skorpion head torques

[bullet350]

i'm currently helping a mate put a new engine in his skorpion.

helpfully the previous owner of the new engine drilled and tapped one of the holes for the exhaust studs, unhelpfully he filled the exhaust port with swarf.

the only way we could get all the swarf out was to take off the head. now we have to put it back on.

two questions:

a) what are the torque settings for the head bolts?

ii) what are the clearences for the valves?

4) why is there masses of wear on the cam to head surfaces, yet virtually no wear on the bore?
       revving when cold?

currently thumperless, but keeping my hand in,

 bullet350


p.s. 200 gas gas on the way!

[andy230]

Hello mate

a) what are the torque settings for the head bolts?

ii) what are the clearences for the valves?

Am off to bed now, but I have this info on CD (for XTZ), will let you know tomorrow (will try to remember!)

helpfully the previous owner of the new engine drilled and tapped one of the holes for the exhaust studs, unhelpfully he filled the exhaust port with swarf.

the only way we could get all the swarf out was to take off the head.

I have seen guys at the racing (in scotland, on a manx), helicoiling a plug thread.  He used a vacuum cleaner with a hose attached to suck as much out as he could!!   

He also justified it by:

a) ally's soft

and

b) it'll come wheeching out the exhaust port quick smart anyway

A brave man, but I suppose he really wanted to get out that day, plus I get the impression he would be freshening up (or probably properly repairing after that meeting anyway, sso nothing to loose)

He didn't win, but he did finish the race!  Understandable tho, not wanting to have this approach on a road bike!

and

p.s. 200 gas gas on the way!

sweeeet!!!   

andy

[andy230]

a) what are the torque settings for the head bolts?

ii) what are the clearences for the valves?

From the 1995 Yamaha SZR service manual.  I'm assuming its the same... Also just checked my 1991 XTZ manual hard copy.  Its the same.

4x flange bolts (M9 thread) 38Nm (3.8 m.kg)
2x flange bolts: (also M9 thread): same
Socket head bolt: (M6 thread): 10Nm (1 m.kg)

I (on Martin Sweet's advice, for the SRX, worked for me on when I had the head off) would also say new (phosphor bronze?) washers if fitted and WD40 on the threads and grease under the head/washers.  And it didnt give any trouble.  But I always like to speak to someone who's done it

Valve clearances:

Inlet 0.1mm - 0.15mm   (4 thou to 6 thou in numbers [strangely!!!] which i use)
Ex 0.15 - 0.2 (6 thou - 8 thou)

Hope thats of use.

andy

ps.  If anyone wants an SZR manual on CD let me know?

[bullet350]

 excellent, cheers andy.

 bullet350