After you find tdc go past until you feel the exhaust valve opening You can feel it through the decompression lever This is the best position to start a b50 Also get an extended idle screw and turn it in half a turn And don't be tempted to open the throttle is Always kick with the Kickstarter returned to the top Don't ever attempt to kick it through compression as the clutch will slip To get the best grip from the clutch you will need to hand deck every plate , friction and plain even if the plates are brand new
@@TheCADengineer it's not the easiest thing to feel through the decomp lever but it is a game changer The trouble is the engine got bigger and bigger in cc but the clutch is basically still a c15 or you could say tiger cub
I have a 1969 T100R Daytona, similar diameter clutch and the Daytona motor has a tad more power, the clutch has a far better mechanism with 3 ball bearings between 2 plates giving a higher force on the clutch pushrod with a lot less effort at the lever. The last of the 650 BSA twins also used it (1969-70) l think the reason it wasn’t used on the B25-B50’s is to keep the engine width as narrow as possible as the 3 ball mechanism is quite wide, whereas on the twins the engines are much wider so not an issue. I don’t know if you watch Mike Wallers UA-cam channel (Britannia Motors) He is building a B44 trials at the moment, he extends the clutch lever pinion arm by about 30mm and alloy welds a new lug for the outer cable on the inner timing case, he then fits stronger springs, this gives him a powerful clutch with very light operation. I have just finished a B25 which l have converted to green lane/trials, l might have a go at doing Mike’s clutch actuation mod on that to see how it goes, however in Australia until June next year, so the bikes are in storage till l get home.
@@TheCADengineer the Daytona engine has more power but far less torque You can easily extend the clutch actuator arm bear in mind you are reducing lift increasing drag
Getting the clutch right on a B50 is a royal PITA try backing off the four nuts on the clutch to a nutral position, put it in gear start loading the cluch nuts about a turn in a half or just slight of slipping, while in gear holding the brake and applying pressure on the kick starter load the clutch about a quarter turn on each nut then stand on the kick starter while in gear, and applying the brake at the same time, you should be able to do short hopps on the kick starter without slipping the clutch and still be able to have moderate pressure on the clutch lever, theres a small sweet spot between too much pressure and not enough, too much pressure and the clutch lever will be too hard to pull, not enough easy to pull but clutch will slip.
Never thought of trying with the bike in gear as a slip test, good idea. Been out a few times since and ended up pulling the cover off again and backing off the clutch hub screws a tad as the pulling the lever was hard work, however had a really good ride out on Sunday, so l think l have now found the clutch adjustment sweet spot.
Lovely looking machine! I had a C15 back in the 70s and recently I've toyed with the idea of a B50. Just fancy a big, light weight single. The primary chain oil used to be separate on the C15 and a different grade to the engine oil. So, the B50 gets main engine oil feed to the primary chain compartment then drains back into the crankcase for scavenge? That sounds like a good idea. Is the compression ratio, on the B50, similar to the Baracuda Starfire 250 (square barrel)?
Hi, The compression ratio is 10:1, so at 500cc it's a bit of a beast to kick over. I have cheated though and put a 2mm aluminium shim under the barrel which knocks the ratio down a tad and It runs better on E10 petrol, but you still have to get used to it and find the knack to start it. I recently sold my C15S which was I fitted with a high compression dome topped piston, but no problem kicking it over. I am also working of a Starfire at the moment which I am converting to green lane semi trials. I am on a dry build at the moment but I gave the engine a run a week or so ago and just like the C15, the B25 Starfire (10:1) is easy to kick over and a decompressor is not needed (although some had a factory fitted decompressor) The B50 also also has large 2 upper holes between the crankcase and primary case due to the large under piston displacement it breathes into that void, hence the big pipe at the top of the clutch case, but not needed on the B25 Starfire.
