Author Topic: Severe Knocking - A10 Road Rocket  (Read 4620 times)

Offline Brucie64

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Severe Knocking - A10 Road Rocket
« on: 17.05. 2015 22:58 »
Hi All,

Well the enevitable happened today, my bike for the first time needed to be transported back home on the back of a low loader (Rescue Service). Fault yet to be ascertained.

What started out as a rattling last night gave way to a severe knocking today and to save any further damage I decided to pull over during my run out and phone the AA.

Question......my immediate thought being an eternal pessimist is I must have a worn timing side bush resulting in big ends wear etc due to oil stravation. However my oil return feed to the oil tank still seems to me to be fine. Should I be seeing a reduced return oil flow to the tank if oil is bypassing the timing bush?

Regards
Brucie64
Bruce
Spitfire
UK

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Re: Severe Knocking - A10 Road Rocket
« Reply #1 on: 18.05. 2015 00:30 »

 So long as the pump is functioning properly (obviously is), in a severe case (no pun intended) it could be bleeding as you say straight past the mains bush and straight into the sump to be scavenged without much going through the crank to the big ends and thereby flogging them, I think normally a worn main is indicated by a rumble (a signal) more than a knock (which ultimately came)...could be wrong but sounds like you need to investigate anyway
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Re: Severe Knocking - A10 Road Rocket
« Reply #2 on: 18.05. 2015 12:48 »
Sorry to hear that Brucie64. It could be a multitude of things. At least it didn't stop with a bang.
With the plugs out get a mate to kick her over a few times and have a listen. Drop the timing cover off and check for up & down movement of the crank.
Good luck.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Offline nimrod650

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Re: Severe Knocking - A10 Road Rocket
« Reply #3 on: 18.05. 2015 19:05 »
sorry to hear hope all goes well you can always be sure of advice and help from people on here with years of working on a10s good luck

Offline Beezageezauk

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Re: Severe Knocking - A10 Road Rocket
« Reply #4 on: 18.05. 2015 20:00 »
Heyup Brucie,

What part of the country are you from?  There may be somebody with a bit of hands on experience in your area who could help or advise.

Beezageezauk.

Offline Brucie64

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Re: Severe Knocking - A10 Road Rocket
« Reply #5 on: 18.05. 2015 21:58 »
Hi Beezageezauk,

Currently residing in South Bucks (near Oxford) but originally from Newcastle. Anyone from this next of the woods with experience in the dark arts of BSAdom?

Just started to strip it down tonight, primary chain looks a little loose but don't think I could be a lucky as that being my engine clanking. I will tighten it sometime this week and start her up again before removing anything else.

Regards
Brucie



Heyup Brucie,

What part of the country are you from?  There may be somebody with a bit of hands on experience in your area who could help or advise.

Beezageezauk.
Bruce
Spitfire
UK

Offline Brucie64

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Re: Severe Knocking - A10 Road Rocket
« Reply #6 on: 18.05. 2015 22:04 »
Brings tears to my eyes  *sad2*

Bruce
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Offline Brucie64

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Re: Severe Knocking - A10 Road Rocket
« Reply #7 on: 18.05. 2015 22:10 »
Hey Muskrat,

Thanks for the tips, you've got me thinking. How much up and down play should there be?

I took the primary chain off tonight and the engine sprocket so I could get my hands on the crankshaft. There is definitely a slight movement up and down with a little clunking noise (no sideways movement), but how much should there be?

Regards
Brucie
Bruce
Spitfire
UK

Offline a10gf

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Re: Severe Knocking - A10 Road Rocket
« Reply #8 on: 18.05. 2015 22:26 »
^^^ check for crank play on the timing side.

ref your picture above, what a nice machine.

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Offline Brucie64

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Re: Severe Knocking - A10 Road Rocket
« Reply #9 on: 18.05. 2015 22:39 »
Cheers a10gf,

Yup it helps I suppose if I get at least choose the right side to do my wiggling, thanks for the heads up.

