SlantEyedStoner
Scoot Junior
Just had a few mins so I decided to jump on here and see whats going on.
Posts: 13
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Post by SlantEyedStoner on Mar 5, 2015 1:07:47 GMT -5
I'm getting ready to do total performance rebuild on a 2012 Keeway Hurricane 49cc scoot. When I got the scoot torn down I noticed that the motor isn't your usual looking 139QMB. After looking at the case its a QM137QMB. The top end and valve cover look totally different. After talking to my buddy, he told me that he believes that it's the same motor, but with a longer stroke.
Does anyone know about these or have any input they can give to help out?? Will a 50mm BBk for a 139QMB fit or be compatible for this motor?? If it does have a longer stroke, would that give it much more top end speed or any type of more power?
We're holding back from ordering the kit and parts until we know for sure if they'll work. So any input you could give me about this motor would be Greatly Appreciated.
Thanks, "Slant"
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Post by dude on Mar 5, 2015 5:34:41 GMT -5
139qmb BBK will not fit.
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Post by stevec on Mar 5, 2015 10:37:33 GMT -5
Qlink/Keeyway, totally different engine, has ceramic coated cylinder and some have 3 valves.
you can't fit 139QMB parts.
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SlantEyedStoner
Scoot Junior
Just had a few mins so I decided to jump on here and see whats going on.
Posts: 13
|
Post by SlantEyedStoner on Mar 5, 2015 17:30:06 GMT -5
Does anyone know where i might be able to find a 50mm bbk for this motor? I've search around on the net and can't find anything on it. I do have a backup 139qmb case. Should I just go ahead and avoid the headache and build it up instead??
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Post by dude on Mar 5, 2015 18:04:33 GMT -5
I needed a head for a 137qmb no luck. I also was looking for a BBK with no luck. I ended up just installing a 139qmb. They are a 2 vavle motor.
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Post by Fox on Mar 5, 2015 18:27:38 GMT -5
Is that engine like this one? If it is then yeah the cylinder studs don't line up with a standard 139QMB top end.   |
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Post by dude on Mar 5, 2015 21:20:51 GMT -5
Fox that looks like a 139qmb-3. The one I had looks like a cycle motor. With the 2 large removable nuts over the vavles. That doesn't sound proper lol.
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SlantEyedStoner
Scoot Junior
Just had a few mins so I decided to jump on here and see whats going on.
Posts: 13
|
Post by SlantEyedStoner on Mar 5, 2015 21:43:20 GMT -5
Dude, You're absolutely right. Tat looks like a 139qmb-3 to me and yes tis 137qmb has the 2 large removaable nuts over the valves to asdjust them. The valve cover on this is also bolted to the rocker arm and top end studs all in one. Would you know where to get a bbk from?? We'd like to build this motor up and see what kind of speeds we can get out of it. Thanks for your help.
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Post by katastroff on Mar 5, 2015 21:51:38 GMT -5
Ebay: Found none.
Aliexpress: Found none.
I would build on the 139qmb you have and swap the engines.
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Post by dude on Mar 5, 2015 21:53:38 GMT -5
Sorry no BBK that I know. Some pit bikes are close?
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Post by Fox on Mar 5, 2015 21:56:51 GMT -5
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Post by 90GTVert on Mar 6, 2015 11:07:46 GMT -5
If you're doing a swap the scooter engines with CVTs would be way easier. Pit bike engines have a gearbox and use chain drive. You'd have to fabricate a swingarm in addition to new mounts. Would be really cool if you wanted a project and you could use full auto, semi-auto, or a manual trans with a hand clutch.
Maybe you'll be lucky and the pit bike stuff will work, but from pics I've seen (never seen a 137 in person) they don't look close enough to me that I'd expect it to work.
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Post by stevec on Mar 6, 2015 18:40:01 GMT -5
give pete a call at superior scooter in meriden CT, he sells scooters with the 137 engine and may know where to get good parts for it, they do all of their work on site.
Telephone (203) 634-0464
430 So. Broad St. Meriden, CT 06450
tell him steve from waterbury said to call.
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SlantEyedStoner
Scoot Junior
Just had a few mins so I decided to jump on here and see whats going on.
Posts: 13
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Post by SlantEyedStoner on Mar 8, 2015 5:24:08 GMT -5
Well we decided to go ahead and do a swap. We traded another friend of mine the complete 137qmb, for a 1p39qmb (long case). Thanks for all the help and info. You all saved me from a major headache and confusion. We ordered parts tonight and hoping the express priority delivery gets them here in a cpl days. This build has now gone from a simple BBK install to an entire frame up custom. All plastics are off at ready for spray, and the new motor is torn down and getting ready for inspection. I'll keep you guys posted with details during the build with pics and etc, Once again, Thanks for all your help guys.
~Slant~
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Post by arcangel572 on Aug 30, 2021 9:52:55 GMT -5
Parts are hard to find and pricey, but are available for the Keeway 4t scoots like F-Act 50. I've been able to find some here in the US and mostly Europe. Here's a link en.50factory.com/XNUMX-engine-crankcases-XNUMXqmbForwarding...If you need a crankshaft be prepared to pay $400 US!! I need crank bearings but have to get a new crank to get them. The 137qmb has a 46mm stroke and 37mm bore where a 139qmb has a 41mm stroke and 39mm bore. You can get a 44mm stroker crank for the 139qmb which with a 52mm bore (same bore as 125cc) will give you 95cc's. I'm going to try to take a 137qmb connecting rod, because it's longer, and install it on a 44mm stroker crank for a 139qmb and use a piston with a shorter compression height. This would decrease the rod angle, increase the rpm range and spin up quicker. I'm a motorcycle mechanic and I've been racing all my life. Making horsepower is what I do best. I have a couple 50cc scoots that I've built up and they are fast. Matter of fact I'm on vacation this week and I'm about to tear down my 52.4mm bbk engine and install a 44mm crank. I was riding last week and the crank broke sending the flywheel across a ditch! It was turning over 12,000 rpm and running over 60 mph when it broke and tore the ignition pick up and blower cover off the engine!! If I can answer questions or help anyone feel free to ask. I look forward to helping out when I can. |
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