Texas Two Step Taco

teazer

Well-Known Member
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I see that Rick M is still selling those one way clutch sockets. The drive nut in that example happens to be the same thread as the extractor/puller, so that it threads into the ignition rotor. I had qa starter nut on an ex kart TZ motor that fitted over the crank nut and sat in teh rotor recess and was located with 2 off 6mm socket head screws. that's enough to start a simple little two stroke.

That top end is starting to look really sexy. And is that Bill B firing up the H2?
 

Texasstar

Can't is a four letter dirty word
I see that Rick M is still selling those one way clutch sockets. The drive nut in that example happens to be the same thread as the extractor/puller, so that it threads into the ignition rotor. I had qa starter nut on an ex kart TZ motor that fitted over the crank nut and sat in teh rotor recess and was located with 2 off 6mm socket head screws. that's enough to start a simple little two stroke.

That top end is starting to look really sexy. And is that Bill B firing up the H2?
Why thank you! Bandera loves compliments!


Mr B is working on his mule. It only has 1 cylinder. His 280cc mule can whoop my 360cc taco. He has wires all over the place like Einstein’s hair and is figuring out a new data collection system. Have you seen this https://www.cycledrag.com/author/bill-baxter? Take a look at Ralf’s cylinders and heads.

So there are a bunch of Femsa rotors out there that are worthless and make nice paper weights. The Femsa also has right hand threads for the rotor pulling tool like the TZ it just needs to be threaded in the opposite direction or tack welded for that to work and then a new nut like the taco head nuts needs to be machined to hold the rotor in place
IMG_5119.jpg
. So the goal is to make a beautiful functioning part from one of the Taco rotors. Zeke and I watch a lot of This Old Tony so I have been working on my machining skills. I prefer MNC to CNC. Picture of the new proposed nut below.


Zeke is currently making a dash for his Ducati in Fusion 360 and I showed him Ralf’s prototype and he said, “he just did this and this and this.” Lol I called him Ralf Jr. Let’s hope so...

Have also been doing a little programming for the Zeeltronic
IMG_5015.jpg



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teazer

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DTT BOTM WINNER
That's a pretty flat timing curve......

I'd start at 19 degrees and add more at lower revs where it's off the pipe up to almost 30 degrees and past peak drop it back fairly fast - just as a place to start testing. Too little advance is always safer than too much - within reason.

Ralph's work is amazing though.

On Yamaha twins, Mototplat and Hitachi rotors both had a large hex cast in, but Femsa didn't.
 
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teazer

Well-Known Member
DTT BOTM WINNER
BTW, Radical Ducati out of Madrid made some amazing cafe racers out of that SS Ducati base without a lot of heavy duty modification. Even the tank can stay.On the ST and Monster they have to use 999 tanks and that requires more cutting and welding to make them work. And that motor is prettier than an ST3.
 

Texasstar

Can't is a four letter dirty word
That's a pretty flat timing curve......

I'd start at 19 degrees and add more at lower revs where it's off the pipe up to almost 30 degrees and past peak drop it back fairly fast - just as a place to start testing. Too little advance is always safer than too much - within reason.

Ralph's work is amazing though.

On Yamaha twins, Mototplat and Hitachi rotors both had a large hex cast in, but Femsa didn't.
Thank you. Just got off the phone with micro blue Craig. If we micro blue the cylinder and piston we will need to retard the timing even more according to a Craig. I did return all the standard bearings today and ordered the micro blue https://www.microbluebearings.com/ I am going to wait to micro blue the cylinder until we dyno this configuration and get a baseline. He claims significant gains with micro bluing the cylinder and piston. We will see. Well if we beat Zeke I can say I did it with my small transfers and micro blues.


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teazer

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DTT BOTM WINNER
Nice video but peak power at 6500 may have been because that's where the pipe resonated or what the exhaust timing or area or other ports restricted it to. Ask BB what exhaust duration that pipe was designed to work with and from there you can work out whether the pipe or exhaust duration is the issue and if they match the restriction is elsewhere.

If you plug your numbers into teh GW basic version of Bimotion's port-time area target app it will quickly show you which ports are the issue. Or use their graphic port and pipe tools which will show you the target T-A for transfers at a given RPM and output target. The tools are there. Then use MOTA for the simulations.

If you want a hand PM me off line.

On those bearings, they are basically claiming such a significant reduction in friction that you need to retard ignition lead because the pressure rise after ignition would be such that it will get to peak pressure before it would with average old bearings. That sounds bogus.

The largest source of friction loss is between the piston and bore. The largest pumping loss is compressing gas, so the difference in friction may be measurable, the overall effect is likely to be small to immeasurable. Dyno is the only way to get timing right and BB can lead you in that direction. He knows what he's doing there.
 

