Hitchcocks Forum

Can anyone tell me the torque value of the head bolts pete snidal says 25lb psi manual says 285 lb psi a bit confusing?Bob

Hi ROBERTO ---- TORQUE figures are given in either lbs-inches OR lbs-feet, not psi which stands for "per square inch" and is a measurement of PRESSURE, in imperial units...... I don't have a Pete Snidal disc/manual but my copy of Royal Enfield's MAN16 also gives the cyl. head nuts (5/16") as 285lbs-inch, or}--- 3.30Kg-m (ie Kilogram-Metres, the metric equivalent)..........Also in MAN16,if you look further down the list of torque values you will see that the handlebar clamp bolt is very near at 286lbs-inch.......I can't see Mr.Snidal's figure being correct. That sounds more like the rocker block nuts to me.(125 lbs-inch).....

Mr H has thoughtfully printed all the torque settings in the printed parts catalogue. Have a look at page 27 which gives the head settings in most common variations of metric and imperial. * The only ones not stated are Newton Metres, but the conversion is simple, for example, 0.90 Kg-m = 9NM and 1.10 Kg-m = 11 NM etc. etc. * Please don't mix Lb-inch with Lb-Ft, that would be an expensive mistake!

Thanks Alan R and Midge,All clear now,never noticed our hosts notes before,athough ive looked at the parts book often enough.Bob.

--------- Well I never !! So they are-----have just checked the "on-line" catalogue and they are in there as well..... all these years of reading it and never noticed !!!... Nice one, MIDGE..... Mind you, 24lbs-ft seems a lot for a 5/16" nut with a 26tpi thread.

I'm with Alan, I thought that was a bit much. I did mine to 23ft lbs and I haven't had a problem. Dry of course - any lube throws the torque setting way out.

-----------just to update you, 2 of my mates run a BSA B40 350cc each and their head nuts are 25lb ft.on an Aluminium head and an iron barrel.

I have an early 350 bullet, I tightened the head down to 25ftlbs which was to the specifications in an enfield manual and pulled the studs out of the crankcase.
After helicoils did it to 18ftlbs, its been perfect for 4 years now.
Victor

Thanks for that info VICTOR. By coincidence I'm fitting my 500 head back on soon so will give 20lbs-ft a try (composite gasket fitted).

Been doing 20 lbs for years, never game enough to go any higher. It is a matter of knowing what ally is capable of handling and after a lot of years you get a feel for these things. Blindly following a book can lead to trouble