Texas Two Step Taco

John Murray said:
I think you'd get away with that, though it'd be nice if the reluctor and pickup didn't force the wheel so far out.
An earlier version I used on my Metralla had the pickup mounted outside the case, sensing a notch in the periphery of the flywheel.

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I am a hack. We will see if this works. I just added the reluctor to the rotor on the inside. The rotor sits exactly where it was on the taper before. That reluctor was broken off another reluctor rotor and was sitting on a shelf all rusty. I probably need therapy also lol.

I have another idea but this rotor won’t allow it but the one to the left will. Having a convertible rotor that allows weight to be added or removed and able to change the moment of inertia. The other rotors have two steel plates riveted together to hold the cast aluminum in place.

Zeke was making new handle bars on the lathe and I put the rotor on the lathe and this is what happened lol. Glad to see he is experimenting with tool angles lol.



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Just a thought if I had to do it all over again I would not use the bultaco cylinder sleeve. It would be better to have a new cast cylinder sleeve to start with. I have never welded any steel except for stainless that melts like butter. This Spanish steel on this frame melts and flows like butter. I can only imagine what the cylinder does...no I don’t need to imagine after seeing what two runs did to the previous cylinder. The measurements I think prove this theory.

Also we need to get rid of the cylinder studs coming through the cylinder. These guys did that


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Here is what I am thinking for a remote starter. Let me know what y’all think. A ford push button solenoid and a yamayeehaw starter
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You have to remember that the starter won't have the benefit of the big gear reduction it normally has with the pinion/ring gear; it has to be able to turn the crankshaft directly. So you need a good sized starter with an internal gear reduction. The one I used was from a 4 cyl Toyota diesel, and even it will struggle a bit if the battery isn't fully charged. I use a little hand trolley to carry the battery, with a couple of hooks welded on in front of the handles. I coil the cables round the hooks then hang the starter on them. Nearly all starters will have a solenoid attached so you just need a small push button switch to actuate it.
 
There is still time to replace the cylinder sleeve, weld up the outer muff and port it for lots of extra transfer port area. All it takes is time and money. If a more or less stock Aprilia RS250 can make 60hp and our old RS125R Honda race bike made around 40 hp, a Bul should make 70hp with a just a little bit of radical work.

You could follow John's approach with either the water cooled top end or an RM 250 or similar top end (air cooled) with around 40hp out of the box with more to come. maybe try to build a billet top end with minimal fins, three pairs of transfer ports plus boost ports above the reed box.

Or drop a Yamaha twin motor in there for an easy 60HP plus.

Lots of ways to keep you occupied during this plague.

Note John's comments on starter reduction gearing. Most starters won't have the torque without gearing things down even if they have planetary gears. You could buy a starter clutch from Accu-products but still need a strong enough motor to kick it over.
 
teazer said:
There is still time to replace the cylinder sleeve, weld up the outer muff and port it for lots of extra transfer port area. All it takes is time and money. If a more or less stock Aprilia RS250 can make 60hp and our old RS125R Honda race bike made around 40 hp, a Bul should make 70hp with a just a little bit of radical work.

You could follow John's approach with either the water cooled top end or an RM 250 or similar top end (air cooled) with around 40hp out of the box with more to come. maybe try to build a billet top end with minimal fins, three pairs of transfer ports plus boost ports above the reed box.

Or drop a Yamaha twin motor in there for an easy 60HP plus.

Lots of ways to keep you occupied during this plague.

Note John's comments on starter reduction gearing. Most starters won't have the torque without gearing things down even if they have planetary gears. You could buy a starter clutch from Accu-products but still need a strong enough motor to kick it over.
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Agreed. Something to keep in mind - the Buls great strength was their very light weight, they don't need to make a million horsepower to be very quick. When my Metralla was on the road it's power was only in the 50's yet it was bloody quick and I spent a lot of time climbing over the handlebars. In hindsight, there was really no need for me to build the water cooled engine - the Pursang motor would have been able to set class records. And it probably will get a run on the salt at some stage. And there is something very cool about a pure Bul taking on the newer bikes.

It's interesting to compare the Bandido cylinder to the later Pursangs - they're very different. The pic is the barrel from my air cooled engine - much more transfer area. Having said that, Suzuki were able to make pretty good power from a single pair of transfers back in the day.

barrel.jpg
 
John Murray said:
Agreed. Something to keep in mind - the Buls great strength was their very light weight, they don't need to make a million horsepower to be very quick. When my Metralla was on the road it's power was only in the 50's yet it was bloody quick and I spent a lot of time climbing over the handlebars. In hindsight, there was really no need for me to build the water cooled engine - the Pursang motor would have been able to set class records. And it probably will get a run on the salt at some stage. And there is something very cool about a pure Bul taking on the newer bikes.

