brakes, clutch and exhaust

[bultoboy]

Hi guys

I have spent 2011, buying bits and pieces to finally build up a modified/competative bultaco and have been trying to find out what modifications work and dont work.

My questions are what are the best hubs to use for braking performance?

I have got steel linners in my 159 and they produce ok stopping power but nothing compared to some TYs, honda,fantics and certian pre 65 scotish winning bikes i know.

Has any one tried a different exhaust on there bikes?

the bultaco ones seem heavy take up a lot of room and get a lot of mus stuck between it and the rear tyre......i was think a yammaha ty pipe work may work better.

last of all..... the clutch. my clutch works fine on the 159 but i came across a bsa bamtam with a hydraulic clutch which was nothing but impressive and trust me the chap on it gave the mono boys a dam good run for there money just wondering if any one has tried it on a bultaco?

thanks

bulto boy

[pschrauber]

Brakepads:

As you already have steel lining,

NewFren still produces grooved brake pads for Bultaco, they are an improvement,

btw. as newer the pads as softer and better they grip, (the age of your pads

can be your problem, aslo do the have full contact with the linings in the

hub?

Newfren: NewFren Italy

I believe Bultaco UK has them too.

Exhaust:

No experience with other exhaust as the original one,

(beside a second custom modded Bultaco exhaust, end and mid section),

will get the engine more lively without gaining noise,

(not more noise is very important IMHO).

Clutch:

Never have tried a hydraulic rebuild of the clutch, is this contemporary?

Hans-Jörg Pfahler in Germany still offers a complete clutch rebuild where he

will modify the actuator and the clutchbasket, ... with different plates, ...

at the end you get a one finger clutch ...

Pfahler Bultaco

(no hydraulic components used)

Or ask Wayne Weedon from billetparts, he can also enhance the clutch actuator:

billetparts,

This is alraedy a big improve over the standard set up, in my experience.

To rework the complete clutch, add hydraulic actuating,... (belongs to the owner so it's up to you).

I have a second sidecase with the modificated clutch actuator,

so if I want too, I can always switch back to the original set-up,

(therefore had no need for the Pfahler modification, (my personal view)).

Edited January 3, 2012 by PSchrauber

[woody]

You're on the path to wasting a lot of money for no real gain with some of those ideas.

Clutch

Mine is light enough to use with one finger and will take 3rd and 4th gear launches with no slipping. The actuator is standard, just a longer arm (about 20mm max I think in order to keep the cable line straight and not kinked) Position the arm so that it is pulling straight, don't have it positioned too rearwards so that it is pulling 'around' the pivot. Use a new low friction featherlight Venhill cable.

I use Barnett kevlar friction plates. They are thicker than the original steel plates so to fit them in the basket you have to replace one with a steel friction plate (or at least I did in mine)

If your clutch has the nuts to tension the springs you can back off the tension. The kevlar plates have more bite so less tension is needed. However, if you back of the tension by unscrewing the nuts they will foul the inside of the casing (and make a mess, believe me) The nuts are quite thick so if you turn them down to half their thickness you can then back off the tension without fouling the case. How much is trial and error. This does mean there are no longer holes to take the locking wire so you will have to redrill if you want to lock them. I don't and have never had a problem.

If you have an earlier clutch with the pins there is little you can do with tension. It's possible to fit the other clutch by modifiying it I think, as they aren't a direct swap, but I've never tried it. Or you could try threading the pins. Or remove the pins and replace with threaded pins (I think they are welded in from the back of the hub)

Finally, get the clutch set up by diconnetcting the cable, screw in the central adjuster until it meets the pushrod (you'll see the arm move) and back of a little so there is play in the arm. Refit the cable and then adjust the tension of each spring to ensure the plates seperate evenly. Make sure all the pins are straight and centred in the cups before fitting the springs - they'll bend with leverage from a screwdriver to centre them. That will ensure the springs run free and don't bind against the cups. Make sure you take out the actuator from the timing cover and clean it and its housing and grease it before replacing.

Hydraulics really aren't necessary

Brakes

A lot of the classic boys use Saftek linigs. Send them your shoes, they will fit a softer compound lining, oversize. You then get them turned down to match your hub and presto, good brakes. If you can do the machining, or get it done, then it is worth skimming the inside of the hub to true it before turning down the shoes to match (assuming they aren't fitted with new liners)

The Bultaco hubs with liners work fine with this arrangement.

http://www.saftek.co.uk/index.htm

Or fit a Grimeca front wheel. I have on in mine and it just needs the brake plate sleeved for the smaller spindle. I can't remember if I sleeved the bearings as well or found some that will fit the hub and the 12mm spindle (Grimeca takes a 14mm spindle)

For the rear brake, if you don't mind the left hand brake pedal, a rod gives a better feel. If you use the right hand pedal you will need the cable and these will work perfectly well (as I've ridden a couple of Puma Bultacos with them) but I haven't worked out how yet. You can fit a TY or 247 Cota rear wheel as they have the brake and sprocket on opposite sides which will enable a rod operated rear right hand brake

Exhaust

Keep the standard item. (assuming it is the later clubfoot type) Repack the middle silencer. The rear, open up the rear box section, remove the baffle plates and replace with straight through perforated tube and packing. Also cut open and repack the lower section below the shock as that is also perforated tube and packing. It will rev more freely with the baffles out.

Motor

If you want it to pick up a little quicker, replace the 350 ignition flywheel with a 250 item which is nearly a kilo lighter. If you really want it quick, replace the double weighted clutch crank weight with a single weight from a 250 as well. It will pick up like hell but stall a lot easier too. Probably a little excessive doing both weights...