@@TheCADengineer Thank you for the reply. I did wonder about the pipe coming out above the clutch although, like you say, it's quite a lot of air to displace under that 500 piston. After watching the video, I subscribed to your channel and will make my way through your previous videos, they also look interesting. I did watch the short video of you riding the C15 around the paddock ...... that sound is unmistakable 👍My C15 was a 1967 model with the points on the timing side of the engine, great little bike! I notice, from the heading on your channel, that you are a CAD man. Coincidentally, I spent nearly 40 years as a draughtsman/CAD designer in mechanical engineering. I'm retired now but still get my hands dirty (bikes and car) when the need arises. I also still use CAD (Rhino) on my laptop. I might have left engineering but it'll never leave me 😊Cheers for now, Phil
@@PAGallagherI bought and refurbed that 1959 C15S in the video as that was the model bike I had when I was an apprentice, since then I have refurbed a 1962 T20 Tiger Cub, then the B50 and now the Starfire. My next one will be a Triumph 650 TR6C or S as that was the first big bike I bought in the early 70's when I passed my motorcycle test. I also spent many years on a board before being moved onto AutoCad (2D) and used a green screen with an OS Pet PC and a Puck before mouse commands were written into the programme, then was moved on to parametric modeling with AutoCad's Inventor and ending up on SolidWorks. I am well retired now by quite a few years, but still do a bit of 2D stuff with Draftsight, I know of Rhino but have never used it (surface modeling software?) We had it at a college I worked for but I only taught AutoCad products and SolidWorks.
@TheCadengineer I wish I had thought of shimming the barrel while I had it apart, Mine pings on 93 octane, I live close to Atlanta raceway, so I can get 100 octane, but it's 10$ a gallon.
@@patstenzel The p/n for the barrel shim is 71-3634, the one I fitted is an aftermarket one which is 2mm which would be about 80 thou, however they were factory fitted to some of the very last Triumph versions (TR5MX) and are slightly thinner. I do have somewhere a genuine BSA NOS one, next time I see it I will measure is. PES also make them in 3 different thicknesses.
One trick is to bead blast the metal surfaces of the steel disks..if you ride it hard clutch goes fast.
After you find tdc go past until you feel the exhaust valve opening
You can feel it through the decompression lever
This is the best position to start a b50
Also get an extended idle screw and turn it in half a turn
And don't be tempted to open the throttle is
Always kick with the Kickstarter returned to the top
Don't ever attempt to kick it through compression as the clutch will slip
To get the best grip from the clutch you will need to hand deck every plate , friction and plain even if the plates are brand new
I have the extended idle screw but haven’t felt for the exhaust valve start to open, l will give that a try, thanks.
@@TheCADengineer it's not the easiest thing to feel through the decomp lever but it is a game changer
The trouble is the engine got bigger and bigger in cc but the clutch is basically still a c15 or you could say tiger cub
I have a 1969 T100R Daytona, similar diameter clutch and the Daytona motor has a tad more power, the clutch has a far better mechanism with 3 ball bearings between 2 plates giving a higher force on the clutch pushrod with a lot less effort at the lever. The last of the 650 BSA twins also used it (1969-70) l think the reason it wasn’t used on the B25-B50’s is to keep the engine width as narrow as possible as the 3 ball mechanism is quite wide, whereas on the twins the engines are much wider so not an issue. I don’t know if you watch Mike Wallers UA-cam channel (Britannia Motors) He is building a B44 trials at the moment, he extends the clutch lever pinion arm by about 30mm and alloy welds a new lug for the outer cable on the inner timing case, he then fits stronger springs, this gives him a powerful clutch with very light operation. I have just finished a B25 which l have converted to green lane/trials, l might have a go at doing Mike’s clutch actuation mod on that to see how it goes, however in Australia until June next year, so the bikes are in storage till l get home.
@@TheCADengineer the Daytona engine has more power but far less torque
You can easily extend the clutch actuator arm bear in mind you are reducing lift increasing drag
@@baz1086 Well worth watching Mike’s mod.
