New engine not starting

Just finished installing a new engine to my 91 fzr250. The new engine is a combo of a new bottom end, and the old top end. I can't get the thing to start, however the old engine did have similar trouble starting. It just cranks over and over and there is the occasional misfire. I actually got it to start a few times, however it wouldn't rev, and I pretty much had to hold the throttle open just to get it to idle, and even then it didn't sound right. I've been fiddling with the pilot screws and it didn't seem to make much difference. The correct setting is 3x360 degree turns yeah?

Have checked the leads and they seem to be putting out a spark when tapped against a screwdriver. Fuel pump seems to be delivering fuel. Float level of the one carby i could get to was at the line. Not sure what else to check. Also, can anyone confirm the correct lead order for the 3LN1? I've found that one picture floating around, but wasn't sure if its the same for this model.

 

Well I took apart the carbies and cleaned them out. They didn't seem dirty or anything. Put it back together and didn't really notice much improvement. I took a video of me trying to start the thing. Sometimes it would barely run without holding down the starter. Most of the time it would die as soon as the throttle moved. You can see this in the video. I also noticed a bit of smoke coming out of the exhaust after I turned it off. Didn't seem right, but that could just be oil burning off it.

http://www.youtube.com/watch?v=uZeXQPrmnGc

 

Ok thanks. I had to install the new engine due to my old one destroying a rod bearing. For the fuel mixture, I turned the pilot screw three turns out, however how do I know if the screw is in all the way to begin with? I know there is a spring on the screw, and it was getting harder to turn the more it compressed, until it got to the point where the screw driver would start to slip off it. When it got to that point, I turned it back 3 turns.

I will try a propane test next. Would this product perform a similar function? - http://www.nulon.com.au/products/Aerosols/Start_Ya_Bastard_Instant_Engine_Starter/#.TwoxSG9OBoM

That would be easier for me to obtain that a propane tank, however it may not have the same result.

When I cleaned the carbs, I took all 4 apart. Took out every part in the carb and washed them with carby cleaner. Choke seems to work fine. Checked that it worked when I had the carbies out, however I am fairly new to bikes so I am not sure how I am supposed to use the choke properly.

 

Tried the propane thing. Didn't seem to do anything. I wasn't able to find proper propane, so I used a butane bottle. Don't think it would cause too much difference. I think propane is a bit harder to come by in my country.

I haven't got any tools to check valve clearances unfortunately. This is my first bike so I'm new to all this. Only rid the bloody thing once before the engine died.

I sprayed the gas into the airbox sealed with the fuel tank removed and tried to get it to start. Got no response from it other than the usual. That was with the choke open too.

Does the kickstand switch make any difference to this? I think the cable is a bit dodgy where it connects to the stand, so I disconnected it and tried again but it had no effect.

 

Yeah I tried each spark plug against a screw driver and they all had a spark. Not sure if it was a strong spark but it was there. Had a feeling my leads could be dodgy or in the wrong order, as the end that goes on the spark plug came off a couple of them. Had to screw them back on after chopping a bit off the lead, so thought they could be damaged.

Is there a way to check if a fuel pump is dying? It seems to make different noises on startup from time to time, but seems to pump fuel when i take the hose off.

 

Well I had some success. The floats all go up to the float level mark also.

I got the bike to run, without any starting spray or propane, etc. Been fiddling around with the pilot screws and starting it with the choke on. It would start, but I would usually have to hold the throttle open, press the start, then close the throttle and it would idle. I also had to fiddle with the idle screw a bit.

It seemed to have two different ways it wanted to run. First, the idle pretty slow, and if i touched the throttle it would usually not do a lot and then want to stall. Then randomly the idle would jumped up a fair few revs, and from then I could touch the throttle and rev it and it would settle down fine after that. Then it would go back to the slow idle and do the same as mentioned earlier. Posted another video to try demonstrate.

Thanks for your help so far guys. I think I'm getting close to sorting this.

http://www.youtube.com/watch?v=SgQloEUf00I&feature=youtu.be

Sorry for the crappy sound in the video. It drops to the low idle around 45-50 seconds in, when I try rev it again before it dies. It also has the low idle between 5 and 10 seconds.

 

Hmm air leak would make sense. I will look for that next.

I also believe I have found some problem to do with the fuel filter/pump. I could get the bike to start with a quick shot from the butane tank, but then it would die after about 10 seconds or so. Decided to try bypass the pump, and ran a pipe directly between the fuel tank and the carbies. Ran a lot better. It didn't die, would idle and wanted to rev. Didn't seem to do the slow to fast rev changes like before but I will keep testing.

 

My headache continues. I got the bike running with a new fuel filter, so fuel pump is working wine. Must have just been clogged. Still can't get the thing to rev properly from idle though. It starts up fine without any assistance, however each of the carbies behaves differently. I could not find any evidence of an air leak anywhere either.

I tried fiddling with the slides by opening each one manually and noting what happened.

Carby 1 (closest to the choke) - Would rev a little, then the bike would die. Fiddling with the pilot screw has made this a bit better.
Carby 2 - Revs drop a little, nothing else happens.
Carby 3 - Nothing noticable happens
Carby 4 - Bike revs a lot, and continues to stay revving after I let go of the slide. I'm guessing this carby is working fine with the air fuel mixture.

I could not get the bike to rev up from idle unless I touched the slide for carby 4. If I opened the throttle, the revs would stay low and the bike would sound like it was struggling a bit. Once I touched carby 4's slide, even slightly, the bike would rev ok and I could get it to go up to 8k or so with the throttle.

I believe it could be an electrical problem also. I unplugged each of the two coils while the bike was running. If I unplugged the coil for 2&3, the bike started to struggle a little bit but continued to run. If I unplugged the coil for 1&4, the bike died pretty much immediately.