How to...for Skyteam V-Raptor (Retro) 250

Panic-Pete · 10-03-2016, 12:14 AM

Valve cleareance, control and adjustment, at the 233cc Honda clone engine, used in the Skyteam V-Raptor 250.

"my01", asked for a maintenance tutorial for the 250 V Raptor.
There already are some very good threads about Valve cleareance in the stickys, though i can´t see the pics anymore... anyway, here it is.

The Motor is an 233cc overhead camshaft, two valve, four-cycle engine.
Valve cleareance is 0.05mm for both, intake and exhaust valve (according to owners manual.)

Take off seat and tank and remove the horn. Disassamble the three bolt bracket holding the cylinderhead to the frame.

Horn assembly

clylinderhead bracket

note the three washers located at the right side. these will by reassambled just like in the picture.

Remove the Valve caps as well as the small covers on the generator side of the engine, also the sparkplug.

You need a 24mm hex-ringspanner.

Spanner and surplus material on the frame might need to be grinded down some.
it´s a tight fit on the intake side.

note washer as a makeshift tool for control orifice cap.

Turn the crankshaft on the generator side, counterclockwise, with a 14mm hex socket wrench.

Observe the intake rockerarm going down and up again. Turn farther until the index marks appear in the control orifice.

left index stands for fire/ignition, right and longer marking stands for Top-Dead Center.

Do not turn the engine anymore.
This is the position the Valve cleareance has to be checked and/or adjusted, if necessary.

To check, slide the feeler gauge between adjusting screw and valve stem. Slide in sideways because 0.05mm is way to flimsy to push it through.

While drawing it out between the two surfaces, you should feel a slight resistance. No resistance means a too big clereance. If you can´t get the gauge in, at all, or if resistance is strong, the cleareance is to small.

To adjust, open up the 10mm jam nut and turn the adjustingscrew with your fingers. Turn clockwise until you feel, it just touches the gauge.
Or open it up (couterclockwise) for the same result.

If the cleareance ist properly adjusted, secure the jam nut.

Than check again. It might need a few times until you get it right. jamming the nut does two things at the same time. First it turns the screw a bit and second, rises it up.
these movements are micro-small... but they can ruin the adjustment and have to be taken into account.
Theoretically the adjustingscrew can be hold by the square on it´s top with a tool.....practically there´s no space for it. perform the procedure on both, intake and exhaust-valve.

If things are set alright, turn the crankshaft several times. Then turn it into "Ignition Top Dead Center" as described
(Intake valve opens, intake valve closes.. next index markings are your´s for Ignition-TDC)

Then check again., if necessary re-adjust. Then re-assemble and run the engine to check for noise and leaks. (all sealing-surfaces like O-Rings should be oily for re-assembling, though, check for dirt-particles.)

slightly bigger cleareance like 0.07mm is okay and does not hamper the engines performance

Bigger means that the motor starts tickin´ away. Way too big, it starts "hammering"
No question, this will harm the engine and has to be re-adjusted.

If cleareance is too tight it´ll harm the valves, may be, up to the point of total destruction of valves and engine.

Drive safely.

Jürgen

10-03-2016, 12:14 AM	#1
Panic-Pete Join Date: Jan 2012 Location: Frankenbrunn, northern Bavaria, Germany Posts: 43	How to...for Skyteam V-Raptor (Retro) 250 Valve cleareance, control and adjustment, at the 233cc Honda clone engine, used in the Skyteam V-Raptor 250. "my01", asked for a maintenance tutorial for the 250 V Raptor. There already are some very good threads about Valve cleareance in the stickys, though i can´t see the pics anymore... anyway, here it is. The Motor is an 233cc overhead camshaft, two valve, four-cycle engine. Valve cleareance is 0.05mm for both, intake and exhaust valve (according to owners manual.) Take off seat and tank and remove the horn. Disassamble the three bolt bracket holding the cylinderhead to the frame. Horn assembly clylinderhead bracket note the three washers located at the right side. these will by reassambled just like in the picture. Remove the Valve caps as well as the small covers on the generator side of the engine, also the sparkplug. You need a 24mm hex-ringspanner. Spanner and surplus material on the frame might need to be grinded down some. it´s a tight fit on the intake side. note washer as a makeshift tool for control orifice cap. Turn the crankshaft on the generator side, counterclockwise, with a 14mm hex socket wrench. Observe the intake rockerarm going down and up again. Turn farther until the index marks appear in the control orifice. left index stands for fire/ignition, right and longer marking stands for Top-Dead Center. Do not turn the engine anymore. This is the position the Valve cleareance has to be checked and/or adjusted, if necessary. To check, slide the feeler gauge between adjusting screw and valve stem. Slide in sideways because 0.05mm is way to flimsy to push it through. While drawing it out between the two surfaces, you should feel a slight resistance. No resistance means a too big clereance. If you can´t get the gauge in, at all, or if resistance is strong, the cleareance is to small. To adjust, open up the 10mm jam nut and turn the adjustingscrew with your fingers. Turn clockwise until you feel, it just touches the gauge. Or open it up (couterclockwise) for the same result. If the cleareance ist properly adjusted, secure the jam nut. Than check again. It might need a few times until you get it right. jamming the nut does two things at the same time. First it turns the screw a bit and second, rises it up. these movements are micro-small... but they can ruin the adjustment and have to be taken into account. Theoretically the adjustingscrew can be hold by the square on it´s top with a tool.....practically there´s no space for it. perform the procedure on both, intake and exhaust-valve. If things are set alright, turn the crankshaft several times. Then turn it into "Ignition Top Dead Center" as described (Intake valve opens, intake valve closes.. next index markings are your´s for Ignition-TDC) Then check again., if necessary re-adjust. Then re-assemble and run the engine to check for noise and leaks. (all sealing-surfaces like O-Rings should be oily for re-assembling, though, check for dirt-particles.) slightly bigger cleareance like 0.07mm is okay and does not hamper the engines performance Bigger means that the motor starts tickin´ away. Way too big, it starts "hammering" No question, this will harm the engine and has to be re-adjusted. If cleareance is too tight it´ll harm the valves, may be, up to the point of total destruction of valves and engine. Drive safely. Jürgen __________________ Je suis Paris, je suis Europe ! Liberte Egalite Fraternite ! Last edited by Panic-Pete; 10-03-2016 at 10:45 AM.
	2