im getting the exhaust all set up with a wideband so once i start hacking everything up over the winter ill have all the necessary tools to make it run correctly right off the bat. im hoping that with the wideband it will take a lot of the guess work out of switching jets up.

 

Hi All. Haven't said much recently but I've been busy. So here's what I've been up to .

I took the carbs off again and rested them upside down to access the bowls. Took the float bowls off and recleaned every jet. Counted the amount of turns on each air screw before stopping, recorded the count and removed them. Cleaned off some crud with vinegar ( works a treat ).
Removed the slides and diaphrams , then blasted every hole with carb cleaner. Checked it came out from the pilot jet to the air screw hole, the 4 small ones close to the butterfly in the ventury and one further up the ventury , I think on the exit side of the carb. But i did notice that when the butterflies are closed, these 4 small holes are covered by varying degree's which I guess is linked to the carb balancing. Some are completely closed of others are not.

Anyway, cleaned the fuel tap filter and ran fuel through a filter via the fuel pump to clean that.
Reassembled all with new K&N air filter ( no rejetting required)
So I'm fairly sure I have a clean fuel system now.


She runs now and ticks over OK at about 1000RPM , but I'm still not happy
So I'll post a video as soon as I can to get your opinions.

Rides ok though.
Cheers All
Mikey

 

maybe you already covered this... but if any part of your carburetors that you cleaned with carb cleaner have a rubber ring on them, or a rubber seal, rubber diaphram, then you could have destroyed part of the carb by putting carb cleaner on that rubber, because it rots it... so I'd go back through the carb one last time, make sure there's no holes in the diaphram etc... have you checked the compression of the 4th cylinder?

 

As promised.

http://www.youtube.com/watch?v=1-UYBDb8pxw

Although its ticking over ok-ish there a sort of 'hunting sound ' . So I'm at the stage of looking too closely now and you guys to tell me if you agree or is that how most CBR1000's sound. I think I've some cam chain rattle in there as well.
Goloth, you've got a point. I'll check the manual to see if there are any seals at risk.

SO comments welcome. Am I going mad and chasing something thats not there ?
Cheers
Mikey

 

Don't run the idle below 1250 RPM
If it sound like it's hunting - try carb sync.

 

Cheers Shadow. I'll up the tick over and balance the carbs. Thats tonights job then .

Also very pleased that I picked up a nose cone for £40 on ebay which is in very good condition for the age.

 

Did you see that ad on e-bay.uk guy has a lot of parts he wants to sell.
http://cgi.ebay.co.uk/HONDA-CBR1000F...item414f8c8ea5
He lists a whole bunch of stuff elsewhere, too - see the advert

 

Hey, i did but I think I've got all the parts I need now. That nose cone was too good to miss.

So an update. carb balancers are a little costly at the moment for me so I thought I would investigate a home made version to see if the problem lies there.

To cut a long story short, I ended up with 4 clear tubes going into a sealed 'jam' jar with the lid on all sealed , with some engine oil in the jar. Started up , and expected the oil to get sucked up the tube until a balance of vacuums in the pipe and the jar. So comparing the pressure / vacuum in the jar and each individual tube. My reasoning is that if the carbs are balanced then each column would reach the same height . Thats the theory.

I found that cylinders 1 & 2 were equal , 3 was down a bit , but 4 didn't suck up any oil. So I swapped over the tubes. Cylinder 4 still not sucking !. Took the pipe off the carb and there was some suck!


So I'm concluding that
1. I've gotta buy some gauges
2. Either the no. 4 carb is well out of adjustment or the cylinder has a problem

I think I'm going to get a compression tester now as may be the exhaust valve is sticking open a bit. If thats the case would there be any other symptoms ?

Cheers

 

I like your thinking on the vacuum unit - very original and no reason that it wouldn't work.
I'd say there's a problem with 4th carb due to perished o-rings or maybe a hole somewhere in a diaphragm - the pressure of vacuum doesn't lie, no matter what system you use. I guess it could be a valve but you'd surely have more than a little "miss" if that was the case........?? If the valve was open at ALL you'd have no vacuum not just a little.......?

 

Thanks Shadow. Cant take all the credit as I found a similar device on other forums. I wanted to be sure on how it would work. Still desspite my best efforts , getting a little air sucked into the system as column 1,2,3 keep rising. But, thinking out loud, maybe thats coming in via no. 4 tube ?. When I get it right , may be I'll post on how to make it.

As a recap, this problem occurred after its first short runs after 10 years of being idle.
So maybe a rubber seal in the carb has / was perished and failed. I'm going to have to study the break down of the carb to see what I've missed. I have checked the slide diaphram by hold it up to the light and it seems ok.

My biggest nag in my head, and no its not the wife , is the observation that butterflys 1 and 2 seemed fully closed were 3 and 4 were opened just a bit to show some or all of one of the pilot jet holes . A photo of 1 ( dscf3080.jpg ) and 4 ( dcf3077.jpg ) uploaded.

Cheers
any comments welcome
mikey