Okay guys I could really use your expert advise right about now. Yesterday I was out riding (not hard or aggressive) and I had a spark plug blow out. The bike starts makingthis horrific sound. So I pulled over. I could see through the faring what had happened. The coil appeared to have popped off the plug (or so I thought).

Finally got the bike home. Took the plastics, tank, radiator off so that I could get to the coil properly.After a closer look it looks like the plug blew completely out of the chamber. I tried to screw the plug back in but it wouldn't grab the threads. I did a pretty good inspection of the plug. It doesn't apprear to be damaged or stripped, but I just cant get it to screw back in. I searched the forum and found this https://cbrforum.com/m_143642/tm.htm.

I'm praying this is not my issue. If any one can provide some help here I would really appreciate it.
Also in that thread the guy with the problem had an 01 F4I, and so do I. Is this a known problem??

 

It sounds as if either:

a) When the plug was last installed it wasn't installed tightly enough
or

B) (more likely) the plug was installed cross threaded, or too tightly, causing the threads to get stripped.

You now have two options. Replace the head, or repair the damage. Some professionals are really good at installing helicoil type repairs. The other possible repair is to remove the head, overbore the hole and install a sleave. This is the more permanent of the two repair types.

Sorry - sounds crappier than it is... but if you take it to a good mechanic for a few ponies you'll be back in the saddle.

 

You should just be able to have someone rethread the surface if that is the issue. Probably the cheapest way to go

 

Is it possible to rethread with out taking the head off?

 

you can rethread without removing the head, but I don't think you can sleave without removing the head...take it to some one who knows what they're doing and they'll do the rethread (if they can)... otherwise it's the later option.

 

it'll be very tricky to helicoil or rethread without taking off the head. gotta get that cylinder at full compression and then do your drilling, etc...then get a shop vac with a small attachment to suck all the metal shaving out...trick is to get ALL out...or else...BOOM...

 

Don't try to tap it on the motor. Youhave a good chance ofscoring the cylinder. $150.00 turns into $1500.00

 

Just take the head off!

Its not worth the risk of leaving a little bit of metal shavings in the cylinder. I have never taken a head off a bike, but I have on a few different cars, and as long as all the bolts are accessible it is very easy. heres what id do: (assuming the threads are what caused this problem)

1)Download the F4i manual.
2)Take the head off your self.
3)Take just the head to a machine shop to have it re-threaded.
4)Replace all necessary gaskets, and throw the head back on!

Seriously, I doubt its very hard to take the head off or put it back on, as long as you keep everything organized and can keep track of where all the bolts go.

 

Update: I've been doing some checking here with local shops. I can have the bike picked up and have a shop do all the work for about $200 - $800. Best case scenario is that I can have a helicoil put in w/o dropping the engine and removing the head, or worst case is dropping the engine and replacing the head all together. I've seen mixed reviews of the helicoil method...although its cheap it may not be a long term fix if it comes out. There's also Timesert which is very similar. If I decided to do the helicoil method and don't get all of the metal shavings out the engine is a goners. I'm mechanically inclined but I would much rather a shop do the work so that I can get some sort of guarantee on the work.

 

Removing the head does not require you to drop the engine. Take a look at page 8-11 of the service manual.

It's actually not as big a deal as you may think.