[Hook]

imported post

1988 1500.



Issue: All good. Shut off bike, restarted and appears to have lost 3 cyls at idle & low speed. Once past low speed, runs OK.



Thoughts: Bike has inhaled one of those #@%!&*& EMGO fuel filters. Probably along with all the crud it had collected before the filter broke off internally.

I'm thinking that there is a piece of something in a low speed jet in one carb.



The Plan:I am in the research phase now...

Once in the garage phase, I will pull the (reasonably new) air cleaner off & inspect the carb tops for any sign of obstruction. Then, inspect for vacuum line issues, then would like to DRAIN the carbs and see what flushes out.



The Question: I see from forum searches that there are carb drain lines. HOW/where do you drain the carbs?



Other suggestions?

 

[englishted]

imported post

There are drain plugs in the float bowls, but if bits of air filter got into the carbs, draining the bowls probably won't clear the bits out.

 

[satan]

imported post

If you've lost low-speed on one carb - you coudl quickly check sync just to be certain that the throttle plate is allowing airflow at low speed (easy-peasy 2-minute check - the older throttle styles do go outta sync more often than the later rear throttle models)



Draining the carb bowls may not clear anything that's lodged in a jet - but it could be helpful in flushing out anything that hasn't settled into an important bit of carb yet ...

the drain screws are just above the collant-plate's collant hose connections.



This photo (linked from this good site) shows were the drain hoses connect at the bottom of the carbs. Following the bosses to the front face (down in this photo - notice the linkage) ... the drain screws (small brass - often confused as mixture screws) face forward out of these bosses:

You can see the drain screws in this photo {line is the sync, so ignore that}: (thanks to Jim)

 

[javis]

imported post

Satan:

How I could quickly check sync?

Thanks

Javis

satan wrote:

If you've lost low-speed on one carb - you coudl quickly check sync just to be certain that the throttle plate is allowing airflow at low speed (easy-peasy 2-minute check - the older throttle styles do go outta sync more often than the later rear throttle models)



Draining the carb bowls may not clear anything that's lodged in a jet - but it could be helpful in flushing out anything that hasn't settled into an important bit of carb yet ...

the drain screws are just above the collant-plate's collant hose connections.



This photo (linked from this good site) shows were the drain hoses connect at the bottom of the carbs. Following the bosses to the front face (down in this photo - notice the linkage) ... the drain screws (small brass - often confused as mixture screws) face forward out of these bosses:

You can see the drain screws in this photo {line is the sync, so ignore that}: (thanks to Jim)

 

[Hook]

imported post

Can you get at the drain screws with the carbs still on the bike?

 

[dadztoy]

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Yes, you can drain the carbs from the front of the bike... It will be easier if you remove the radiator cover... Do this by first removing the middle front cowl, then remove the 2 acorn nuts that hold the radiator cover...

Then get yourself a very long blade type screwdriver - you'll probably need one that is at least 18" long... Then shine a flashlight toward the carburetors and you'll see the 2 drain screws... They will be the slotted recessed screws which are seen in one of Satan's photos...

Les

 

[Hook]

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Thanks Dadztoy,

I'm in Garage mode now. Will do the disection tonight.

 

[satan]

imported post

javis wrote:

Satan:

How I could quickly check sync?

Thanks

Javis

(sorry, I had NO idea that the full sized photos were so enormous :?)





Since sync is basically a comparison of the vacuum drawn at idle and the 1500 has only 2-carbs you can usually check it quickly with one vacuum meter and a set of hemostats (or other quick way to cross-clamp a vacuum line).



With the bike warmed and at a stable idle armed with a vacuum meter equipped with a hose, quickly cross-clamp one of the vacuum lines from the center port of the intake manifold disconnect the clamped line and quickly measure vacuum at that port... disconnect the gauge, reattach the clamped hose, remove your cross-clamping job and move to the other side and repeat.



Remember the reading from both sides and compare. If it's off by two orfewerin-Hg you're prolly OK (for your purposes here, a closed carb would be off by much more than 2 in-Hg).



This is only a quick check and won't get you comparison to balance the values (that needs to be done in real time), but it'll let you know if you've got one carb closed a bunch more than the other carb



(I usually work from the right-side first since my '88 has the vacuum petcock fed from that side; if my numbers are waay off, I'll go back and remeasure or just go for the sync to be certain.)

 

[Hook]

imported post

Update:

The bike is now running fine and the low speed is back to normal.

I removed the air cleaner and blew out the air bleeds with a can of computer duster compressed gas. That seems to have dislodged what I think was a piece of Emgo fuel filter in the pilot jet.

On trying to drain the carbs, that didn't happen.

At the top center of the radiator grill (behind the forks) there is 2 access holes that corrospond to 2 dents in the frame member behind that. From there, with a 12" blade screwdriver, you can get to the pilot air screws for adjustment.

According to the Clymer manual carb picture, the drain screws are just below the pilot screws. I could not see them.

I will attempt to drian the carbs once I can get the bike up on a hoist, and have use of a friends snake camera tool.

Thanks for the helphere.

 

[machinehead]

imported post

Hi Hook , glad to hear you slayed your dragon ., would also be very interested if you find out how to drain those 1500 carbs.? For those who have a winter to deal with , a procedure to drain carbs. instead of the fuel stabil thing would be great. Even if a special tool has to be made to do it.