Fitting R&G Honda CB500 Crash Bungs. Torque or hand tigh

daws0n · Borekit Bruiser Joined: 03 Jul 2017 Karma :

Hey guys

Quick question re: torque rating for the engine frame bolts that came with my R&G crash bung kit....

The original honda ones took a fair bit of force to remove, I ended up using a 1/2 wrench to get them to go. The threads are coated in some kind of white locking paste where as the R&G bolts are going on dry. I've fitted the bungs to frame without any problems, but I'm not sure what to do about the torque rating. The instructions state:

"Turn a little more so that you feel the compression increase slightly. Then apply a quarter turn.
Do not over tighten as damage can occur to the bike. Do not exceed 40Nm of torque. "

They "feel" tight enough using a 1/4 wrench, but setting the torque to a conservative 30nm it's not clicking yet. Should I keeping going and apply more pressure?

I doubt they'll vibrate off it a hurry, but given their purpose I figure they need to be on good and proper should the bike hit the floor.

Nobby the Bastard · Harley Gaydar Joined: 16 Aug 2013 Karma :

McJamweasel · BCF Junkie Joined: 22 Mar 2002 Karma :

What does the service manual list the torque as? Engine mounting bolts are pretty important. If they should be more than 40Nm then I'd throw the R&G in the bin and stick the original bolts back in at the proper torque.
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MCN · Super Spammer Joined: 22 Jul 2015 Karma :

Torque it to the OEM's bolt spec.

ps I don't call them Crash Bungs.
They don't work.

I've never crashed after I've fitted them. Embarassed

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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

daws0n · Borekit Bruiser Joined: 03 Jul 2017 Karma :

Thanks for the advice, I don't have a service manual for the bike (yet) so no other figures to compare to at the moment. The R&G bolts are much longer than the original honda bolts so swapping them around is not an option. Looking at the R&G site further the FAQ states:

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

If it feels like it's not getting any tighter and you're not up to torque yet, STOP, back them out and inspect the threads on both the bolt and the thing it's bolting into. This is a sign something is amiss. You may be stripping something.

Also check your wrench is actually clicking by putting it in the vice.

Also make sure there isn't too much oil on the threads, this can lead to massive overtightening.
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Hong Kong Phooey · World Chat Champion Joined: 30 Apr 2016 Karma :

McJamweasel · BCF Junkie Joined: 22 Mar 2002 Karma :

MCN · Super Spammer Joined: 22 Jul 2015 Karma :

Ste · Not Work Safe Joined: 01 Sep 2002 Karma :

What year CB500 is it?

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

daws0n · Borekit Bruiser Joined: 03 Jul 2017 Karma :

daws0n · Borekit Bruiser Joined: 03 Jul 2017 Karma :

daws0n · Borekit Bruiser Joined: 03 Jul 2017 Karma :

Hmm ok threads are looking good both sides and bolts in hand tight then fastened with 1/4 wrench. There's a little resistance due to the paste on the old bolts but it's smooth enough.

I've started to re-tighten the bolts using a lower torque rating, taking baby steps from 10-15-20nm etc. Torque wrench is behaving as it should as far as I can tell.

At 30nm it's pretty tight... I can keep going, but I am hearing the fixtures squeek as they compress and the bungs are starting to turn as I tighten. I've stopped at 30nm click on the torque wrench and considering the instruction "Turn a little more so that you feel the compression increase slightly. Then apply a quarter turn." I felt like it's a done job. An email from R&G has come through since stating:

Falco · Traffic Copper Joined: 26 Nov 2015 Karma :

The torque for the front engine mount bolt is listed as 45Nm for the models up to 2002, so that seems consistent even across the "refresh" that gave the F and X.

They look a lot less faff than the set of crash bars that have been sitting in my shed for the best part of a year. To top it off, I wouldn't even have to cut through the lower engine mount bolt that is siezed absolutely solid Thumbs Up

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daws0n · Borekit Bruiser Joined: 03 Jul 2017 Karma :

I bet they seize up good and proper given enough years on the road.

The barrels on the CB500 motor go straight through allowing all manner of irk to get in. I've blast them with ACF50 to try and keep corrosion out.

Said bolts have been torqued up a little more to 35nm and that's me done... My torque wrench was a tidy one when bought (Halfords Professional range) but it's 12 years old now... I don't trust the calibration enough to go right up to 40nm spec. Does the calibration drift with age or use?

I wish this bike wasn't so new and shiny, as admittedly I am faffing more than I usually would... it's an expensive Christmas present to myself and I'd be gutted if I accidentally stripped a thread!!

In another news, rear hugger is on with far less fuss and looking all the better for it Smile

Hopefully it will keep a lot of winter crud off the swing arm and suspension. Next up is the radiator guard.