Crankcase front bolt

[Binman180]

Hello all,

So I've just managed to knock the price down on my own 400f. See pic.

I tightened this bolt to 4ft-lbs, Perhaps too much? and that piece pinged off somewhere in the room.

are there any recommendations to tart this up? Is this a big deal even? I would weld it and smooth it over but it depends on the alloy and the casting as to how well that would turn out and I don't feel like trial and error. Maybe someone else has tried?

Thanks, Ryan.

P.S. the hair line under the bolt is just a hair.

[royhall]

Is that a hole through to the bolt I see. Looks like the bolt in there is too long. I would take the bolt out and have a poke with a piece of wire to see if anything has pinged through to the inside. Then take a full thread off the end of the bolt. Should be a relatively easy fix if its not gone right through.

[mike the bike]

Iv'e had some success with an epoxy filler with metal in it.  Use the link below

http://www.ebay.co.uk/itm/321680191336?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

[SteveD CB500K0]

Is that a hole through to the bolt I see.

Sorry Roy but I read that first line and it instantly took me back to my "O" Level English...

"Is this a dagger which I see before me,
The handle toward my hand? Come, let me clutch thee."

Sorry...

[SteveD CB500K0]

Yes, but what should he do with the dagger?

[royhall]

Don't think there's anything wrong with the clutch Steve.

[SteveD CB500K0]

Took me a few seconds, but     

[mike the bike]

I think the dagger in question is actually a clutch lever

[Binman180]

Hey, thanks for the responses. I did think about the epoxy route but I didn't know if it would be any good there?

Regards to the bolt being too long - that was my first thought. so I checked the parts list for the correct size bolt (8x60) and the bolt is definitely that.

After a little investigation I found there to be some sort of old clear silicon type stuff at the very bottom, about the size of a pencil rubber perhaps, my guess - old crank case sealant previously applied enthusiastically. Anyway this appears to have built up enough pressure to blow out the side.

Really annoyed at myself for this. Considering I took the time to wash every blind bolt hole out with solvent and a high pressure airline with a long small nozzle it obviously wasn't enough. I even put the bolts in by hand first and I don't remember feeling anything too out of the ordinary. In hindsight I should have put a bit of wire in there too. I've spent what I consider to be a lot of money on this bike so far given the high price I paid (Unwittingly) to begin with.

hopefully if anyone is currently doing a rebuild as a novice, hopefully they'll see this and be extra vigilant in their build. I'm lucky this wasn't on a more critical part.

Thanks, Ryan.

[Bryanj]

If you have the piece glue it back in as ther is no pressure there, if not try Devcon F ( i think is the alloy one) used it in the merchant navy and never found anything better, i believe its a sit down before checking price though.


http://www.ebay.co.uk/itm/DEVCON-10611-ALUMINIUM-PUTTY-F-500G-for-Industrial-use-/251150193639?pt=LH_DefaultDomain_3&hash=item3a79b7d3e7#ht_1214wt_806

£43 and its past its use by date, new stuff £70 ish

[royhall]

Used Devcon a fair bit when I worked at the Nuclear site. May be expensive but you wont find anything better. Not sure how well it stands up to constant expansion and contraction though. May break out again in time, have had it happen on a compressor before now. I would TIG weld it carefully then grind it back. Do you know a good reliable welder with a good TIG set. Will need to be an AC/DC set with pedal control at least,  and a bit of skill behind it.

[AshimotoK0]

I use industrial epoxy resin  filled with aluminium powder to make a paste/putty. PM me your address and I will send you enough to re-bond the broken bit or build up the damage.
If you look inside old Honda crankcases (750K0 for e.g.) Honda actually used very similar stuff to blank off inside the castings in production in the 60's/early 70's. We have Decon at work but to be honest I prefer my own stuff. I also use ceramic powder filler which is rock hard when it cures, I will send you a bit of that too. I can only spare a bit of the aluminium powder though 'cos I am waiting to get some more. Don't want anything for it.

Ash