.



 I'm well aware that CV carbs prefer an air box, but this is hot rodding and I'm stuck with working with what I have. I actually got rid of some dual throat K&N filters (that I once used with good luck on a CB650 with CV carbs) and went with the rubber stacks/RamAir filters on suggestion of the OldSkoolSuzuki guys. The stacks are supposed to really help.
'73 CB500/550
'71 CT70
'14 Triumph Scrambler

 and too many projects...

Offline Fezzler

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Re: Will this be OK? Carb/tank/petcock, air filter clearance
« Reply #4 on: October 10, 2018, 07:38:10 pm »
May not be economically realistic, can you get a custom filter made?
1978 Honda CB550 Four K4
1971 Honda CB500 Four K0
2008 105th Anniversary Edition HD Road King
(Sold) 1998 Honda Shadow ACE Deluxe VT750

Offline 754

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Re: Will this be OK? Carb/tank/petcock, air filter clearance
« Reply #5 on: October 10, 2018, 09:51:11 pm »
He is holding one in the last pic..
Maker of the WELDLESS 750 Frame Kit
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73 836cc.. Green, had it for 3 decades!!
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