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Discussion Starter · #1 ·
Hey everyone, I'm having a hard time finding out some info I thought would be easy to find out, the hose routing of the carbs. I have the triangle boxes, that came in a box with the bike. As of now, the carbs are just dry fitted to the bike, with no hoses connecting to them at all. I'd like to sort it right from the get go best as possible so any tips or diagrams would be great.

I believe the hoses from the brass 90' fitting on the carbs go into the black triangles via some one way valves. I have those in a box, but maybe those things suck and should be dealt with in other ways.

Can't find any good threads on this besides this one, that's missing a diagram that might help
https://www.ducati.ms/forums/57-supersport/187041-95-900ss-mikuni-carb-hose-question-2.html

Thanks a lot everyone!!! If I haven't botched the carb rebuild, and can get all the lines hooked up, I think she'll START!!!!
 

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1994 900SS CR, 2002 998 Trackbike
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Bike should be able to start with these completely missing actually. They are breather hoses for the diaphragm chambers, all they need is some still air at the end, so that there is no ram air effect or suction from high speed riding. Hence the triangle box.
The black one way valve things are actually very primitive filters, to prevent dirt getting in there. There should be a bit of porous foam inside.

The other triangle box is for the carb bowl overflow hoses I believe. Unless you care about making things 100% OEM, you can also just route those to the ground.
 
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My Bimota DB2 has the same set up since it has the 900SS engine you have. The hoses for the carb vents are larger in diameter and each one had an inline screen - these look like one way valves, but aren't - and then each went to its own tri-box. The boxes do absolutely nothing other than to possibly catch a low probability spill or puke of gas by the carb somehow up through the diaphragms. I now keep them in a box. The vent screens, however, you do need even though the screening is very coarse. These will stop frogs and small children from entering the carbs, but the former only if it has claws.

The other two hoses are inlet and return fuel lines for feeding the carbs although I cannot remember if each carb has a bowl vent line.
 
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Discussion Starter · #4 ·
Here are 2 diagrams that I can find via the parts and workshop manuals.

In the diagram of the tank B2, we have 3 lines, A fuel out, B fuel in and then C a breather that probably vents to the bottom of the bike. I think in my case there is no hose on that fitting out of the tank.

In the diagram of the carbs B, we can see the dual 2 piece hoses with the coils around them, which I'm pretty sure come off the copper 90' fittings on the carbs. I believe I have most of these parts, but probably not all, so if there is a "no boxes" mod that works well that would be great.

In the diagram of the carbs alone B3, there is 1 of the 2 T-fittings (by 12, the o-rings), this one is closest to the airbox. I think this is where the line A in the tank diagram should go..so this is FUEL IN?

And then finally we have the 2nd T fitting that's crammed up more "inside" in between the carbs. I believe that there was a hose connected here that was quite short and came off with the carbs but I can't be sure.

Any help would be appreciated and sorry if this is a basic bitch question. I should have taken pics, but.................yeah I swore I had a diagram of this or had seen one online or was sure there was one so didn't worry. Thanks a lot everyone
 

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the ones off the elbows at the back are the choke air feed. they'll only be taking air when the choke valves are open.

the one at the front is the float bowl vent. you need to keep it out of moving air.
 

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The breather hoses for the diaphragms are very flimsy and prone to collapse. They must transfer air both directions freely. The tiny in line filters must be kept clean. I replaced mine with fuel hose and in line fuel filters.
 
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The carburators:

The two brass pipes (one on each carb) are connected with hoses and inline air filters to the triangular box (the one on the inside, near the carbs). This box has two holes were the hoses enter. Make sure you cut these hoses at an angle to prevent blocking them when pushed against the inside of the triangular box. We'll come to the outer box when talking about the T-shaped connectors in a moment.

The float bowls each have 2 nipples at the bottom where a hose can be attached to. The ones which can be opened and closed with the screw next to it are the drains. No hoses here. Until you wanna drain the carbs. The other ones are the float bowl overflows. They have hoses that go around the front of the alternator cover (left side of the bike) and then backwards. On the bottom of the alternator cover is (or should be) a clamp where you can put these hoses in. Cut them a few inches beyond this clamp.

