43 replies to this topic

[Blackpin]

If all is well you can look at my Crack on this link

http://www.facebook....mp;l=ef7f5d7b1e

black pin

[Studley Ramrod]

ooooh yeah

[dapleb]

Doozer...wonder what the inside looks loike.

[Blackpin]

In bits at last

Take of list its long

A 12 pack to start with

Drain the oil out, you can do it with out but it makes last bit harder if you
leave it in.

Get bike off floor fount and back.

Pre - crack as many frame engine nuts as you can.

Don't forget the back bolt under gear box.

Shocker bottom bolt these some time stick.

When de-plunging wires take care we think this is going to be the hardiest
bit to re-build

After 8 hrs.and a 12 pack you should be ready for the welder

THING LEFT ON bars and head stock wiring harness

Yes to say wot we left on was the best way to make the list
of wot to take off.

Off to welder in the morning

jd

[Studley Ramrod]

yeah, not much in the 'left on' list.

Did you find any cracking around the inside of the frame ?

[Blackpin]

DO NOT LOOK AT THESE IF YOU ARE OF A NERVOUS DISPOSITION NOT NICE PHOTO'S AT ALL

http://www.facebook....2...7338&type=1

Yes it is cracked very bad but not how you would think at all off to welders

jd

[Studley Ramrod]

Makes ya wonder what cudda caused it

[Rallyist]

Well I have a theory ... On mine I had bad vibration in the left hand footrest when revs were around 4500 and when pushed higher up the rev range felt like a worn out chain, chain & sprockets were replaced tested again vibration not quite as bad but still bad checked all engine mountings all tight but the rear engine mount where the frame crack appears to have originated was squeaking tortuously when tightened so I removed it and checked threads, it showed signs of butting up to the end of thread shoulders so I reinstalled with steel brake size washers, ordinary washers will not fit in hole, and liberal copper-slip and torqued up to the factory figures +5%. Road-test again vibration now only apparent at around 3500 and 4500 rpm and not really intrusive, smooth as a babies bum at the upper rev range.

My theory is that the manufacturing tolerance of this part of frame and engine allow this engine bolt to appear tight but in fact is slightly loose allowing flex and vibration resonance in this frame area hence causing a crack, whilst when new the bolt is full securing when it has been removed the natural stretch of the bolt compromises the tension that is being applied in this area, I may be wrong but in Blackpins case his bolt was broken and as he rarely gets to 3000 rpm Trialsrider he had not experienced what I had, so I told him to check it that's when he found it.

[Studley Ramrod]

You could be onto a winner there, sounds perfectly plausible !

I wonder if a bad batch of said bolt cudda been fitted when the bike was being made. Or possibly over-tightened.
Whilst your theory works, it assumes the bolt has been undone/removed a few times previously and you'd only undo the bolt if you were takin' the engine out. Still perfectly possible though

[Studley Ramrod]

Interesting................ the long allen bolt for the 1991 and 1995 mk1's have a different part number

1991 90110-10175-00
1995 90110-10299-00

It's on the 'Frame' page, item No.8, in the parts fiche.

[Rallyist]

So it would appear that I may be correct cos this cracking only effects 91 -to- 95 models.

and it is listed as a part "Not Sold" and no price anywhere

Edited by Rallyist, 11 October 2011 - 01:41 pm.

[Blackpin]

Well back from the welder only to find when we got there the lower bracing under
the gear box was snapped right through all now welded up now to start the long rebuild.
I hope this has helped all on the site .
the Welding was 30 mins work.

these are the photo's of of the cracks and the welding work

Most of all look at your Engine bolts as posted by rallyist

Ride safe

jd

http://www.facebook....mp;l=83014e79a7

Edited by Blackpin, 11 October 2011 - 05:59 pm.

[Catteeclan]

Just so happens I have a K plate in the garden at the mo. Gonna get checked tomorrow.

[Studley Ramrod]

How's the rebuild going John ?

[Studley Ramrod]

Dappers has 3 shims (he's a star !) and I've just ordered the 4th wan John I'll let ya know when they've arrived and then sort out a time fer fittin' 'em.

Really nice meeting you and Rallyist and scooter man (Alan ?) !

[3vd]

Not the tidiest welding there?



Hopefully this will look better once painted?

[Rallyist]

Painted??? don't be silly it's a bike that belongs to 'Tatty-Man JD' aka Blackpin.

[Blackpin]

just got a bucket of ASDA price black T###########



Thanks on the shims

[Studley Ramrod]

Shims have arrived

[Blackpin]

Shims have arrived

Thanks for the fitting but a bit cold job

jd