Alternator Bolt end of crank

motoddrob

motoddrob

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Location
S/W Australia
Another question re: series2 alternator set-up. The bolt that goes into the end of the crank looks to be a M10. The original is missing, have tried to screw an M10x1.5 but it doesn't want to fit. It does seem to be a R/H thread though. Could it be a M10 fine?? Don't have a M10 fine to check
Cheers
Rob
 
Hi Rob, should be M10 x 1.5, may be left handed, I seem to recall finding a LH bolt in one once but am not 100% sure what year.


    Keith
 
Hi Guys, well, M10x1.5 only wants to go 1 turn before binding, found, I think, an engine mounting bolt M10x1.25 that does screw in 4.5 turns ~6mm before resistance. Thinking I should run a M10 fine tap down it????? Also what is the length of the bolt that goes in there?. Was reading that some had L/H thread and some right. Looks like some might have had fine threads as well then.
Confused in Walpole.
Just spotted your post Steve, I think you could be right
 
Bit of indecision at the factory eh... got one in my hand from a late RGS and that is M10x1.5 (40mm long) The parts book lists the bolt as M10x1.25, I'm pretty sure the left handed one I encountered was on a series 2 180 but I don't recall the pitch. Sounds like yours is definately 1.25 Rob.


    Keith
 
 
Series 2 engine has M10 x 1.25 right hand bolt
is the same as the 120 engines I thought, never actually compared them but my alternator puller fits 120 and series 2 engines
so must be the same


 
There were both L/H and R/h threads used - R/H is most common and (I believe) superceeded the first L/H jobbies - think only R/H on 120's -Regards - Phil
 
Seems like a classic case of "ask a simple question..."  :D

To further muddy the waters, I have two webs here, both M10x1.25RH, one is a rusty unknown that came from somewhere, the other I removed from my Corsa crank.  Two other RG's and an 81 180 Jota I can confirm are also RH fine pitch.

Of course, all 750's and Mk1 triples use LH external threads.

In any case, it sounds as if Rob's got an M10x1.25RH on his hands there, clean up that thread and on you go mate.  Leave the rest of us trainspotters to squabble over our pitch gauges.

Cheers
Steve

PS: It is possible that bikes with a 1.5 pitch have been bodged up by some DPO/DPM who lost the bolt, though the same can't be said if there are confirmed LH thread Mk2's.

 
That bolt pales into insignificate now that I've moved on to fitting the barrels and now have ring problems :o
Anyway I'll run a M10x1.25 tap down it to clean it out.
Rob
 
Rob,

If the bolt head carries any sort of wording/numbers etc, it will be RH.  If the head is plain flat, it will be LH thread.

The Factory used proprietry bolts whenever they could, the LH bolts they needed to make themselves... not sure if they were used on Mk II 180s only.

M10 x 1.25 in both cases.

piet
 
Always interesting to find out gems like this, as I have worked on a fair number of Mk2 engines but never encountered a LH thread. 
Good to know it is a possibility (if a slim one).
Cheers
Steve B
 
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