Replacing fuel injectors

[BigT]

 I just had an issue with the front cylinder fouling out plugs that looks to be unburnt gas/ rich condition.  I had installed new plugs over the winter and the plug wires seems to be fully engaged. The old plugs looked a tad rich but not that bad. The bike was properly tuned and had been running great. I was told it could be possibly a bad fuel injector. Is it possible to replace an injector without removing the manifold and throttle body from the bike? What else could cause one cylinder to go out of tune?

[Don D]

Just as a precaution before replacing anything I would pull a compression test.

[BigT]

Just as a precaution before replacing anything I would pull a compression test.

I had thought about that. A recent cranking compression test had showed both cylinders at 225 with a RS552 cam but a leak down test would show an issue.

[Don D]

Oil getting into combustion will still pull decent numbers on both tests. Ring number 2 just not doing it's job or valve seals / guides. if the plugs smell of fuel that is a give away of other issues.

[rigidthumper]

Do you still have the plastic intake manifold?

[Tacocaster]

Have you tried swapping plugs, cylinder for cylinder to see if trouble moves or even both swapped-out with a known good one(s)? You do state news plugs installed over the winter and it wouldn't be the first time one was bad.

[BigT]

Do you still have the plastic intake manifold?

No, it is a SE 64mm manifold ported by Ward.

[hrdtail78]

To the OQ.  Yes, pull tank and remove horn bracket.  Be careful of the clocking dawgs on the fuel manifold.  They are plastic and can break.  Pull straight up.

[BigT]

Have you tried swapping plugs, cylinder for cylinder to see if trouble moves or even both swapped-out with a known good one(s)? You do state news plugs installed over the winter and it wouldn't be the first time one was bad.

Good chance if I swap the fouled plugs from the front cylinder to the rear the problem will move to the rear   I plan on installing new plugs and wires

[BigT]

To the OQ.  Yes, pull tank and remove horn bracket.  Be careful of the clocking dawgs on the fuel manifold.  They are plastic and can break.  Pull straight up.

Thanks!