Victoria! Zeke's CB175 Build

[xb33bsa]

looks like it has CURNUTTS ;D

 

[Texasstar]

http://www.ridermagazine.com/road-tests/retrospective-bultaco-montadero-360-1968-1972.htm/



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[Texasstar]

nope not that one, its a plonker proly wont rev much past 5k,the factory tune is going to be very much like a sherpa t trials bike than a racer and it will be very smooth,slow revving and there wont be any bite to it its going to be a great machine to ride the hill country if you are going to play tuner/speed racer with 2 strokes, leave this one be,find something else, you can't do it it with this one is too far away, besides it is quite valuable ,the bandido is the most sought after AND RARE dirtbike type bultaco in the lineup

I just want to thank you Xb33bsa!!!


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[Texasstar]

Heavier flywheel makes it rev 'slower' but it should still be a lot quicker building rpm than either four-stroke bike.
Just be careful, no reed valves means it may 'bite you'

Crazypj I want to thank you for "watching out" for my son! Even with the heavy flywheel it has 3x the torque of any bike Zeke has been on. His other 2 stroke he has driven through the neighbors fence and has helicoptered off after hitting the lawn mower showing off for the neighbor girls..


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[teazer]

Thanks for the Hartzell links. I'll pass those along.

BTW that IS the dyno that I first ran my CB72 race bike on back in 1980 or so. Dynojet 250 is much easier and faster to use but I'd really like a Factory Pro eddy current.

All we need to do now is to work out how to convert a CB motor to that sort of cam chain management. Compare those to a long floppy chain with a rubber wheel pressing on it and it's easy to see the room for improvement.

 

[crazypj]

Having some way to increase tension towards top end of rpm and a better quality tensioner wheel will be just as effective and maybe lower rolling resistance?
The reason for feeding high pressure oil into back of tensioner is to increase chain tension and prevent chain 'flutter' less tension is needed at low rpm, idle, etc
A full length slipper tensioner must have a relatively high 'drag' or manufacturers wouldn't go to the trouble of fitting hydraulic assist
Just read review on Bultaco, 32~33 bhp isn't too shabby for the age of bike, will be 'quite interesting' to ride

 

[teazer]

A wheel will always allow the unsupported chain to wave in the wind. Our race bikes with nice tight new chains still deflect massively and chew up barrels. The chain sort of continues to follow the sprocket at high revs and that generates waves in the chain and on and off the throttle cycles tension forces from front run to rear run and that exacerbates the problem.

 

[Texasstar]

Static compression is EITHER the same as Geometric OR the same as what Matt refers to as Dynamic. It all comes down to definitions.

Dynamic aka effective CR is really the actual CR which does change with rpm based on VE.

In the 2 stroke world they use either Geometric or ... some other term that I don't recall. Duh. So Geometric is from BDC so it uses full swept volume. "Calculated" CR is from the point at which the exhaust port closes. There are people around that will tell you to ignore one and only use the other and they are all full of BS. They are just numbers and both ignore the effect of harmonics in the ducts which is what really makes a huge difference.

Same in a 4 smoke. CR is usually measured as full swept volume because measuring from port closing doesn't add anything to the knowledge of what the effective CR really is at any particular RPM.

In theory there are two possible waves that boost effective CR. First is in the intake duct where we want a positive (stuffing) wave to arrive just before teh intake closes. On the exhaust side we also want a positive wave to arrive just before that valve closes. In the real world, a slightly constipated exhaust port/pipe will have almost as mush (or more) effect on CR as exhaust pressure waves.

In the real world none of that matters. Well it all does, but what we want to measure is cylinder pressure after you light the fire. The rest is all nice in theory, but largely irrelevant. So an effective combustion chamber with good fuel atomization and well placed spark plug and low CR will probably generate higher peak cylinder pressures than a great breathing motor with high CR (calculate however you want) with poor combustion.

We used to use a DOS based programs called ENgine Expert from Alan Lockheed and associates. The latest versions can predict power output much better than getting lost in a morass of theoretical calculations that don't help a whole lot.

Yes, in general a later closing valve will tend to reduce effective compression particularly at lower revs, but you already know that. Calculating it doesn't help much in predicting power output.

Just for giggles though, you could calculate the CR from valve closing for a range of valve closing points and plot them on a simple 2D chart to see the basics. Start at stock vlave timing and move in say 5 degree changes up to the raciest cam around just to see what that looks like. It won't predict power at the rear wheel but will show a trend in CR that will have SOME correlation to real world results at low revs.

It won't show any duct harmonics or wave activity but will explain one variable in isolation and will provide some insight into why shifting cam timing has an impact on the shape of the power curve.

i just found a good example of your explanation "So an effective combustion chamber with good fuel atomization and well placed spark plug and low CR will probably generate higher peak cylinder pressures than a great breathing motor with high CR (calculate however you want) with poor combustion." Honda puts a pocket in the piston for the fuel, relocates the injector, and closes one intake valve to create a swirl for better fuel atomization to take advantage of an ultra lean 65:1 fuel mixture from Honda http://world.honda.com/news/2003/4031127/video/index.html


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[Texasstar]

Which totally explains why you teased us in the direction of the piston that was "on my (your) bench"


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[Texasstar]

we hope you will take our new web site for www.zoomwithzeke.com for a test ride and give us your feedback. Thank you for everything!

