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Post by humanshield on Mar 29, 2016 9:21:17 GMT -5
I saw this ebay listing for a new piston offered by Scooters To Go.... High Compression PistonWhen I was working hard to get my Big Valve Head to work on my BBK conversion, those of you who followed the thread know I went through great lengths to get it to work but the problem at the times was that the big valve head had too much chamber volume and the stock stroke could not develop enough compression. I tried flycutting various heads and went through a VERY long and tedious process....but at the end....I couldn't get it to work out. Fast forward to today...and this High Compression piston. This "COULD" be the solution.......IF......the valves will clear the dome of the piston. If it will, then I would think that nearly everyone who wants to upgrade their 49cc scoot to 83cc (by using the 50mm BBK kit) and maximize performance using a Big Valve Head would beat a fast trail to get this piston. I'm also using an A9 cam so that is another consideration. I'm anxious to find out if this would work out or if the piston will not clear the valves. Anyone tried it yet who has a 50mm (83cc) kit. Remember, the 50mm 83cc kit is normally called the "100cc" kit. If noone has tried it, I might. If it worked out, I'm almost certain it would move me comfortable into the 50-55mph (actual) top end speed range with a gearing change. Maybe even the high 50's maxed out.
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Post by cwazywazy on Mar 29, 2016 9:25:46 GMT -5
I was considering it, but I decided to go with the 52mm kit that came with a domed piston. I'd like to see what this one is like though.
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Post by humanshield on Mar 29, 2016 9:28:15 GMT -5
I was considering it, but I decided to go with the 52mm kit that came with a domed piston. I'd like to see what this one is like though. Are you using a Big Valve Head?
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Post by 90GTVert on Mar 29, 2016 9:35:20 GMT -5
If piston to valve clearance is close but not enough, you can cut the reliefs deeper/larger yourself most likely. I just used a flat stone in a rotary tool on one of my old builds.
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Post by cwazywazy on Mar 29, 2016 10:06:38 GMT -5
I was considering it, but I decided to go with the 52mm kit that came with a domed piston. I'd like to see what this one is like though. Are you using a Big Valve Head? Yup. This one. Ported it and lapped the valves and stuff.
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Post by humanshield on Mar 29, 2016 10:36:53 GMT -5
If piston to valve clearance is close but not enough, you can cut the reliefs deeper/larger yourself most likely. I just used a flat stone in a rotary tool on one of my old builds. But it could be WAY off........
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Post by humanshield on Mar 29, 2016 10:39:43 GMT -5
Are you using a Big Valve Head? Yup. This one. Ported it and lapped the valves and stuff. That's got to be one bad ass formerly 50cc scoot Is there a write up somewhere on the performance results? How many miles on it (since the kit install)? Any blown head gaskets? Have you had to go back in and fix stuff since the original install? I had considered the 52mm kit, but there was more than enough warnings over the 50mm kit. Most suggested the 72cc kit was ideal. The general consensus was that the 52mm kit was a grenade in waiting.
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Post by sumo210 on Mar 29, 2016 12:40:13 GMT -5
I did a 50mm head issue and i ran into the same issue.. the head was not producing any compression so i just stuck on my old one and badda bing badda boom I have a beast of a scoot. Might help you with your issue if you just put on the stock head
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Post by cwazywazy on Mar 29, 2016 13:26:56 GMT -5
Yup. This one. Ported it and lapped the valves and stuff. That's got to be one bad ass formerly 50cc scoot Is there a write up somewhere on the performance results? How many miles on it (since the kit install)? Any blown head gaskets? Have you had to go back in and fix stuff since the original install? I had considered the 52mm kit, but there was more than enough warnings over the 50mm kit. Most suggested the 72cc kit was ideal. The general consensus was that the 52mm kit was a grenade in waiting. Hasn't even run at all yet. I installed the 52mm kit and big valve on Sunday and lost a thing for the Bendix. There's pics and stuff in my Peace Sports thread. I've got no doubt that itll eventually wreck my crank, but it's not like I rely on it to get me places or anything. Also hopefully I'll have a parts scooter soon.
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Post by humanshield on Mar 31, 2016 14:45:54 GMT -5
Ok.
Hard to tell. But once you start riding it, keep us posted on the miles you get out of it.
I've got a little over 3,000 on my 50mm kit and it's going strong. Had to change the cam once but that was a head gasket issue. Not related to anything but my mistake.
I can run a solid TRUE (not indicated ;-) 43mph on flat ground with no wind. Take off from zero to 30 is pretty good. Can usually jump out in front of traffic for the 60ft run...then it's all over.
Stock 50cc scooter is about 3hp at 6000rpm
I'm thinking that right now I'm making about 4.5hp I'm pretty sure the Big Valve head (with porting work) and domed piston would up that to around 6-7 due to increased rpm range and breathing. But at that point a carb size up grade to 19 or 20 would probably nudge it up to 7.5 - 8hp Custom made free flow pipe....maybe 9.
Guesstimating
I believe 10hp is about average for 150cc scoots. So a 150 would still probably walk me.
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Post by cwazywazy on Mar 31, 2016 15:44:04 GMT -5
I'm thinking that right now I'm making about 4.5hp I'm pretty sure the Big Valve head (with porting work) and domed piston would up that to around 6-7 due to increased rpm range and breathing. But at that point a carb size up grade to 19 or 20 would probably nudge it up to 7.5 - 8hp Custom made free flow pipe....maybe 9. I kinda doubt that, to be honest. It's a ton more powerful than stock, but I doubt it makes more than 5-6hp right now. Probably will make a bit more when it's actually tuned correctly though. Hopefully I'm getting a "parts" Taotao ATM50 or whatever (It actually runs according to the seller) so if I can get that riding I'll do a comparison with the ass dyno. EDIT: According to this, the 50mm tops out at 5HP. 49ccscoot.proboards.com/thread/2953/displacement-torque-tables-gy6-139qmb
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Post by kagetenshi on Apr 2, 2016 10:15:41 GMT -5
All that being said, I would expect 50mph on a flat. My stock taotao VIP (49.6cc) will do 45 MPH on a flat with no tail wind in good conditions, without tucking in. GPS verified and verified with a friend in his car. So if you can get it running it should zip right along.
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Post by cwazywazy on Apr 2, 2016 10:46:15 GMT -5
All that being said, I would expect 50mph on a flat. My stock taotao VIP (49.6cc) will do 45 MPH on a flat with no tail wind in good conditions, without tucking in. GPS verified and verified with a friend in his car. So if you can get it running it should zip right along. Yup. I've barely even touched the CVT at all and it hit 51 on GPS yesterday.
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Post by dude on Apr 2, 2016 18:57:59 GMT -5
I bought a few of the 50mm BBK Kits a while back. Installed one on a Taotao GT5 with the stock head. I sold it I believe it has over 5,000 miles now. The scooter was new it ran good but I believe once it was broken in it would run better but being new not opening the cvt I'd say it needed lighter weight. I sold it with just a few miles of new.
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Post by dude on Apr 2, 2016 19:42:42 GMT -5
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