Author Topic: 550f running rich?  (Read 4823 times)

Offline DomP

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Re: 550f running rich?
« Reply #15 on: October 11, 2025, 05:35:22 PM »
Just to clarify, the breather hose isnt blanked but its connection to the airbox is.  The hose itself is routed to the same place as the carb breathers
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

Offline DomP

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Re: 550f running rich?
« Reply #16 on: October 11, 2025, 05:36:40 PM »
There is a simple test to check if the valve timing is a tooth out.
No cam cover removal just something to do with what the valves are doing at tdc?
IIRC Bryan or Ken posted it ages ago.

I've forgotten what you do, it might be in my 500 rebuild blog.

That's interesting Ted, be great to know what the method is to rule that out.
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

Online McCabe-Thiele (Ted)

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Re: 550f running rich?
« Reply #17 on: October 11, 2025, 05:56:35 PM »
It's on my 400 project  build, I cold not remember if I set the valve timing to tdc or on the F mark. It's sort of mentioned on P 19.

I suspect I asked the question on the 400 section
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

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Re: 550f running rich?
« Reply #18 on: October 11, 2025, 06:05:35 PM »
The springs have been trimmed byba preious owner, if anything one is too taught.  The advancer itself has benn taken apart and greased so should be no free movement problems.

I'm suspicious of this as a modification generally, also the logic behind it.

Ignition is retarded to first start it  .... without it trying to go backwards!  .... secondly to make it tick over smoothly and  to prevent it "hunting" around but stay calm when not needed.

Other than that, and say above 1500rpm, then advancing it quickly will usually increase torque from low into mid range output .... which is desirable. To delay that effect seeming pointless as you want it to get on and go a bit.

They are quite low compression for the output, and so will not usually be at risk for getting the advance going as early as possible.  To mod them with tighter springs apppears to fly against optimal running

Offline DomP

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Re: 550f running rich?
« Reply #19 on: October 11, 2025, 08:52:30 PM »
That's interesting,  I did look at 750 advancers thinking the springs might be the same as i cant find any 550 advancers.  One of my springs has been over trimmed in my opinion
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

Offline Bryanj

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Re: 550f running rich?
« Reply #20 on: October 11, 2025, 09:45:23 PM »
500 is same as 550

Offline DomP

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Re: 550f running rich?
« Reply #21 on: October 12, 2025, 09:50:58 AM »
500 is same as 550

The advancer springs Bryan?  What about the cam chain check Ted mentioned?
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

Offline Bryanj

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Re: 550f running rich?
« Reply #22 on: October 12, 2025, 10:58:29 AM »
The complete advancer is the same, cam timing should be on the tdc mark and wouldnt make it rich, silly question is there anything under the seat obstructing airflow? Had a customer do that 40 years ago, caught him removing waterproof leggings from under seat when leaving it for a problem!

Offline DomP

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Re: 550f running rich?
« Reply #23 on: October 12, 2025, 12:59:01 PM »
No nothing under the seat Bryan, ive tried it with the air filter out as well.
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

Offline DomP

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Re: 550f running rich?
« Reply #24 on: October 12, 2025, 01:57:49 PM »
https://ebay.us/m/i2p9BH

Do you think these advancer springs will fit, they appear to have the correct number of coils
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

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Re: 550f running rich?
« Reply #25 on: October 12, 2025, 02:32:53 PM »
While I agree that cam out of correct timing wouldn't make it rich, running like that will most definitely make it hard to decipher anything tangible in regard to faults that are in place.

Verification is needed, given it's just been assembled, to definitively remove that from the scene.

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Re: 550f running rich?
« Reply #26 on: October 12, 2025, 03:36:11 PM »
I found the relevant section, it was Bryan that showed me the path to enlightenment.

I don't know how to copy the text  found it by searching valve timing  item 7 iirc.
« Last Edit: October 12, 2025, 05:26:06 PM by McCabe-Thiele (Ted) »
Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline DomP

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Re: 550f running rich?
« Reply #27 on: October 12, 2025, 08:42:31 PM »
Not sure i follow Ted?
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675

Online McCabe-Thiele (Ted)

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Re: 550f running rich?
« Reply #28 on: October 12, 2025, 09:19:51 PM »
I've reposted it today it was Bryans tip, checking valve timing on a 400/4.

Select Home its about the third item down.

Honda CB400NA Superdream (current money puddle)
Honda CB500 K1 (second money pit)
https://www.sohc.co.uk/index.php/topic,28541.0.html
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html
This is a neat 500 restoration in the USA.
http://forums.sohc4.net/index.php/topic,151576.msg1731556.html#msg1731556

Offline DomP

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Re: 550f running rich?
« Reply #29 on: October 12, 2025, 10:00:37 PM »
Just a query Ted, what do you mean by T bar?
1975 XS650B
1976 CB550F1 current project
2012 Triumph Daytona 675