Texasstar

Can't is a four letter dirty word
“On those bearings, they are basically claiming such a significant reduction in friction that you need to retard ignition lead because the pressure rise after ignition would be such that it will get to peak pressure before it would with average old bearings. That sounds bogus.

The largest source of friction loss is between the piston and bore. The largest pumping loss is compressing gas, so the difference in friction may be measurable, the overall effect is likely to be small to immeasurable. Dyno is the only way to get timing right and BB can lead you in that direction. He knows what he's doing there.”



Sorry I didn’t make that clear. Craig didn’t say we needed to retard the timing for installing the bearings he did say we would need to if we micro blued the cylinders and piston. That is where he said we would see significant gains. I am waiting to do that until after we get everything dialed in and dyno’d with the rebuild first. Then we can see if his claims are true.


Will pm you for help understanding but more importantly knowing. What I found interesting is that Doug’s exhaust port timing came back identical to the Bandido timing. I really want to know why. Will gather the information and get back with you!


Have you taking your drag bike for a spin yet?




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Texasstar

Can't is a four letter dirty word
Nice video but peak power at 6500 may have been because that's where the pipe resonated or what the exhaust timing or area or other ports restricted it to. Ask BB what exhaust duration that pipe was designed to work with and from there you can work out whether the pipe or exhaust duration is the issue and if they match the restriction is elsewhere.

If you plug your numbers into teh GW basic version of Bimotion's port-time area target app it will quickly show you which ports are the issue. Or use their graphic port and pipe tools which will show you the target T-A for transfers at a given RPM and output target. The tools are there. Then use MOTA for the simulations.

If you want a hand PM me off line.

On those bearings, they are basically claiming such a significant reduction in friction that you need to retard ignition lead because the pressure rise after ignition would be such that it will get to peak pressure before it would with average old bearings. That sounds bogus.

The largest source of friction loss is between the piston and bore. The largest pumping loss is compressing gas, so the difference in friction may be measurable, the overall effect is likely to be small to immeasurable. Dyno is the only way to get timing right and BB can lead you in that direction. He knows what he's doing there.
The Magee pipe was designed for 203 on the exhaust duration on our dyno run for the Stock Bultaco M51 was 185.


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teazer

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DTT BOTM WINNER
203 is 3 more than a TZ and 185 is quite modest but that's what keeps the revs constrained. I suspect that the exhaust pulses are way out of time with that pipe. But was the pipe just a loaner from BB or is that the one you intend to run on the bike?
 

Texasstar

Can't is a four letter dirty word
203 is 3 more than a TZ and 185 is quite modest but that's what keeps the revs constrained. I suspect that the exhaust pulses are way out of time with that pipe. But was the pipe just a loaner from BB or is that the one you intend to run on the bike?
We we just messing around and put the Magee pipe.


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Texasstar

Can't is a four letter dirty word
“That sounds Bogus.”


I have been doing my due diligence on micro blue and I can’t find any empirical evidence for its longevity or performance gains. It maybe snake oil. I am disappointed in myself.

However, I have a problem that I was hoping to solve with microblue. We have 3 expensive hedge trimmers that are seized because our guys run them WOT. This year we changed from 50:1 and run smokeless oil at 40:1. That is not the direction I wanted to go in the land of Greta. It is only the hedge trimmers we are having this problem with. Weed eaters and blowers don’t have this problem. I can’t get my guys to not run them WOT. It is like telling a racer to slow down. They are so fast that buying a new hedge trimmer is worth it at the end of the season rather than trying to slow them down. Part of it is they are holding the hedge trimmer upside down. I found one video that said the OEM’s were having a similar problem with the cars that come to a stop and restart at a light and were using Micro blue. It is a coating and not a plating. I grew up in the land of charlatan snake oil salesman on Sunday mornings and feel a little disappointed in myself.


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teazer

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DTT BOTM WINNER
JT is the real deal. The rest of us are just kids playing in the sandbox. Doesn't mean we aren't having fun though.
 

Texasstar

Can't is a four letter dirty word
JT is the real deal. The rest of us are just kids playing in the sandbox. Doesn't mean we aren't having fun though.
Such a gentleman! I don’t think I knew the difference between a 2 and 4 stroke when this was written.


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Texasstar

Can't is a four letter dirty word
On measuring the exhaust port diameter won’t a port map give you the chordal port diameter by measuring it flat on a table?


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Texasstar

Can't is a four letter dirty word
Has anybody used this 2 stroke exhaust calculator? http://birdcagesoft.com/ It is by AUMechanic on Youtube

Currently watching it to measure my exhaust ports. Curious to see how this calculator compares to other software that is out there.


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