Another Rough 'Bird

[brant]

Hi all,

I've read through several likely looking threads with interest - like the original "Rough 'Bird", but I don't think they relate to my problem hence this plea for advice. If any one can point me in the right direction I'd appreciate it.

I have a CBR1100XX-W 1998 carbed blackbird European import... with 35k miles.

The bike ran perfectly for about 5k miles after I bought it, but developed a slight intermittent misfire and a cam chain rattle....

I had the bike professionally serviced and the cam-chain tensioner replaced.... And now the bike is much, much worse. The rattle has been cured, but that's the only good news.

Symptoms are;

• Sooting up of the 2nd spark plug
• Intermittent misfire at about 2,000 to 4,000 rpm
• Occasional backfire, splutter, if using a lot of throttle
• The bike stinks of petrol and I only get 65 miles per tankful (this is very bad indeed)

The bike has stalled three times in two weeks (in three tankfuls! - about 150 miles) when dual carriageway riding (doing a mere 50 - 70 mph). A rest for 5 minutes or so allows the bike to recuperate and then will start up and run perfectly for a while. This has only happened when the fuel guage is on [or nearly on] reserve.)

The bike idles fine when warmed up. And some of the time rides like normal (always smells of petrol though.) The exhaust fumes are petrol heavy but it never smokes.

What has been done so far?
Before the bike was serviced I did the following;

• I replaced the coils and HT leads with other second-hand ones (made no difference)

After the service I tried swapping the plugs around - but it's always cylinder 2 with the problem

• Checked the fuel pipe for leaks - there aren't any.

The dealer did the following;

• Replaced the Cam-chain tensioner
• Replaced the plugs,
• Air filter replaced ( I never saw the old one - so I now have the suspicion that it was non-standard before (maybe? can I test that?) - although the mechanic didn't mention it.)
• Oil change

Note: This "service" didn't help (in fact made things much worse apart from the rattle) so I took the bike back for more work as follows.

• Checked the plugs are sparking as they should (apparently okay)
• Balanced the carbs... no change...
• Stripped off and cleaned the carbs - no improvement...
• Checked the shim clearances - reported as all okay (no need for adjustment)

That's about it, but it's still running like pig.... You don't want to know how much I've paid so far - but I have lost confidence in the workshop - and I don't want to go back again to offload more dosh for nothing. Mostly I'm well-annoyed that they keep telling me it's "all done".

Additional info; The bike has non-standard (road legal, I'm sure) "Venom" exhausts - it ran perfectly with these for 10 months + and they haven't worn out yet!

I swapped the clocks console from the original european one (with km/h speedo) to a UK spec one about 7 months (3k miles) ago. (Can't see this being relevant but who knows? I don't!)

I'm not sure how the fuel pipes and others fit on to the fuel tap. Could it be the pipes are on wrong? There appear to be 4 ports to it (two major feeds for the carbs are obvious) one from the back of carb 2 for vacuum - and a port at the bottom that is currently connected to what looks like a carb overflow or breather tube - I can't find any mention of the correct fitment in my Haynes.) Clasping at straws now.

Thanks to anyone who can help me with advice.... Any other info that might be relevant I'll gladly supply if I can.

Steve

 

[Judge Dredd]

[*]The bike stinks of petrol and I only get 65 miles per tankful (this is very bad indeed)

Sounds like flooding on one of the carbs. Possibley due to a jet having dirt in it. or the float bowl covered in petrol goo and causing it to stick. I would suggest taking that carbs off and cleaning out the bowls and making sure the needle jets are clean and not worn also have a word with JAWS, what he does not about blackbirds is not worth writing about.

 

[Jaws]

I think a lot of the bases have been covered but would be interested to know what plugs they fitted and if anyone has actually checked the velocity stacks are the right way round ( I have seen this problem a few times esp after Honda ( so called ) mechanics have been at bikes.. )
But I am with JD really.. I have a strong suspicion it is going to be carburator related..
Either a slightly iffy float bowl needle or worse, a perforated diaghram

Mind you, what is coincidental is that the rev range is absolutely classic for an iffy coil.
I appreciate you have tried different coils but just for peace of mind I would swap them over and see if the iffy cylinder moves ( so to speak )

 

[andyBeaker]

Probably unlikely, but it might be a leaking/badly fitted vacuum pipe betweeen manifold and fuel tap. Replace the whole pipe (spare Scotoiler tube fits a treat) and the worst thing you will do is eliminate this for 30 seconds effort.

