@Pipes, sounds weird...as if the depressing the master results in no (or restricted or limited ) displacement of the brake fluid. I've experienced something similar which was found to be a collapse (or restriction) of the inner lining of a flexible brake line. The more pressure was applied, the more the line became restricted. The only other issue that comes to mind is the available travel of the piston in the master in its installed position (ie, the the piston bottoms out before it has displaced enough fluid to activate the caliper). Linkage geometry issue maybe?
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Flat track project
- Thread starter Pipes
- Start date
Yeh I did wonder about the lever operation and in fact I modified it today to accept a rose joint rather than the solid lug it had...the lever itself may get a makeover during winter storage...I knew I was going to get one or two teething problems and I do use the front about 90% of the time but I do like a rear when in traffic or slower speeds.
I'll report back if the mod has improved anything but I'm not holding my breath.
I'll report back if the mod has improved anything but I'm not holding my breath.
If that's a new disc, those pads are screwed up. No way they should dig into the disc that bad
I agree with Jim. Aggressive pad compound tearing up the surface of the disc, the pedal is hard and still no braking??? If there is no braking, how is the pad tearing up the disc that bad? Something is really amiss here. I am still thinking insufficient displacement of brake fluid because either the master bottoms out and/or the master bore is too small? The pad material seems far too aggressive.
As a point of comparison, when I need to do a quick-and-dirty pad change on a vehicle without replacing or surfacing the discs, I use a semi-metallic pad which beds in fast regardless of how badly the disc is glazed or scored. The pads rough up the disc, but not nearly as aggressively as Pipes' disc. A ceramic pad won't do that and tends to aggravate the glazing of the disc.
Cheers for the replies guys...I haven't had chance to check the news pads out but you can definitely tell they are softer..
As for the master,it's bore size is 1/2" the same as a standard yz250 one although this one is not from a yz or even a yamaha if I remember correctly..I'm not sure it's bottoming out because it still has travel when the bleed nipple is opened. The lever moves down a few mm (1/4") during normal operation but moves another inch during bleeding....??
As for the master,it's bore size is 1/2" the same as a standard yz250 one although this one is not from a yz or even a yamaha if I remember correctly..I'm not sure it's bottoming out because it still has travel when the bleed nipple is opened. The lever moves down a few mm (1/4") during normal operation but moves another inch during bleeding....??
Update on the master cylinder affair,just in case anyone else has a similar issue but it seems I've been an idiot but I won't know for sure until another replacement comes through the post.
I did buy another but needn't have bothered..it seems I made a mistake while searching for parts compatible with my YZ250 caliper which means 1/2" bore master BUT it's actually a YZF250 caliper...one more letter but an 11mm bore master which it seems makes a whole world of difference
.Let's see if the second replacement makes it work...
Also I've been fettling the Heiden oil filter kit as in making the aluminium cover fit better in the casing recess as it weeped oil and it seems the cover was a slightly too tight and didn't allow for casting imperfections..At the same time I replaced the oil filter element as its a newly built motor and I think its good practice..The cost is negligible its a no brainer..But I still had a heavy weep when running which reduced when I put a second gasket under the cover..To improve this issue I turned down the half moon insert the thickness of a gasket.This means the outer cover will seat better.. Job done??..no..once back together the engine drop its oil even worse...on closer inspection it seems the new filter cartridge is slightly bigger than the other one meaning the work I done was 'undone'..another gasket made and added showed improvements...I find it annoying that I could potentially have this issue every time I replace the cartridge if the manufacturer has poor quality control..I'm going to try a single thicker gasket or a oil resistant rubber one and see how it goes...Either that or I'll put the o/e mesh screen back in..
I did buy another but needn't have bothered..it seems I made a mistake while searching for parts compatible with my YZ250 caliper which means 1/2" bore master BUT it's actually a YZF250 caliper...one more letter but an 11mm bore master which it seems makes a whole world of difference
.Let's see if the second replacement makes it work...Also I've been fettling the Heiden oil filter kit as in making the aluminium cover fit better in the casing recess as it weeped oil and it seems the cover was a slightly too tight and didn't allow for casting imperfections..At the same time I replaced the oil filter element as its a newly built motor and I think its good practice..The cost is negligible its a no brainer..But I still had a heavy weep when running which reduced when I put a second gasket under the cover..To improve this issue I turned down the half moon insert the thickness of a gasket.This means the outer cover will seat better.. Job done??..no..once back together the engine drop its oil even worse...on closer inspection it seems the new filter cartridge is slightly bigger than the other one meaning the work I done was 'undone'..another gasket made and added showed improvements...I find it annoying that I could potentially have this issue every time I replace the cartridge if the manufacturer has poor quality control..I'm going to try a single thicker gasket or a oil resistant rubber one and see how it goes...Either that or I'll put the o/e mesh screen back in..
So...I've sorted the oil filter weep using a thicker oil resistant rubber gasket but now I have an annoying leak from the tacho drive boss..I have a tacho delete cap fitted but the oil is coming from the steel insert itself.I have replaced the o ring twice now yet it still leaks..any tips?
Curious...did a different master sort the brake issue?Update on the master cylinder affair,just in case anyone else has a similar issue but it seems I've been an idiot but I won't know for sure until another replacement comes through the post.
