Lightning rebuild

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Benchracer1

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Jun 23, 2024
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Morning guys. I'm new to this site. I have a friend who wants me to rebuild his 650 lightning motor. I've rebuilt chevy, dodge, vw and all the Japanese motorcycle. I am wondering if there is any black art to the British motor or if caution and a good manual will sofice? Also would be interested in which manual you guys recommend as well as a good machine shop and parts source.....Steve
 
I don't think it's a black art. The same attention to detail is needed as with any engine. The number 1 rule on British bike rebuilds is to clean the sludge trap in the crankshaft. The BSA service manual is great. Its available online for free on sites like Classic British Spares. Get a good set of Whitworth wrenches and sockets. Where are you located? I might be able to recommend a good machine shop.
 
Benchracer1 said:
Morning guys. I'm new to this site. I have a friend who wants me to rebuild his 650 lightning motor. I've rebuilt chevy, dodge, vw and all the Japanese motorcycle. I am wondering if there is any black art to the British motor or if caution and a good manual will sofice? Also would be interested in which manual you guys recommend as well as a good machine shop and parts source.....Steve
Click to expand...
You can get factory workshop and other manuals here: https://classic-motorbikes.net/manuals/
 
With an a65 motor the timing side bush fit to crank has to be perfect
This is the Achilles heel of the motor hence various conversions to needle roller main
But they can be ok as standard if built properly
And the oil is changed frequently
 
baz said:
With an a65 motor the timing side bush fit to crank has to be perfect
This is the Achilles heel of the motor hence various conversions to needle roller main
But they can be ok as standard if built properly
And the oil is changed frequently
Click to expand...
I agree. This is very important on an A65. You need to measure the crank journal and the bushing to determine if its still in tolerance. If not, you need to have someone who knows this process do the machine work. It must be line bored so it is concentric with the bearing in the left hand case. Morrie's Place in Ringwood, Illinois is a good shop that knows how to do this.
 
The TS bush has already been mentioned, I converted to the roller bearing and oil end feed, oil pressure with a new hepolite cast iron oil pump is rock solid 60-70 psi at speed, and 20 psi hot idle. Invest in a good oil pump regardless of what you do with the TS bush. Also pay attention to the gearbox, shimming the layshaft properly is critical as is ensuring full engagement between the gears and dogs. The cam plate should be renewed and all bearing surfaces on it polished. One last piece of advice, make sure ALL the outer case bolt hole threads are good while it's apart.
 
Well, I have the bike disassembled and it definitely has a bad rod bearing. Packaged up the affected engine components and sending them off to Morries place for the necessary machine work. While I'm waiting for that to be completed I am going through the rolling chassis. I'm going to change the steering head bearing(rust).I'd like to get a set of tapered roller bearings. Does any body have any recommendations for Amy particular brand?.....Steve
 
Benchracer1 said:
Well, I have the bike disassembled and it definitely has a bad rod bearing. Packaged up the affected engine components and sending them off to Morries place for the necessary machine work. While I'm waiting for that to be completed I am going through the rolling chassis. I'm going to change the steering head bearing(rust).I'd like to get a set of tapered roller bearings. Does any body have any recommendations for Amy particular brand?.....Steve
Click to expand...
SRM sell a tapered bearing kit. Have a look at the swingarm bushings as well, you didn't say what year it is, may have silentbloc bushes. There are better options that require machine work depending on how far you want to go, I converted mine to oilite bronze bushings
 
baz said:
With an a65 motor the timing side bush fit to crank has to be perfect
This is the Achilles heel of the motor hence various conversions to needle roller main
But they can be ok as standard if built properly
And the oil is changed frequently
Click to expand...
How can you fit needle or roller bearings to the oil feed bushing? I once threw a rod through the case of my A65 due to not checking the clearance when I changed the crankshaft.Too much clearance in the bushing will reduce oil pressure. I can't imagine how a needle bearing would impact the oil feed to the crankshaft.
 
Dan1950 said:
How can you fit needle or roller bearings to the oil feed bushing? I once threw a rod through the case of my A65 due to not checking the clearance when I changed the crankshaft.Too much clearance in the bushing will reduce oil pressure. I can't imagine how a needle bearing would impact the oil feed to the crankshaft.
Click to expand...
Plenty of people do this conversion
You can do it yourself if you have a decent shop
But devimead were the main people and now SRM do it
The crank and the case are modified for a two piece bearing
A needle roller and a ball race to control end float I believe but it's a long time since I've seen one
The crank is drilled and a quill fitted and the oil feed is re directed into the end of the crank
No loss of oil pressure due to wear https://images.app.goo.gl/hDFsXwxGerHRw6dK8
 
Last edited:
Dan1950 said:
How can you fit needle or roller bearings to the oil feed bushing? I once threw a rod through the case of my A65 due to not checking the clearance when I changed the crankshaft.Too much clearance in the bushing will reduce oil pressure. I can't imagine how a needle bearing would impact the oil feed to the crankshaft.
Click to expand...
You can see pics of the conversion in my A65 build thread here:

acadian

Post in thread 'A65 teardown'

Early christmas for the A65 project, end feed/bearing conversion is back from Michigan, you can see the re routed oil feed to the crank through the PRV cavity, the welded boss that holds the new crank seal and clip, the dowel feed / o-ring from the inner to outer cover, and you can also make out the needle roller combo bearing under the worm gear. Also new carillo rods and 10.5:1 forged pistons. Also decided to mount the dunstall fairing I've had lying around for years, IMHO the fairing spitfire tank combo is fantastic, sending that off for paint this week...
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Benchracer1 said:
Well, I have the bike disassembled and it definitely has a bad rod bearing. Packaged up the affected engine components and sending them off to Morries place for the necessary machine work. While I'm waiting for that to be completed I am going through the rolling chassis. I'm going to change the steering head bearing(rust).I'd like to get a set of tapered roller bearings. Does any body have any recommendations for Amy particular brand?.....Steve
Click to expand...
2 diff frames were used, what year bike? last 2 yrs 71-2 are known as oif - oil in frame, same as triumph used with t120 - t140 models but with diff engine mounting locations fitted

en.wikipedia.org

BSA Lightning - Wikipedia

en.wikipedia.org en.wikipedia.org

utube dude has fab engine teardown/rebuild vids i'll look up the link, meantime..



edit - here, viewing at utube gives a 6 vid playlist by scrolling down
 
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