301
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302
British Bikes / Re: Re sprag clutch
« on: March 02, 2015, 08:51:11 PM »
Hi Rick,
As I described, the cams must be able to move relative to each other but not "hop" over
I cannot remember if the inner nut is fully tight or not, the outer is then locked to the inner to prevent it coming undone.
On My L25 theres about 1/8th of an inch of threads showing outside the locknut.
It wouuld be well worth your while to try and get hold of one of the "Pitman" BSA books that deal with the 30's models, something like this ??
http://www.ebay.co.uk/itm/1937-VINTAGE-MOTORCYCLE-HANDBOOK-THE-BOOK-OF-THE-BSA-PITMANS-LIBRARY-/331494842758?pt=LH_DefaultDomain_3&hash=item4d2ea1e186
HTH
John
As I described, the cams must be able to move relative to each other but not "hop" over
I cannot remember if the inner nut is fully tight or not, the outer is then locked to the inner to prevent it coming undone.
On My L25 theres about 1/8th of an inch of threads showing outside the locknut.
It wouuld be well worth your while to try and get hold of one of the "Pitman" BSA books that deal with the 30's models, something like this ??
http://www.ebay.co.uk/itm/1937-VINTAGE-MOTORCYCLE-HANDBOOK-THE-BOOK-OF-THE-BSA-PITMANS-LIBRARY-/331494842758?pt=LH_DefaultDomain_3&hash=item4d2ea1e186
HTH
John
303
British Bikes / Re: Felt washers
« on: March 02, 2015, 08:36:05 PM »
Hi Rick,
On the primary side, use some placistine or putty wrapped in a piece of foil, to measure the gap between cush drive boss and crankcase, place the foil wrap into the recess and bolt on the drive in place, this will squash the foil wrappped putty to the thickness of the gap where the felt fits
Fit the felt so its lightly clamped in place,
When finally fitting the cush drive assembly make sure the tapers are clean and oil free, I usually add a drop of bearing fit as well and make sure the sleeve nut is fully tight
Then add some drops of oil to the felt
A similar method can probably be used on the timing side, My L25 is an earlier model and does not have this feature
HTH
John
On the primary side, use some placistine or putty wrapped in a piece of foil, to measure the gap between cush drive boss and crankcase, place the foil wrap into the recess and bolt on the drive in place, this will squash the foil wrappped putty to the thickness of the gap where the felt fits
Fit the felt so its lightly clamped in place,
When finally fitting the cush drive assembly make sure the tapers are clean and oil free, I usually add a drop of bearing fit as well and make sure the sleeve nut is fully tight
Then add some drops of oil to the felt
A similar method can probably be used on the timing side, My L25 is an earlier model and does not have this feature
HTH
John
304
British Bikes / Re: Re sprag clutch
« on: March 02, 2015, 08:24:39 PM »
HI Rick,
I think you are referring to the cush drive assembly ?
The early BSA ones have a nut and locknut, It must be tightened enough to prevent the cams physically riding over each other,
ie, the spring must be coil bound before the cams can reach the peaks.
If the cams are allowed to ride over it will result in a damaged crankshaft
(imagine a jackhammer attacking the crank !!!!!)
On later types with the splined crankshaft the nut must be fully tightened, A,B and M models 65ft lbs
HTH
John
I think you are referring to the cush drive assembly ?
The early BSA ones have a nut and locknut, It must be tightened enough to prevent the cams physically riding over each other,
ie, the spring must be coil bound before the cams can reach the peaks.
If the cams are allowed to ride over it will result in a damaged crankshaft
(imagine a jackhammer attacking the crank !!!!!)On later types with the splined crankshaft the nut must be fully tightened, A,B and M models 65ft lbs
HTH
John
305
British Bikes / Re: End float
« on: March 01, 2015, 10:03:51 PM »
Hi Rick,
I have found out in a BSA book, maximum end float for the taper fitting cush drive crank assemblys is 0.005in.
HTH
John
I have found out in a BSA book, maximum end float for the taper fitting cush drive crank assemblys is 0.005in.