Getting the clutch right on a B50 is a royal PITA try backing off the four nuts on the clutch to a nutral position, put it in gear start loading the cluch nuts about a turn in a half or just slight of slipping, while in gear holding the brake and applying pressure on the kick starter load the clutch about a quarter turn on each nut then stand on the kick starter while in gear, and applying the brake at the same time, you should be able to do short hopps on the kick starter without slipping the clutch and still be able to have moderate pressure on the clutch lever, theres a small sweet spot between too much pressure and not enough, too much pressure and the clutch lever will be too hard to pull, not enough easy to pull but clutch will slip.
Never thought of trying with the bike in gear as a slip test, good idea. Been out a few times since and ended up pulling the cover off again and backing off the clutch hub screws a tad as the pulling the lever was hard work, however had a really good ride out on Sunday, so l think l have now found the clutch adjustment sweet spot.
Lovely looking machine! I had a C15 back in the 70s and recently I've toyed with the idea of a B50. Just fancy a big, light weight single. The primary chain oil used to be separate on the C15 and a different grade to the engine oil. So, the B50 gets main engine oil feed to the primary chain compartment then drains back into the crankcase for scavenge? That sounds like a good idea. Is the compression ratio, on the B50, similar to the Baracuda Starfire 250 (square barrel)?
Hi, The compression ratio is 10:1, so at 500cc it's a bit of a beast to kick over. I have cheated though and put a 2mm aluminium shim under the barrel which knocks the ratio down a tad and It runs better on E10 petrol, but you still have to get used to it and find the knack to start it. I recently sold my C15S which was I fitted with a high compression dome topped piston, but no problem kicking it over. I am also working of a Starfire at the moment which I am converting to green lane semi trials. I am on a dry build at the moment but I gave the engine a run a week or so ago and just like the C15, the B25 Starfire (10:1) is easy to kick over and a decompressor is not needed (although some had a factory fitted decompressor) The B50 also also has large 2 upper holes between the crankcase and primary case due to the large under piston displacement it breathes into that void, hence the big pipe at the top of the clutch case, but not needed on the B25 Starfire.
@@TheCADengineer Thank you for the reply. I did wonder about the pipe coming out above the clutch although, like you say, it's quite a lot of air to displace under that 500 piston. After watching the video, I subscribed to your channel and will make my way through your previous videos, they also look interesting. I did watch the short video of you riding the C15 around the paddock ...... that sound is unmistakable 👍My C15 was a 1967 model with the points on the timing side of the engine, great little bike! I notice, from the heading on your channel, that you are a CAD man. Coincidentally, I spent nearly 40 years as a draughtsman/CAD designer in mechanical engineering. I'm retired now but still get my hands dirty (bikes and car) when the need arises. I also still use CAD (Rhino) on my laptop. I might have left engineering but it'll never leave me 😊Cheers for now, Phil
@@PAGallagherI bought and refurbed that 1959 C15S in the video as that was the model bike I had when I was an apprentice, since then I have refurbed a 1962 T20 Tiger Cub, then the B50 and now the Starfire. My next one will be a Triumph 650 TR6C or S as that was the first big bike I bought in the early 70's when I passed my motorcycle test. I also spent many years on a board before being moved onto AutoCad (2D) and used a green screen with an OS Pet PC and a Puck before mouse commands were written into the programme, then was moved on to parametric modeling with AutoCad's Inventor and ending up on SolidWorks. I am well retired now by quite a few years, but still do a bit of 2D stuff with Draftsight, I know of Rhino but have never used it (surface modeling software?) We had it at a college I worked for but I only taught AutoCad products and SolidWorks.
@TheCadengineer I wish I had thought of shimming the barrel while I had it apart, Mine pings on 93 octane, I live close to Atlanta raceway, so I can get 100 octane, but it's 10$ a gallon.
@@patstenzel The p/n for the barrel shim is 71-3634, the one I fitted is an aftermarket one which is 2mm which would be about 80 thou, however they were factory fitted to some of the very last Triumph versions (TR5MX) and are slightly thinner. I do have somewhere a genuine BSA NOS one, next time I see it I will measure is. PES also make them in 3 different thicknesses.