Won't start

Well I should say that it has never started with me. When I bought it it had been sitting for some time. It would try to start with carb cleaner but that was it. I took apart the carbs and cleaned them out, I replaced the diaphragms with the JBM Industries ones, I changed the jets to match the exhaust and intake. I also changed out the float needle and what ever else came with the carb kit. I have yet to check the valves but that will be next, I am waiting on the tool to be delivered.

Here's what it does, it will basically make a chugging sound and white smoke will come out of the exhaust. If I spray carb cleaner in the carbs it will pop and shoot out a flame from the exhaust. Sometimes the exhaust will come out of the carbs. I am guessing my valves are way off but not certain. Any tips? I'm sure my carbs aren't sync'd correctly so I may take them to a shop and have them go over them but I would rather find the issue myself.

 

Sounds like its flooding to me,did you change the jet sizes?

 

Yes, I upped the main and pilot per Chacal's calculation

 

Hi. It's my understanding that your valve clearances should be checked/adjusted before even thinking about any other changes/adjustments. Hopefully some of the more knowledgeable folks will chime in here to help you out. Just my 2 cents worth-good luck to ya.

 

It might help if we knew what bike, what mods you're jetting for, etc.

Basically, IN ORDER:

-Valves in Spec
-Carbs clean and pass the clunk test
-Float levels wet-set individually using fuel and clear tubing
-Accurate Benc Sync

then it should run well enough to do:

-Running vac sync (with YICS blocked if applicable.)
-Mixture tuning.

IN ORDER. Skip any, take shortcuts, be less than meticulous with ANY of the steps and you'll just have to go back and do it right.

 

1983 XJ750 Maxim, 2 sizes up on the main jets and 1 size up for the pilots. Mods are pod filters and 4-2 open exhaust. Currently the exaust is just open at the header pipes while the exhaust is being fabbed.

Waiting on the valve tool to be delivered to check valves should be here some time soon. I followed the carb cleaning faq, dipped the carbs in chem dip to clean them out. I don't feel comfortable doing the float levels and/or bench syncing with the guides currently available. I feel like I am missing something because it never comes out right.

Anyone in the Dallas area want to give me a hand?

 

Chem-dip is a great product for cleaning carbs but it will eat any rubber and plastic it comes in contact with. I hope you totally dissambled the carbs before dipping them. If not your throttle shaft seale are probably leaking badly now. If you left the carbs assembled and dipped them I would recommend taking them apart and replacing all those rubber pieces. Don't be afraid of bench syncing or float checking, its not hard. If skipped durring carb checking you will have problems.

 

I removed the spark plugs and they were black, I grounded them out and they produced a white spark