Hey guys, Im new here.

I bought this CBR about a month ago and ive been slowly working on it.

I bought it with the engine out of the frame, so i recently put the engine back in the frame. I also disassembled the carbs and cleaned them up.
Next i took out the spark plugs, They all looked like new, but cleaned them anyways.

All the plugs get a nice blue spark on the tip when grounded to the head of the engine.

As it sits right now, I have it without any of the fairings on, no tank, engine in the bike with carbs installed (new intake boots, old ones were cracked)
Throttle cable hooked up to the carbs.

I have the two into one fuel line and i have a funnel hooked to the end of the line filled with fuel to fill the floats on the carb.

I have the battery fully charged, Plus i hooked up a car battery with jumper cables because it seemed like it was cranking a little slow.

I tryed starting it, and got nothing. no sputter no anything. then out of nowhere a big BANG, backfire.

Cranked for a while longer after that and then got a second big BANG.

Decided to stop for that day because im sure im neighbors wouldnt like to think i was firing off a shot gun.


Next time i tryed about a week later, I tryed starting again. Got nothing at all. Pulled the plugs, they seemed almost dry, barley any fuel on them. So i poured some fuel into the carb intake and tryed...still got nothing.

Kept trying and trying got nothing, got a couple more loud back fires, and a few small ones.

With choke fully on that day and barley any throttle, it kind of sounded like it wanted to start but just didnt have that extra Umph.

any more then that little bit of throttle and i got nothing at all. Any less then that and i got nothing. But full choke tiny bit of throttle and it seemed like it was about to, but just wouldnt start.

I have no idea what the deal is, if anyone has any ideas, please let me know! Im lost as to what it could be.

Only two things i can think of are, One, theres two nipples on the carb above where the fuel lines are that according to bike bandit are supposed to have a piece of fuel tubing on them and then cross each other outside of the airbox, and do nothing else. SO im pretty sure that thats not affecting it.
The second thing being that the guy i got it from re-wired the stator, so instead of the stator connecting to the main wiring harness, it went straight to the Reg/recit and then off the volt reg went to the green/red wires off the main harness. And i do not have that hooked up, i still have to look and see exactly where the wires go. But that "shouldnt" affect anything because it has a pulse generator on it so the only thing it Should be used for is to charge the battery once the bike is running.


Please help me before i scrap this thing

Thanks!

 

There are three things to check when trying to start any engine....
Compression, Fuel and Fire.

How's the compression on each cylinder? I'd expect something over 100psi - probably like 140 without checking any references... If you have crappy compression, it can be due to all sorts of issues.

Next - fire. You've got spark which is great. Is the timing aligned? Spark at the wrong time is really bad for an engine. From your backfire description, I'd guess that this is your problem.

Last - fuel. Fuel gets atomized by the carbs - dumping fuel inside is a bad idea. Get some starting spray at the auto store. It's basically ether - you shoot some around the carb intake and crank the engine.... but check your timing first! especially on a non-running engine.

If the timing is over advanced, you can easily put a hole in a piston and kill an otherwise perfect engine. (That's experience talking)

Will

 

The compression i have not checked yet, because i dont have a compression gauge.

How do i check the timing on this bike? since it has a pulse generator?

I forgot to mention in my post, i did try starting fluid sprayed directly into each carb opening, and it didnt do anything. It actually made it sound Less like it wanted to start then without it

I thought about timing too at first, but kind of ruled it out due to the pulse generator. But if theres a way that it could be off, id like to check that.


Thanks for the help

 

Well guys, went out today to try and start her up. Same thing, car battery with jumper cables hooked up to it. Cranked it for a while full choke and tiny smidgen of throttle and it sounded like it wanted to start.
Kept doing this, and it kept starting to sound like it wanted to start more and more, and then finally after around 5-10 minutes of cranking it, she fired up!

Let it run for a little bit. then stalled it. Checked to make sure no leaks and everything was good. (Theres two bolts on the valve cover that look like theyre spitting a little bit of oil) What does this mean and how do i fix it??

Went to start it back up and still VERY hard to start. had to use choke still and got a back fire or two then finally started again.

Sounds pretty good when shes running though.

Any help would be awesome, Thanks guys!

 

Try adjusting the pilot jets so it gets some more fuel!