Question on motor mounts

[mykul]

I recently bought a 1980 hardtail. I noticed that all the motor mount bolts have been left slightly loose. Is this typical. I get an annoying rattle that I believe is coming from them . Would it be o k to use high temp "o" rings on the bolts and nuts? This would still allow the motor to vibrate free of the frame. The bottom bolt is rigid (tight) but the rest are all slightly loose with Ny-lok nuts.

 

[jd750ace]

That is typical if your goal is to have the bolts fall out going down the road, and wear out the mount holes in random elliptical fashion. Most of us bolt the fire maker down pretty good.
Just sayin.

There is a chance he tried to tighten them to spec, but did not add the running torque of the nylon insert to the final torque value. If you are torquing to 300 inch pounds, and you have 120 inch-pounds of drag, you will only get the clamping force of 180 inch-pounds on the fasteners. It would be necessary to increase the set point to 420 inch-pounds to get the required value on the stack-up. This is seldom if ever accounted for in torques referenced in manuals.

 

[angus67]

tighten them bitches!!!!!

 

[mykul]

Thanks for the advice! After closer inspection I think the motor was on its way to falling out!!! I tightened up everything and not only are all the rattles gone but it reduced the vibration by about 50 %.

 

[Indiana Drew]

Loctight is your best friend !

 

[jd750ace]

He has self locking nuts. Loctite is wasted on them. Won't hurt anything, but they do not back off unless you have run a tap through them.

 

[Detale]

Loose bolts=bad not just for motor mounts anymore!!!

 

[Indiana Drew]

He has self locking nuts. Loctite is wasted on them. Won't hurt anything, but they do not back off unless you have run a tap through them.

All his mounts were loose bad lock nuts for sure he could put blue on them and fix it for the short haul .

 

[jd750ace]

I've been a mechanic for 25 years and never got a batch of "bad lock nuts", much less seen any back off. They were not tightened properly to begin with.
As I stated, you can ruin them, but they do not just "go bad".

Just sayin.

 

[Indiana Drew]

30 year old metal lock nuts who knows how many times they have been taken off and on ? Metal band locks when i take them off i replace with new they are never the same after you take them off . I use loctight on everything on my vert twins yama BSA and triumph they all shake your teeth out . but thats just me .

 

[jd750ace]

30 year old metal lock nuts who knows how many times they have been taken off and on ? Metal band locks when i take them off i replace with new they are never the same after you take them off . I use loctight on everything on my vert twins yama BSA and triumph they all shake your teeth out . but thats just me .

O.P. stated they were Nylon locking inserts. Not original equipment.

 

[Indiana Drew]

Sounds like a trip to fastenal to me . They will work loctight and tourqe it .

 

[hotrdd]

I have some lose ones that I've retightened a few times but they don't seem to hold. They are the original nuts so I assume that they aren't tight enough. What is the correct torque and is there a torque sequence? I'm assuming NO

 

[Indiana Drew]

25-28lbs in the book i do mine at 35