Hi,

I posted up the other week about my prop coming loose. As I was driving I heard a whirring noise, stopped and found my prop adaptor had a few mm of play.

I assumed that this meant it was loose, and about to fall off so waited 4 hrs for the RAC to take me home.

I thought it was the inner bolt that secures the prop adaptor to the drive shaft from the engine that had come loose as the 4 bolts that secure the prop to the prop adaptor were all in place and working fine.

I have been on my jollies for a few weeks, so started on it the other night, and have finnally got the prop off the prop adaptor tonight (pig of a job! )

I have now found the centre bolt is tight - very tight and only the prop adaptor itself has the play in it, it moves about .5mm approx in all directions, and if the bolt was loose it would make perfect sense, but it is not loose and has no play whatsoever.

So I'm confused, as I didn't fit the prop adaptor or prop myself, can anyone enlighten me how the main bolt in the centre of the prop adaptor can be tight and not budge even with significant force applied, but the prop adaptor that I assumed it secured has a very small amount of play...

The prop adaptor hasn't actually moved at all, and only has this small amount of play - is it ok?

I have a track day next wed and I have missed the last two trackdays I have booked due to technical problems (bikes not cars!)- I really REALLY dont want to miss another one!

Any advice welcome, and specifically how the prop adaptor is secured to the drive shaft.

Thanks folks!

My first thoughts were the nut bottoming out but if the play is in all directions then my money would be on the output shaft bearing.

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Originally posted by prawnabie
My first thoughts were the nut bottoming out but if the play is in all directions then my money would be on the output shaft bearing.

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I do seem to remember a post from someone saying be careful where you buy the adapters from as some of them are a loose fit.

1.does the bolt move with the prop adaptor? or 2.does the bolt stay still with the prop adaptor wobbling in relation?

1. Prob the gearbox bearings
2. bolt has bottomed out without gripping the prop adaptor, prob needs a washer of sorts.

This may hjelp, to sve re-typing...
http://www.locostbuilders.co.uk/viewthread.php?tid=110150

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Originally posted by ReMan
This may hjelp, to sve re-typing...
http://www.locostbuilders.co.uk/viewthread.php?tid=110150

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quote:

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Originally posted by welderman

quote:

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Originally posted by ReMan
This may hjelp, to sve re-typing...
http://www.locostbuilders.co.uk/viewthread.php?tid=110150

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The only prob with that is, that there are two conflicting pieces of information on that thread:- Yours and Andy Bates (I think) are contradicting each other. I could be wrong though.

In response to OP.
Some people say that it is actually preferred to have some play in the prop adaptor, others want it tight...

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I had the same problem on mine, I had a spacer washer made up to ensure the bolt did not bottom out. Barry

quote:

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Originally posted by welderman

quote:

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Originally posted by ReMan
This may hjelp, to sve re-typing...
http://www.locostbuilders.co.uk/viewthread.php?tid=110150

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The only prob with that is, that there are two conflicting pieces of information on that thread:- Yours and Andy Bates (I think) are contradicting each other. I could be wrong though.

In response to OP.
Some people say that it is actually preferred to have some play in the prop adaptor, others want it tight...

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The nut that screws onto the splined shaft is recessed on one side. the recess has to go facing the prop adapter. I had mine on the other way making the adapter loose despite the nut being tight. When the nut was put on the right way, it clamped the adapter up tight without bottoming out on the end of the thread.

Some of the prop adaptors floating about(pun) are made of 'free machining' steel. ie very soft.

Take the end bolt out, and see if the adaptor is flopping on the shaft. If it is, bin it and get a hardened item.

Cheers,
Nev.

I got it from ab performance so I think it will be a good quality item.

Can anyone confirm if having some float will be safe for the trackday, and I can sort it afterwards? Cheers

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Originally posted by Dangle_kt
I got it from ab performance so I think it will be a good quality item.

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Hi,

I called Andy and wanted to post up the bones of his reply, for future reference if anyone else has this problem.

When I explained the centre bolt (securing the prop adaptor to the drive shaft of the engine) was tight, but that the prop had some play in it, he imediatly said this comes up a lot.

This is as it is designed, as it isolates some of the force from the prop undoing the prop adaptor, and that if the adptor is tightly secured using some form of spacer, all that happens is the forces from changing gear (lash I think was the term he used) over time makes the centre bolt work undone.

He added that r1 prop adaptors often are an exact fit and so the first thing he does is skim 1mm off them so that it has this same play.

I explained that this seems to have started recently though - and he replied that it is usual after a few miles (ive done about 150ish in total) that the grease is flung from the UJ's on the prop, leading to them loosening up, and the slight play in the prop adaptor causes the prop to become a little noiseier than it was when packed with grease. he said I would be best using a grease gun sort out the nipples, and also check the rear of prop is secure as the prop can transmit sound so it sounds like the front when it is the back.

Just so everyone knows Andy's take on the situation, I thought I'd explain, as to be honest I didn't grasp that from the last thread on it.

Mines loose at the engine end and has been that way since SVA 3000 miles ago seems ok