NC35 Master Cylinder Upgrade

[SPOONDIDDLY]

G'day all,

As the title suggests, I am considering upgrading the master cylinder on my NC35 race bike, and wanted to hear about your experiences and which master cylinders are a direct fit for the NC35 with the least amount of mucking around.
Are there any master cylinders off more modern bikes that offer a cost effective alternative to the top-end Brembo units?
Are there any particular master cylinders that are better suited to the NC35 than others?

Towards the end of a session I begin to experience a bit of fade and feel that I could be running out of brakes, which starts to affect confidence when approaching high speed corners. I also really like the feel of the brakes on my mates cbr600rr & RSV4 which have a much shorter throw and great initial bite.

I have done a search and most threads end with people recommending to do other brake related maintenance/upgrades before touching the master cylinder, so here is everything that I have done to my braking system prior to considering this upgrade:
- Rebuilt stock master cylinder
- Rebuilt front calipers
- High quality rotors
- Braided lines
- High temp fluid (replaced every 2-3 track days)
- Goldfren sintered pads
- Zip-Tie brake trick performed before every track day

[magg]

"Fade", longer lever travel or less stopping power?

[SPOONDIDDLY]

Longer lever travel to maintain the same level of stopping power

[CMSMJ1]

I've the larger Nissin calipers from a CBR600 FX on my NC30 - they are excellent and paired with a 929 blade master cylinder. nissin HH pads adn I'm good to go.

if you are ziptieing (s) to the bars, then is there a leak or air in system - this would give your fade?

I;ve never found goldfren pads to be any good - nissins, bremobo pads or the SBS semi race have all been superb.

[magg]

The phrasing of my question may have been poor, by longer travel I was referring to distance before take up of free play, stopping power the amount of pressure applied after free play take up.

If take up distance remains constant but you need to apply more pressure, which could appear as a small increase in lever movement, I would consider that the pad material does not offer sufficient resistance to heat build up. What is the basis of pad selection, have you tried different pads materials?

Increasing noticeable lever travel before take up, after repeated application, suggests fluid and/or structural changes as a result of heat soak. If this is the case , changes to various parts of the brake system may be needed.

Hope my deliberations are of assistance.

[SPOONDIDDLY]

Yeah there could potentially be air or a leak in the system, but I feel that the leak is likely coming from the master cylinder as there has never been an issue with any fluid leak, even at lower points in the system.

Either way if I replace the master cylinder I will probably rebuild the rest of the system too.

I have experimented with some other pads but they didn't perform as well as the Goldfren, however there are still plenty of other brands to try.

The problem is that there is still a fair amount of lever travel when the bike is at a standstill and there is no heat in the system, even after doing the zip tie trick when compared to other more modern bikes, so i'm hoping that going with a new master cylinder might alleviate this?
After performing the zip tie trick I can feel that there is no air in the system as there is no compression and the system feels firm, yet the lever travel is longer than I would like.

I assume that this is by design?

[magg]

OEM levers are adjustable. Are you saying that the adjustment range is insufficient to reduce the free play to an acceptable amount.

[gavins]

Something to consider - a friend had a similar issue and it actually turned out to be a very small hole in one of the copper crush washers.

[SPOONDIDDLY]

OEM levers are adjustable. Are you saying that the adjustment range is insufficient to reduce the free play to an acceptable amount.

I'm running aftermarket adjustable levers, and I have them adjusted correctly to minimise free play.

The problem isn't that there is free play, the problem is that the travel is long and feels as if the piston in the master cylinder isn't moving enough fluid to the calliper for each mm of travel compared to more modern bikes that I have ridden. The initial application of force to the disc rotor occur immediately, however the level of force is less than I would like.

When the bike and braking system is cold and you spin the wheel on the stand or are riding at low speed the stopping force is applied within 1/3 of the lever travel, however once the bike has some momentum I need to pull the lever significantly further. This isn't a major issue early in the session as it gives me plenty of room to modulate the brakes as I see fit without overdoing it.

It's not until later in the session that it becomes an issue, as I feel like I'm running out of lever travel to apply and slow down accordingly!
Having said that, I've never run out of brakes on the track, however I feel that I am adjusting my riding rather than finding the limit.

Ultimately I want to achieve similar braking performance and firm feeling to that of a modern sport bike on the track.

[SPOONDIDDLY]

Something to consider - a friend had a similar issue and it actually turned out to be a very small hole in one of the copper crush washers.

Yeah could definitely be that. did they have any weeping of fluid from the washers?