Honda CBR XX Forum banner
1 - 20 of 22 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter · #1 · (Edited)
Hey all,

so I kinda screwed up.

I have a 1996 (yes, really) CBR 1100 XX.

I had some fuel leaks in the carburetor that I was able to fix.

Unfortunately when re-assembling the bike again (aka connecting carburetor, air filter and fuel tank again), I accidentally connected the vacuum pipe starting from cylinder 2 (visible in https://www.cbrxx.com/attachments/98fuelhose2-jpg.86258/ as vacuum source connection, the one in the pic with the thin pipe connected) directly to the overflow or whatever outlet of the fuel tank (visible in http://www.cbr1100xx.org/forums/uploads/monthly_03_2007/post-2671-1174168197.jpg, the thing marked as "NOTHING!", lmao. I should have connected it to the thing marked as "VACUUM" instead).

The XX went roughly 400m before dying.

I removed the carburetor again and saw the cylinder 2 is now filled up to the top with a fuel/oil mixture. Hitting the starter with removed carburetor quickly made the bike pump the stuff out into the exhaust, as far as I understand how it works. After that I confidently cleaned the carburetor, re-assembled the bike again and tried to start, but cylinder 2 is still not doing its thing. The bike runs on 3 cylinders with white smoke through the exhaust and cylinder 2 is refusing its job and the engine dies quickly when you stop accelerating excessively. It occasionally spits out a mixture of fuel/oil through all the overflows it has. It looks very unhealthy.

Any hope or advice on how to fix this without disassembling the entire engine?

Not sure if that is clear, but I have no idea what I am doing, but what I am lacking in skill I compensate with madness, so I got that going for me which is nice.
I also got the professional XX repair guide, so I am basically an uber pro, but the 500 page .pdf doesn't seem to cover user-stupidity.

Thanks for all advice in advance.
 

·
Registered
1998 Blackbird
Joined
·
55 Posts
Hey all,

so I kinda screwed up.

I have a 1996 (yes, really) CBR 1100 XX.

I had some fuel leaks in the carburetor that I was able to fix.

Unfortunately when re-assembling the bike again (aka connecting carburetor, air filter and fuel tank again), I accidentally connected the vacuum pipe starting from cylinder 2 (visible in https://www.cbrxx.com/attachments/98fuelhose2-jpg.86258/ as vacuum source connection, the one in the pic with the thin pipe connected) directly to the overflow or whatever outlet of the fuel tank (visible in http://www.cbr1100xx.org/forums/uploads/monthly_03_2007/post-2671-1174168197.jpg, the thing marked as "NOTHING!", lmao. I should have connected it to the thing marked as "VACUUM" instead).

The XX went roughly 400m before dying.

I removed the carburetor again and saw the cylinder 2 is now filled up to the top with a fuel/oil mixture. Hitting the starter with removed carburetor quickly made the bike pump the stuff out into the exhaust, as far as I understand how it works. After that I confidently cleaned the carburetor, re-assembled the bike again and tried to start, but cylinder 2 is still not doing its thing. The bike runs on 3 cylinders with white smoke through the exhaust and cylinder 2 is refusing its job and the engine dies quickly when you stop accelerating excessively. It occasionally spits out a mixture of fuel/oil through all the overflows it has. It looks very unhealthy.

Any hope or advice on how to fix this without disassembling the entire engine?

Not sure if that is clear, but I have no idea what I am doing, but what I am lacking in skill I compensate with madness, so I got that going for me which is nice.
I also got the professional XX repair guide, so I am basically an uber pro, but the 500 page .pdf doesn't seem to cover user-stupidity.

Thanks for all advice in advance.
 

·
Registered
1998 Blackbird
Joined
·
55 Posts
I'm no Bird expert but a bit confused as to how fitting a vacuum pipe incorrectly ends up causing this issue.

So just so you know there are a few really good knowledgeable Birdies on here who will be along later and will have some answers and solutions for you. A 96, so an early Bird.
 

·
Registered
2000 titanium
Joined
·
20 Posts
MY two cents - If the spark plug checks out ok and the oil changes don't help, check compression on cylinder two. Could have inadvertently blown the valve seals or the piston rings. That much fluid in the cylinder is a strong indicator of a leak.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #6 ·
fml, thanks guys I'll check it out.

Will inspect the spark plug and do the oil change if spark plugs shows no issues.

Or do you strongly recommend changing the oil + filter regardless?

The fear is a seal might be broken and the oil is now mixed with gasoline, or did I misunderstand?
 

