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Bolt Type?


neonsurge
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While replacing the chain tensioner block on my Rev-3 I noticed that the tensioner arm itself was very loose. It wouldn't tighten either and closer inspection revealed that the thread had amost completely stripped from the hole in the swingarm. I ended up having to tap it out to 10mm but I'm struggling to find a replacement bolt or come up with an alternative solution that allows the tensioner arm to move up and down freely. The original bolt is partially threaded with the unthreaded section being of slightly larger diameter than the rest (so that it fits snugly into the hole in the arm) and of a length slightly more than the thickness of the arm (I realise all chain tensioner bolts are probably like that and you're laughing at my crappy description but this is the first time that I've had cause to remove it on any of my bikes).

The question is, what is this kind of bolt called so I know what to ask for when I try to buy another? Failing that, where can I buy metal "sleeves" that I can put on a 10mm to achieve the same thing - I know these things exist, but I don't know what they're called!

Sorry for my probably excessively verbose description and thanks for any information anyone can provide!

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mr neonsurge if you can post a picture of the bolt in question i will try to make you something up or see if i have one on the shelf,I think what is needed is called a socket shoulder screw, anyway let me know as much as possible and i will pop one in the post for you f.o.c :hyper:

www.ksupplies.co.uk

Edited by mozchops
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Thanks mozchops, I'll get the various bits measured up tomorrow and post the details - if you're at Hawkstone this year I'll buy (bring) you a beer.

HondaRS: You're absolutely right of course but this all happened last night (Saturday) and I had a trial today so I had to bodge something together using a dodgy and frankly unsatisfactory arrangement of washers - not a permanent solution by any stretch of the imagination!

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Neon Has this happened today at the trial?

Yep, and it was all a waste of time as it turned out. On the first lap I went flat on my back in the river on section 5, almost skewered myself of the bars in section 7 on that step out of the gulley (groin first) twisting my already fragile back in the process and while refuelling before starting lap 2 I noticed that my chain tensioner bodge wasn't really working and the chain was flapping around quite a bit. At that point I uncharacteristically made the sensible decision to put the bike back in the van and finish the trial as a spectator.

It was worth it to see Michael and the boys riding those "super expert" lines though! That massive launch up the rock out of the river at section 5 was just amazing :hyper::D First time I've seen catchers used in a club trial!

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Did you see me I bust my handlebars at section 11 but i was there for about 1 hour sat waiting for a replacement m dont think i saw you though.

How did you do on section 2 i thought that hill was pretty tough 1st time round but i cleaned my second and got a 2 on my 3rd lap. ( and that was with dodgy bars which i didnt like ).

Shame it rained for the last couple of days really i had to have a 5 5 5 on section 9 just wasnt happening really and didnt want to drown my bike in the river. Then i sort of retired halfway through lap 2, couldnt ride with the replacement bars they were different size and my clutch was touching my light switch thing. (anyoing ). Have to get a new bar set up for Wed night.

you riding that ?

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OK, here are all the details. The photo shows the tensioner arm and the M10 bolt that I've been using as a (failed) bodge solution. Unfortunately, I seem to have lost the original bolt, probably thrown across the garage in fustration on Saturday so I've made some measurements and hopefully it'll all make sense.

The hole in the tensioner arm has a diameter of 13mm and is 8mm deep. So what I'm looking for is either:

(1) An M10 bolt approx 26mm long with a "shoulder" (unthreaded section - blue shaded bit in the photo) with a diameter of slightly less than 13mm (12mm?) and approx 15(+?)mm long to allow the arm to rotate freely and a wider (at least 20mm) head (red shaded bit photo - head thickness isn't too important) OR:

(2) A spacer approx 13mm long (to allow the use of a 2mm washer with the existing bolt) and 1mm thick with an outer diameter of approx 13mm to allow fitting over the M10 thread (11mm internal diameter).

As usual, I apologise for my verbosity - I've searched all over for a solution to this problem with no luck and if anyone can point me in the right direction I'd appreciate it.

Edited by neonsurge
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While replacing the chain tensioner block on my Rev-3 I noticed that the tensioner arm itself was very loose. 

the tensioner on our 05 beta's is the same, i assume there is play on them to allow for the wheel getting out of line,and not derailing the chain

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Wouldnt it be a great deal easier to find a good engineering shop, with a "Nutsert" thread repair kit, and get them to repair the original damaged thread, so you dont have to mess around with getting things machined etc?

You're probably right, but what's done is done (tapped to 10mm) so I'll need to find a solution somehow unless a Nutsert can bring the thread back down to 8mm.

Live and learn... :hyper:

Edited by neonsurge
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Just for reference, that type bolt is normally referred to as a "stripper" bolt.

Sometimes also called socket head shoulder bolts.

I would go with the heli-coil, keensert, twinsert, timesert or whatever the local machine / fab shop had handy and get back to 8mm.

If it was me, I would buy the kit, but in how many years of riding have you not needed one? A local machine shop or good auto repair shop probably has the kit there handy.

A twinsert, Keensert etc. will go into the threads you already have tapped. But in my neck of the woods they are not as common.

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