Topic: Clutch Lifter Plate Torque Specs

[Jake1990]

Hey hows it going everyone? I have a 1974 Honda CB750 and the bolts holding my clutch lifter plate in came loose. So I was wondering if anyone has the torque specs for the 4 bolts holding the plate in? Thank you all in advance!

[City Boy]

Hi.There is in fact a torque value,though most builders and tinkerers know from experience to ignore the spec on 6 mm aluminium threads.I always tighten them evenly as you compress the springs until the plate bottoms then a pinch more.Not sure how you would have had them come loose as they are under constant spring pressure.  Cheers

[martin99]

^^^^^
What he said. Of course, if you've already over-tightened them you may have stripped the threads, which might explain why they feel loose. I hope not

[Jake1990]

Thanks for the advice. So just to make sure the clutch lifter plate should bottom out on the four posts that come out of the clutch basket? Also I don't know if it matters but I have "High Proformance" clutch springs. I just don't want to break the plate, I have broken one in the past.

[flybox1]

Thanks for the advice. So just to make sure the clutch lifter plate should bottom out on the four posts that come out of the clutch basket? Also I don't know if it matters but I have "High Proformance" clutch springs. I just don't want to break the plate, I have broken one in the past.

1/2 turn of the socket at a time.....takes a while, but you wont crack it.
bottom out and a tad more.  not torqued. 

[lucky]

Here is WHY the lifter plate breaks even when you carefully tighten the bolts.

The pieces do not align.
To keep the plate from breaking, turn all of the bolts a turn or so then tap the assy with the handle of your rachet a few times before you continue to tighten.
You will notice that every time you tap on it then go to tighten the bolts some more that the bolts are loose. That is because you have the alignment right after tapping on the assy.  So tight tap, tighten tap...etc.,.

[Cevan]

I don't mean to hijack this thread but can someone answer a question for me?  As you tighten the four bolts and start compressing the springs, should the clutch plates and pressure plates start to squeeze together so that once the lifter plate is bottomed out, the clutch is effectively "out" and engaged? 

In my case, they are not.  In fact, the plates can rattle around even once the lifter plate is bottomed out.  Also, if I put the clutch cover on, the throw out part doesn't even touch the lift plate, even with it adjusted all the way.

[City Boy]

Hi Cevan.I think what may be happening is that U have the clutch pressure plate and clutch centre misaligned.Pull both pieces off again.You will likely find that the pressure plate is not fully engaging the splines of the centre.Rotate the pressure plate until the two parts fully engage then reassemble. Good luck.

[Cevan]

Hi Cevan.I think what may be happening is that U have the clutch pressure plate and clutch centre misaligned.Pull both pieces off again.You will likely find that the pressure plate is not fully engaging the splines of the centre.Rotate the pressure plate until the two parts fully engage then reassemble. Good luck.

Got it.  Yup, the two aluminum pieces weren't engaging. 

[MCRider]

Hi Cevan.I think what may be happening is that U have the clutch pressure plate and clutch centre misaligned.Pull both pieces off again.You will likely find that the pressure plate is not fully engaging the splines of the centre.Rotate the pressure plate until the two parts fully engage then reassemble. Good luck.

Good catch CB. There have been many threads on this issue. This is by far the biggest reason for broken lifter plates. With the splines properly engaged you can atuallly tighten the plate dwn safely with just 2 bolts. I have done so for exhibition purposes and posted pictures of such here. It is not so delicate if the spines are engaged.

In the future, one should mark the top of a spring post and the area on the hub adjacent to it so reassembly with engagement is assured. Use a sharpie type pen. There are 4 chances only 2 of which will work. So one has a 50% chance to get it right without knowing it. But if its wrong, look for a broken lifter plate.

Once all 4 bolts are seated, a simple 5lbs torque is fine.

[MiGhost]

Here is WHY the lifter plate breaks even when you carefully tighten the bolts.

The pieces do not align.
To keep the plate from breaking, turn all of the bolts a turn or so then tap the assy with the handle of your rachet a few times before you continue to tighten.
You will notice that every time you tap on it then go to tighten the bolts some more that the bolts are loose. That is because you have the alignment right after tapping on the assy.  So tight tap, tighten tap...etc.,.

Also the reason for how the bolts could come loose.
When the lifter plate catches. You get a false reading on the tightness of the bolts.

[MCRider]

There are only 2 of 4 possible ways the hub can go with the pressure plate. IF you've picked one of the bad 2, all the tapping in the world will not align the splines. It must be disassembled, rotated 90deg, and reassembled.

[Cevan]

I ended up assembling the whole thing on my work bench and put two springs in and two bolts (with some spacers) to hold the whole thing together with just a little spring pressure and then inserted it in the engine. 

Btw, Hondaman's book gives a torque value of 70-90 inch/lbs for the bolts.