brake master cylinder recomendations?

[mavis cruet]

the throttle action is decidedly ropey on my sexton project and i am thinking of replacing the whole brake/ throttle assembly. when it comes to choosing a new master cylinder, am i best sticking to a similar diameter or will something from a bike with twin front discs be an improvement? or make it worse? i am thinking of using something from an old xt tenere (ivj) or ktm adventure.
im also wanting to replace the throttle assembly, has anyone had success with anything else? (ive got one throttle cable going to a splitter.)

any thoughts appreciated....

 

[Picon biere]

the throttle action is decidedly ropey on my sexton project and i am thinking of replacing the whole brake/ throttle assembly. when it comes to choosing a new master cylinder, am i best sticking to a similar diameter or will something from a bike with twin front discs be an improvement? or make it worse? i am thinking of using something from an old xt tenere (ivj) or ktm adventure.
im also wanting to replace the throttle assembly, has anyone had success with anything else? (ive got one throttle cable going to a splitter.)

any thoughts appreciated....

Do not quote me on this but if I remember correctly the internal diameter of the master cylinder (handel bar end ) is matched to the slave cylinder on the front fork. If you go six pot calliper for example then the master cylinder diameter changes (more fluid to move). If you have an R80/100GS then a modified calliper from a K100 with some machining to make it fit was a good way to go without changing the master cylinder. Bit fiddly but is a definate improvement over the original

 

[Canuck]

If you have an R80/100GS then a modified calliper from a K100 with some machining

Machine 0.158 inches off the tabs of the caliper! Also fits r80 ST forks but not the g/s.

 

[mavis cruet]

at the moment it is a standard bmw 13mm cylinder, mated to a brembo 4 pot from something unknown (which you cant get parts for im told) bolted to a set of wp upside downies. im just trying to work out how to work out what else i can use, but not sure where to start.... cheers anyways.

 

[litelfun]

at the moment it is a standard bmw 13mm cylinder, mated to a brembo 4 pot from something unknown (which you cant get parts for im told) bolted to a set of wp upside downies. im just trying to work out how to work out what else i can use, but not sure where to start.... cheers anyways.

ok the cheepest way to upgrade is to swap the master cylinder from a r100r or r100rt on earlyer bickes but you need to check the year as the changed the bodys on them around 1989 you just need to swap the piston hausing from underneith saving you a lot of work

 

[litelfun]

ok the cheepest way to upgrade is to swap the master cylinder from a r100r or r100rt on earlyer bickes but you need to check the year as the changed the bodys on them around 1989 you just need to swap the piston hausing from underneith saving you a lot of work

15 or 16mm work the best wth a 4 pot singel disc

 

[(RIP) Arkwright]

YOU DO NOT WANT A 15 or16mm MASTER CYLINDER WITH A 4 POT CALIPER.

It will be absolutely wooden for feel, the bigger it is the worse it is, with a single 4 pot caliper you need a 14mm Master Cylinder. (DAMHIK)

 

[litelfun]

YOU DO NOT WANT A 15 or16mm MASTER CYLINDER WITH A 4 POT CALIPER.

It will be absolutely wooden for feel, the bigger it is the worse it is, with a single 4 pot caliper you need a 14mm Master Cylinder. (DAMHIK)

well I have been doing some thing wrong then for the past 20 years
been racing supermotos for 13 years and thats all they use
ok on a GS r100 with the smaller disc its not quite a the stopping what you would expecht from a 320mm disc so all the more reason to use a stronger pump when I put a brembo 4 pot on my hp2 it wouldent cope the standard 13mm cyclinder my brackes used to faile I have a hp2 and a r100gs both working on a 16mm with a brembo p4 and allso one with 13mm pump witch you have to pull the lever back till it touches the bar to stop just waiting till one on ebay comes allong at the wright price and then it be a 15 or 16mm I have allso run bickes with 6 and 8 pot calipers from PVM and phonix but the brembo p4 is as god as any depending on the wieght of your bicke of course if your doing a lot of of road work the kraper your brackes the better

 

[Picon biere]

at the moment it is a standard bmw 13mm cylinder, mated to a brembo 4 pot from something unknown (which you cant get parts for im told) bolted to a set of wp upside downies. im just trying to work out how to work out what else i can use, but not sure where to start.... cheers anyways.

If I understand you correctly you are using a set of 4850 front forks from a KTM/Husaberg? If so I may be able to help. I've got in my garage a KTM/Husaberg calliper , stainless steel line and matching slave cylinder and bar clamp. I'm not sure if its 4 or 6 pot and I don't know the rotor size. I bought it for a project that didn't happen. However I'm on holiday for another week and can't check things till I get home. If you are still on the lookout let me know. Failing that I have a very nice front end of an Aprillia motocrosser. Marrzocchi usd forks,front wheel, tyre, spindle, wavy disk, calliper, slave cylinder and triple trees. A work of art (another shelved project)

 

[Canuck]

If it remains unwanted and it fits a 4860 front fork ill take that brake setup off your hands! Hoping to fit a 310 rotor such as found on a ktm 690 enduro

 

[Picon biere]

Calliper

If it remains unwanted and it fits a 4860 front fork ill take that brake setup off your hands! Hoping to fit a 310 rotor such as found on a ktm 690 enduro

Ive just been and checked the calliper. It fits a 4860 fork leg but will only take a 260 rotor unless you have the extension bracket. Its a 2 pot Brembo with speed sensor and the slave cylinder is a Husaberg.