First of all, I really like my new (to me) 2000 TTR-250.
But, is there a modern, small bike on which this is a more difficult task to do well? First of all, little bay in which the plug is placed is a terrific place to collect dirt leaves, small rocks, sand, etc. Second, you can't see what is there to make sure that it is OK to remove the plug without having debris fall into the cylinder. So, you remove the tank, which makes it a lot easier to access the spark plug for removal, and you bring out the shop vacuum to remove the dirt and debris, but the space is so small that the end attachment of the shop vac can't get close enough to the dirt to suck it up. So, with duct tape, you attach a section of old garden hose to get down close enough to the dirt to suck it out. Then, after you have started to remove the plug, you notice that there is still more dirt under the hex flange of the spark plug, which you must suck out before completely removing the plug. The U.S. owner's manual simply says, "Remove the spark plug."
Is there an easier way to accomplish this maintenance task? What do you guys do if, God forbid, you have to change a plug out on the trail? Perhaps the dependability of the TTR makes that scenario an unlikely event?
Anyway, I thought that I would share my experience (and surprise) in the hopes of eliciting some suggestions to simplify my procedure, or to confirm that, indeed, that is the way of the beast.
I had the same issue when I changed my plug for the first time. I have a mate that has a compressor at work so we used that to blow out stones and dirt from the recess. We then wound the plug out a touch and blew the recess again to be sure no debris was left in there before removing the plug.
For the reasons you mention, I only ever change the spark plug if an engine isn't starting or running properly just to eliminate a possible faulty spark plug. I run the NGK CR9Es and I can honestly say that I have never had a problem and they seem to stay in adjustment for ever.
Just in case, I always power wash the spark plug "bay".
If I really really have to change the spark plug then, in addition to blasting out the bay with the power washer, I give it plenty of blasts with the air line before the final removal
The only time you would have to remove a plug out on the trail (I guess) is if you flood the engine. In which case there is a good chance that the water that flooded the engine will also have cleaned the bay. Otherwise just be as careful as you can be.
Brian
PS I think there are quite a lot of other dirt bikes with the same problem.
I had the problen that you describe and ALL TTR owners will get if the "use" their bike.
To prevent it clogging up so much I have shaped and fashioned a conical wedge of foam rubber with a central hole and shoved it over tyhe plug before fitting the ignition lead.
If you do this then all the crud sits on top of the foam and can be flicked away before removing the foam to check the plug.
It works - but I really prefer to leave it alone - as Brian says, "change the spark plug if an engine isn't starting or running properly".
Thanks to all of you. You've told me that I am not missing something (other than, perhaps, the tool kit that that originally came with the bike), so thank you. And thank you for the suggestions. I do use the said NGK plug, and I have never had to change out a plug on the trail, myself. I am sure that you're correct, Brian, and I just don't have owner experience with very many different dirt bikes. The foam rubber sounds nifty, Martyn, though I am a bit surprised that it doesn't melt sitting on the engine head.
I am still working on the ignition miss issue, but stuffing a copper grill cleaner in the rear of the muffler seemed to help a bit... and it is noticeable quieter.