Major issue with bike possibly carbs

[Forbin99]

Hey all, new to the forum would really appreciate some help. Excuse the long post

Bought an 85 max with 14k on it

After riding all summer one day on my way home it started backfiring like crazy and riding like crap. Barely got it limped back home

Upon inspection i noticed the airbox wasn't totally seated on the carbs and the breather house was not attached and there was oil all over/in the carbs

I cleaned them off and tried the peashooter and shotgun methods and changed plugs and had a little success as it ran great again for about 30 minutes then went back to backfiring and totally died

I decided to take the carbs off and completely clean them but i am still having issues. The bike will idle but when i give it any throttle it instantly dies

I noticed the boots under the carbs were all cracked so i ordered some new ones that I'm waiting on now but i fear this won't solve my issues.

I also noticed that the tachometer isn't moving anymore since the carb cleaning

Any ideas?? Thanks in advance

 

[Fire-medic]

One thing at a time, wait to get your carb boots and put those on and see whether or not you have your vacuum leak cured, that's what it sounds like.

You need the air box and air filter and lid in place for the engine to run properly on a stock engine. If you're trying to see if the engine will run with it off it's not going to run right.

Did you try using some starting fluid around the boots with the engine running to see if the revs picked up?

About the tachometer take a look at a wiring diagram and check the connections it's probably nothing more than a loose connector.

 

[Forbin99]

thanks for the reply. the carb boots just came so i slapped a headlamp on and ripped the carb stack off. While i was shining the lamp down in the vboost intake manifold i noticed there was all kinds of black sludge in there. i am assuming this isn't good. i am going to take them off and clean them tomorrow AM before putting the new boots on.

re: the tach. the thing i found strange is that the tach only seems to not work when the bike is in this bogged down state. it died when the whole bike dies the first time then came back to life after the shotgun cleaning when the bike ran temporarily. weird.

anyways i will clean the intake manifold, put the new boots on and report back tomorrow

 

[Forbin99]

Update: so when the boots came i completely disassembled the carbs again and cleaned them.turn i reassembled with the boots and it ran. It wasn't perfect but it ran. I could never get my airbox on there right and the boots were never able to clamp down on the carbs and i chalked it up to that.

I took it out that night to dinner, took it home. The next day i rode out to the store, everything was ok.

The following day the same issue reappeared. Would idle perfectly but die under throttle. So i ordered some air pods from Amazon. I know these aren't great without rejetting the carbs but the vmax is my only mode of transportation right now and Amazon could get them to me the next day for 12 bucks shipped... I'm just trying to see if i can get it running

So i slap the pods on and finally get all the carbs synced up correctly and this thing is running amazing. I take it out for a half hour and this thing just runs great, better than it ever has.

I take it home and go to fire it up the next day and guess what? Same damn thing again. Idles perfect, dies under throttle! Argh!

So i pull all the carbs AGAIN and completely disassemble and clean them. No help...

Anyone have any ideas??

 

[Forbin99]

Oh this thing is also coughing through the carbs constantly whenever i try to give it throttle

I've tried every a/f mixture screw in every position..

 

[Traumahawk]

With the pod filters on, your actually getting to much air into the carbs....and so you need air correctors.

I read above that youve tried a shotgun to clean the air fuel circuit? With the problem clearing.....and then coming back.....I wonder about rust from the tank. Has the fuel filter been replaced?

The boots....were they new or used? if they were new, then everything shouldve slipped on. The carbs have a lip around them, and that should fit into a groove on the boots, so loosen up the clamps, spray the inside of the boots, and see if that helps getting them on the carbs and getting the airbox back on?

 

[Forbin99]

Yeah i know I'm getting too much air with the pods but that's an issue I'm going to worry about later. I had the thing running amazing with the pods after a carb cleaning before it went back to dieing under throttle. I just bought them because i cannot get this air box to fit on the carbs for the life of me. I need new airbox boots but went with the pods because of the next day shipping just to get something on there and see if i can get the bike running.

I've done a lot more than shotgun that was just the first thing I've did. I've had these carbs completely apart and cleaned half a dozen times now.

I haven't changed the filter but when i bought it guy told me it was new. Gas coming out of the pump and drained bowls looks crystal clear.

The boot not fitting issue was in reference to the airbox boots. I have the carbs connected to the vboost manifold just fine.

Thanks for the reply

 

[Traumahawk]

One thing that happened to a friend of mine. The brackets that hold the carb rack together, go in a certain way. If the brackets are bolted in the wrong order, or together incorrectly, the airbox wont fit.

 

[putin]

Interesting. Looks like you can solve the problem with replacing the whole carburator.