Which engine is the better one?

My engine guy does 706 bores but has to take thinner cuts so the liner doesn't flex where it extends below the cylinders. If being done a lot, a guy should prolly make a lower liner support for boring....
 
picture of one piston from the sized engine, made with my canon camera in macro and the best I could do,
I'm pretty sure now what it means, after all the helpful lesions I got the last couple day from you guys,
maybe you confirm that numbers,
thanks and have a good weekend,
 

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Apologies if this is un-needed advice. Hard to tell from the photos how cruddy the barrels are but given the pistons were seized solid, you might need 1st oversize - 75.25mm - or that might not be enough. Do you have a helpful machine shop? Could take the cylinders and ask them to bore roughly that size and see if all damage is removed? If not, take it out to 2nd oversize. Once they are are happy with the bores, buy pistons, give them to the shop and get them to finish to size and hone the bores. Hope this helps.
 
for sure, thanks for your suggestion;
my buddy ( old school machinist) want to see the barrels first before ordering any oversize pistons, and I thought why not going to 706cc bore by the way,
5 twins posted the link about :Cruzinimage, with affordable oversize Pistons
Gary talked about it, what are the advantages or disadvantages, what extra parts I need? meaningful or likely the most necessary ? I did not want to spend my entire budget on my first motor, want to use my existent already rebuild 1979 BS36 with pods, the stock ignition with points, but going with the aftermarket oil filter on bottom and the heidenau system in the right cover located to the pump,
 
have another question for you guys,
found this in the German XS-Laden, XS Performance, on sale now EURO 75.00, is that available in the States or Canada? cannot find it, or sold out!
whats your experience?
thank you guys,

NOTICE:
sorry guys, the picture I tried to upload is not available, CopyRights wise,never mind
 
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Just a heads up on the 706 bore. Most machine shops will leave out the taper on the bottom of the cylinders because of the fact you are going thin. So you have to use a good ring compressor to install pistons and go slow. This is how you bend rings easy. Done about 15 706 motors with cruzinimage pistons and have been using them for about 20 years. Fast service and great prices. If you go with the 706 it comes with a copper gasket and a good copper sealer is needed. His stock bore drop in pistons work very good if your bore is good and can be checked with a bore gauge. I have used many of his CB750 836 kits too and all are still out there running. Both the XS650 kits and CB750 kits. I contacted them about doing some Triumph kits but no response.
Looks like you are ready to build HAHA Starters on the way.
Just my two cents I like the 447 motors because of the ease of getting parts and all the 256 motors I get they go to some guy out there in Texas who has a barn full of them and keeps promising me he is going to send good weather my way. I am old and my bones hurt NEED WARM WEATHER. LOL
May have to go to Texas to deliver a Sportster Chopper I am finishing up and visit a couple biker friends.
Have a great SUNDAY and KEEP CHOPPIN!!!
 
Just a heads up on the 706 bore. Most machine shops will leave out the taper on the bottom of the cylinders because of the fact you are going thin. So you have to use a good ring compressor to install pistons and go slow. This is how you bend rings easy. Done about 15 706 motors with cruzinimage pistons and have been using them for about 20 years. Fast service and great prices. If you go with the 706 it comes with a copper gasket and a good copper sealer is needed. His stock bore drop in pistons work very good if your bore is good and can be checked with a bore gauge. I have used many of his CB750 836 kits too and all are still out there running. Both the XS650 kits and CB750 kits. I contacted them about doing some Triumph kits but no response.
Looks like you are ready to build HAHA Starters on the way.
Just my two cents I like the 447 motors because of the ease of getting parts and all the 256 motors I get they go to some guy out there in Texas who has a barn full of them and keeps promising me he is going to send good weather my way. I am old and my bones hurt NEED WARM WEATHER. LOL
May have to go to Texas to deliver a Sportster Chopper I am finishing up and visit a couple biker friends.
Have a great SUNDAY and KEEP CHOPPIN!!!

What clearance for the pistons do you usually have your machinist bore the cylinders to for the cruzinimage 78mm pistons?
 
OK folks ,
today I berried myself in my shop again, cleaning like a chef, the barrels from the seized motor 447- 800387 now clean enough for the bore,
when I looked at the cylinder head 2H104 I found this, seen on pics 4 and 5, looks like the crack came from a hammer, the previous owner was pretty rough to the motor.
I have another cylinder head # 9148 who looks good,
question now: can I use the cylinder head with the crack without hesitation, and-or, are the two cylinder heads interchangeable for the case 447-800387. ?
pictures 10, 11, 12 showing the clean barrels, the marks from the seized pistons on picture 11
Thanks in advance, Scrap
 

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Someone had a loose lash screw nut, they get caught between the cam and that oil fence, many have kept right on going with that crack. Yes any 447 head will interchange but keep heads and cam covers as sets.
 
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Someone had a loose lash screw nut, they get caught between the cam and that oil fence, many have kept right on going with that crack. Yes any 447 head will interchange but keep heads and cam covers as sets.

This happened to me like gggGary described and while it did run down the road my leg and the side of my bike was covered in an oil mist. I would personally get another head without a crack or get a professional machinist who can weld the aluminum and fill the crack.
 
Thanks a lot Gary,
will put the head with the crack in the shelf, use the 9148 head with the matching cam and cam cover, looks better overall even with no visible wear on the rockers
appreciate your quick and knowledgeable response, cheers and have a good weekend
Scrap
 
This happened to me like gggGary described and while it did run down the road my leg and the side of my bike was covered in an oil mist. I would personally get another head without a crack or get a professional machinist who can weld the aluminum and fill the crack.
thanks for your advise too, its great to have someone to ask
Scrap
 
Cruzinimage sell sizes, 2nd over, 4th over, ......6th over, (680cc), .......8th over, (706cc).

Boring out to 680cc and saving the sleeves for another enlargement............or buy some barrels with sleeves that need to be bored out to take a 706 kit. ...........Shame to waste a decent set of barrels when cheap alternatives, (yea cheap alternatives do cost some money), and have got a spare set of good barrels with plenty of life in them
 
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