I did buy another but needn't have bothered..it seems I made a mistake while searching for parts compatible with my YZ250 caliper which means 1/2" bore master BUT it's actually a YZF250 caliper...one more letter but an 11mm bore master which it seems makes a whole world of difference
Also I've been fettling the Heiden oil filter kit as in making the aluminium cover fit better in the casing recess as it weeped oil and it seems the cover was a slightly too tight and didn't allow for casting imperfections..At the same time I replaced the oil filter element as its a newly built motor and I think its good practice..The cost is negligible its a no brainer..But I still had a heavy weep when running which reduced when I put a second gasket under the cover..To improve this issue I turned down the half moon insert the thickness of a gasket.This means the outer cover will seat better.. Job done??..no..once back together the engine drop its oil even worse...on closer inspection it seems the new filter cartridge is slightly bigger than the other one meaning the work I done was 'undone'..another gasket made and added showed improvements...I find it annoying that I could potentially have this issue every time I replace the cartridge if the manufacturer has poor quality control..I'm going to try a single thicker gasket or a oil resistant rubber one and see how it goes...Either that or I'll put the o/e mesh screen back in..
No,not really....it's still performing poorly but I do have an idea about changing the brake lever for better leverage or rather the pivot position but that's a winter job...
OK,so I've put a few miles on the bike now and I already have changes to make.It was always an unknown when I first started building the bike so it's no surprise really.The main changes are the back and front
.
The current forks are OK in the way they perform,but just OK...not great but you could live with them,but I'd rather have a good front end.I love the look of them but they cannot cope with rougher roads in that the compression and rebound do not work in harmony with each other.They are fine on dips and smooth rises but that's because they are soft which has its own problem when it comes to braking.I am using almost all of my travel and I've not had to brake in an emergency situation which could prove problematic.Stronger springs and pre-load spacers of various sizes haven't help and oil is either giving me some dampening or rock hard stiffness...I think I've tried almost every trick to get them to work....
This means I'm now looking at the go to R6 fork set-up or possibly Sv650....my only concern is how they would work with the bike seeing as its much lighter than a stock R6,hence the Sv650 idea,....although I could get some lighter springs for either,but they will definitely be more suited to the roads unlike the current Paoli forks I'm using now.
Then there's the back end....
The whole idea of using a linked monoshock was the exercise some engineering into the bike,to think outside the box as it were..but this too has its own issues..not that it doesn't work you see,it does.It is a little firm at the moment but simply having a couple of different linkage plates with different hole spacings would solve that..simple..however the main issue is the wheelbase..now I know its a road bike and not an all out racer but when I mocked the whole thing up during its early days I tried to keep the wheelbase no different that that of a standard XS,at least not longer that is...but once the wheels are in,chain tensioned and complete it has actually turned out to be 50mm longer than standard...
This may not be a big issue but flat track bikes are normally short and squat and the monoshock uses a lot of space..in fact the more I look at it the more I see length.....
I have two options..1 I lose the shock reservoir and use a simpler monoshock shrink the arm by 50mm or go all out and go traditional twin shock and gain a whole load of space in which to shrink the length...twin appeals to me in classic look and simplicity but goes against the original 'outside the box' mentality however we do know it would work and still look cool...
I have some decisions to make
OK,so I've put a few miles on the bike now and I already have changes to make.It was always an unknown when I first started building the bike so it's no surprise really.The main changes are the back and front
.The current forks are OK in the way they perform,but just OK...not great but you could live with them,but I'd rather have a good front end.I love the look of them but they cannot cope with rougher roads in that the compression and rebound do not work in harmony with each other.They are fine on dips and smooth rises but that's because they are soft which has its own problem when it comes to braking.I am using almost all of my travel and I've not had to brake in an emergency situation which could prove problematic.Stronger springs and pre-load spacers of various sizes haven't help and oil is either giving me some dampening or rock hard stiffness...I think I've tried almost every trick to get them to work....
This means I'm now looking at the go to R6 fork set-up or possibly Sv650....my only concern is how they would work with the bike seeing as its much lighter than a stock R6,hence the Sv650 idea,....although I could get some lighter springs for either,but they will definitely be more suited to the roads unlike the current Paoli forks I'm using now.
Then there's the back end....
The whole idea of using a linked monoshock was the exercise some engineering into the bike,to think outside the box as it were..but this too has its own issues..not that it doesn't work you see,it does.It is a little firm at the moment but simply having a couple of different linkage plates with different hole spacings would solve that..simple..however the main issue is the wheelbase..now I know its a road bike and not an all out racer but when I mocked the whole thing up during its early days I tried to keep the wheelbase no different that that of a standard XS,at least not longer that is...but once the wheels are in,chain tensioned and complete it has actually turned out to be 50mm longer than standard...
This may not be a big issue but flat track bikes are normally short and squat and the monoshock uses a lot of space..in fact the more I look at it the more I see length.....
I have two options..1 I lose the shock reservoir and use a simpler monoshock shrink the arm by 50mm or go all out and go traditional twin shock and gain a whole load of space in which to shrink the length...twin appeals to me in classic look and simplicity but goes against the original 'outside the box' mentality however we do know it would work and still look cool...
I have some decisions to make
Maybe remove the entire tacho drive assembly, and buy or machine an alloy blanking plug? This is definitely a cleaner option. But NOTE that you need to remove the clutch cover to do this, otherwise that small thrust washer will end up on its own, and creating problems!
Yep..removed the drive shaft and a slightly more robust o ring has halted the weep for now...although the shaft may go back in as I may fit a cable driven tacho as opposed to the electronic one I'm using...
I'll add it to the winter list
I'll add it to the winter list
Did you fish out the small thrust washer at the lower end of the tacho shaft/ worm screw? This is known to cause grief.....Yep..removed the drive shaft and a slightly more robust o ring has halted the weep for now...although the shaft may go back in as I may fit a cable driven tacho as opposed to the electronic one I'm using...
I'll add it to the winter list
Item #8 in the parts diagram:
https://www.cmsnl.com/yamaha-xs650-1977-usa_model8639/partslist/D-02.html
