CV Carb Issues Part 2 - GS450E

[Westy62]

Well, I have replaced everything on and around the carbs like in my previous posts, and have had them off 6+ times.....I figured for sure it was a problem with the vacuum diaphram not lifting the needle jets (or were lifting but no fuel was there)......I took the suggestion to gut the airbox (remove the seat also), and try to spray some carb cleaner in the carbs when it bogged......and NO BOG!! It runs like crazy without the seat, airbox cover, and air filter!! I didn't have to spray in anything....

There must be some restriction not allowing enough air in to lift the CV carbs needle....I put the seat and airbox cover back on (no filter), and the problem comes back, but not as bad......Carbs have been rebuilt.

Any clue why the needles aren't lifting under normal airflow? This is madning, but at least I finally had something change the problem!

Whew!

[chef1366]

Check the diaphragms through a bright light or sunlight and look for pinholes.

[DimitriT]

Are you sure its a carb problem?

I recently had the carbs off the 550 and did a final cleaning and install as part of some top end work.

While the were off I played around with the sliders a bit.

You can test the sliders by gently puffing some air into the slider intakes. You can either use a compressed air nozzle (from about a foot away) or the compressed air we all have.. your lungs.

Gently puff some air into the slider and it should lift and slowly drop. It doesn't take much.

If you slider diaphragm is leaking you may have to get a new one. These are really expensive to replace.

When I first got my 550, the carbs had already been abused by the previous owner. One slider had been dropped during an old cleaning and there was a burr of metal which kept it from moving smoothly. I sanded it off and it worked alot better.

It wouldn't hurt to go over the carbs and check this stuff but you should also check other items such as your valve clearance and your charging system.

These can also cause running problems.

[Westy62]

I'll look for pinholes again....they seemed to be in great shape when I've looked at them.....I even put some grease around the seal area to help with possible leaks there. The charging system ignition, and valve clearance have all been adjusted/checked.

Can the diaphram springs be stiffer than normal from a long storage? It was stored by the previous owner.....They seem to be in good shape and springy though.

I blew compressed air in, but had to get a few inches away from the air vent hole that travels into the diaphram, I couldn't just blow air a foot away in general, the needle wouldn't rise.

Either way, I need to look at that whole setup in there....the sliders just need too much air to lift, that must be the issue.

Thanks!