Replace Carb rubber parts - what to replace

[Oldschool1]

Hi,

Before i put my carbs back in (cooling tube replacement) - which carb tubes/seals should i definately change (vac tubes and .........) and which should I consider changing.

Is there a viton bulk hose i can buy - i don't care to go around the local auto shops as you never know what they are really selling you - nor do they know.

I"ll be placing an order for the coolign system (every rubber part) and would like to get carb parts there too.

ST is a 94 and all original, garage kept so rubber is about the best it can be for that age.

Thanks,

Paul

 

[Bigmak96]

It's no fun pulling the carbs as you have seen. Not a huge deal but not something one wants to do more than they have to. That being said, I would recommend replacing all the rubber under there while the carbs are off.

 

[Oldschool1]

It's no fun pulling the carbs as you have seen. Not a huge deal but not something one wants to do more than they have to. That being said, I would recommend replacing all the rubber under there while the carbs are off.

I'm with you on that! Specifically just the tube network on the bottom right? I think it i replaced all the tubes I'd have to salvage the bike - whew never seen so much rubber!

Also on my 83 Nighhake there are carb interconnect aluminum fuel tubes that have orings on them to seal (it's a nasty mess), please tell me the ST does not have these such that the carb assembly has to be disssembled to change them. It's pretty hard to see on the microfiche parts diagram.

I'll have to take a picture and point to them - a bit later.

Thx.

Paul

 

[Bigmak96]

No,,,the carbs can come of without taking them out of their assembly. There are no o-rings to deal with either. Just take some time and study the way the tubes are routed. Take lots of pics to refer to.They go back on the same. Read as many posts as you can find so you can envision the reassembly process. Some will say to start one side first then the other. Some will say to start all four at once. It can be a little frustrating to get all four boots to slide onto their carb. It's one of those things that after you do it you kind of see the path for next time.

 

[GitSum]

Also on my 83 Nighhake there are carb interconnect aluminum fuel tubes that have orings on them to seal (it's a nasty mess), please tell me the ST does not have these such that the carb assembly has to be dissembled to change them. It's pretty hard to see on the microfiche parts diagram.


Thx.

Paul

The ST1100 uses the same type of "connectors" although I have never heard of anyone having to actually replace the o-rings. And your right - all four carbs have to be separated to get them. Unless your having problems, I would leave them be. I was actually chasing down a leak - which is why I pulled these out and it turned out to be the seal on the float bowls

Have you considered removing the pair system - to eliminate a possible failure point? There are some vacuum lines that probably could use updating

Check the diaphragms

 

[Oldschool1]

Thanks.

On the previous oring seal around the aluminum tubes - the bike had been stored dry for 10 yrs. So my theory is that the oring shrank and split (on all tubes) - also they were crispy hard. Pehaps if they don't dry out, kept wet with fuel, they can last 30 yrs? I'd be happy with another 12yrs.

As long as we haven't heard of these failing commonly - I'd say it won't happen until a bike is stored dry long enough for the oring to dry and shrink. If i remember right the swell on the oring is about 40% in fuel, then it takes a set at that swell shape, then when dry out many years later - cracko from shrinkage.

I'm not going to change them. Thx

 

[Oldschool1]

Have you considered removing the pair system - to eliminate a possible failure point? There are some vacuum lines that probably could use updating

Check the diaphragms

I'd better read up on this. I was going to leave it in - I know John O just cleaned his PAIR system. I guess removing is robust - just more work. HMMMMMMMM

 

[pago cruiser]

Hey Oldschool1; how is your work going?

I'm going thru the exact same thing at this moment; so figured I'd add onto your post instead of starting another almost identical/

Lost the cooling fan commuting back and forth to work a couple weeks ago. Since I had so much plastic off, figured it was about time (60000 miles on an 02) to do some pre-emptive carb work. I replaced the 4 carb mounts, everyline that carries gasoline, and all the tiny vacuum hose. Did not replace vent/drain lines. Did the de-Pair. I did NOT replace the o-rings on the aluminum tubes, nor did I pull the carbs from their common mount. Also replaced the carb slides, float/seat/filter,and base gasket. Debated hard (with myself) regarding the slides; was prolly not needed, but I had issues with these on my GL1200s at about the same mileage. I use the ST for work travel, so it has to be as reliable as I can make it. So I bit the bullet, at about $100 each... OUCH. Also replaced the timing belt and water pump; and coincidentally, the cooling tube: It was rotted about half way thru the metal just outside the o-ring sealing surface...
A bit of a PITA, but should have er back together after a long weekend wrenching.

If you still have it apart, you may want to check the slide needles. One of my slide needles has what appears to be a 1/4
long nick, maybe 10 thousanths deep on the surface, about 1/2" below the slide base:



I'm not sure its a big issue - yet; but I'm sure it should not be like that. Odd. I ran out of the tiny vacuum tubing, so I'll have to pick up a new needle when I get another couple feet next week after the holiday.

Good luck with yours.

