Plugged Silencer/Spark Arrestor

[fireburns99]

Have any of you guys ever had a plugged spark arrestor. About a year ago i bought one of the fmf turbine core because it had a spark arrestor in it,(i don't want to be responsible for any fires in so cal,we have enough already) and recently i was having problems with head gaskets blowing.

So i rebuild the motor and kick it over a couple of times to get some fuel in the cylinder, than turn the switch to the on position and kick it. BOOM!!!! The pipe was blown off the end of the exhaust flange of the motor, (springs stretched and was stuck off to the side) and the joint in the middle of the expansion chamber was blown apart. The only thing i could think of was the silencer was plugged(it has a spark arrestor) and that caused enough back pressure that it blew the pipe apart.

Does this seem reasonable reasoning to anyone else? Has anyone ever experienced this?

[C-LEIGH RACING]

It is possable to have a backfire in the pipe if gas has gathered up in there. Most times though its from a half firing about fouled spark plug. When a plug fouls, sometimes at the very start of it going bad the plug will fire late & you get the results of an explosion in the pipe.
Now far as the silencer being plugged, could be, what does a spark arrester do, stop sparks from exiting the pipe, its got to plug itself over time thats how & why its made.
A spark arresting silencer needs maintance, cleaning to ensure a good flow.
Anytime you restrick the exhaust flow on a two stroke you bottle up heat in the system & it will cause problems in other areas of the engine. It could very well have been the plugged silencer that caused the head gasket to leak.
Neil

[fireburns99]

I didn't know that about a fouled spark plug, but it makes sense. I just can't see why the spark arrestor plugged so quickly, i really don't get all that many chances to ride. Do you have any idea on about how often it should be cleaned, or serviced?

[C-LEIGH RACING]

Cleaning the spark arrestor would be according to how much you ride & how old the pipe is.
An old pipe will have more carbon build up in side & more chance of pieces flaking off to get caught by the silencer.
It could be you would need to clean it everytime you ride or every other time.
Is the spark arrestor part of the silencer or an add on part that can be easy removed.
Neil

[fireburns99]

Here is a link to the silencer i have:
http://www.rockymountainatv.com/productDetail.do?prodFamilyId=4682&navTitle=Exhaust&webCatId=18&pageLinkUri=&vehicleType=&webTypeId=146&navType=type
The spark arrester is actually riveted and integrated into the back of the silencer. The The silencer is about 12 inches long, and the first 8 or so is the packing and then the spark arrester is the last 4 inches.

Now that you mention carbon buildup, when i put the silencer on i was running an fmf pipe, but then i switched it to a sparks TT i bought right before the problem started. I never even put two and two together.

Thank you for all of the help.

[fireburns99]

Also after i replaced the head gasket the first time, it would run, but it wouldn't rev out at all. Which i'm going to assume was caused by the backpressure in the pipe? I put the sarks silencer that cam with it, and it started running fine. But then again theres no spark arrester to get plugged.

[C-LEIGH RACING]

That sounds like the arrestor is plugged, suspect it needs a good cleaning out.
Neil