HTH
John
306
British Bikes / Re: Smoking Triumph
« on: February 26, 2015, 08:04:02 PM »
HI Boo,
When the engine was rebuilt was it rebored?
what brand of pistons were fitted? some of the "new" pistons available have crap rings fitted
T90's are also known to suffer from porosity of the cylinders when rebored
HTH
John
When the engine was rebuilt was it rebored?
what brand of pistons were fitted? some of the "new" pistons available have crap rings fitted
T90's are also known to suffer from porosity of the cylinders when rebored
HTH
John
307
British Bikes / Re: End float
« on: February 23, 2015, 11:56:50 PM »
HI Rick, & John K,
The BSA's of the period I have worked on have do not bolt the cush drive solid to the main bearing
A sleeve with tapered bore bolts onto the crank end to take the cush drive, the crankcases and sleeve have slightly conical faces to match each other, a felt washer is fitted between the sleeve and crancase
As for end float, I would aim for 10 to 20 thou
As long as theres some end float so as the bearing rollers are not pinched endways it will be ok
The crankcases will expand more than the crank as the engine heats up and clearance will increase
HTH
John
The BSA's of the period I have worked on have do not bolt the cush drive solid to the main bearing
A sleeve with tapered bore bolts onto the crank end to take the cush drive, the crankcases and sleeve have slightly conical faces to match each other, a felt washer is fitted between the sleeve and crancase
As for end float, I would aim for 10 to 20 thou
As long as theres some end float so as the bearing rollers are not pinched endways it will be ok
The crankcases will expand more than the crank as the engine heats up and clearance will increase
HTH
John
308
European and Other Bikes / Re: 1953 Terrot 125cc
« on: January 15, 2015, 06:58:18 PM »
HI Joe,
Theres a 55 for sale on Ebay, the photos may help in identifying parts you need or where parts you have fit !!
http://www.ebay.co.uk/itm/1955-Terrot-125-ETDS-vintage-motorbike-project-bobber-cafe-racer/221648648467?_trksid=p2060778.c100276.m3476&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D28722%26meid%3D2c36daaf17224573b85743a8ea53edff%26pid%3D100276%26rk%3D1%26rkt%3D4%26sd%3D181634768681
HTH
John
Theres a 55 for sale on Ebay, the photos may help in identifying parts you need or where parts you have fit !!
http://www.ebay.co.uk/itm/1955-Terrot-125-ETDS-vintage-motorbike-project-bobber-cafe-racer/221648648467?_trksid=p2060778.c100276.m3476&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D28722%26meid%3D2c36daaf17224573b85743a8ea53edff%26pid%3D100276%26rk%3D1%26rkt%3D4%26sd%3D181634768681
HTH
John
311
Japanese Bikes / Re: 1962 YD3 -- Running 1 cylinder??
« on: December 13, 2014, 07:40:19 PM »
HI,
If both cylindrs have 140psi than I would think the rings are ok
maybe the left crankcase is just flooded with fuel /oil??
A lot of older twostroke bikes had a crankcase drain screw for such events, I dont know if the Yam has??
If not, remove the sparkplug and exhaust on the left, place some rags on the head and in front of the ex port to reduce mess, ground out the lefthand plug lead securely
start the engine on the right hand cylinder and blow out all the excess fuel / oil from the cylinder
fit a new sparkplug and then see if the engine runs on both cylinders
The capacitors connected across the points can detioriate with age, when the engine is runnning seee if there is a lot of sparking at the points
HTH
John
If both cylindrs have 140psi than I would think the rings are ok
maybe the left crankcase is just flooded with fuel /oil??
A lot of older twostroke bikes had a crankcase drain screw for such events, I dont know if the Yam has??
If not, remove the sparkplug and exhaust on the left, place some rags on the head and in front of the ex port to reduce mess, ground out the lefthand plug lead securely
start the engine on the right hand cylinder and blow out all the excess fuel / oil from the cylinder
fit a new sparkplug and then see if the engine runs on both cylinders
The capacitors connected across the points can detioriate with age, when the engine is runnning seee if there is a lot of sparking at the points
HTH
John
312
Identify these bikes! / Re: HELP to identify this old bike
« on: December 02, 2014, 12:29:42 AM »
Hi,
Francis Barnett built like a bridge
https://www.google.ie/search?q=francis+barnett+built+like+a+bridge&biw=1120&bih=820&source=lnms&tbm=isch&sa=X&ei=NQd9VNaGA_Lg7QbUjIBA&ved=0CAYQ_AUoAQ
I'm sure someone more enlightened on the various models will be more exact
Can you find any engine or frame numbers?
HTH
John
Francis Barnett built like a bridge
https://www.google.ie/search?q=francis+barnett+built+like+a+bridge&biw=1120&bih=820&source=lnms&tbm=isch&sa=X&ei=NQd9VNaGA_Lg7QbUjIBA&ved=0CAYQ_AUoAQ
I'm sure someone more enlightened on the various models will be more exact
Can you find any engine or frame numbers?
HTH
John