55 G9 engine sprocket and rear mudguard

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magnusk750
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55 G9 engine sprocket and rear mudguard

Post by magnusk750 »

Frustrated. Received a set of W sockets this week and thought I´d finally be able to undo the engine sprocket. Chain around the sprocket, chain clamped to throlley, but no luck. The chock absorber does it's job shock absorbing. Tapped with a hammer on the bar too, no succes. Is there any clever ways to do it? The engine was rebuilt 25 years ago and not driven since, I'd prefer not taking it apart.
IMG_9355.JPG
Then there is the long lasting nuisance of the rear mudguard, now extended to a belief that that the frame is bent. The bike is a bitsa, but pretty much made up from 1955 parts. Rear mudguard is older, early type with hinged rear end, small bolt holes by the shock absorbers, and fastening holes for pillion saddle. Seems straight and nice, but will not fit properly.

Does anyone know how much an early mudguard differ from a late jampot type mudguard, or lets say should differ? I made new holes, around 16 mm diameter, for the upper jampot bolt, in what I thought should be more or less the correct place, when I measured the rear end from pictures. Hoped it should be good to go then, but not.

It's like the mudguard dont center in the frame. The whole shebang want to sit some 10 mm to the right, and even then the front tip is dangerously close to the tyre, on the right side. Conclusion is sadly that probably is the rear loop of the frame is bent. Holes line up, when I put rods in place for rear and front axle they do line up and the frame, but still the mudguard will not line up. Difficult to capture in pictures, and straigthening a frame is beyond what I will take on myself, but any input welcome.
IMG_9354.JPG
Mudguard bracket, left side. Bought from the club. Cant be placed in any other direction (?)
IMG_9356.JPG
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uas526
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Re: 55 G9 engine sprocket and rear mudguard

Post by uas526 »

Perhaps the PO has used threadlock/loctite on the thread, in which case heat will be required to soften the theadlock. For tapping with hammer, a simple bar handle (i.e. not a ratchet) is preferable.
uas526
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Re: 55 G9 engine sprocket and rear mudguard

Post by uas526 »

Oh, I see, not a ratchet, but still more flexibile than a straight bar. Unsealing loctite requires a fair bit of heat.
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clive
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Re: 55 G9 engine sprocket and rear mudguard

Post by clive »

It's a bit of a faff but if you preload the spring by winding it round with a t-bar on you socket and then hitting it you may find this works. I find a lighter rather than heavier hammer allows you to get more momentum into the blow. Mind your fingers though.
clive
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clive
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Re: 55 G9 engine sprocket and rear mudguard

Post by clive »

I am struggling to understand the mudguard problem, but also your photo appears to show the gearbox adjuster on the same side as the clutch. It ought to be on the other side. You will not get the primary chaincase in place the way it is.
clive
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clive
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Re: 55 G9 engine sprocket and rear mudguard

Post by clive »

Further look at your photo and I would say the mudguard needs to come slightly lower so the the indentation is closer to the swinging arm and then the whole lot needs to come across. You may need to curt some more out. One of the disadvantages of trying to get different years bitsa to fit is working out what to cut, which holes to make your reference point and where to redrill them if needs be. I have a 1952/3/4/ M18 and it was a challenge to get the chainguard to fit so I know the problem. You might be better centralising the mudguard at the lower brackets, (making sure the chainguard you have will then fit) and then seeing where the other bolt holes need to be. Braze up the other holes once you know what fits.
clive
if it ain't broke don't fix
magnusk750
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Re: 55 G9 engine sprocket and rear mudguard

Post by magnusk750 »

Thanks clive and uas526 for input. Yes, it's a swiveling socket bar. I was quite happy when I found that rear mudguard, genuine Plumstead road in good condition. I think I'll have to check the frame more thoroughly too. When I look at it from upside it's not 100 % symmetric.
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Re: 55 G9 engine sprocket and rear mudguard

Post by Mick D »

Hi

Get a 'real' breaker bar, around 18" or longer, take up the shock absorber play and then lean on the bar - the nut will undo. (The shock absorber should not ride over the cams if it assembled correctly). I would avoid using heat to break any potential Loctite bond as you may adversely affect the temper of the spring or shaft.

Regarding the mudguard installation, are you sure you have the rear wheel correctly located? is the wheel alignment correct? does the wheel rim have the correct offset?

Regards Mick
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clive
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Re: 55 G9 engine sprocket and rear mudguard

Post by clive »

magnusk750 wrote:Thanks clive and uas526 for input. Yes, it's a swiveling socket bar. I was quite happy when I found that rear mudguard, genuine Plumstead road in good condition. I think I'll have to check the frame more thoroughly too. When I look at it from upside it's not 100 % symmetric.
The mudguard will not be symmetric near the bottom bolts. Part of it should be cut away as in your photo to allow clearance for the chainguard. Once that is fitted the cutout is not visible. Centering the mudguard between the two sides of the rear loop is your aim, then ensuring the rear wheel is centred too with the correct spacers, these spacers often change according to the year. Put up photos of the guard off the bike.

Did you notice my comment on the gearbox adjusters?
clive
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magnusk750
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Re: 55 G9 engine sprocket and rear mudguard

Post by magnusk750 »

Clive, yes, noticed about the adjusters, good point. Almost 30 years since I dismantled the bike that was the beginning of this project, engine and a few fasteners left from that one. This evenings project will be to remove the frame rear loop and check it for straightness, then the mudguard will come off too. I'll keep posting.
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