tdc

hey guys,
i know this has been proberbly answered before but im in need of help!
when you guys adjust the valves (i have 2005 fe450e) do you guys remove the rocker cover? i have trouble getting feeler guages in little covers?
also can someone please explain the best procedure to find top dead centre as my valves feel tight and not sure if i have top dead centre.

pull the plug out and turn the engine with the bike in gear. left hand on the rear tyre slamming it hard to get the engine to move. in your right hand a long philips screw driver resting on the piston.

you should have the valve inspection covers off anyway so what you're looking for is to STOP the engine just as the inlets close. then put your philips in and tap that wheel until the piston is at the highest point give or take 2-3mm.

don't bother with feeler gauges-just gently flick the screwdriver gently to lock and then back off 1/6th of a turn. think of two numbers on the clockface!

as you tighten the spanner clockwise: try to force the screwdriver anti-clockwise to keep that gap!

easy-peasy lemon squeezy!

regards

Taffy

Taffy said:

pull the plug out and turn the engine with the bike in gear. left hand on the rear tyre slamming it hard to get the engine to move. in your right hand a long philips screw driver resting on the piston.

you should have the valve inspection covers off anyway so what you're looking for is to STOP the engine just as the inlets close. then put your philips in and tap that wheel until the piston is at the highest point give or take 2-3mm.

don't bother with feeler gauges-just gently flick the screwdriver gently to lock and then back off 1/6th of a turn. think of two numbers on the clockface!

as you tighten the spanner clockwise: try to force the screwdriver anti-
clockwise to keep that gap!

easy-peasy lemon squeezy!

regards

Taffy

Click to expand...

If you use the 1/6 turn method, you can also use the hex nut itself as a guide. The length between any two adjacent points of the adjuster locking nut equals exactly 1/6 of a turn.

hey thanx guys

I would strongly recommend not putting a screwdriver ( or a pencil!!) into the sparkplug hole. Use a straw instead. When searching for TDC, the piston has a tendency to suddenly rise up in the cylinder and damage is easily incurred with a hard foreign object in the cylinder.

sorry chas, quite right. i forgot to mention i know what i'm doing :evil:

none of you try this at home folks but if you must please lock away the wife and children.

regards

Taffy

TDC can blow me........TDC-what about valve overlap? are both valves truley closed at TDC on the compression stroke or the exhaust stroke? and which stroke are you on? and I ain't never puttin nothing down that spark plug hole again although my stepdad made a nice dial indicator tool for me as a result of my pencil disaster.

The technique I use I was taught by MotoXotica's mechanic is simpler. Leave the spark plug alone. Take off the valve tappet covers. put the bike on a stand, in neutral. Stand at the left side of the bike, used a rag to soften the feel of the kick starter lever on your right hand. Use your right hand to plunge the kickstarter down. Watch the rocker arms move and notice while one set dives down the other set rises up.

Now as you plunge the lever down and the bike goes thru its cycle, some times the bike will goes swoosh and other just turn over, but the bike will jump/run thru these parts of the cycle, the trick is this WATCH the tappets as one set starts to dive down......there is a moment just before the pistion runs away from you again where the intakes are down and the exhaust are up. ( and vice versa on the other part of the cycle) EASE the kick starter just there and the bike will Stay in that position no block of wood needed in the tire. Now with the intakes down and exhaust up ( exhaust valve closed) you can check/adjust the exhaust valve ( vice versa when the exhausts valve rockers are down and the intake rockers are up ( intake valve is closed) you can check/adjust it then.

You know you will be at that magic spot just before the bike runs thru it. Its all about touch...having an experienced mechanic stand there and train me to do this meant every thing to me. I do it easy now.

PS oh yeah, go to your good dirt bike shop..Motion pro sells a set of tappet adjuster wrenches with tiny screw drivers.......great tools and you can get a feeler guage made for this job too with 0.004 and 0.005 feelers on a stif thick bar...perfect for the job. ask your dirt bike shop. I got mine set at a yamaha dealer.