What's the best way for a novice to check up and down movement on the timing side, grab the dynamo sprocket?

Regards
Bruce
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Offline a10gf

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Re: Severe Knocking - A10 Road Rocket
« Reply #10 on: 18.05. 2015 22:55 »
I'd choose to remove the inner timing cover, then remove the pump. Technically the crank pump gear should be removed to take the pump out, but the shortcut is unscrewing fixing studs. If you want to remove the pump gear, remember the crankshaft has counter-clock threads!

Comments about removing oilpump: http://www.a7a10.net/BSA/Oilpump.htm

Quote
Can be done by removing 3 nuts & the two lower studs (carefully, do not destroy threads). This makes it possible to get the pump out without having to disturb the crankshaft driving pinion. To prevent all the oil spilling out you can plug the feed holes while working, or do the work in conjunction with an oil change. Check or change the gasket at the back of the pump, & remember the small gasket at the front stud or you may bend the pump's housing when tightening the nut.

To check play, a tyre lever (or something like that) carefully under the pinion, and watch\feel whats going on. My impression, if you even see\hear\feel movemnet, then it's time to do something, others here may come up with what's admissible.

btw, any tiny powdery non-magnetic residues in the oil? (for example from small end bushes, also a possible cause of noise).

Hoping some of this is useful. Good luck.

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Re: Severe Knocking - A10 Road Rocket
« Reply #11 on: 19.05. 2015 13:42 »
G'day Brucie.
If you haven't taken the inner cover off yet you can put a screw driver between the oil pump and crank. Moderate (careful) pressure will show any movement. As a10gf said " if you even see\hear\feel movemnet, then it's time to do something". It's a bit academic as you can feel play on the primary side meaning she's due for a refurb.
You'll have her sounding as good as she looks in no time.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Offline Brucie64

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Re: Severe Knocking - A10 Road Rocket
« Reply #12 on: 20.05. 2015 10:11 »
Hi Muskrat & a10gf,

Ok too late to check for movement between oil pump and crank as I removed the inner timing case last night. All looks ok so far, checked for up and down movement on the crankshaft pinion but it all seemed fine, no movement what so ever. I also took out the plugs, removed the primary side chain and turned the engine over just to see if I could hear any undue noise/clanking but found nothing again. All sounded smooth nice and smooth and noise free.

Just wondering if it is something as simple as a loose primary chain and it did seem slightly looser than I would have liked but it didn't look as though it had been catching the primary side casing at all. I will have another look at this over the next few days. Failing that I am a bit stumped.

Slightly worried however by your comments Muskrat "play on the primary side meaning she's due for a refurb"  *sad2*

Cheers
 
Bruce
Spitfire
UK

Offline Topdad

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Re: Severe Knocking - A10 Road Rocket
« Reply #13 on: 20.05. 2015 10:26 »
Hi Brucie, Musky's referring to your prev post
 "  I took the primary chain off tonight and the engine sprocket so I could get my hands on the crankshaft. There is definitely a slight movement up and down with a little clunking noise (no sideways movement), but how much should there be?"
If you consider the additional trust taken by that d/side roller bearing in addition to the normal engine loadings any wear means a problem so if you can feel movement then sooner rather than later that bearing will go and who knows what could go with it .
I'd pull her down and investigate working on better safe than sorry , best of luck whichever way you go , regards BobH.

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Re: Severe Knocking - A10 Road Rocket
« Reply #14 on: 20.05. 2015 11:45 »
Quote
  I took the primary chain off tonight and the engine sprocket so I could get my hands on the crankshaft.

Hi Brucie
mostly wear is checked at the timingside which can still be done with the inner case off, should be no play on the primary side though.
Just a thought though, as you've removed the engine sprocket did you also remove the sleeve , so that you are just wiggling the crank about and not the sleeve on the crank.
think it's a bit unusual (but not impossible) for the timingside crank bush to be ok and the primary bearing to be gone
All the best - Bill
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