Manual Clutch for 3/4" Crankshaft (Replacement for Centrifugal)

GoldenMotor.com
mapbike

mapbike

Well-Known Member
Mar 14, 2010
5,502
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Central Area of Texas
Dan said:
I hear ya Map. Been beating my head trying to do a semi-VT but is coming together. (Machining the sheave is turning out to be a hassle. 20.5*!) The off the shelf CVTs are just to big, IMHO.

But I really think this will be a great alternative. Can rev the engine up a tad before engaging. Will really help with getting off the line at a stop light. I really like the idea of pop-starting. (bump) I feel kinda silly starting my 4 smokes like a lawn mower.

LOL, I will look just as silly if the pop-starting doesn't start but at least I will already be facing and going the other way
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The way I start my bikes doesn't bother me personally, most all of the first ATVs had to be pull started and after all we are dealing with a bicycle with an engine......lol!

I know it may seem like I'm being negative toward the manual clutch here but im no at all, just expressing my thoughts on it based on what I've seen in the demo vids, Im a little curious about how well a 79cc engine will do just toodling around at low speed if it has been geared for good topend cruise speeds, seems like your gonna be on and off the clutch lever constantly and doing lots of clutch slipping which causes lots of wear and heat on a clutch, the clutch should really shine for cruising and for a race bike though.

I like the idea but im curious to know if any of my concernes are actually warranted or just my mind running wild about the possibilities. .......lol!

Patiently waiting for the results to come in on how it performs on a bike.

Map
.wee.
 
maurtis

maurtis

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Dec 14, 2011
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Kyle, TX
Was the subject of rebuilding them addressed? Are there pads or wear surfaces that can be replaced, or is it replacing the whole clutch when it dies?
 
Dan

Dan

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May 25, 2008
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Ya didn't come off negative at all, Map. Good to chat about stuff like that. Makes ya think.

Will look for a pic the Brothers posted. It is sort of a pancake deal and all parts can be replaced, Maurtis.

Can't find it but at the top of their web page is a rotating series of pictures. One of them shows it apart. http://www.downsbrosracing.com/index.html
 
mapbike

mapbike

Well-Known Member
Mar 14, 2010
5,502
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Central Area of Texas
Dan said:
new vid of it on a minibike; http://www.youtube.com/watch?feature=player_embedded&v=AfqKU1iVt08
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Thats a pretty good video Dan, works great on that mini bike, still question how long a dry clutch like that will hold up to days, weeks or months of that kind of abuse, but all that will be known in time.

Wonder how many times of dumping the clutch from a stand still it will take to wreck the rear wheel spoke on a bicycle wheel, just keep having these questions come to mind regarding use on a bicycle, and what the long term durability will be like, a $175 clutch would be a huge investment if it would need a complete rebuild every couple of months or so, I can build a bicycle with a belt drive that uses an idler and lever to get a direct drive from engine to rear wheel, it would be way more clunky looking but cheap to build and maintain, that has been one of my plans for a future build.

I like the clutch and I would like to have that on a mini bike to cruise around on no doubt.

Map
reddd
 
LabRat

LabRat

New Member
Dec 24, 2011
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Ruston, Washington
Just can not believe that finally this clutch has arrived and I am tied up with the puma build. Getting this clutch on motor assisted bicycle meh, just not happening directly. Wizzkid got the other one I ordered and I feel he will beat me by a long shot. He is not working on anything else and has his engine, frame and wheels already.

As for wheels he and I are both using worksman rims on moped hubs.

Soon a few of us will be reporting something so we all wait....

Hurry up guys!!! What did I get myself into REPORT
 
Dan

Dan

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May 25, 2008
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Moosylvania
Always some thing, Lab. Either ya don't have the time, parts, tools or money to do some thing. The tinker-er's lament. "I got every thing I need. Almost" lol

Been on a gear reduction for months. Every time I turn around, I have every thing I need, almost.
That song plays a lot in my head.
 
chainmaker

chainmaker

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Jan 19, 2010
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Ma USA
SlowBalt said:
Will their be a 5/8 clutch?
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I asked on the OMB forum a few months ago and it was depending on how many people were asking for one. There are adapter sleeves with larger keys on eBay but I think these guys should market one to fit this clutch specifically.
 
C

CoolCruiser

New Member
Jun 15, 2012
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Massachusetts
chainmaker said:
I asked on the OMB forum a few months ago and it was depending on how many people were asking for one. There are adapter sleeves with larger keys on eBay but I think these guys should market one to fit this clutch specifically.
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I'd also like to see a 5/8" version. It looks like a 79cc HF motor on that mini bike so I guess you can use a shaft adapter. I'd think there is a bigger market for this in 5/8 than 3/4- no?
 
maurtis

maurtis

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Dec 14, 2011
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CoolCruiser said:
I'd also like to see a 5/8" version. It looks like a 79cc HF motor on that mini bike so I guess you can use a shaft adapter. I'd think there is a bigger market for this in 5/8 than 3/4- no?
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Yes, if this clutch was developed for MaBs. But it was not, it was developed for the minibike market which tends to use bigger motors with 3/4" shafts.
 
maniac57

maniac57

Old, Fat, and still faster than you
Oct 8, 2011
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memphis Tn
I been waiting myself for a real world report.
I keep hearing about it but nobody has seen one in use.
Please don't break my heart again!
The lack of a good manual clutch is the only thing that has stopped me from some wild four stroke builds, especially lately. I recently had a shot at a Briggs Vanguard V-Twin for stupid cheap, but I hate centrifugal clutches so I passed. Someone builds an affordable, decent manual clutch and I'll buy the first 5 off the line, but I want a real world report before I buy.
 
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Velodrome

Velodrome

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May 27, 2011
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Phoenix-ish
Mine looks GREAT but I hav'nt tried it out yet. Everything I've seen so far has been on "minibikes" Have yet to see on on a bicycle build. Their are several videos on the O.M.B. forum
 
Velodrome

Velodrome

Well-Known Member
May 27, 2011
2,387
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Phoenix-ish
Dont know what to tell ya as I dont know... This being a holiday weekend I doubt youll get an answer till next week. Let us know if it shows up over the weekend. What tdid DBR ( http://www.downsbrosracing.com/ ) tell you when you ordered it. I know they had a limited amount of clutches; bout 100 as I recall for the first batch, If they were sold out they should have told you. I was in the first opening bunch of buyers when sales opened but I know they had some leftover from the opening frinzy. From opening of sales to having it in my hands was about 2 1/2 weeks but they had LOTS of people to ship ti first with pre orders. I'd try calling / emailing / PM ing on OMB forum ect them Fri but dont hope for much. better luck after the holiday wekend is over... Neil. Watcahyouu doon their boy? Did ya git ya one? If so; hows bout a little report?
 
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