·
Registered
Joined
·
1,359 Posts
If you have fuel in the crankcase it will destroy your bearings. From your description I'm thinking you will. Not worth risking it.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #8 ·
That much fluid in the cylinder is a strong indicator of a leak.
Just so we are on the same page - you do realize that the vacuum pipe is directly connected to the cylinder that is being affected? I have seriously no clue why an engine has a vacuum pipe but my monkey brain assumed that instead of sustaining that vacuum, the fuel tank gave off fuel through the overflow that I accidently connected the pipe to, allowing the vacuum pipe to suck fuel directly from the fuel tank into the cylinder, explaining why there is so much liquid in it, or is that entirely bs from my side? So my assumption would be that the seals are probably fine, no?
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #10 ·
Did it run OK in the first 400M? After replacing spark plug, I'd also re-check your float settings on that carb.
Yes it did, then suddenly it felt like it ran out of fuel. It also did run fine before the whole operation - the whole 299km/h fine, apart from a small fuel leak. I'll check the float height also, thanks.
 

·
Registered
Joined
·
11 Posts
A small piece of debris may have gotten between the needle and seat. If that happens, the fuel will not turn off and will flood the cylinder. I have had that happen to a car before. Also as said, it could also be a float setting.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #12 ·
I just failed to test the compression and I feel really stupid right now.

What sort of compression tester do you guys use precisely?

I used this exact kit and almost lost my mind trying to attach the whobbly hose with the 10mm attachement to the spark plug thread. I gave up after roughly 45min.
 

·
Administrator
Joined
·
9,530 Posts
Kabuse
Because of the shouldered plug the BB uses you have to use a longer specialized adapter to enable a compression test. 07AMJ-MENA200. It's not cheap around 75.00
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #14 ·
Thanks, lmao yea that's not going to happen.

I also noticed a hefty gasoline smell coming from the engine oil, which I'd assume to be "not normal". So again I assume the chances of me blowing up the engine, even if I get it to start with fresh oil and spark plugs are quite high. Guess I'll have to take it to a shop.
 

·
Administrator
Joined
·
9,530 Posts
If your smelling gas in the oil then it sounds like from your initial synopsis that the float for #2 carb is still not seating. Until you can get that fixed do not fire the bike up. I would also do an oil and filter change once you get the leak stopped. Fire the bike up let it idle for about a minute. Drain the oil, change the filter again and then I would feel safe that you have gotten all the fuel out of the lubrication system.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #16 ·
Until you can get that fixed do not fire the bike up.
Too late, already ran it on 3 cylinders weeks ago when I had no idea what was going on. I hope I didn't nuke it 😱😬

Thanks for the advice.

I'll do an oil + filter change, test/replace the spark plugs and see what happens. If cylinder 2 won't work then it's probably a RIP XX.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #17 ·
My dearest gentleman, I am delighted to announce that I did in fact not nuke the engine.

I swapped the oil twice and the filter once and replaced the spark plugs.
Originally I drained around 5 liters, so the shit in there was 80% oil and 20% fuel. Originally I had the bike running on this shit on 3 cylinders for roughly 3-5min and I feel really bad about it.

After swapping the oil very thoroughly , there was a lot of white smoke for ~10 minutes coming from the exhaust but the engine sounds absolutely fine and the smoke eventually stopped.

Two small issues remain:
  • As before the entire ordeal, the bike is leaking fuel through the thing labeled as "NOTHING!" in http://www.cbr1100xx.org/forums/uploads/monthly_03_2007/post-2671-1174168197.jpg. This only happens while the engine is running. It's like 1 drop every 2 seconds. Any advice? This time I am positive that I attached the hoses correctly. And yes, this is the reason why I originally thought that I had the vacuum pipe connected incorrectly and put it there instead :<
  • After 10-15min of idle running, the bike started producing a very high frequent noise, not loud at all, that instantly went away with the slighest bit of throttle. Sounded like an electrical component that tried to start spinning but didn't succeed. Maybe the air fan? It didn't spin, but I guess I can figure that one out myself if nobody has any advice.

Thanks again for the great advice.
 

·
Administrator
Joined
·
9,530 Posts
That nothing is the port that lets you know the diaphragm is failing. You need to shut the bike down until you get that fixed or your going to end up with another crankcase full of fuel.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #19 ·
I don't understand why you believe that the crankcase can fill with fuel again. In my mind, the vaccuum pipe that was incorrectly connected to that port before allowed the fuel to directly pass into the engine, or is that not what most likely happened?

So don't I just need to replace this thing and I am good to go?

Sorry for being nitpicking even though I have no clue about bikes, I really just want to get the XX figured out and working again.
 

·
Administrator
Joined
·
9,530 Posts
The reason I made that statement is that port I'd designed to let you know if the diaphragm has ruptured. If it is leaking out of that port it is likely being pulled into cylinder and crankcase as well.
Yes replacing that should cure your issues.
 
1 - 20 of 22 Posts
Top