It's interesting to compare the Bandido cylinder to the later Pursangs - they're very different. The pic is the barrel from my air cooled engine - much more transfer area. Having said that, Suzuki were able to make pretty good power from a single pair of transfers back in the day.

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I bet you have twice as much transfer as the Bandido/Montadero however Ajs in spain has solved this problem for us! They have a cylinder that fits the Bandido engine with ports like yours! The TSS350 was derived from the Bandido platform. I have an idea this money burn I mean love affair will continue. If I steal my wife’s stimulus check I can get both the straight cut gears and cylinder!
 
Here's a little inspirational story for you Texasstar. In 1972 Benjamin Grau won the prestigious Barcelona 24 Hour endurance race at Montjuic Park. He rode an unfaired 360cc Bultaco using an engine based on the air cooled El Bandido. Not only did he win his class but took the outright honors, competing against much bigger factory bikes from Japanese and European makers, and setting a new record in the process. The little Bul was reputed to have a top speed of around 135mph.

The same bike was entered in the 1973 race, this time ridden by an amateur team. Again, the bike performed amazingly well, finishing a close second behind the works 860 Ducati and beating many other factory teams, including the third place
Egli-Honda.

The photo shows Grau sweeping the race-winning Bul around the outside of a 500 Suzuki.

grau.jpg
 
John Murray said:
Here's a little inspirational story for you Texasstar. In 1972 Benjamin Grau won the prestigious Barcelona 24 Hour endurance race at Montjuic Park. He rode an unfaired 360cc Bultaco using an engine based on the air cooled El Bandido. Not only did he win his class but took the outright honors, competing against much bigger factory bikes from Japanese and European makers, and setting a new record in the process. The little Bul was reputed to have a top speed of around 135mph.

The same bike was entered in the 1973 race, this time ridden by an amateur team. Again, the bike performed amazingly well, finishing a close second behind the works 860 Ducati and beating many other factory teams, including the third place
Egli-Honda.

The photo shows Grau sweeping the race-winning Bul around the outside of a 500 Suzuki.

View attachment 225077
Click to expand...
Thanks John! We are going to get there! To do a 24 hour with no seizures is very inspirational! I have Teazers, Kop’s, and soon your picture will be hanging in the shop as inspiration.
 
Did some weighing last night. We will be able to shave 24-28 total off the front and rear rotational mass with a tire and wheel change. The Montadero rear wheel weighs 20 lbs alone and the slick weighs 15 lbs. A cb175 rear tire and wheel weighs 21ish and will probably go cb175 hub front hub and a Sava Mc11 2.5” tire
 
Texasstar said:
Thanks John! We are going to get there! To do a 24 hour with no seizures is very inspirational! I have Teazers, Kop’s, and soon your picture will be hanging in the shop as inspiration.
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Seizures should and can be a non-issue and are easily avoided. I've had Bultacos for over 40 years now and in that time have had two seizures. One was just a light nip up of a Wiseco piston that I failed to break in for long enough. The other one was on the salt when flakes of paint partially blocked a main jet. Both avoidable, both due to stupid oversights.

You just need to:

Break in your pistons properly. Not a big deal for cast pistons, absolutely critical with forged

Warm up the engine before running it hard (and it takes time to do this too, a piston seizes because it got hotter than the cylinder.
Back in the day riders would warm up the water cooled TSS engines for 15 minutes or so before a race)

Ensure you have an adequate fuel supply

Ensure the engine is properly cooled (good airflow around it, and a head that actually has fins fer chrissakes)

No detonation or preignition (the big Buls need a very cold plug due to marginal head cooling. I like surface gap plugs but they need a very good ignition)

An appropriate tune - not too much advance in the midrange especially, not lean anywhere

Plenty of oil - for a race engine this means 20:1 castor. If the tune is right it'll barely smoke on this at WOT

Do these things and seizures will become something you don't even think about.
 
Teazer in a previous post you were right about certain hubs being boat anchors. The Montadero is 18 lbs.
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Have an aluminum 45 tooth sprocket coming for rear cb200 hub and wheel. Even with the slick that will shave 8 lbs off the rear rotational mass. The cb200 wheel with the Sava mc7 is 21 lbs.


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I bought a counterclockwise starter for my remote starter and it is not turning counter clockwise. So I looked up john’s hilux Toyota diesel starter and it is a clock wise rotation. So if you are building a remote bump starter for a bultaco in the future you will need a clockwise rotation starter in order to start the bultaco from the flywheel side. Lesson learned.


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It can be a bit confusing - starter direction is the direction it turns when looking from the pinion end. So if we want to spin the flywheel counter clockwise looking at the flywheel we need a clockwise starter. These are by far the most common type.
 
John Murray said:
It can be a bit confusing - starter direction is the direction it turns when looking from the pinion end. So if we want to spin the flywheel counter clockwise looking at the flywheel we need a clockwise starter. These are by far the most common type.
Click to expand...

It would of been easier if I just looked up the Hilux rotation in the first place! Lol


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