Low end stutter put put put

[RIQUE]

After a long Saturday I did the valves, rocker arm play, cleaned and synched the throttle bodies, flushed the engine put in new oil and cleaned the spark plugs.
Bike starts instantly but if I pin it from 1000 RPM up it stutters and goes put put put.
I ran the GS911 on it an no faults.

After searching the archives it seems this is typical of bad spark plugs. Having said that the plugs on the bike are the OE and 5 years old.... I will put in new NGKs tomorrow but wanted to know if there is anything else I should consider that might cause this.

Riq
R1200S

[flatbutt]

fuel filter?

[brentw1]

did it run correctly before you adjusted everything?
clogged air passages?
did you get both throttle cables seated.
does it stumble to rich or to lean?
can be lots of things.

[RIQUE]

no, it idled poorly and had same problem. Now it idles nice but still stutters. Only things I did not change are plugs and air filter. Seems to stumble to lean. What do you mean by seating cables?

[brentw1]

the cable sheath can come out of the adjusters on the throttle body,
so when you open them up one will be totally starved.
and the tps will be wrong.
unless you have over 25k on it, under no load not likely the plugs.
but a simple plug inspection will sort that out.
i have had bikes with bad coils.
also just as a test you can slide back the intake horns to eliminate
air restrictions.
also make certain you did the valves correctly.
if all of that is good look at the fuel supply, if you have a fuel pressure tester
that makes testing it easier.
and it can have clogged injectors or a bad sensor etc.

[brentw1]

also do a compression test.

[LeftCoast Peter]

All good stuff from Brent. Also, do you have an after market fuel injection controller?

[RIQUE]

Originally Posted by brentw1

also do a compression test.

For a compression test should I remove only one of the spark plugs? what numbers should I get?

[brentw1]

remove one from each cylinder during the test so only the tested cylinder will have compression
with the gauge replacing the removed plug.
I don't have the specs in front of me and the absolute measurement isn't critical,
what you are concerned about is both sides should be close within 5-10 psi,
but on r11xx motors at least 150psi and I think my 1100s gave me 180
but a search will show up what it should be.
unless you have a bleed down tester.

[RIQUE]

Changed the plugs to NGK and stutter is gone. Bottom plugs were black as if they were not firing real strange. I have not been able to run a compression test cause my snap on set does not have a motorcycle adapter. Will have to get. Bike has 1780miles on it so it basically has not been broken in yet. I guess I will have to ride.

How is idle of the 1200 compared to the 1100? seems not to be as smooth am I right?

[nail24fac]

Bottom plugs stayed ugly on my '04. Run some Seafoam in her to clean the injectors.

[brentw1]

it should run on just one coil on each side,
you probably have bad lower coils

[brentw1]

the idle should be smoother, it has a balancer and automatic idle bypass adjustments
my st was smoother, should be similar

[brentw1]

were the valve out of adjustment ?