[Ghostrider.1127]

will do compression and leak down tests before all
also are you sure intake of cyl 4 is well sealed? check that too
suggest to not try to syncro. aswel

 

[Ghostrider.1127]

thank you ghostrider. good thought to check seal. will avoid synchro - the service manual doesn't say anything specific, but makes it sound like there's a factory set, then electronics take care of ongoing adjustments. but of course, there will be limits...

I guess the best way of seeing if cyl 4 really is running lean is just to 'read' the spark plugs?

Dunno in canada , but here in europe with this (shitty) 5% ethanol in the fuel also spark plugs read is not that easy

 

[Ghostrider.1127]

Actually is not that easy on our bike , on race bikes is usually done
Have u got a full workshop manual?
Checked for leak on intake ?
Checked Iacv?
bike got 110000 km , are you sure no rubber line got damaged?
cyl 4 is also in charge to move the flap on air filter intake ( right side )
sure also this line is ok ? (common error...)

 

[Ghostrider.1127]

your are partially right , iacv is doing that but not for all rev range
also i will quite say not possible a burned valves (if they were checked every 24000)

 

[Ghostrider.1127]

update: all is well!
the leak-down test showed only 8% in cyl #4; interestingly #1 ( which was nit my concern) was 15%. neither figure is problematic, especially with an engine over 100,000 kms. and the mechanic noted that once you got the bike on the stand and 'opened up' a bit, you could see that, in fact ALL the headers were blued to some extent. #4 is just more visible...
as well, while the plugs were a tiny bit white, that's is characteristic of modern lean-burning engines. so I'm all good...

headers:

IMG_6636 (2) by Don Serl, on Flickr

plugs:

IMG_6637 (2) by Don Serl, on Flickr

the electrodes look tiny, but that's just characteristic of the iridiums...

as for throttle body balance, the mechanic reckoned that it's the two screws paired on the bottom on each pair that do this job ( my first post; bottom sketch). but since Honda specifically say to not adjust, we didn't...

As i told before can be done , but is a shit job
must keep the bike between 70° and 80°(HRC manual for sc 57) there is not too much space
glad you solve the "issue"


do not buy titanium header

 

[Ghostrider.1127]

cbr1000rr 2004-2007 had a complete different system compare to cb1000r