steel length of engagement is minimum 1 x dia . while cast aluminum is typically 1.5-2 x dia because it so much softer. thread coarseness also has a relationship to the material. if you want to go deep here is a calc i have used tribology-abc.com/calculators/e3_6e.htm
here you can see you need a about 1.75 times the diameter with a steel fastener in 6061-t6. I don't know what alloy these engine cases are but it is for sure softer than 6061, i would assume you want at least 2x diameter
Thanks guys. I'm wondering now if I should pull out the helicoils that are already in and replace them with longer ones. I put 1D inserts in (only had 1D and 3D and the 3D ones were too long). I've got some 2D ones on the way. I figure with the increase in diameter (for the aluminium threads) the 1D inserts are probably equivalent to having about 1.25 times diameter in a normal M6 thread. Thoughts?
A 1D insert in the head (assuming 150-200 MPa tensile strength) would mean that the insert is the stronger than a 4.6 steel screw (tensile strength 400MPa). I figure that should be fine, but I'll probably still swap them out
Swapped out all seven helicoils with longer ones today. They were supposed to be 2D which would mean 12mm or 12 windings (pitch: 1mm). They were more like 10 windings and maybe 10.5 once they were installed - I'll call them 1.75D and move on They'll definitely hold and are better than the short ones. Let's see if I get the cams back in without having to put in a couple more...
Got the new coil brackets last week, just need to weld some nuts to them and give them a coat of paint. Also got the control housings ready for the clear coat but the temps have dropped here so I'll have to put off any painting for a few days.
Need some help on this one. Apparently, the cams have been swapped out on this bike. I can't confirm this as this is the first KZ I've taken apart (first bike for that matter). I checked the cams and they have a capital R (exhaust) and S (intake) stamped on one side and a capital M in a circle as well as R1 stamped on the other side. There are no other discernible markings.
Tried searching for some info but came up empty (or rather, got so many results that I can't find what I'm looking for). Can anyone identify the cams for me?
Thanks. I did see some Z 750 GT cams on ebay with R1 (intake) and R2 (exhaust) stamped in the same way as mine. These had the tach drive (didn't know the GPz had an electronic tach). Leads me to believe that these cams have been pilfered from another 750 model.