 

[Trevor May]

Has anyone tried to hire you guys yet?

 

[Texasstar]

Has anyone tried to hire you guys yet?

Mom puts us to work on a regular basis. Zeke fixes the neighborhood carbs for free...don't know if that counts. We hope to inspire others to get out there and wrench together find their passion, follow their dreams. We do have two motorcycles 4 sale to fund our Bultaco projects.


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[Texasstar]

Has anyone tried to hire you guys yet?

Dutch do we need to change the title? I am trying to think what your comment means. We are not promoting a business but we are trying to pay forward what we have been given...the gospel of go. We also want to consolidate our story into a more concise format for those who have short attention spans. Maybe the heading needs to be Zeke and Patrick DeZeeuw build vintage motorcycles for Fun??? On the mobile phone format the navigation can be overlooked. In our blog we are going to share things we learned what NOT to do. We also wanted a public place to promote and thank our Sponsors. Your feedback is appreciated.


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[simo]

Hi Patrick
Only thing I can suggest is having a VERY clear picture of who your target audience is . If you think of sites like DTT or Hondatwins the name sums up the content and what you'll find inside, and though you're not necessarily building your site as a forum the principle holds true. Understanding your audience allows you to modify your content delivery to suit. That's why I don't do facebook, twitters, et al since I'm not really interested in fast content over good content (I'm not the target audience) so the sites hold no appeal

 

[Trevor May]

Dutch do we need to change the title? I am trying to think what your comment means. We are not promoting a business but we are trying to pay forward what we have been given...the gospel of go. We also want to consolidate our story into a more concise format for those who have short attention spans. Maybe the heading needs to be Zeke and Patrick DeZeeuw build vintage motorcycles for Fun??? On the mobile phone format the navigation can be overlooked. In our blog we are going to share things we learned what NOT to do. We also wanted a public place to promote and thank our Sponsors. Your feedback is appreciated.


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I'm famous for not explaining things very well. I also only meant, as an idle curiosity, whether or not people have seen your bike and when you refuse to sell, try to hire you to build one just like it. Lots of people have money, but lots of people don't have those skills.

Right now, I could freeze a glass of water in my garage in an hour, and those temperatures are not likely to change until April. I'm jealous of people who can work 12 months out of the year outside. Right now, I would like to do some paint work, and some fiberglass work, neither of which are going to happen until it's warmer. Even touching cold steel parts is daunting. I live vicariously through these pages for bike related activities until spring.

 

[Texasstar]

I'm famous for not explaining things very well. I also only meant, as an idle curiosity, whether or not people have seen your bike and when you refuse to sell, try to hire you to build one just like it. Lots of people have money, but lots of people don't have those skills.

Right now, I could freeze a glass of water in my garage in an hour, and those temperatures are not likely to change until April. I'm jealous of people who can work 12 months out of the year outside. Right now, I would like to do some paint work, and some fiberglass work, neither of which are going to happen until it's warmer. Even touching cold steel parts is daunting. I live vicariously through these pages for bike related activities until spring.

Well move on down to TEXAS! I won't tell you that we have been riding way more than we have been wrenching then...We have a bad case of M.A.S. (Motorcycle Acquisition Syndrome) Mom has been asking us the same question...are you ever going to bring money in than keep sending it out? We promised mom we would sell the Bultacos but when Zeke got his home he said, "I am keeping mine lol"


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[Texasstar]

Hi Patrick
Only thing I can suggest is having a VERY clear picture of who your target audience is . If you think of sites like DTT or Hondatwins the name sums up the content and what you'll find inside, and though you're not necessarily building your site as a forum the principle holds true. Understanding your audience allows you to modify your content delivery to suit. That's why I don't do facebook, twitters, et al since I'm not really interested in fast content over good content (I'm not the target audience) so the sites hold no appeal

Simo thank you! The only target audience we have is for Kids. Hence Zoom with Zeke. If we can get kids off video games and in the garage great!

Our blog is going to include (my) mistakes like trying to sledge hammer the Pistons out, not know the difference between a two stroke/four stroke, not having safety equipment for Zeke, etc. Little things like what is a impact screw driver.? Macgyver thinks like using a square screw to adjust your tappets


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[crazypj]

Mom has been asking us the same question...are you ever going to bring money in than keep sending it out?
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I think my sister came up with one of the best lines for my brother and I
'You Jones boys have a knack for turning money into scrap' ;D

 

[Cafe Mike]

Wednesday can't get here soon enough. So excited

 

[Texasstar]

Wednesday can't get here soon enough. So excited

Zeke has been dreaming and drawing...he calls this Blast From the Past 2025 'Victoria'

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