Vacuum Diaphram cap switcharoo

[TK'S 78 GL1000]

Anyone get the caps mixed up on the carbs? Think i did and now have one that sticks grrrrrrr. Ive been experimenting with switching them around and test riding but its a pain. If i only had a flow bench.................

 

[dan filipi]

Topic moved to General Shop Talk forum.

 

[steveb123]

Anyone get the caps mixed up on the carbs? Think i did and now have one that sticks grrrrrrr. Ive been experimenting with switching them around and test riding but its a pain. If i only had a flow bench.................

You have a shop vac, don't you?

 

[slabghost]

try aluminum polish inside each cap. then rub on a light oil.

 

[TK'S 78 GL1000]

Anyone get the caps mixed up on the carbs? Think i did and now have one that sticks grrrrrrr. Ive been experimenting with switching them around and test riding but its a pain. If i only had a flow bench.................

You have a shop vac, don't you?

 

[dan filipi]

I've always read the caps should be put back and kept matched to their slider so I'm curious how you make out with sorting this.

I gotta bet your not the first to mix them up.
There has got to be a way to sort this out.

Would polishing the slider and cap surfaces not bring them back to "pre-broke in" then they would break in on their own?

 

[Steve83]

I've never seen any actual wear in the caps, and the part numbers are all the same. I would think if they are clean and move smoothly, without lots of side play, they should be OK. Synching the carbs should compensate for any slight differences between them. Just my humble opinion...

 

[dan filipi]

I've never seen any actual wear in the caps, and the part numbers are all the same. I would think if they are clean and move smoothly, without lots of side play, they should be OK. Synching the carbs should compensate for any slight differences between them. Just my humble opinion...

Agreed.

If the slider bounces freely on the spring while inverted in the cap with no interference, it's my opinion that's all that's needed.

 

[dan filipi]

Just wanted to point out that syncing the carbs is matching the vacuum to all carbs so they are the same.
It has nothing to do with the sliders.

 

[TK'S 78 GL1000]

Anyone get the caps mixed up on the carbs? Think i did and now have one that sticks grrrrrrr. Ive been experimenting with switching them around and test riding but its a pain. If i only had a flow bench.................

FOLLOW UP: yesterday after i spent a week thinking about it i did drag out the ole' shop vac. You are able to do this with the carbs still on the bike (hate takin' them off!) if you take off just one intake runner the other supports the carb stack well enuf. remove the air cleaner box and put a small flashlight into the plenum. Set the cruise control to wide open throttle and you should be able to see light thru the carb. fire up the shop vac and put the hose up to the carb. Here's what i found:
Carb 1 & 3 exhibited a sticking slide. 4 seemed ok, 2 would not open at all. I unscrewed the two screws slightly, no difference. i noted that if i picked up just slightly on one corner of the cap the slide would abruptly snap open. i rotated the cap 180 and retightened the screws. #2 now works smoothly. no snapping open. AH HA! now i know how they are suppose to move! Took the bike for a 50 mile ride on the interrstate, worked great at speed. 80 mph nice response. however, once back down from ludacrist speed, upon accleration, im back to a sudden snapping open of one of the slides. Note that all of these cap/slide combinations work flawlessly dissassembled in my hands, and, I have polished the interior with a dremel and aluminum polish. i am convinced there is a missalignment or perhaps binding/distortion on assembly to the bodies. perhaps this is due to the screw torque or over torque in the past...... round 21 today! I'll keep you posted.

 

[dan filipi]

Interesting thread TK.

I suspect sticking slides could be more common than we know. A good test for them would be valuable when rebuilding for sure.

 

[joedrum]

oh yes this is the one spot that cause the most problems if sticking ....its as important as a clogged jet for sure ...I must say ive mixed a lot od caps and slides ...this is more bs than real problem ...human error and just not getting it clean is the biggest problems I had and a good teaching it was

 

[ekvh]

Some have found that the slides initially stick on the carb throat. There can be a slight burr there. Suggestion was to dress the upper edge of the throat where it meets the slide. There is a lot of slop there but it doesn't take much to make it hesitate to move up.

 

[slabghost]

Some have found that the slides initially stick on the carb throat. There can be a slight burr there. Suggestion was to dress the upper edge of the throat where it meets the slide. There is a lot of slop there but it doesn't take much to make it hesitate to move up.

Yes those edges are normally quite sharp. Smoothing those edges helps a lot.

 

[TK'S 78 GL1000]

Anyone get the caps mixed up on the carbs? Think i did and now have one that sticks grrrrrrr. Ive been experimenting with switching them around and test riding but its a pain. If i only had a flow bench.................

FOLLOW UP: yesterday after i spent a week thinking about it i did drag out the ole' shop vac. You are able to do this with the carbs still on the bike (hate takin' them off!) if you take off just one intake runner the other supports the carb stack well enuf. remove the air cleaner box and put a small flashlight into the plenum. Set the cruise control to wide open throttle and you should be able to see light thru the carb. fire up the shop vac and put the hose up to the carb. Here's what i found:
Carb 1 & 3 exhibited a sticking slide. 4 seemed ok, 2 would not open at all. I unscrewed the two screws slightly, no difference. i noted that if i picked up just slightly on one corner of the cap the slide would abruptly snap open. i rotated the cap 180 and retightened the screws. #2 now works smoothly. no snapping open. AH HA! now i know how they are suppose to move! Took the bike for a 50 mile ride on the interrstate, worked great at speed. 80 mph nice response. however, once back down from ludacrist speed, upon accleration, im back to a sudden snapping open of one of the slides. Note that all of these cap/slide combinations work flawlessly dissassembled in my hands, and, I have polished the interior with a dremel and aluminum polish. i am convinced there is a missalignment or perhaps binding/distortion on assembly to the bodies. perhaps this is due to the screw torque or over torque in the past...... round 21 today! I'll keep you posted.

Well guys, it seems the slides wanted lubricated. I noticed the chrome stems that fit into the bronze bores had a "residue" that was NOT slippery and the bronze bores had the appearance of being "run dry". I oiled all 4 generously and reassembled. All 4 worked flawlessly. I'm left to conclude that there must be a reason Honda coated them with Teflon. Long term test coming up.

 

[dan filipi]

Maybe another reason to run atf in the gas?

 

[TK'S 78 GL1000]

ATF ? Haven't heard of that, I did consider 2 cycle oil though, I use it in my John Deere regularly.

 

[joedrum]

atf good ...better than two cycle oil ..about 6-8 oz per tank ...it may smoke some at first while its cleaning thing up just back off mix amount till it dosent smoke much ...no down side at all in oldwings

 

[TK'S 78 GL1000]

Carbs are rebuilt, wondering what needs cleaned up??

 

[joedrum]

inside of motor carbon buildup and it will clean your carbs even better than you