First of all: Thank you. You guys were spot on in your analysis.

Cam timing should be good according to the line ups but I'll drop the engine from the frame (hard to work with it in the frame) and check it together with the cams. But I am a sure this time that I did not mix the cams up. I checked, I double checked and then I checked again before I put the cover back on. But still, there must be something wrong with it...

By the way, a -94 engine would fit right in if I'm not mistaken, correct?

 

I don't know. I'm sure the answer is somewhere on this forum though.

 

Ok, here's a couple of my random thoughts.

yes, a 94 engine would bolt right in. 91-94 are all the same.

You don't need to drop the engine to check the cams and timing. Drop the radiator and pull the airbox/coils/carbs and you should have room to check everything. The cams say in/out on them. Also, did you put all the shim/buckets back in the same places? If not you will have to reshim all the valve as your clearances will be off and you may have valves that aren't fully closing.

Compression readings should be around 175 psi or 12 bar. Even if you lined up the ring gaps, you should be getting more than 12 psi. Double check to make sure the compression gauge is working. Did you lube the pistons and rings when you put them in? If you put them in dry, then put a squirt of motor oil in each cylinder and see if the reading go up.

The F2 is an interferance motor. If your timing was way off, the motor wouldn't turn all the way over. If it's off by a little, you should be getting some kind of popping/firing. From the recording sound, it turned over fine, but it didn't sound like it was firing at all on any cylinder. My first guess would be electrical, no spark. Just for kicks, try putting just a squirt of gas in each cylinder. If you get a pop, then you've probably got spark, so at that point it's either fuel or timing.

 

Phil, my hero! Thing is, I just found an engine quite cheap just around the corner that I will try to buy. That way, I could put the new one in and work on the other one just for kicks.

And you know what? I just spoke to a mechanic who said the same thing. Even if I lined the rings up I should be having more compression than that. I think I'll test the compression gauge on a bike I know is working to be sure.

As far as the cams, I am sure that I put them right. It's one of the few things I'm sure about. And since I removed everything one at a time and put back, I am positive that I didn't mix up any shims either (yeah, I know, I impressed myself with being that thorough). I did lube everything but maybe I was a tad to cheap on the lube too. But shouldn't having tried to start it so many times have lubed it up by now?

Tomorrow I'll check the plugs too. They are brand new iridium plugs, so maybe I didn't put them in properly. I'll check for spark anyways.

Again, Phil, thank you very much!

 

I'm still thinking it's something electrical. Here's why.

There aren't a lot of things that will cause you to have low compression in all cylinders. So either the gauge doesn't work or your valves aren't closing fully. You could try doing a leakdown test if you have the equipment.

Fuel is also fairly straight forward. Carbs just dump some gas down the intakes. You can fake this by just pouring a bit of gas in each cylinder and crank the motor. Most engine cough sputter and run just a bit.

What you're seeing is a lot of cranking with not even a pop. You've had the entire harness out of the frame and the frame coating. It could be a bad ground somewhere. It could be a disconnected wire from the crank sensor. It could be no power to the coils. Or a relay not hooked up correct. There are a bunch of electrical things that could prevent getting a spark. Double check the harness and all connections. If this is the case, you put a new motor in and there's no guarantee it is going to start either.

Anyway, I'm not questioning your ability in any way with anything I've said. You've done an incredible job and a lot of work so far. But anyone can have just a moment of brain fade after a long day and forget something.

 

This is the kind of help that gives me hope for humanity. Thanks Phil. I question my ability all the time since this is my first real wrenching experience and I think it's great that you, and the rest of you guys, come with thoughts, pointers, warnings and so on, because it forces me to think things through and learn. I don't have any friends with mechanical skills nor did I grew up with a wrench in my hand so all this is foreign territory, and all your help has been invaluable to me.

Anyways, you might be onto something. The powder coating has been causing a lot of trouble, not only because of the poor job of masking the holes which has made it difficult to bolt things back, but also the ground issue. The starter is grounded really well with a cable of my own design but I'll check all the other connections too. One of my maybe far out ideas is the side stand sensor. A faulty sensor there could prevent ignition, if I'm not mistaken. In any case, electrical work comes far more natural to me and is way easier to solve/build/check so I guess I'll start there. Maybe it's something obvious that I just haven't seen...

 

I checked the spark plugs today, and got spark in all of them. However, I discovered that it a mix up between the two ignition coils, at least according to the wiring diagram. Not that bad really, only that the cable with equal amount of blue and yellow went to the coil for carbs 1 and 4 and not 3 and 4 as stated in wiring diagram. I doubt it has a real difference but changed it back anyways. I also noted that the firing order seems to be correct: 1 - 2 - 4 -3.
This I did by cranking the engine for really short bursts and watching the intake valves open. I don't know if it's a valid method but it seemed right. Of course I cannot be sure that this means I haven't mixed the cams anyways but still a good sign.

So what went wrong today? Well, I tried to put the carbs back on and they were leaking today as well, but this time, I think I got too much fuel in the inlets. When I removed the carbs and cranked the engine with the starter, flames shot up and I had some minor fuel dosed patches on the engine catching fire too, and of course a major scare. I still believe that I have compression and that it is the tool which is broken, but I have yet to verify that.

Anyways, for a second, just before the flames shot up, it sounded like it was about to fire up. Well, back to the diagnostics again.

 

Sounds like your getting spark at the wrong time. F2 is a wasted spark system. Both 1&4 fire at the same time and 2&3 fire at the same time. They fire every revolution on both the compression and exhaust TDC.

Yes, the firing order is 1-2-4-3
right side coil is for 1&4, Left side is 2&3
the coil connectors - yellow wire w/ blue is for the 1&4 coil, blue w/ yellow is for 2&3.
Mixing up either the spark plug wires or the coil wires could cause this.

Oh, and I just found this. Thank 91-cbr600-f2 for this, it's awesome. Scroll to the 3rd pic.
https://cbrforum.com/forum/cbr-600f2...roject-147419/

 

Thanks, Phil! I checked everything today and it is just like it is supposed to be with coils and connectors. I do here a popping sound every time I crank the engine, isn't that an indicator of pressure in the cylinders? I couldn't crank it that much today because I had drained the battery doing this but for the first few runs it popped. I tried to get it on a video but the camera keeps cutting that sound for some reason.

I am starting to give up now. I will either buy used engine from a -94 which hasn't been started since 2009 but never been dismantled either or drop it off to a mechanic and have him work on it. Don't know which road to walk here. I know in my heart that I could probably fix it if I had enough time and patience, but I don't. Work is demanding right now, summer is soon to be here and I have many other things to do. Besides, the guys I share a small space with were okay with me taking up all the space during winter but now they understandably want to take their bikes and drop them off, so I have a hard time finding some place to be if I have to take the engine apart again. Well, problems of the first world, right...? Anyways, thanks for all the feedback, I really appreciate it.

 

What all have you done to the carb?
Did you adjust the pilot screws at all?
Are you sure you have the fuel going to the fuel joint pipe and not the air vent joint pipes? (someone previously did that to the suzuki carbs I was recently working on)
Is the choke sliding correctly?
Do the vacuum pistons slide up and snap close properly?