Front brake master cylinder question

[twistedgrip]

Hey y'all, I am a new member on here and joined primarily to ask some questions. I own a shop where we service major brands of motorcycles. Recently I have had 4 or 5 BDM in the shop for regular services but have one that is kicking my rear. I have a BDM that has a bad front brake master cylinder. I have not been able to locate an exact replacement so I decided to go with a set of HD controls (with the customers approval) but they won't fit the bars. I then thought I would change the bars but the more I think about it, I'm not sure that will work either since BDM uses the micro switches. SO … the question is, can I use the new bars, HD switches with the BDM wiring harness? Does anyone have or can direct me to a wiring schematic? NO, I don't have a service manual on this bike since I work on so many different bikes and I can't afford a service manual for ALL of them. (I'm a cheap arse too) The bike I'm working on is a 2004 model with a 117 ci S&S with a 6 speed tranny. Any help would be appreciated. :bang:

 

[Brew]

Why not buy the master cylinder rebuild kit or do you mean it's physically damaged on the outside?

If just a rebuild kit is needed you can order one here:

http://deadonecustoms.com/b_dm_chassis_and_suspension_accessories.html

 

[BadDawg Bill]

You can't use the Harley switches with the stock system or a wire-plus replacement set up. I just got the wire-plus and wanted to put on a new set of bars and Harley controls and switches but it won't work.

You may be able to grind a 1/4 inch out of the Harley master brake set up to fit the BD bars or just go on Ebay and see if you can find a rebuild kit. Or do the guy a BIG favor and rewire the whole bike with Harley wires and controls. It will save him $$ in the end.

 

[twistedgrip]

The cylinder is scored on the inside and the brakes stick when you apply them. I have read that the cylinder can't be honed due to it being work hardened (ball hardened). I tried polishing it but it still sticks bad. I have spent several hours trying to find a new master cylinder but have not been able to locate one any where. I spoke with the customer and he told me to do whatever needed to be done to correct the issue. I thought about just replacing the controls which means replacing both sides so they will match but the holes in the bars are on the top of the bars rather than the bottom PLUS the bars are physically too large for the stock HD controls. I can drill another hole but fear that would weaken the bars right at the grips/switch housings so really don't think that is an option. I could replace the bars to work with the controls but then I get into the electronics on the BDM. I am open to suggestions and/or possible solutions. Does anyone know where I could get a new master cylinder?? Thanks, Twistedgrip

 

[twistedgrip]

I really don't wish to get into a complete rewire just for a new master cylinder, but it isn't looking good.

 

[Brew]

Have you asked bigdogpartsking? They're vendors that bought out most of the bigdog parts when the company and parts store when under. You might want to call or PM them and see if they have one in stock. Here's their number: 620-257-2009.

 

[BadDawg Bill]

I really don't wish to get into a complete rewire just for a new master cylinder, but it isn't looking good.

Sooner or later they will re-wire the whole bike. It's just a matter of time. Maybe like me they will spend $1,000 on a wire-plus kit to find out it won't work with Harley controls and then spend another $1,200 doing a Harley set up. Either way the custom parts BD used are getting harder and harder to find and more expensive. Hell, $600 for a sissy bar? $250 for a set of foot pegs? $350 - $450 for an ECH? $200 for a Thunderheart ign?

You would have to be insane to spend that kind of money. Spend the $1,200 and make it easy to replace parts and more reliable. There is a company out there selling 1 1/4 inch controls but that's just a band aid for what's to come.

 

[JeffM]

I had a similar issue with the front brake master cylinder years ago on a mates Moto Guzzi.
We used a "speedy sleeve", they are Stainless steel and are (were) available in thousands of sizes. Took a fare amount of time to get the correct fit up and then it is a matter of aligning the sleeve, applying locktite, tapping into position.
You then use the original repair kit. Still working to this day as he now races it in Vintage road races.
Good luck.

 

[pauly]

I had a similar issue with the front brake master cylinder years ago on a mates Moto Guzzi.
We used a "speedy sleeve", they are Stainless steel and are (were) available in thousands of sizes. Took a fare amount of time to get the correct fit up and then it is a matter of aligning the sleeve, applying locktite, tapping into position.
You then use the original repair kit. Still working to this day as he now races it in Vintage road races.
Good luck.

Exactly what I had done on obsolete cylinders.
Check that there is Dot 5 fluid in there as others might cause the stickiness
even if the whole system has been washed properly. (certain rubbers do not like Dot 4)

Paul

 

[Rickey Quinn]

Go to ebay an look under Big Dog parts. If you don't mind paying the price you can buy new master cylinder for the bike you are working on.

 

[Rottweiler]

Go to ebay an look under Big Dog parts. If you don't mind paying the price you can buy new master cylinder for the bike you are working on.

I think he has it fixed by now.