I'm new to trials and mechanics in general but enjoy learning on a 2006 4rt. After oil change, the bolts that secure the side cover on (about 6 or so) have to go on soooooo gently or "SNAP". I got a torque wrench and set it to 16 pounds/ sq. ft. as manual says.....and SNAP, again! I'm soiling my trousers over this! Not really.

Is this an issue for anyone else? Do replacement bolts have to be purchased from Honda only?

THANKS!!!!

put high tensile bolts in it mate. check the head of the bolt, must be 8.8 (or higher) stamped into it.

make sure they are the correct thread pitch and length

Are they all same length, high tensile Are 10 8.8 is normal, just make sure, they still shouldn't snap at 10 lbs though

12.9 grade bolts are essential. Reccomended torque setting for m6x8.8 is 10 lbs/ft, will definately snap at 16 lbs/ft.

Socket cap screws marked A4 or A2 are no

Torque wrench not correct / calibrated?

That is far too much torque for a 6mm dia. thread in a ali case. About 95-100 in/lb(8-9 ft lb) would be more appropriate.

That is far too much torque for a 6mm dia. thread in a ali case. About 95-100 in/lb(8-9 ft lb) would be more appropriate.

Off the top of my head:-

7 to 9 lbs/ft seems a good value for most 6mm screws/bolts unless we're talking about a brake disc bolt or an axle pinch bolt...which we're not???

Off the top of my head:-

7 to 9 lbs/ft seems a good value for most 6mm screws/bolts unless we're talking about a brake disc bolt or an axle pinch bolt...which we're not???

:agreed: Your going way to tight , especially threading into the ali case ! Check your specs again !!!!

Thanks for the info guys (or "mates").

The broken bolts are 8mm. Must have read the manual wrong to be at 16 pounds/sft. Also, the torque wrench was new and the cheapest I've seen in the states for $30 (normally $80+). Box says wrench is pre-calibrated.... but I'm not so sure now. I'll go soft on the torque.

I don't know where to get "high tensile bolts" that match but I'll research it. I bought true Honda 8mm bolts after the first break, didn't help. I'm in the US where parts are rare.....this awesome sport is still in it's infancy here and I can't believe it!! I bought my sprockets on Ebay and the "nearest" location to buy from was the UK. Worked great though.

It's been posted before in this forum, but, again, figures from Montesa Manual

Standard torque values

M5 bolt 5Nm or 3.5 lb.ft

M6 bolt 10Nm or 7 lb.ft

M8 bolt 22Nm or 16 lb.ft

There are exceptions where higher figures are used, eg bearing sets, sprocket bolts.

Some torque wrenches show settings in several different units. Check which units you are using too not just the number and try and understand them,. No torque wrench was ever set to 16 pounds/ sq. ft

Also you say the broken bolts are 8mm, standard is 6mm, could you be confusing the size of the hexagon head with the diameter of the threaded portion of the bolt?

Says something about the aluminium cases and the length of thread if you're snapping the bolts rather than stripping the threads out.

Edited July 19, 201214 yr by gii

Picked up my new 4RT on Friday and put on a case saver and my manual definitely says to torque crank case bolts to 16 lbs/ft

As a good friend of mine says, tight's tight and bust's buggered

Fom:

The Ministry of Stating the Bleedin Obvious.

If the recommended torque values and thread sizes are OK then surely it can only be the bolt bottoming out?

Picked up my new 4RT on Friday and put on a case saver and my manual definitely says to torque crank case bolts to 16 lbs/ft

Fair enough, I'm trying to help, not look for an argument,

Both the 2005 + 2008 manuals page 4-49 say the same:

Install the left crankcase cover being careful not to

damage the oil filter cover O-ring.

The left crankcase cover (stator) is magnetically attached

to the flywheel, be careful during installation.

Install and tighten the bolts in a crisscross pattern in 2 –

3 steps.

Install the new sealing washer and engine oil drain bolt,

tighten the bolt to the specified torque.

Torque: 22 N•m (2.2 kgf•m, 16 lbf•ft)

Note 2 things

• It is the crankcase cover bolts not the crankcase bolts that Montytess is snapping
  
• The above instructions do not say tighten the crankcase cover bolts to 16 lb.ft
  

Presumably your 2010 bike manual is different

Fair enough, I'm trying to help, not look for an argument,

Niether am I, to be honest I thought 16lb was rather high and while I was tightening up mine I was sweating a bit

Fom:

The Ministry of Stating the Bleedin Obvious.

If the recommended torque values and thread sizes are OK then surely it can only be the bolt bottoming out?

Dony maka ***** if if bottoms, a 6mm will still twist off at 8mm specs!

Now I can tell you that after running a few thousand different bolts on Jap crap and beyond, them boys can get things tight! And with the usually decent bolts they use, they will withstand some abuse, but not that much for a 6mm thread!

Glenn will likely be the only one to understand this!