Bike Still Won't Start

[bpratt18]

Hi Everyone,
Looking for some suggestions on my 84' VT700C. Recently was running, but would suddenly lose power and appear to be running on only one cylinder. So, I changed the fuel filter and made sure gas was getting to the carbs (which it was). After this the problem was fixed for a little while, but then came back. I then removed the carbs, and soaked them over night replacing the o-rings and float needle. There was a crap load of gunk in the float needle filter. They were bench synced and reinstalled. Now the bike won't start at all, I thought maybe some water got in the fuel line so I drained it and put in some Heat. Any ideas?

[MarineCorpsFlorist]

did you check the spark?

[dgraves49]

The Shadow uses a fuel pump and takes quite a bit of cranking to fill the carbs.
Turn the ignition on and rock the kill switch off and on several times. That should pump the fuel to fill the carbs without wearing out your starter. If that don't work, have you checked for spark?

[mattyo]

Originally Posted by bpratt18

They were bench synced and reinstalled.

What do you mean by that? When I prepared my carb for re-installation, I set the a/f screws to 2 turns out, set the idle screw so the first butterfly was just barely touching the wall, then set the sync screw so the second butterfly was just barely touching the wall. When I put the carb back on the bike I had to turn my idle screw in 3-5 more turns to get the engine to start and when I sync'd my carbs, they were initially way out of sync. So I'm not sure what you mean by "bench sync" but if it's similar to what I did then I wouldn't trust it too much.

+1 on what was already said. Make sure you have a good spark and fuel in the float bowls. When you cleaned your carbs did you blow out all the little holes and passage ways with an air compressor? I've read other posts here where guys clean their dirty carbs the first time and some dirt or gunk gets freed from one place but then gets lodged in a little hole or something somewhere else. So they pull out the carb and clean it again paying a little more attention to all the little holes and passages and generally have better luck afterward.

[bpratt18]

Thanks everyone. Going to check for spark tonight when I get home. In regards to the bench syncing process, I followed exactly the procedure you listed above, but maybe you're right about adjusting the idle screw. If that doesn't work then I will pull the carbs again and make sure all ports are clear. I'll let you know how it goes, thanks for the advice!

[John Hopkins]

Originally Posted by bpratt18

Hi Everyone,
Looking for some suggestions on my 84' VT700C. Recently was running, but would suddenly lose power and appear to be running on only one cylinder. So, I changed the fuel filter and made sure gas was getting to the carbs (which it was). After this the problem was fixed for a little while, but then came back. I then removed the carbs, and soaked them over night replacing the o-rings and float needle. There was a crap load of gunk in the float needle filter. They were bench synced and reinstalled. Now the bike won't start at all, I thought maybe some water got in the fuel line so I drained it and put in some Heat. Any ideas?

You have done everything that you should have done but if you have loose rust in the fuel tank it will just need doing again until you clean the tank..as to the carbs..well all the work is wasted if either you have a pinhole in the diaphragms or you trapped one putting them back together or one of the floats is stuck..even putting the choke cables back wrong can be the problem...I would bet money that you have to strip the carbs again before this problem is fixed.

John.

[stlouisaaron]

If the spark looks good, check into the pulse generator. I had the exact same issues with my '83 this summer. The running on one cylinder could be the ignition coil, the cdi boxes under the seat, or the pulse generator... or the wires. Mine ended up being the pulse generator. My bike would run ok when cold, then go to one cylinder - and I would lose my tachometer at the same time. Also, check your main fuse - on a bike this old, it can be corroded and not be conducting enough juice to start the bike, but enough to get power and turn the starter.

[bpratt18]

Okay so I pulled the carbs, re-cleaned them and blew out all possible ports to make sure they weren't clogged. After reinstalling them, I made sure I was getting spark and noticed the plugs looked a little gross (blackened, with some build up). Bought and gaped new plugs along with new connection caps and the bike still wouldn't start. I noticed that the reservoir tank would make gurgling noises after I tried to start it. After reading around I found a post describing a possible clog due to using a tank liner. I used a tank liner for the top tank only, is it still a possible cause for a clog? I'm going to check the fuel flow tonight and see if there is any restriction. Any hints?

[TxShadow49]

What kind of bike do you have that has 2 tanks. If you are talking about yout reserve that is not a separate tank, its just a pickup that goes lower. You may have gotten tank liner in the petcock or reserve.

[John Hopkins]

Just spray some gas into the carbs, if it starts you need to clean out the fuel supply from the tank down to the carbs.

John.