2018 Vader motor mount problems

[Megadan]

Originally Posted by 2LZ

One of the mistakes many people make is that they tremendously over-tighten the motor mount bolts (and most other bolts).
The secret to motor mount bolts in helping stop vibration is not their torque as much as making sure they have even torque.
Most small motor mount bolts only live around 18-22 pounds of torque depending on bolt shank thickness.

If going by Honda Grom specs, then the Upper, lower, and front "Engine Hanger Nut" bolt torques are 40ft-lbs.(54nm)

[Chinabike]

Originally Posted by Megadan

If going by Honda Grom specs, then the Upper, lower, and front "Engine Hanger Nut" bolt torques are 40ft-lbs.(54nm)

grom engine mount bolts are 10mm. the Hellcat is only 8mm. Im not sure about the vader are

[JerryHawk250]

Originally Posted by Chinabike

grom engine mount bolts are 10mm. the Hellcat is only 8mm. Im not sure about the vader

The pictures are too small and I can't tell from the pictures but couldn't you just drill out to 10mm without really decreasing the structural integrity of the block? We're only talking about 2mm.

[Megadan]

Or, only torque the motor mount bolts to around 30ft-lbs and use either loctite, or nylock nuts (or both if you are paranoid). As 2LZ mentioned, they don't have to be super tight. In terms I understand. Less ape, more feather. lol

[Majordoomsday]

Where should I go to get my bolts and yes the grom bolts are bigger (10mm) compared to the 8mm bolts on these

[Megadan]

Originally Posted by Majordoomsday

Where should I go to get my bolts and yes the grom bolts are bigger (10mm) compared to the 8mm bolts on these

Can you give me some measures? Namely the total length and shank length of each fastener? M8 x ???

It shouldn't be too hard to find suitable bolts from Fastenal or McMaster Carr. Just need to know the specs.

[JerryHawk250]

The Grom bolts are 10mm for a reason. A Japanese engineer sized them to the correct size so they don't break. Me personally, I would drill the block out to the 10mm. After looking at some picture of the Chinese 125cc engines it looks like there is plenty of meat where those bolts pass through. I don't think 2mm will affect it. This is only my opinion and not suggesting that you do it as I haven't seen any close up pictures or taken measurement on your engine.

[Majordoomsday]

Their the same length as the grom top and back motor mount bolts, I can’t look them up rn, I’m at work

[Megadan]

Originally Posted by JerryHawk250

The Grom bolts are 10mm for a reason. A Japanese engineer sized them to the correct size so they don't break. Me personally, I would drill the block out to the 10mm. After looking at some picture of the Chinese 125cc engines it looks like there is plenty of meat where those bolts pass through. I don't think 2mm will affect it. This is only my opinion and not suggesting that you do it as I haven't seen any close up pictures or taken measurement on your engine.

I actually agree with this, but some people aren't comfortable with drilling on a motor. A good quality M8 bolt should be sufficient enough if installed properly though.

[2LZ]

Originally Posted by Megadan

A good quality M8 bolt should be sufficient enough if installed properly though.

Here here...........

[Chinabike]

Originally Posted by Majordoomsday

Their the same length as the grom top and back motor mount bolts, I can’t look them up rn, I’m at work

I don't know about Vader but the Hellcat bolts M8x135 and M8x110

Grom bolts are M10X130 and M10x110

[Chinabike]

Originally Posted by JerryHawk250

The pictures are too small and I can't tell from the pictures but couldn't you just drill out to 10mm without really decreasing the structural integrity of the block? We're only talking about 2mm.

You can click to enlarge.

[Megadan]

Originally Posted by Chinabike

I don't know about Vader but the Hellcat bolts M8x135 and M8x110

Grom bolts are M10X130 and M10x110

Ok, so for the M8 x 135... You can go with M8x130 or M8 x 140 as easy to find alternatives.

M8x1.25x130mm Grade 10.9 - https://tinyurl.com/y899vjpu

M8x1.25x140mm Grade 10.9 - https://tinyurl.com/y9ndbra6


As for the M8 x 110mm. - https://tinyurl.com/ya4a89su

So keep one thing in mind with fasteners, and the reason why I agree with Jerry that using the M10 Grom bolts would be the best option. Grade 10.9 M8 bolts have a maximum recommended torque value of around 20-25ft-lbs. M10 bolts are a little more than double that, which is why the Grom bolts torque spec is 40ft-lbs. You try 40ft-lbs on an M8 bolt and it will break.

So, if you don't want to drill to use Grom bolts, then I highly suggest using Nylock nuts or loctite on the nuts. You could also run a longer bolt and back up both the head of the bolt and the nut with a lock washer, or serrated flanged head/nut.

[Majordoomsday]

Thanks bro I appreciate it! This should be a sticky!

Originally Posted by Megadan

Ok, so for the M8 x 135... You can go with M8x130 or M8 x 140 as easy to find alternatives.

M8x1.25x130mm Grade 10.9 - https://tinyurl.com/y899vjpu

M8x1.25x140mm Grade 10.9 - https://tinyurl.com/y9ndbra6


As for the M8 x 110mm. - https://tinyurl.com/ya4a89su

So keep one thing in mind with fasteners, and the reason why I agree with Jerry that using the M10 Grom bolts would be the best option. Grade 10.9 M8 bolts have a maximum recommended torque value of around 20-25ft-lbs. M10 bolts are a little more than double that, which is why the Grom bolts torque spec is 40ft-lbs. You try 40ft-lbs on an M8 bolt and it will break.

So, if you don't want to drill to use Grom bolts, then I highly suggest using Nylock nuts or loctite on the nuts. You could also run a longer bolt and back up both the head of the bolt and the nut with a lock washer, or serrated flanged head/nut.

[Bruce's]

I have drilled several Honda horizontal clones for larger motor mount bolts ,easy to do and no problems down the line with breakage .I put a 190 cc in a z50 that was street ridden ,and there was a few problems with the original little bolts snapping so it was a no brainer to go to a larger bolt .