Hi all

I have to move, and have only been given one months notice so I thought I would get the CBR up and running.

Around 2 weeks ago I got a whole set of plastics, the lot!

The bike had been sitting outside in my storage arear for around 6 months, and was very hard to start when I put it away, so I did the following.

Cleaned carbs
Did valve adjustment

Now the bike will only run on 3 cylinders, with number 2 not running.

I ran a compression test and came back 130+psi on all apart from number 2 which was 105psi. The engine has done 87,000 miles.

Very annoyingly, I now only have a short period of time to sort it out, or to decide to scrap.

I have done lots of little bits like brake overhaul etc, HT leads and plugs etc.

Am thinking of maybe getting a MK1 bike and swapping the good bits onto it, but im pretty sure the plastics wont fit.

Any ideas?

 

Even with only 105 pounds #2 should fire. Check the headers when the engine is running - or immediately after shut down. The cooler header will tell you which cylinder is not firing. You could have a wiring problem, a bad spark plug, etc. You might recheck the valve settings on cylinder two. Not that I'm speaking from experience or anything like that.

 

That what I thought,

Yes header number 2 is cold, I have spark, I have fuel and I have compression.

I am going to get some new fuel as the one in the tank has been there for 7 months now, after lots of head scratching it might be the issue!

 

Given you've provided compression numbers, a leakdown test seems to be in order. If the valves are adjusted correctly, one would think a bad exhaust seat. Leakdown will show.

 

Oops sorry to make the problem seem more difficult...is the #2 plug sealed correctly? Good gasket, no grit in the way, crap in the plug well or drain through cylinder head et cetera.

 

Right update for everyone. I bought a spare set of carbs from a running bike, installed, now I get coughing on cylinder 3 and it wont run.

It coughs through the intake every now and backfires out via the exhaust, but thats it.

Im going to put the original carbs back on to see if there is an issue there.

Im really trying to get this bike up and running without replacing the engine as I need it back together and going in 20 days! argh

 

All good on that side, no chuffing noises from the plug wells and have put a new set of plugs in as well just to confirm.

 

Another question? Are the plug wires and coils correct for their respective cylinders? Ie right place right sequence?

 

BINGO!

God im an idiot.

About 4 months ago I nicked a coil to test on my VN800, and I completely forgot that coil 1 feeds 1 and 4 not 1 and 2 and vice versa!

Put them in the correct order today and it fired up!

Thanks for the help all! Now I just need to sort the rest and it can go for an MOT. Happy days.

 

Cheap fix
Guarantee you won't make the same mistake again..........
(I speak from experience)
Put the spare carbs away for spares........