Texas Two Step Taco
- Thread starter Texasstar
- Start date
John Murray
Been Around the Block
It's the mounting platform for the Rotax cylinder. The transfer passages for it were actually just a tad smaller than those in the Pursang barrel and the rear transfer passage was carved into the pad and cases. I didn't want to weld on the cases any more than I had to so used a methanol resistant novolac epoxy to fill the transfer passages in the cases. Pic shows epoxy and passages roughed out.
John Murray
Been Around the Block
No. Yes. Maybe.
Normally an engine with A & B transfers would have the A ports crowded forward, closer to the exhaust, which of course would enable more options for sizing and aiming the B ports. As it is you'll have various limitations with added B ports. But I guess what it comes down to is will the additional transfer ports provide enough benefit to warrant the time and effort required to cut them. My gut feeling for what it's worth (ie. nothing) would be to leave it be for now, and just try to get it on the dyno within a reasonable timeframe. Once it's on the brake, broken in and tuned you'll have some good baseline data to guide you on the way to reaching your target. I'd be trying to avoid getting sidetracked til then.
Out of curiosity, what was the design rpm and power for the porting? There seems to be plenty of scope there for more blowdown and transfer width (the ring locating pins permitting) just looking at the photo.
Normally an engine with A & B transfers would have the A ports crowded forward, closer to the exhaust, which of course would enable more options for sizing and aiming the B ports. As it is you'll have various limitations with added B ports. But I guess what it comes down to is will the additional transfer ports provide enough benefit to warrant the time and effort required to cut them. My gut feeling for what it's worth (ie. nothing) would be to leave it be for now, and just try to get it on the dyno within a reasonable timeframe. Once it's on the brake, broken in and tuned you'll have some good baseline data to guide you on the way to reaching your target. I'd be trying to avoid getting sidetracked til then.
Out of curiosity, what was the design rpm and power for the porting? There seems to be plenty of scope there for more blowdown and transfer width (the ring locating pins permitting) just looking at the photo.
Texasstar
Can't is a four letter dirty word
We will leave it for now. It will be interesting to see the evolution just basted on additional transfers.
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Texasstar
Can't is a four letter dirty word
All new crank seals and orings we are ready for a pressure test.
Sent from my iPhone using TapatalkView attachment 225551
Sent from my iPhone using TapatalkView attachment 225551
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John Murray
Been Around the Block
I don't like Hylomar at all, though some people do. It doesn't set so it's easy to clean up but it doesn't seal so well. Permatex No 3 is the same - horrible messy bloody stuff. Any good silicone will be fine - I like the grey stuff cos it's a bit harder - generally the Permatex or Loctite brand but I think any quality brand will do. It's a pain to remove but that's just a side effect of an effective sealer.
Texasstar
Can't is a four letter dirty word
Thanks John! Yes and I can see the importance of a good sealant. Bultaco wasn’t real concerned about things not leaking IMHO.
Btw I didn’t have to press the old crank out it! It was soooo loose. Lifted it out. The new crank just took a tap with the lead hammer.
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Btw I didn’t have to press the old crank out it! It was soooo loose. Lifted it out. The new crank just took a tap with the lead hammer.
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John Murray
Been Around the Block
Do you have port dimensions for this barrel? They look small for 8500rpms but maybe it's just the camera making it look that way.
Texasstar
Can't is a four letter dirty word
50gary
Under the Limelight
How fast will a Bultaco 360CC go? "Are those tires speed rated by any chance?"
I would have used a bandsaw to cut 90% of that flywheel off, then finished it on the lathe.
Why does the orange drag bike have the leading axle forks seemingly turned backwards? I'm not familiar with Bultacos or why this would be done?
I like the idea of using the bike for multi-purpose events.
Cheers, 50gary
I would have used a bandsaw to cut 90% of that flywheel off, then finished it on the lathe.
Why does the orange drag bike have the leading axle forks seemingly turned backwards? I'm not familiar with Bultacos or why this would be done?
I like the idea of using the bike for multi-purpose events.
Cheers, 50gary
