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Post by endru on Apr 9, 2013 21:15:25 GMT -5
On the old forum I got involved in a thread discussing some of the "anomaly" engines where the case bolts aren't spaced correctly for a typically bore kit upgrade. scootdawg.proboards.com/index.cgi?board=discussion&action=print&thread=55131. I wasn't really able to come to a solid conclusion though on whether an upgrade would fit my Puma Amor 50. I would really love to put on a 50mm or even 52mm kit this summer, and the kits are really affordable (especially from Scrappydog) but I'm afraid of buying the cylinder only to have it not fit. The best way to be certain is to remove the head and cylinder (and all the other stuff included in that process) and measure the spacing of the bolts. But man, that's a lot of work just to measure something... So I guess I'm just trying to reopen the discussion with the following questions. Has anyone had any updated experience with installing BBK's on znen (puma) 50cc engines? If I were to buy the kit and it didn't fit, is it feasible to drill new, correctly spaced holes to fit the kit? Any other relevant advice for me? |
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Post by docxen on Apr 14, 2013 8:41:14 GMT -5
i got the puma romeo 50 and had a new bbk put on it did little if anything to improve. I wouldn't waste the cash if i were you.
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Post by teddy554 on Apr 14, 2013 9:10:23 GMT -5
has for drilling new holes dont think that would be a good idea but I know one person that might be of help.You should be able to put the kit on if not i am sure you could sale it here to recoup some money back
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Post by millsc on Apr 14, 2013 9:12:42 GMT -5
I put a 50mm ebay bbk on a puma no problems fit as normal it had 69mm valves scrappys 52mm kit requires no case mods either so you'll be fine with either
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Post by carasdad on Apr 14, 2013 9:23:36 GMT -5
On the old forum I got involved in a thread discussing some of the "anomaly" engines where the case bolts aren't spaced correctly for a typically bore kit upgrade. scootdawg.proboards.com/index.cgi?board=discussion&action=print&thread=55131. I wasn't really able to come to a solid conclusion though on whether an upgrade would fit my Puma Amor 50. I would really love to put on a 50mm or even 52mm kit this summer, and the kits are really affordable (especially from Scrappydog) but I'm afraid of buying the cylinder only to have it not fit. The best way to be certain is to remove the head and cylinder (and all the other stuff included in that process) and measure the spacing of the bolts. But man, that's a lot of work just to measure something... So I guess I'm just trying to reopen the discussion with the following questions. Has anyone had any updated experience with installing BBK's on znen (puma) 50cc engines? If I were to buy the kit and it didn't fit, is it feasible to drill new, correctly spaced holes to fit the kit? Any other relevant advice for me? I have put BBK's on Znen scoots for customers. It is not necessarily an anomaly engine like the QJ 4 strokes that are part 4 stroke and part 2 stroke parts. Problem with the Znen's and a BBK is the frame design. It is a very solidly built frame and has a cross bar that goes over the top of the engine. This does not allow you to remove the cylinder and head. So we just unbolt one end of the shock and hoist the rear end up...or place the scoot on a milk crate(Be sure it is stable on the crate!! We use ties down straps to hold it secure) Once it is hoisted or on a milk crate the rear wheel and read end drop down...giving you PLENTY of room to do the BBK.  The BBK did improve power and speed...but you have to tune the variator with the proper weights and springs. Then they really had speed and power. I have never had luck with a stock Znen..getting them faster..all the hi po parts did nothing... It seemed to be in the rear driven pulley springs. Clutch and Contra springs are too light...so engine engages too soon and loads the engine. docxen..as stated above..JUST a BBK is not going get ya moving out with better take off and higher speed...variator weights and rear springs must be changed. ;D |
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Post by millsc on Apr 14, 2013 9:28:47 GMT -5
I took off the intake studs and the head came right off on the puma i did
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Post by carasdad on Apr 14, 2013 10:04:51 GMT -5
I took off the intake studs and the head came right off on the puma i did millsc....heya that should work too.. I just do it as I stated in the above post...because these 50yo eyes are not so good anymore...and I need all the light and room I can get.  I call Znen scoots the Cadillac of scoots as they ride so smooth..feel very solid and handle well. Would LOVE to get my hands on a Bintelli though...do a nice review and post it everywhere..cause from what I have seen from pics...adds etc. They are well above things such as what Scooterdepot and Happyscooters sell. NEVER saw a customer scoot that came from either company above....that was worth a hoot. I was convinced they were buying and selling the 'didn't quite pass QC' scoots that were culled out from the good ones.  |
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Post by endru on Apr 14, 2013 19:37:32 GMT -5
Hey everybody thanks so much for the valuable input.
I have had some luck so far with modifications. Everything is just so touchy - one poorly made modification will bottleneck the whole performance. Valve adjustments, variator weights, contra springs, jetting... everything has to be exact in order to get acceptable performance. My point is, once a get the BBK, I'm sure I'll see a significant power increase since I've become very comfortable with tuning the other things that would affect power. And the Pumas run on the same GY6 platform as every other Chinese clone scoot. So a Puma not performing better after a BBK install could be remedied the same way as the other brand scoots having that issue... we've seen plenty of that on here and the old scootdawg. Taller gears for instance would be in the plans shortly after installing a BBK.
The bar on the frame that goes over the valve cover is a real pain. Even a plug chop is cumbersome. Thanks for the advice on how to pull it apart.
Anyway, thanks again everyone, it really helps to have people who have more experience than me.
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