Topic: Hardware question

[amitr0]

I have posted some dumb questions in this forum, gratitude to all you folks for being patient with me, but this one perhaps is the dumbest one so far....

I got a set of alan head stainless steel bolts for the engine case, and they look different from the screws already on the bike.

Most of the screws on the mc have the windings all the way to the top, these don't.

Why is that? What is the advantage of this design over the older ones, and most importantly, are they interchangable.

I am assuming i need to just go by over all bolt length and thread gap to find out where to swap?

[69cb750]

Original case bolt are partially threaded and use a thick washer.
Length needs to be the same and use the thick washer.
https://www.ebay.com/itm/334051095574?hash=item4dc6ff3416:g:~EEAAOSwx8Jg01l0

[Alan F.]

And use a little anti-sieze compound on the threads as you place each screw in its final position.

[amitr0]

This bolt set is for the alternator cover, chain aide casing etc, they are stronger than the original screws obviously as they are only partially threaded. They didnt come with washers though.

Yes antiseize is there in my list, thank you.

Is there a torque chart reference i can find somewhere to use. Since the originals were screws, i don't think the book will have it, but a generic chart which i accurate to the max torque a thread size can have would be very useful to a noob like me.

[bryanj]

DONT torque them you will strip out threads, also screws didnt have washers so whywould you want to put them on

[amitr0]

DONT torque them you will strip out threads, also screws didnt have washers so whywould you want to put them on

I was assuming that since i am replacing screws with bolts, they would need washers?

Generally speaking, when and when not is a washer needed?

[PeWe]

I tighten mine CB750 engine covers 5Nm, retighten the day after if gasket is new.

I have tightened them harder before but thread failures take time to fix and happen when time is short.
All precautions to not get metal burrs in engine take longest time.

If M6 thread depth is 15mm, 7.5Nm possible
5Nm is about what you can tighten manually with a good gripped screwdriver.

I have a good reliable 1/4' torque wrench with range 2.5-25Nm.

Measure the depth first before using the screw in each hole.
Risk to mix them up, too long can hit the bottom and pop the often thin alu bottom that come loose into engine.

Happened me. Not much torque needed.
 I was not sure if that had happened before. I found the alu piece at next oil change.
It had a mark from transmission mangled it. It could have gone bad $$$.

Nm vs ft lb
https://www.metric-conversions.org/energy-and-power/newton-meters-to-foot-pounds.htm

[slikwilli420]

DONT torque them you will strip out threads, also screws didnt have washers so whywould you want to put them on

Allen heads are smaller than the original JIS screws so washers are a good idea. I know that no one torques them but I do with an inch pound wrench and go to 75 inch pounds. Never an issue. Anti seize is a must as well.

[Alan F.]

Washers are needed where the factory used them.
Some have used them on stainless case screws because the heads of these are smaller. No oil is going to leak from these holes, its a matter of preference. Finding flat washers with a small enough outer diameter to fit may be difficult.

Since you're new to all of this you may not be able to "go by feel" when tightening nuts and bolts, after you finish with these stainless case screws you'll have mastered it.
Thread them in and tighten just a little, once all of the screws on a particular cover are tightened just a little, go over them again, break them loose and tighten again by feel and maybe make them a tiny bit tighter.

I read a few threads where the type of anti-sieze to use on these was the topic. Aluminum based anti-sieze seemed to be the preference, zinc and copper followed. There was some discussion that bronze high temp anti-sieze could over time cause thread damage, so it's probably best kept to the very high heat areas then.

[RAFster122s]

Part of the reason for anti-siege is to reduce the galvanic corrosion from dissimilar metals. Stainless steel and aluminum are more reactive than the zinc plated steel screws and aluminum cases.  With SS the aluminum is sacrificed instead of the zinc going first…

Usually is the bike is kept clean and relatively dry you don’t see much if any galvanic corrosion when anti-siege is used with stainless fasteners in aluminum cases.
If you are in a coastal area, then do Not use SS fasteners in aluminum cases…

[Stev-o]

I am assuming i need to just go by over all bolt length and thread gap to find out where to swap?

Yes.  Your bike came with JIS [Japanese Industry Standard] scews, they look like a "Philips" but are slightly different.

The screws in the pic you posted are Socket Head Screws, a common upgrade for attaching the covers on your engine. No washers are needed.  I use a [small] 1/4" ratchet when installing them, dont over tighten! 

A small machinist scale is handy for measuring the length of the screw, dont include the head.


And for future maintenance, a set of Vessel screwdrivers is a must...

https://www.amazon.com/VESSEL-MEGADORA-IMPACTA-Screwdriver-PCS/dp/B084TDXB89/ref=sr_1_21?gclid=CjwKCAiAzrWOBhBjEiwAq85QZ21vfpjRUseyPSNbEhgKDGScK58KQQJcUMBi4F55-vRKh4rGKCV9-BoCu1QQAvD_BwE&hvadid=190516507846&hvdev=c&hvlocphy=9028253&hvnetw=g&hvqmt=e&hvrand=7846901621289338189&hvtargid=kwd-304962656332&hydadcr=29040_10165993&keywords=vessel+jis+screwdriver+set&qid=1640899454&sr=8-21

[amitr0]

I am assuming i need to just go by over all bolt length and thread gap to find out where to swap?

Yes.  Your bike came with JIS [Japanese Industry Standard] scews, they look like a "Philips" but are slightly different.

The screws in the pic you posted are Socket Head Screws, a common upgrade for attaching the covers on your engine. No washers are needed.  I use a [small] 1/4" ratchet when installing them, dont over tighten! 

A small machinist scale is handy for measuring the length of the screw, dont include the head.


And for future maintenance, a set of Vessel screwdrivers is a must...

https://www.amazon.com/VESSEL-MEGADORA-IMPACTA-Screwdriver-PCS/dp/B084TDXB89/ref=sr_1_21?gclid=CjwKCAiAzrWOBhBjEiwAq85QZ21vfpjRUseyPSNbEhgKDGScK58KQQJcUMBi4F55-vRKh4rGKCV9-BoCu1QQAvD_BwE&hvadid=190516507846&hvdev=c&hvlocphy=9028253&hvnetw=g&hvqmt=e&hvrand=7846901621289338189&hvtargid=kwd-304962656332&hydadcr=29040_10165993&keywords=vessel+jis+screwdriver+set&qid=1640899454&sr=8-21

Thanks, yes i recently got introduced to the vessel JIS screwdrivers and have their impact driver as well.

PO badly damaged the original JIS screws, hence the effort to replace with Alan head screws. However upon close measurement i see that the alan heads are less im diameter than the pan heads around the head, so was thinking if a washer is needed to compensate for it and also having a more uniform force distribution.

[MauiK3]

I use washers with Allen heads to help spread the load on the soft aluminum.
I almost always torque to 70-75 inch pounds, going by feel is unreliable. Just my opinion, based on some lab experiences I’ve had.
Anti- seize is a must.

[ekpent]

 I bought a couple of nice complete 750 engine allen head kits off E-bay in the past that worked very well and they came with all the needed washers and instructions about the best paste..

[amitr0]

I bought a couple of nice complete 750 engine allen head kits off E-bay in the past that worked very well and they came with all the needed washers and instructions about the best paste..

Can you pleaae share a link to that online store