 

[Oldschool1]

Hey Oldschool1; how is your work going?

I'm going thru the exact same thing at this moment; so figured I'd add onto your post instead of starting another almost identical/

Lost the cooling fan commuting back and forth to work a couple weeks ago. Since I had so much plastic off, figured it was about time (60000 miles on an 02) to do some pre-emptive carb work. I replaced the 4 carb mounts, everyline that carries gasoline, and all the tiny vacuum hose. Did not replace vent/drain lines. Did the de-Pair. I did NOT replace the o-rings on the aluminum tubes, nor did I pull the carbs from their common mount. Also replaced the carb slides, float/seat/filter,and base gasket. Debated hard (with myself) regarding the slides; was prolly not needed, but I had issues with these on my GL1200s at about the same mileage. I use the ST for work travel, so it has to be as reliable as I can make it. So I bit the bullet, at about $100 each... OUCH. Also replaced the timing belt and water pump; and coincidentally, the cooling tube: It was rotted about half way thru the metal just outside the o-ring sealing surface...
A bit of a PITA, but should have er back together after a long weekend wrenching.

If you still have it apart, you may want to check the slide needles. One of my slide needles has what appears to be a 1/4
long nick, maybe 10 thousanths deep on the surface, about 1/2" below the slide base:



I'm not sure its a big issue - yet; but I'm sure it should not be like that. Odd. I ran out of the tiny vacuum tubing, so I'll have to pick up a new needle when I get another couple feet next week after the holiday.

Good luck with yours.

Just back from a week of travel and about to pull the float bowls off and take a look inside. I figured i would pull the slow jets and make sure of now clogged ports. Runs fine currently though has a 50 rpm oscillation at 1100 rpm and if idleing in first gear it is not perfectly smooth due to this oscillating rpm i suppose.

I've decided not to worry about the drain line tubing, not to worry about the carb interconnect tubule orings (as it has not been stored dry). Looks like the only thing i need to be concerned about is that the carbs are clean, and the fuel lines to the carbs are in good shape - which they show no signs of degradation. I will replace the float bowl gaskets.

I'm not sure about de-paring at this point whether to or not - though i do have to remove the pair to change out the water pipe seal and the "onring under the "COVER, WATER 19514-MT3-000" that the water pipe connects to.

I'm not sure if i really need to change these two seals any thoughts on this?

Thx,

Paul

 

[John OoSTerhuis]

....Also replaced ... the cooling tube: It was rotted about half way thru the metal just outside the o-ring sealing surface.......

What is this "cooling tube" you replaced? What Honda calls the Water Pipe? If so, it's the first I've ever heard of a problem with that part.

Just wondering...

John

 

[pago cruiser]

Sorry so long to respond. Yep, it is the water pipe. Which MH did not have in stock; with no expected delivery...Found one on ebay NOS; he called it a cooling tube...The part was not leaking yet, but it is such a pita to pull everything apart, I tend to solve every potential problem with a shotgun... I'm guessing it sat awhile with some goofy coolant in it from the PO... But it's all better now. Got the new carb needles from MH yesterday (also backordered), and got the carbs on tonight. Tomorrow finish the timing belts/ radiator/new fan motor (which started all this STuff). Then I have a 600 mile ride to Big Spring TX for work on Monday; be nice to get on the road again...

Hey Oldschool1 - When you put the carbs back on, don't forget about rotating the front right carb clamp to its "correct" (as in your screwdriver accesses the clamp screw from the FRONT of the carb, not in between the carbs) position. You'll know when you go to twist the throttle and it only goes about half way... The normal fix is to pull the carbs again and flip the clamp; but with diligent work with a pair of mechanical fingers you can pull the clamp off and flip it WITHOUT pulling the carbs.

 

[Mark]

Good to hear you're getting close to getting it back on the road.

Mark

 

[Oldschool1]

Hey Oldschool1 - When you put the carbs back on, don't forget about rotating the front right carb clamp to its "correct" (as in your screwdriver accesses the clamp screw from the FRONT of the carb, not in between the carbs) position. You'll know when you go to twist the throttle and it only goes about half way... The normal fix is to pull the carbs again and flip the clamp; but with diligent work with a pair of mechanical fingers you can pull the clamp off and flip it WITHOUT pulling the carbs.

Pago - i was just planning on putting "that" boot clamp on the way it was factory installed. It was a pain to remove -but doable with a nutdriver with exactly the right length driver (upper fairing still on) at exactly the right angle.

When i removed the carb to boot clamp for this front right carb, the screw was accessible on the front side of the carb - not in between the carbs. I think you are just saying install it in the factory original position - correct? If other perhaps you can provide a picture.

Thanks,

Oldschool.

 

[pago cruiser]

Oldschool - Sounds like you did it right the first time; much easier that way! It has been a couple months since I tore mine down and waited for parts; so stupid me just put them all on the same way... I'm just glad I checked the throttle before I spent half a day and re-installed all the tupperware...