The standard pipe is way too short and is easily dislodged/nipped when refitting the tank. A slight leak and it runs like a pig, if it comes right off it won't run at all.Best of luck and keep posting as someone will have the answer (probably JAWS:bow: the git!)

 

[Jaws]

Good point that Andy..
I dont suppose there is a Scotoiler fitted and the vac pipe has come off ? ( mind you, that would then make a cylinder run weak rather than rich )

But yes, def worth checking all the inlet manifold plugs and or vac pipes are in place.

 

[andyBeaker]

I think you are great too John3ck04

Can you post up for the man where the various pipes from the fuel tap go; I know it's on here somewhere, but...........:dunno:

Smell of fuel suggests otherwise, but just might be the answer? Let's hope so.

My problems with the vacuum pipe were after an 'expert service' as well, funnily enough.

By the way Brant, from Ilford to JAWS:bow: is a piece of wotsit, get up to him and get your Bird serviced properly for proper money next time!!

 

[Jaws]

LOL !! Mutual admiration society !

Ok, cannot find the picture showing where all the pipes go, but it IS posted on this forum somewhere..

However.............

Look under the carbs and you will find 3 small bolt heads that have cross heads cut into them. Under the forth will be a pipe.
That pipe is the vacuum pipe which goes to the petrol tap. It operates a diaphram which turns on th epetrol tap.
It is very common for that pipe to either come off or worse, be fitted back to the tap wrongly.
You may think that is daft but if you look at the tap you will see what LOOKS like a tube sticking out the bottom of the tap body.
That is actually a blank.. The pipe fits on a tube that is up to one side or the other of the tap body ( note it is still on the tap body, the other tube that is brazed into the bottom of the tank a breather )

Whilst checking that it might be worth making sure the tap is actually turned all the way on !

 

[morphgarth]

John, I don't know where I;'m going with this yet so bear with me!! If the vacuum pipe was off the fuel wouldn't flow at all unless the fuel tap is shagged and it flows all the time as if it were priming. So the pipe being off woudn't make it run rich?

Should be easy enough to see if it's flooding past the tap by either disconnecting the pipe from the tap. With the engine off there shouldn't be any flow. I imagine you could unscrew the drain on a float bowl and see if it continues flowing?

Is it parked on the side stand? If the float valves are playing up it tends to affect 1 & 2 more if it's on the side stand?

It was electrical at the coil it would affect more than one cylinder wouldn't it. I imagine the coils are 1&4 and 2&3 with a lost spark? Worth swapping 3&2 to eliminate this? As you say the fault should move to that cylinder. You can check the spark but coils sometimes only play up under load.

Equally I can't see how a fuel pipe problem would only affect one cylinder?

When you say the carbs were cleaned how do you mean? If you're not going for ultrasonic cleaning then carb cleaning on a four takes me over a day to do it properly. I strip them on a stainless steel bench, soak everything in carb cleaner (or vinegar - acetic acid - very cheap and effective) for 24 hrs and then dry with compressed air, and blow everything through. They have to be practically surgically clean. I find it quite therapeutic!!!

Did you get the float heights right? Were the float needle valves checked for wear lines, after time they can get a ridge on them which stops them shutting properly because they're tapered. (TBH I've stripped and rebuilt dozens of carbs but not the birds yet but they're all much of a muchness).

If not the carb on number 2 then I would do a compression check. Is there any smell of petrol in the oil?

Have you got a laser thermometer to check the temperatures at the exhaust manifolds?
Hope I haven't confused the issue, but the key is you have to be completely systematic on the fuel, LT circuit, HT circuit.

This sort of stuff is where you find the difference between real mechanics and fitters (I'm a fitter - I fit parts!!!!). Diagnosis is the real art of mechanics.

 

[Jaws]

Phew !
Point one.. Yes, I agree it should indeed make it run weak as I said above

Point two.. I agree again BUT have seen those bloody petcocks do all manner of very odd ( and theoretically impossible ) things, including running fine even with the vac pipe off on one bike, and stopping dead on another !


Ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

Shit !!!!!!!!!!!!
Sorry, was gonna go through the rest but !!!!


Got it !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
So obvious ..

It is the petcock diaghram that has gone.
The reason number two is rich as hell is cos it is sucking petrol straight into the inlet manifold from the tap !!!!!

It is that simple
You need to replace the diaghram young man :-0)

 

[Centaur]

Brilliant deduction John but...

