T-H-K, Just my opinion but if you can find one, go for a 69 or 70 Thunderbolt. With the single carb it is much less trouble than the twin carbs of the Lightning. The 69 & 70 have a much better braking system than the 68's. I had both a 67 & 69 Thunderbolt bought new, so I speak with a little experience. The difference is almost like day & night. They also had converted a lot of the nuts and bolts to American thread, where the 68's still had mostly British threads. Makes a big difference when you are trying to locate the inevitable ones that vibrate off. My 69 Thunderbolt was one of the sharpest looking & best handling bikes I ever owned. It was no slouch either. I don't remember "running" against a Lightning but I bet I would have been right there with the Thunderbolt until we were well into 4th. It actually would lift the front end in 3rd gear.
Also, if your located on the South Shore there is a great BSA guru located over in Plainville, should you run into any kind of mechanical trouble. Good luck. Skeet
Skeet Enjoy life....it has an expiration date.. 1964 Hornet 1970 TR6R 1971 Norton 1972 XLH
Re: So....what's the difference between a bsa lightning and a thunderbolt?#37581 04/12/0811:55 pm04/12/0811:55 pm
Beezerhatch, nice looking bike and a great photo. They are the nicest looking late '60s Pommy bikes IMHO. I have a big Triumph prejudice but BSA made them pretty, I used to think that the '69 Firebird was the best but now lean toward the Lightning, the Thunderbolt is let down in looks by the lack of a tacho. Is that an RD500 [RZ500 in Australia] in the shed ? If so do not ride the bloody thing hard, Yamaha made some absolute dogs like the TX750 but the big RD's faults [handling] are life threatening.
1969 TR6R 7.62 x 51 is not a maths puzzle.
Re: So....what's the difference between a bsa lightning and a thunderbolt?#37585 04/13/083:00 pm04/13/083:00 pm
apro has it right on the cams. But that myth coming up about a "Spitfire" cam. There is no such thing as a "Spitfire" cam for the unit twins. There were exactly 2 cams available. 68-0103 was the original cam. 68-0473 was introduced on the Rockets, Lightning Rockets, and Hornets in 64. It became the only cam offered on late 650's. The 68-0103 remained as the Royal Star cam to the end.
The Spitfire's were not all that much different engine spec. than the Lightnings. Higher compression, bigger carbies, and that is about it.
If you find a T-bolt, I would encourage you to go after it if reasonably solid. They are not as common as Lightnings, Spitfires, and Firebird Scramblers. They are a very nice bike in their own right. If you find a 68, it does have the big (1 5/8") half width front brake and retains the easier to find fork lowers of the 66/67 BSA twins. 69 & 70 T-bolts share the front end and brake of the dual carb twins.
They respond well to the same sort of tweaking as the dual carb bikes. They will lack a little on top end in comparison, but are every bit as good in the mid range. And they are a dry frame A65...which with some minor suspension tweaks and decent tires, a surprisingly capable bike in the twisties. One of the things people overlook with dry frame A65's.
Life is too short to drink cheap, bad beer.
Re: So....what's the difference between a bsa lightning and a thunderbolt?#37586 04/13/084:17 pm04/13/084:17 pm
I think I remember reading back in the 60's, one of the motorcycle mags, or maybe it was gleaned from actual BSA data, that the difference between box stockt T-Bolt and Lightning was 3 or 4 MPH at the top end??? The twin carb model was faster in the 1/4 mile. True? Ron
Re: So....what's the difference between a bsa lightning and a thunderbolt?#37587 04/13/087:01 pm04/13/087:01 pm
Well I'm really close to closing this deal on a 1968 Lightning so I just wanted to get a little better acquainted with the brand. So thanks for the responses.
You guys may get a laugh out of this but I plan on tackling most things in my project and documenting it all. It seems there is a huge disconnect between folks who are technically proficient and those who want to be.
There is a very high entry barrier. I've visited sites where someone asks something that I feel is a legitimate question only to get responses like "Are you kidding? If you don't know how to do that just give up now" "What the ****? Can you even bolt on a wheel to the frame?" etc. I'll try to do my homework by reading up and buying some books but can't guarantee it'll ramp me up.
So even though I may cave in and outsource the whole damn thing I'm gonna try it out first.
The problem I'll be having is that the bike is going to be collected disassembled and as most people who have taken stuff apart know. It's a lot harder to put back together. Especially if you weren't the one who took it apart! Also, God knows if I'll know to look for all the essential pieces when I take delivery.
Huge leap of faith, but it'll be one hell of a journey either way.
So expect numerous dumb questions from me from here on out. If they're not welcome just let me know! Hopefully one of these days I'll be on the other side dispensing the advice.
Re: So....what's the difference between a bsa lightning and a thunderbolt?#37589 04/13/0810:20 pm04/13/0810:20 pm
Taek-Ho.....that's exactly what this forum is all about. Sharing the BritBike experience with others. We all started knowing nothing, we all end up knowing something. It's a beautiful thing. Welcome to the fray......... Read these posts until your eyes burn...you'll learn immense amounts of invaluable information. Ask questions whenever you wantbut DO search first. Cheers
Life is short but very wide.
Re: So....what's the difference between a bsa lightning and a thunderbolt?#37591 04/18/082:46 pm04/18/082:46 pm
TKD-Buy a good illustrated parts book and Two shop books. Everything will be revealed after reading everything several times-before you start putting the bike together. It is not a cruise missile. You can do it if you want to. People need something to be elitist about, two pistons some valves a cam and a bunch of stuff in between that needs to be clean, in good condition and measured for the proper tolerances and clearances! Riding something that you wrenched yourself is like watching your son hit a home run, as opposed to watching barry Bonds on TV.
Re: So....what's the difference between a bsa lightning and a thunderbolt?#37593 04/18/086:02 pm04/18/086:02 pm
I would recommend having the help of a friendly mechanic type (Brit not really required IMO) to help you with some of the language (whats a cam plate?) and it helps if he has a lathe in his garage too!
I had a lot of help, but "I" built my Thunderbolt and now spend a lot of time trying to explain to folks why I love it so much. (expect the occasional "Why didn't you get a Ducati/Harley comment)I totally agree that there is a great satisfaction that comes from getting the bits together for yourself. Your going to have some class under your ***, instead of the sterile robots that most folks ride. I take my T-Bolt to a local Harley Run and those biker dudes take some real notice to my bike, and always want to come up and offer praises WAY before they even notice some $30,000+ custom "fad" bike. It may take you a couple years (it did me) to get her going, but it is worth it in a lot of ways. I was glad to read the difference between a t-bolt and a lightning in this post, I thought there mus'nt be really much of a difference just because of twin carberation/ slight head difference. My T-Bolt winds up good!