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Post by Kick start on May 29, 2018 14:24:43 GMT -5
Hey dexameth. How fast is your set up running in mph Took 275 home last night. Full tuck 56-60 the whole way but my rpms were way too high for comfort. 8800 at top speed of 62mph downhill but around 8400 it was so smooth and harmonic. Had throttle response on tap. I've been afraid of high rpms with this stroker. Oh, if I sit up and drive normal I'm seeing 50mph all day. You shouldn't need shorter springs either... I tried to put the short valve in already and the valve springs are to big they need to be shorter.
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Post by dexameth on May 29, 2018 16:54:50 GMT -5
Took 275 home last night. Full tuck 56-60 the whole way but my rpms were way too high for comfort. 8800 at top speed of 62mph downhill but around 8400 it was so smooth and harmonic. Had throttle response on tap. I've been afraid of high rpms with this stroker. Oh, if I sit up and drive normal I'm seeing 50mph all day. You shouldn't need shorter springs either... I tried to put the short valve in already and the valve springs are to big they need to be shorter. That's strange, most of the time the base of the head is risen to make up for the longer valves. I don't even sell a shorter valve for the 139QMB motor... just one main size. Even 150's and 50's springs are within tenths of a millimeter and can be swapped. Why are you thinking you need shorter ones? Are they binding? There are different springs, progressive vs linear, and I've found some 150s have thicker coils than others and have a hard time using a performance cam.
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Post by Kick start on May 30, 2018 21:23:17 GMT -5
I tried to put the short valve in already and the valve springs are to big they need to be shorter. That's strange, most of the time the base of the head is risen to make up for the longer valves. I don't even sell a shorter valve for the 139QMB motor... just one main size. Even 150's and 50's springs are within tenths of a millimeter and can be swapped. Why are you thinking you need shorter ones? Are they binding? There are different springs, progressive vs linear, and I've found some 150s have thicker coils than others and have a hard time using a performance cam. The valve springs I'm using are drowsport (GY6 Racing Dual Valve Springs 14,000rpm) and there are two sizes. I have the tall one and they are a bit taller then 150cc springs.
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Post by scootnewb on Jun 2, 2018 4:52:42 GMT -5
Here's the parts list I used on my stroker build. I highlighted in green the bare minimum parts needed to do the build. 10% off this weekend only at partsforscooters.com! Will that carb and intake manifold work on a stock 50cc head or other 50mm BBK heads? Or does it need that BVH?Nevermind. I was way overtired when posting last night or whenever this was.
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Post by scootnewb on Jun 27, 2018 18:50:05 GMT -5
update on Scootie?
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Post by dexameth on Jun 28, 2018 10:42:37 GMT -5
Running strong! No issues at all as of yet, except I pressed the left oil seal (behind the variator) in like a millimeter too far and there's a small leak But I've been pushing it to the max, not holding back at all at 55mph it doesn't seem to rev too high, my tach broke so I can't see exactly what I'm at but I'm going by the almighty butt-dyno. I still gotta hook up the oil-cooler. Been needing to make a bracket to mount the radiator to, but as of now no overheating issues at all... I had to install the OKO Performance cooling fan due to a little mishap, whoops. I feel like the OKO fan is actually better than stock, unlike those "turbo" cooling fans that actually throw less air. Anyhoo, so far so good, I got my 150 torn apart now showing it some love since Scootie is rockin' hard.
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Post by scootnewb on Jun 29, 2018 20:54:56 GMT -5
I hope to see more videos of it. It sounds fast and dialed in for the most part.
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Post by scootnewb on Jul 16, 2018 6:18:54 GMT -5
dexameth,
Did you get a Stella? I was looking for updated videos of the stroker and came across that vid.
It looked a little weird but it sounded really good.
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Post by dexameth on Jul 16, 2018 6:36:40 GMT -5
Yup! Can't wait to get it on the road but I got other projects to handle first.
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Post by AtariGuy on Jul 16, 2018 16:40:40 GMT -5
Dexa - i second a good run video - plus have you tried the stock cam on that scoot? I heard the a9's lower the working/dynamic compression of the cylinder through slightly longer durations. Not sure if its true or not, but i'm considering using your parts list for my own 139 build - and could try testing the different cams on it. Just my 2 cents
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Post by dexameth on Jul 16, 2018 22:12:07 GMT -5
Dexa - i second a good run video - plus have you tried the stock cam on that scoot? I heard the a9's lower the working/dynamic compression of the cylinder through slightly longer durations. Not sure if its true or not, but i'm considering using your parts list for my own 139 build - and could try testing the different cams on it. Just my 2 cents I haven't tried the stock cam, and I'm not sure I want to run my A9 due to bearing wear... Feels grindy in my fingers. So I ran our SSP-G cam that has lobes VERY close to stock just timed better. I've ran that cam ever since the build wae done. Thought about ordering the Amazon A9 cam as that seems to be the only one on the market for the 139 and measuring it up against the others ans you know, testing. On my older builds the A9 was definitely an improvement over stock.
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Post by autotech78 on Sept 4, 2018 0:18:54 GMT -5
Well at least the set up I'm doing will be figured out so others can use it. As the same as the one you are using as well. Do you have any pic of the two pistons
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Post by autotech78 on Sept 4, 2018 0:24:57 GMT -5
I'm gonna be building a set up stroker crank 52mm cylinder and racing head fulllly done with. Ignition upgrades coil over plug and new card and all cvt work gonna try to stick to all hoca parts but what brand u guys rec shows taida hear there good in new to scoots
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Post by fugaziiv on Sept 4, 2018 8:14:12 GMT -5
I'm gonna be building a set up stroker crank 52mm cylinder and racing head fulllly done with. Ignition upgrades coil over plug and new card and all cvt work gonna try to stick to all hoca parts but what brand u guys rec shows taida hear there good in new to scoots Just a friendly reminder that HOCA is no longer and is now SSP-G. Matt
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ratdog
Scoot Enthusiast
Posts: 342
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Post by ratdog on Sept 6, 2018 9:23:05 GMT -5
First, I want to apologize as this has most likely already bee answered somewhere in all these posts, and I did not catch it.
In the past (on different engine platforms) I have install several stroker “kits” these kits had a shorter rod, or special pistons with a higher crank pin. As I understand the strokers for GY6 platform, they are using a different crank that is the stock crank (and rod) for a different bike. This would put the piston too high in a stock jug. I'm guessing that this is being off set by a spacer at the base of the jug.
I already do this on the cylinders we “true up” by taking a cut off the top of the jug. Of course, we are shimming the cylinders to get them back to near stock deck height. If we do a stroker, it would be very simple to just make a thicker base spacer.
What concerns me is the timing chain. I can set the deck height to anything I want, but the thicker the spacer, the more timing chain length I need.
SO this is all a very long way of asking, how much can you raise the deck height before you run out of timing chain?
Scoot pro... You might find the comarision of cams I did in another thread of value.
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