|
|
Post by meniscus on Nov 12, 2020 8:55:52 GMT -5
I had to rebuild a friend's scooter because he failed to keep the proper level of oil with a 72cc (47mm) BBK. I just rebuilt the engine and put in the original camshaft. It runs solid through the entire throttle range and speed. This is an Icebear Maddog with a 255lbs rider, presently doing around 40-41mph top speed. Now I'm wondering if I should put the A9 camshaft in. Before I do, I figured I'd ask a few questions, as follows:
- Does the A9 camshaft contribute to flooding the engine (especially when pilot jet may not be completely clear)?
- What effect does an A9 camshaft have on long-term durability?
- I've seen mention of concerns around the increased compression. Is this really a concern when changing from the stock cam to the A9 cam on a 47mm (72cc) BBK?
- Are there any other concerns I should be thinking about? This scooter is a daily driver for my friend so reliability and durability is the primary goal (to ensure dependable operation, despite changing weather conditions).
I've done my best to research this forum and others, but I haven't seen a lot of data with A/B comparisons. Most of the experiences include some combination of other upgrades and not a before and after test from stock to the A9 cam only.
All feedback is greatly appreciated!
|
|
|
|
Post by meniscus on Nov 12, 2020 9:37:28 GMT -5
Here's a follow-on question. I've read on various forums that the A8 cam is more suited for higher RPM setups. I've also read that A9 helps with mid-range and top-end. However, I have seen where people claim that the A10 cam increases low-end torque.
With that assumption, it would make sense to me that maybe an A10 cam would be more suited for heavier riders who do not see the top RPM numbers, especially when combined with bike on the heavy side. Does anyone have experience with A10 cams or are they even used for anything other than the 150cc GY6 motors?
|
|
|
|
Post by aeroxbud on Nov 12, 2020 9:49:56 GMT -5
From what I have read on here in the past. Not all the A9 cams are the same. So the results might vary.
|
|
Petro
Scoot Enthusiast
Posts: 149
Location: Gothenburg, Sweden.
|
Post by Petro on Nov 12, 2020 12:02:46 GMT -5
Here's a follow-on question. I've read on various forums that the A8 cam is more suited for higher RPM setups. I've also read that A9 helps with mid-range and top-end. However, I have seen where people claim that the A10 cam increases low-end torque. With that assumption, it would make sense to me that maybe an A10 cam would be more suited for heavier riders who do not see the top RPM numbers, especially when combined with bike on the heavy side. Does anyone have experience with A10 cams or are they even used for anything other than the 150cc GY6 motors? I only have experience on A9 but what ever You choose will be a great lift for the bike. The A9 I have now has better torque than my last A9 so there is I guess a matter on which backyard in china the cam was hammered... I would't put much thought on it, buy an affordable one. It will make a big difference from the stock one, less in between the A8-A10. |
|
|
|
Post by meniscus on Nov 12, 2020 14:43:54 GMT -5
I'll try to take a picture of the A9 we have now (which was used when we did the BBK kit the first time). We haven't tried it on the new 47mm BBK.
|
|
|
|
Post by 90GTVert on Nov 13, 2020 14:16:01 GMT -5
- Does the A9 camshaft contribute to flooding the engine (especially when pilot jet may not be completely clear)?
No. The engine may not be as efficient at low RPM, but you can tune it as needed. Also, a partially clogged pilot jet would more likely cause a lean condition rather than flooding, since it's not able to deliver as much fuel with a reduced orifice size. - What effect does an A9 camshaft have on long-term durability?
Most likely you will make a little more power at a little higher RPM. More power and/or more RPM usually mean less long term reliability. That said, the effects should be minimal as long as you get it tuned and setup well. - I've seen mention of concerns around the increased compression. Is this really a concern when changing from the stock cam to the A9 cam on a 47mm (72cc) BBK?
I wouldn't expect high compression to be an issue. Most cams that work well at high RPM will lower dynamic compression. Here's a bunch of detail about my experience with a larger cam in my 150 and how it affected compression. 49ccscoot.proboards.com/thread/14563/2006-roketa-cayman-150-mc?page=5&scrollTo=228887 |
|
|
|
Post by SMALL CC TEK on Nov 13, 2020 23:09:25 GMT -5
From what I have read on here in the past. Not all the A9 cams are the same. So the results might vary. What Aero said! All A9's are created different from my experience pull your calipers and measure for the truth . Flooding nahh Loss of power possibly the head can't flow what a good cam needs so boom your slower lol Sometimes it's just luck of the draw with A9's in 47mm to 50 mm range I have a box with probaly 20 cams from all different bikes and manufactures seems like taida, ban jing worked best with a nice head . But i have had a old Dazon stock qmb 139 cam that was better than all of them Ncy seems to work but i am not much into NCY stuff anymore . |
|
