An email to me by Dave Thomas

...............As to jetting I like to run just slightly rich as lean is really bad for the bike. If the bike runs really strong and the plug stays light brown with no black soot then you are ok. If the plug gets sooty then it is too rich and you will foul a plug eventually. If the plug is really white or blistered then jet it richer!!! To loeans fry's the engine. Pinging can also be a sign of lean jetting but low octane gas will do the same as XR engines run quite hot.

By the way I recommend every one carry a spare plug and chain link. No matter how well you plan and maintain I have seen plugs fail and have broken links several times, especially on rocks.

The puff of smoke is quite common and is usually the valve guide seals on the intake side. When you back off really fast the manifold vacuum is very high and it draws oil down the valve stem. It won't hurt anything but eventually it may get worse and start plug fouling. This takes a long time and I would not worry, It would be quite obvious. If you do your own work and want to fix it be very careful about torqing the head bolts. Honda screwed up and did not put inserts into the cylinder. The are easy to strip if you overtighten, especially if it has been apart several times. It can be fixed by machining steel inserts but if you don't have a shop with a lathe then it will be to expensive and you will have to replace the sleeve. By the way if you really want it to run like a raped ape then consider a Weisco piston. They are domed and boost compression. Stay away from the really high compression ones (ratios > 11:1) they are hard on the bottom end and require really high octane gas. I ran 10.5:1 and it rally ran strong but still requires premium gas minimum. Try aviation gas if it pings really bad before race gas as race gas is usually very expensive. Octane about 100-105 should be good. Don't put any higher octane than you need as octane rating is the gases resistance to combustion under pressure. To high is a waste of money.

Have your shock oil changed ocassionally (every 2-3 years) as they do wear and the seal will blow if not maintained. It is rare but the shock does get full of metal from wear after time. Use a good quality shock oil (not fork oil). Also be very careful when you vent the nitrogen gas. The stem is under the metel cover on the reservoir by the left number plate. A bike shop will recharge the nitrogen for a fee. You must take great care to get out ALL the air in the shock when you reassemble it or it will not function right. I strongly recommend if you ever do this to have it done by a shop. I have done it three times and it is a pain in the rear.

Grease the steering stem bearing ocassionally to. Alot of people never do this and eventually they become pitted from moisture and wear. Use high temp (the stringy stuff) wheel bearing grease as the engine oil circulates through the head and gets it hot. If you use ordinary greas it runs ou the bottom and makes a mess as well as promoted loss of lubrication. Honda was nice enough to use custom diameters on the steering head bearings so you have to buy them from Honda. Very expensive. By the way. You can save a fortune on wheel bearings and such by buying your bearings from a bearing supply house and not the Honda shop. I usually buy wheel bearings for about $5.00 US where as Honda usually wants $15-20 US. Take the old ones with you and they almost always can supply you with replacements for less.

Heavy duty clutch spring make my hand tired. If you are running a mostly stock engine and it never slips then you probably do not need them. Slipping is also a sign of worn clutch plates. I have personnaly never had any clutch problems.

Also unless you are running balls out all the time stay away from hot cam shafts. They sacrifice low end for top end performance. A mild or torky cam is ok but a lot of folks think a really hot cam gets them alot more power. It does if you run at 8000 rpm all the time. For trails the stocker is very good and the piston kit I told you about will more than satisfy you thirst for power. By the way they usually cost less than the stock piston and are forged rather than cast..........