Hey new to the forums here and could use some help. I've looked through some threads already related to this topic and I still cant figure it out so I'll just get to my story.

I bought a 96 F3 at the beginning of the summer and it ran fine, started easily, pulled hard through the revs etc. A few weeks ago I was riding with no problems at all for about an hour, stopped someplace and shut the bike off for about 5 minutes and then when I restarted it I was only running on two cylinders. Above around 6000rpm it would run on all 4 and I got the bike home.

When I came back to issues a few days later I could only get it to run on almost full choke and as soon as you touched the throttle it would die. So I figured carbs. I broke it down cleaned the carbs up which didn't look too bad and threw new plugs in while I was there. I also noticed lots of posts about the fuel pumps going bad on these bikes so I checked that and its working fine.

Anyways put it all back together tonight and it will not start at all. You can smell fuel so I know its getting it. Double checked plug wires are in the right places.

Any help you guys could give me would be great

 

turn over or no ? main fuse good ? battery grounded good ?

Welcome to the Forum BTW

 

Yeah it turns over fine. Battery is good and charged.

 

So pulling a plug out an grounding it ....you seeing spark ??
and wires back on it right order ?

 

Hey Sorry I've been MIA lately. Here's the latest....

Pulled the carbs off again and cleaned them again. Pulled all the plug wires put a plug in them hit the starter and have spark on all 4. Did a couple resistance checks on the coils and the ignition pulse generator that I found in the manual. Both of these were also good.

Put it all back together and it started and ran on 2 cylinders on choke. With choke on or off as soon as you gave it throttle it died. I hit it with some carb cleaner which didnt seem to help at all.

Eventually as the bike warmed up the other 2 cylinders kicked in at idle, I could slowly get it to rev to about 4000 rpm but then it would die (which makes me think high speed jets).

Once the bike was hot, like with the fan running hot, I could rev the bike up but not smoothly at all. The backfires were so bad it is shooting flames out the exhaust.

Any thoughts or suggestions would be great!

 

How u know the fuel pump is working? Sounds pretty much like mine when my fuel pump went out. I took the end of fuel line off from out bound and there were only drops coming out. Should be a stream. The contacts stillooked good so I wasn't sure but indeed it was the fuel pump. So I would check outbound fuel. Make sure to have a shop rag.

 

At this point I've bypassed the fuel pump by putting my own fuel line into the carbs with a primer bulb and these problems still occur.

 

It does "sound" like main jets but seems unlikely that it's more than one. Why would several block at the same time. Are all the hoses connected and flowing correctly. Going from memory there's some that distribute fuel between carbs and of course distribute air from the ram air system. If there is either a block in either fuel or air pressure distribution it could cause something odd like this.

 

I experienced some similar symptoms with mine after leaving it sit for a long time - only full choke and rough until warmed up, and then not being able to rev smoothly once warmed up - along with the backfiring and flames out the pipe!

After seeking advice from a local (ex racer) mechanic, the symptoms indicated it was running too lean - turned out to be the main jets.

Not sure if this'll help, but it worked for me