Phew !
Point one.. Yes, I agree it should indeed make it run weak as I said above

Point two.. I agree again BUT have seen those bloody petcocks do all manner of very odd ( and theoretically impossible ) things, including running fine even with the vac pipe off on one bike, and stopping dead on another !


Ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

Shit !!!!!!!!!!!!
Sorry, was gonna go through the rest but !!!!


Got it !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
So obvious ..

It is the petcock diaghram that has gone.
The reason number two is rich as hell is cos it is sucking petrol straight into the inlet manifold from the tap !!!!!

It is that simple
You need to replace the diaghram young man :-0)

What the feck is a diaghram?

 

[Jaws]

It is a widget that Honda fit in place of a diaphragm.
It is made of Hondurium .. Works the same, looks the same, is the same but is spelt differently,, and of course being made of Hondurium means that no Honda 'mechanic' can see it or knows anything about it. :-0)

 

[Centaur]

Can you get them for women too John? :-0)

 

[Jaws]

Can you get them for women too John? :-0)

Daft sod !
Of course not... The ones for women are made by Suzuki.. All fookin noise and a pain in the arse.. Oh and thery are made of womoanium..

Of course none of that applies to ANY REAL woman.. and as we know only real women have bikes ....

 

[Pugwash]

All fookin noise and a pain in the arse..

Are you sure you have kids John? Sounds like you've been doing things wrong.
Stuck in reverse, for example?

 

[morphgarth]

Phew !
Point one.. Yes, I agree it should indeed make it run weak as I said above

Point two.. I agree again BUT have seen those bloody petcocks do all manner of very odd ( and theoretically impossible ) things, including running fine even with the vac pipe off on one bike, and stopping dead on another !


Ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh

Shit !!!!!!!!!!!!
Sorry, was gonna go through the rest but !!!!


Got it !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
So obvious ..

It is the petcock diaghram that has gone.
The reason number two is rich as hell is cos it is sucking petrol straight into the inlet manifold from the tap !!!!!

It is that simple
You need to replace the diaghram young man :-0)

John, you can tell I'm old bill. My clever cognitive interviewing technique drew the answer out of you!!!!:-0)

 

[Jaws]

LOL !! yes mate .. bloody good technique that !

PW, yes... But they are shiters.. which now I think about it ...... errrrrr :-0)

 

[brant]

Thanks for your help

Got it !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
So obvious ..

It is the petcock diaghram that has gone.
The reason number two is rich as hell is cos it is sucking petrol straight into the inlet manifold from the tap !!!!!

It is that simple
You need to replace the diaghram young man :-0)

That's brilliant!
I stripped the fuel tap today and the diaphragm is torn by 2cm. (First time a torn diaphragm is good news, maybe, but I was already "having kittens" any way.)

I reckon that's the problem solved. I took a pic for anyone who's interested. http://homepages.uel.ac.uk/S.Brant/bird/CBR1100XX-W_torn_fuel_tap_diaphragm_a.jpg

I put it all back together hoping to eke a few more miles out of the poor mistreated bike while I wait for the parts to arrive (I ordered a Fuel Tap Repair Kit from wemoto http://shop.wemoto.com/index.dyn?flag=19&type=fuel%20tap&offset=30). Now the bike won't run for more than a few minutes 'til it dies of what I think is fuel starvation. But I can live with that - no that there's a good chance it'll all be fixed soon.

Thanks to morphgarth, all contributors, and of course to "The Man" Jaws for all your help. The World's a good place again.

Cheers to all,

Steve (Brant)

 

[fearg]

(I ordered a Fuel Tap Repair Kit from wemoto http://shop.wemoto.com/index.dyn?flag=19&type=fuel%20tap&offset=30). (Brant)

Does JAWS not sell them then?

 

[brant]

Getting the goods...

Oh shit... I've obviously missed a trick here... Where do I go to see what's available?

Where are you located, Jaws? How do I buy from you? Do I just ask?

Maybe there's a thread on that topic in this forum that's worth bumping up again.

Sorry if I've goofed on that....

I'll be happy to buy from JAWS in the future.

Steve

 

[brant]

Am I getting the hang of this internet thing?

Hi again,

It's a bit weird replying to my own post - interesting conversation I'm having here (etc., etc) - but at least I had the nous to see the link to the Jaws web site - http://www.jaws-motorcycles.co.uk/bird.htm

Cool!

Steve

PS I have a black one, but my next one will be blue, when I can afford it :violin: ..