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Discussion Starter #1
Hi all,

I've put several months work in a 68 Bonnie restore.
PO had already painted frame and pulled the engine and "rebuilt it".
He seemed to know what he was talking about and works on small lawnmowers and landscaping equipment for a living. He is also a life-long Brit iron guy.

Anyway, I felt ultra lucky to benefit from his engine rebuild, but Ive found a few things lately that make me a bit nervous. Among them:
1. missing tappet guide oil rings
2. inner rear axle nuts on wrong sides of axle
3. overtight or too long engine casing bolt necessitating drill out.
4. Time case center spindle inserted wrong way round (i.e. oil flow blocked)

The engine is back in the frame, however I have the cylinder block off. I really dont want to pull the engine out but wondering if I should take the opportunity to have the engine split and insepected (I know someone locally who can look at it).
Maybe Im being a bit over cautious. Everything else looks good: he's put in the engine gaskets with sealer, put grease on all the different parts, bored and got new pistons, and it all looks very clean.
Thanks as always.
 

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It is most likely ok if he has worked on old bikes before although he has made some errors! When you read stories of engine troubles they are often due to the piston/ bore clearance so if you don't know if it was done correctly you could get that looked at. If new main bearings were fitted then check that they revolve perfectly smoothly when turned by hand, ie no crank fitted . If they don't then they may have the wrong internal clearance. If the big end bearings are brand new the connecting rods should just fall under their own weight.

Can you go back to the previous owner and get some more info?
 

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Hi Kev_England,:)

Dilemma's dilemma's, the big question of do you trust the rebuild.
If the guy was mechanical and it sounds like he is, the chances are it will be ok.

The only things you could check by splitting the cases would be the big end bolts,
the sludge trap and I also think your bike has a breather valve on the inlet cam which should be fitted.

Now the chances are, if you see the two crankcase screws that live under the barrels
and they are tight he has probably done alright.

You can only make sure the crank turns freely and the end float is within reason and there is no big end play, without a split.

The only worry I would have, would be the long screws you mentioned
depending were they where, as they could of popped the back off a blank hole, and that bit could be in the motor.
Me! after a lot of poking prodding and looking would probably give it a go,
but the decision is yours at the end of the day, he has made a couple of boo boo's and that can be expected.

I am a bit puzzled of what a "tappet guide oil ring" is?
 

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Discussion Starter #4
Thanks guys for the feedback.
Yes, it is a bit of a dilema.
At this point I have stripped down, replaced, or refurbished almost every part, nut and bolt on the bike, except for anything inside the crankcases.
But, Im thinking its probably worth a go to get it running and see what happens. if there are any bottom end problems it wont cause me much more work than it will now. If it runs ok ill avoid scratching the frames new paintwork (that PO did) and possibly causing more issues if I split the cases.
By the way, I meant by Oil Ring the "O" ring that sits on the bottom of the Tappet Guide. Part number E7563. One was missing and the other looked ragged.
Thanks again.

P.S. I just read another thread of the high frequency of guys that take out there engines to "clean up the frame" and wind up with a basket case sitting in their garages for years. This is another big reason to keep the engine in the frame!
 

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"But, Im thinking its probably worth a go to get it running and see what happens. if there are any bottom end problems it wont cause me much more work than it will now."

sorry but that has to be one of the most inaccurate statements that i've read here .

if you happen to be lucky a minor bottom end failure will just mean regrinding the crank ,new rods etc . bottom end failures can be catastrophic . resulting in destroyed cranks , cases , rods, cylinders .........

do you know for a fact he did the sludge trap ?

cheers , Woody
 

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Kev,

Sorry man I am in Woody's camp on this one. Even if it runs alright
when you put it back together...

On any long trip that thought will be in the back of your mind,
What if? No quicker way to destroy what should be a fun trip just
thinking if something might be wrong.

With the other problems you have mentioned, just checking the
torque on the rod bolts and making sure the sludge trap plug is
staked right is worth the peace of mind.

Pookybear
 

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Discussion Starter #7
"But, Im thinking its probably worth a go to get it running and see what happens. if there are any bottom end problems it wont cause me much more work than it will now."

sorry but that has to be one of the most inaccurate statements that i've read here .

...

cheers , Woody
Woody, what I meant was it will be almost the same amount of work to dismantle it as it would in its current state. Except I'd have to take off the carbs and head which are not on now.

And yes, thats why i'm worried - if he put a part back the wrong way it cost cost me a fortune.

I think Im going to contact him and try and get more details on what work he did. He did say he cleaned out the sludge trap and said "It wasnt a big deal."!!!! I dont know whether to feel confident or suspicious about that!

Thanks for all the feedback.
 

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You've spent a lot of time and effort on this bike. If you don't mind possible throwing that away, put it together and see what happens.

If it was me, I'd take the engine down and check for myself, besides these engines are fun to work on. That was the best part of my build.
 

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Personally, I'd be splitting the cases just to double check, it's only a weekend's work max. Before you remove the engine, get yourself a couple of bandages and bandage the frame lower tubes, this will avoid any damage to the paintwork on the frame.

Webby
 

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Discussion Starter #10
Here's a couple of pics inside the crank from the front and back. Not sure if it tells me much else.

Crap, I was looking for "Don't worry - just ride it!"
Oh well. :rolleyes:



 

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Hi Kev,

The engine looks clean enough although it doesn't tell you much about what the PO has done. I would still be splitting the cases. Also I see that there are a few marks on the con rods, personally I would polish them out. They are quite soft so they need to be protected from the edges of the case to avoid further damage. A bit of foam pipe insulation or even two toilet roll tubes usually do the job.

Webby
 

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Having seen the pics I agree with Webby that it would be worth polishing out those nicks in the rods. Most rod breaks are caused by the big end seizing on the crank but if you are a racer they can break just from stress and it is at these blemishes that the breakages happpen.
 
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