So yesterday I finally got in a replacement jet for cyl 4 pilot jet. Cleaned out all of the carbs (was pretty nasty in there) put it all back together and the bike finally came back to life...only to show another problem. I can't get the idle back up to the 1200rpm recommendation. Along with that the idle (which is around 600-700rpm) is very rough, and when I go to twist the throttle the bike dies.

Now I'm thinking I may have to check the float bowl levels, but I'm kind of lost after that. I'm a mechanic and I know a lot about fuel injection, but not too familiar with the finer points of carbs. Any and all help would be greatly appreciated.

 

Do a search in the how-to's on carb sync and idle adjust.

When you replace the jets, you need to turn them out a specific
number of turns, that gets you ball-park. Check the manual,
or maybe someone else can pop in with that info.

To get it rightous though, you need to do a final tune with a set of vacume guages
and a RPM guage capable of 50+/- accuracy.

You may have noticed the idle adjust ****, it's mounted on a spring-coil.
You can try that to advance it a bit, so you can warm-up the bike to do your
above-mentioned, final adjustment.

Hope this helps, Ern

 

Thanks, I'll take a look at it tomorrow when I go into work.

I assumed the jets were just screwed down to finger tight, didn't know about the backing off, until after reading your post I double checked my clymer's manual and saw the 2.5 turns out. I'll start with that.

I was trying to play with the idle adjust screw but to no avail. I don't have the vacuum gauges to sync the carbs, besides buying one any idea if there are places that would loan them out? Kind of like autozone does with car tools.

The good news is, after doing an oil change on the bike (which was obviously needed) my chain/valve train clatter went away, I guess it wasn't being properly lubricated. I'll give you guys an update on what I find. Thanks again.

 

Assuming there aren't any other problems it should run ok with all 4 mixture screws approx 2.5 turns out before you do the final adjustment. I can't remember if it's in my factory service manual or clymer manual but there's a good section on syncing the carbs and also the fine tuning of the mixture adjustments.

You can make a DIY manometer (vac gauge) for cheap if you don't want to buy one. The actual number reading isn't really important as getting all 4 carbs even with each other. I made one out of clear vinyl tubing and some t-fittings mounted up to a poster board, and then filled the tubes about 1/3 or so full with ATF. Reason for ATF is so if you accidentally suck the fluid into the carbs if they are way out of sync that it won't hurt the engine. Plus it's really easy to see. The hardest part was making adapters to attach the hoses to the carbs. I ended up using some allen head screws & drilling the center out.

I don't have any pics on my computer, but I can take some tomorrow. It would probably make a lot more sense seeing a pic of it instead of a description.