Then there are two T-shaped connectors between the carbs. The lowest one (closest to the float bowls) is the fuel line. This one connects to the Y-piece of the fuel lines coming from the tank. You'll notice a notch or groove (don't know the exact english word for it) in the bottom of your airbox to make room for this line. Make sure this line stay clear of the throttle cable connectors between the carbs. There should be a small fuel filter in this T-connector. Make sure it is clean. (nr 9 in attachment nr 4)

The other T-shape connector between the carbs is connected to the outer triangular box. On the front of this box is a nipple where this line shoud connect. This line starts between the carbs, goes towards the front of the bike (alongside the fuel line) and at the point it is free from the carbs it turns to the left to reach the triangular box.

The tank:

Check the fuel lines near the Y-connector. In one of the lines coming from the tank is (or should) a restrictor. You can feel it when you squeeze the line just above the Y-connector. This is the return line. (The middle one on the bottom of the tank, line B in your feeding system drawing).

The other one is the feed or send (again, don't know the exact word) line. This one comes form the fuel tap on the bottom of the tank (the one near the right side of the bike). This is line A in the drawing.

The third line is the drain for the fuel cap. Underneath your fuel cap you'll notice a small hole to drain (rain)water. This hole is connected (through the tank) to the bottom of the tank (the connection which is near the middle of the bike) This line runs down towards the ground on the righthandside of the bike. (line C)

Line A and B start from the tank towards the back of the bike. At the around the end of the tank they make a U-turn towards the front and then go between the vertical cilynder head and the cross-section plate of the frame on which the tank is mounted. From there you can zip-tie them against the vertical frame tube and then they reach the Y-connector.

Good luck!!
 

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^^ Very helpful, thank you. The triangular air boxes were also removed frm my bike. My question is, where do they mount?
 

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I believe they mount side by side on a tab on the left side of the frame. Can't look now as I removed mine when I installed FCRs.
 

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^^ Very helpful, thank you. The triangular air boxes were also removed frm my bike. My question is, where do they mount?
I'll take a picture of mine tomorrow and post it for you--My bike is an SS not a CR but my guess is they mount the same
 
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Thanks, everybody ... I'll have a look in the garage to see if I can locate that mounting point.
 

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Here is a picture of mine installed-it should be easy to find the mount points
982393
 
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Very clear now, thanks for the pics. I'm thinking that I'll install the boxes when I renew all fuel hoses. This is the bike I bought end of January, the various breather hoses were either mis-routed or missing. Always some "surprises" with a new-used bike. The slide breather elbows had no hoses attached at all. Now I know how to remove the battery-air box :) The float bowl breather (off the T) was about 12" long and just hanging. Best of all were the float bowl overlfow hoses. I could see hoses ponted to the ground and routed through the clips on both sides of the engine. But nothing attached to the bottom of the bowls. Turns out it was a long length of hose that just looped from one side of the bike to the other, with the ends running the guide clips and pointing toward the ground. I cut the hose in half and attached the freshly-cut ends to the float bowl overflows. In another thread here I read about running the three breather hoses all the way back to the underseat-tail area, which I have done for now. Seems good, but I might go back to the origial layout just to reduce the jumble of hoses running the length of the bike.
 

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Bike should be able to start with these completely missing actually. They are breather hoses for the diaphragm chambers, all they need is some still air at the end, so that there is no ram air effect or suction from high speed riding. Hence the triangle box.
The black one way valve things are actually very primitive filters, to prevent dirt getting in there. There should be a bit of porous foam inside.

The other triangle box is for the carb bowl overflow hoses I believe. Unless you care about making things 100% OEM, you can also just route those to the ground.
Thanks. I had my lines disconnected and facing forward. Had problems at high speed.
 

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93 900ss,2019 Triumph 1200XE, 2017 CRF250L RALLY, 2003 F650GS DAKAR, 1993 KLR250, 1986 HONDA TLR20
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Don't know if this helps I have the rest of the pages if you pm me.
1005963

1005964
 
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