Hey folks. Got my '91 running pretty well finally. Still a few minor issues but the bike growing on me. One thing I've noticed is at lower rpms I get surging or bucking. I've always wondered about these carbs that were in bad shape when I found them. Anyway, it looks kind of funny when I'm trying to put in a low gear (pulling up to get gas) and she starts looking like a bronco farting. The carbs are sync ed. Any ideas? It pulls out of it when I give more throttle. Maybe there's a blockage in one of the carbs somewhere?
Mine did the exact same thing before my rebuild. I am nowhere an expert when it comes to carbs. My stab at this the possibility that you are a tad on the lean side. If you have adjustable needles, move the clip down one position which will move your needle up.
If you have OEM needles place a needle washer under the clip.
Fred
Turn your mixture screws out half a turn and see if that helps. The manual states 3 turns out for my model, but at that setting it hunts at idle ( sounds cammy ) and jerks at low revs. Runs a lot smoother at 3.5 to 3.3/4 turns out.
Make sure your 2 large vent hoses for your carb bowls are not kinked or blocked.
Ask me how I know....ok I'll tell ya, I thought I was being clever and ran longer vent hoses. They were too long and ended up touching the top of the exhaust collector box. You can guess what happened....exhaust collector boxes get toasty hot....the hose ends melted and blocked off air from the carb bowls.
Then, all kinds of interesting things started to happen..... Like surging.
Quote from: Pat Conlon on May 07, 2016, 12:17:55 AM
Make sure your 2 large vent hoses for your carb bowls are not kinked or blocked.
Ask me how I know....ok I'll tell ya, I thought I was being clever and ran longer vent hoses. They were too long and ended up touching the top of the exhaust collector box. You can guess what happened....exhaust collector boxes get toasty hot....the hose ends melted and blocked off air from the carb bowls.
Then, all kinds of interesting things started to happen..... Like surging.
Fortunately, I found the problem. i was checking valve clearances and i noticed One of my homemade plugs gave out on the #2 carb. I had a small piece of hose with hot glue on the end to plug it in a pinch. Well the glue gave way and it was pulling air in. I used epoxy this time. It's all better again.
Thanks for the suggestions
Are those the plugs (caps) on the intake manifold ports?