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#Meet the new bike, same as the old bike.

and it has a little leak. This appears to be due to a (really long) bolt
which the previous owner, Mr. A. Gorilla, tightened up to just past an
inch of its life with the result that it wibbled slightly on the way
home and now won't do up tight. The bolt thread has gained a nice new
ally lining to the grooves at the end to make it smooth i.e. stripped.

A photo of the offending bolt in the engine is here
http://tinyurl.com/NameThatBolt with a finger pointing to it.

I would like to know what this bolt actually does (the HBOL is no use)
and whether I can just seal the hole it tightly (already bodged) or
whether I need to get the engine out and helicoil/retap the thing so I
can actually have the bolt holding something.
I quite like the bodge I've done, but I don't want any rapidly spinning
engine internals to come adrift whilst I'm making progress.

Any info gratefully received.

 

Don't know what it does (oil drain?) but looks like it should be
possible to helicoil that with the engine in situ.

 

Dunno about that - the bolt is only 12mm but is about 4" long and goes
vertically upwards into the engine so I thought access might be a bit of
a pain.

 

How far down the hole does the thread start?

Long bolts usually suggest that the thread is a long way up the hole
and that makes fitting a helicoil insert just a little bit tricky.

 

You're fucked.

You'll either have to split the engine and helicoil the damaged thread
or loctite the bolt in and hope it doesn't shake itself out.

The good news is that it looks as if it's a crankcase bolt and you'll
have plenty more of those to hold it all together.

 

Looking at where the cases split, I'd say it's almost certainly just a
'hold the cases together' bolt. I'm surprised you can't figure it out
from the HBOL though. Has it not got the usual exploded diagrams?

 

As Andy says, looks like a crankcase bolt.

Go to www.cmsnl.com, follow the links to Suzuki and then the model you
want, and have a look at their enlarged microfiches.

 

Crankcase bolt.

Engine out job.

Once the cases are split the thread should be easily
accessible for repair.

 

P.S. If you're worried about your bodged bolt falling out, just drill
the head & lockwire it to the nearest bolt on the cover you're removed.

 

My biggest concern would be what the previous owner had needed to
split the crankcases for and if he was ham fisted enough to strip one
of the bolts what else has he fucked up?

 

I was wondering that as well....

 

Probably some ignorant clart trying to drain the oil. That looks like quite
an old Suzuki, and my recollection of things like the mighty GSX550 is that
they were made out of secondhand pot-metal. I'd go with high-melting-point
Araldite.

 

Thanks for the reply. I'm going with just blocking off the opening as
the original bolt will tighten *just* enough to stop oil coming out, but
if I wiggle it it goes loose again.
I don't think I can get enough loctite in to block it without risking
gumming up something inside as the entrance to the hole has a good 2mm
clearance.

 

It's a 93 GSX750F. Having searched the HBOL again it seems to be
crankcase bolt #11 which needs a copoper washer.
I'd go with him taking it out in mistake of a drain plug, then putting
it back without the copper washer and nipping it up too tight trying to
get a seal.

I've actually gone for an interference fit rubber tube in the hole, with
a 1" long allen bolt which itself is an interference fit in the rubber
tube screwed up inside it.

Seems oil tight when I revved it once it got up to temperature, once I
get all the bits back on tomorrow & test ride I'll know.
Looking at the dribble with the engine running today, it didn't seem to
be a pressurised oil feed.

 

THanks for the reply. My bodge seems very secure so far but a test ride
will tell.

 

Have you tried a couple of turns of PTFE tape wrapped nice and tight
around the threads of the bolt. That should keep it in.
An O ring should stop the oil leak without needing too much tightness.

Why is it that every SOB that I buy has bodges like that ?.

 

Er, not trying to be deliberately negative here.
I'm not sure I agree. Anyone with any pretensions to doing any home
servicing should surely know that a sump plug is larger than an M8
bolt and would be located at the lowest point of the engine (the sump)
and not on the extreme right hand end of the motor.

Whilst you may have successfully stopped the oil weep. That still
does not address the fact that the crankcase bolt is there for a
reason.

I know if it were me, I'd always be wondering if the increased
stress on the surrounding crankcase bolts could lead to further
leaks or early failure of the crankcase crankshaft bearing.

Alternatively, if it's a cheap hack, just rag it till it dies
then move on.

 

Well it's probably one of the main bearing cap bolts. Of
course all the main bearing caps (5 or them) are
cast as a single unit and form the bottom of the
crankcase.

If it was 5 seperate caps then it would be fucked.

Since it is not, I would follow Bonwick's advice if
you are prepared to avoid wringing its neck. If you want to
ride it like you stole it you best get it fixed or
get rid of it. I doubt that you will be able to glue it in
such that is can actually support 1/2 a main bearing
cap so if you are going to bodge it just do whatever it
takes to stop the oil coming out - would be my aproach.

Of course, I understand that this engine was used in
the Bandit 600 and 1200 with few alterations so it
may well be indestructable.

 

<looks at bod43>

<looks at fucked B12 motor>

<looks back at bod43>

<raises eyebrow>

<looks at .sig>

<shrugs>

 

Given the replies I've read, I'd go for a Loc-Tite variatioon called
"Stud'Lok". Normally, it's a **** to break the bond of this stuff, but given
that there's a lot of "wobble", I don't see that as a problem. I certainly
don't envisage it coming loose by itself either.

Just a fort an' all that.

--
Beav

VN 750
Zed 1000
OMF# 19