Deleted
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Post by Deleted on Jan 7, 2015 16:17:15 GMT -5
I don't have the tools for a compression test. Going to look for one when I get some money. Anything you do until proper compression is established is likely wasted effort and lord knows I learned that lesson well, with all the low compression engines I have worked on, thrown money and parts at, to no avail only to discover that it was low compression all along. My compression gauge is my best friend now. A compression test is always the first thing I do. If compression is low, all the new carbs in the world will not make it run.
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tj
Scoot Member
Posts: 56
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Post by tj on Jan 19, 2015 0:19:33 GMT -5
I have a 2014 thunder 50 with a BBK a new head with the bigger valves, A9 cam, performance exhaust, 20mm carb, blue CDI box, DLH variator, 5gram rollers, better coil (orange), NGK iridium spark plug, racing clutch, 1500 rpm contra spring, I have the larger secondary gear set ill put in this week. But what I'm trying to get at is my speed increase really came from the CVT upgrades. I was doing about 40 after the BBK but with the CVT kit my MAX speed was 50 cruising about 45. Also just because you got a BBK you have to make sure everything is able to breath correctly I.E. bigger carb, bigger jets, bigger exhaust and valves. With the new secondary gear set I'm hoping to see a cruising speed of 50 and a 55 max speed. time will tell. I would recommend a TTO tach to really see what kind of RPM range you are in as well. With the CVT upgrades my RPM came up over 1000 RPM from where it was before.
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Post by niz76 on Jan 19, 2015 2:23:58 GMT -5
tj I'm curious as to whether the speeds you're mentioning are from the scoot's speedo? or are GPS? The subject of Chinese scoot speedos has been discussed many many times- they are notoriously inaccurate. Usually at least 10 mph optimistic. Seems like the speeds you're mentioning are a little high for a 4t- just don't want to get someone else's hopes up with inaccurate speed quotes is all
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tj
Scoot Member
Posts: 56
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Post by tj on Jan 19, 2015 6:56:59 GMT -5
GPS. I dont have a mount for the GPS to mount on the front of the scoot yet. but as long as the app is on it records the the max speed and average speed. I have held the phone before and seen cruising speeds of 45 at around 7100 rpm. But I dont think 50 for a max speed @ 7900-8100 rpm from my tach is that uncommon is it? I mean max at 50 could have been on a down hill stretch not 100% on the terrain at the time of the speed.
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tj
Scoot Member
Posts: 56
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Post by tj on Jan 19, 2015 6:58:59 GMT -5
I really dont use the speedo on the scoot at all? On the electronic speedos that can be put on the bike like the one 90 has on his taotao how does that speedo figure the speed?
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Post by 90GTVert on Jan 19, 2015 13:44:36 GMT -5
On the electronic speedos that can be put on the bike like the one 90 has on his taotao how does that speedo figure the speed? A magnet needs to be mounted on the wheel or brake rotor. A sensor is then mounted so the magnet that rotates with the wheel passes directly by it with a fairly small clearance. Each time the magnet passes the sensor it will send a signal to the speedometer. Any good universal speedometer should allow you to input the circumference of the tire that the sensor and magnet are on. This will tell the speedometer how far you are traveling for every signal that it receives. So if you're tire has a 30" circumference, the it travels 30" per signal that the speedometer gets. Knowing this and coupling it with time between pulses or pulses within a certain time frame the speedometer can calculate and display your speed. I have found good ones seem to be more accurate than my GPS when properly setup. For example, they respond more quickly and they experience no signal issues when going through ares that are heavily wooded or with lots of tall buildings around. GPS is far easier to install though. You can get handlebar mounts so it's easy to read and requires no hands. Some offer weather protection as well. Add a charging port (12V receptacle) and it's a good long term solution.
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Post by stevec on Jan 19, 2015 20:52:43 GMT -5
if you are using a stock belt and variator you will not have the power you should have, stock belts tend to slip on takeoff, a gates kevlar or bando will help a lot, a good variator will also help and check the clutch bell for glazing, stock clutches also slip on takeoff, my taotao actually had heat cracks on the stock clutch bell after upgrading the engine, you can find performance CVT kits that come with the clutch and variator. as far as final drive gears are concerned, i would get the CVT tuned properly and see what you get for takeoff and top end and then go for better gearing, my stock gears in the taotao i had were good for 63mph top speed and great acceleration. taotao gearing on the scooters with 12 inch wheels is pretty good.
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tj
Scoot Member
Posts: 56
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Post by tj on Jan 19, 2015 21:13:22 GMT -5
tj I'm curious as to whether the speeds you're mentioning are from the scoot's speedo? or are GPS? The subject of Chinese scoot speedos has been discussed many many times- they are notoriously inaccurate. Usually at least 10 mph optimistic. Seems like the speeds you're mentioning are a little high for a 4t- just don't want to get someone else's hopes up with inaccurate speed quotes is all Well you got me wondering about my speed... made me question my GPS so I put a new GPS on my phone and tried it again I kept the phone in the cubby hole on the scoot and drove home from work this morning. My GPS was off....With all of my upgrades Im seeing cruising speed of 35-37 and a WOT speed of 42-43. I did have a top speed downhill of 53mph. Real big downer to be honest but what can you do I still have the secondary gears to put in and a proper tune. My scoot has started to do something a little weird as well. When i start it up it idles fine. But as I ride a couple of miles and come to a light the idle drops down and eventually stalls. takes about 8 seconds for that to happen. But if I give it some gas it will stay running. but, I think it might be running lean now as it will idle fine at start up since it has the electronic en richer still on it. Im so bad at tuning!!! The idle screw is set at about 2400rpm. Im sure with a proper tune ill gain 1-2mph. Really thinking about biting the bullet and going to the scooter shop and let them tune it, dont really want to sorta a pride thing. I did make an figure out that my scooters speedo was off 5mph. Sorta wishing I would have just bought the scooter and then put in a 150cc replacement motor. Im sure its been done. Dont know how much changing really needs to be done but maybe will be a plan for this fall possibly. My scoot has 12" wheels and a long case figure it wouldn't be that hard to do the engine swap. But will most definitely plan my next thing like that better.
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Post by niz76 on Jan 19, 2015 22:35:22 GMT -5
Don't be too hard on yourself brother- tuning is like anything else it takes time and experience to get good at it! Sounds like you're doing well already... I have limited experience tuning 4t's but there's a ton of tricks and tips and info buried on this site. The tech section is amazing and I still refer to it quite often for different info I'm looking for. I've also found a ton of good info in member's build threads. You can read what others have been through on their quest for speed! If you ever get another scoot consider a 2t and you'll see why we get hooked on them!
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Post by lansingscootguy on Feb 13, 2015 6:18:03 GMT -5
BBK question. I took my scooter into the shop here not to long ago and after going through it. They determined that I was low on compression 120 so they changed the head gasket. No help. Then they installed a smaller head and it brought the compression up to 170. Good news right? Wrong now I have a hell of a time getting my scoot to start. Alot of the time I have to get a jump. Suggestions?
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Post by walleye1963 on Feb 13, 2015 10:17:04 GMT -5
You might need s performance starter.that a lot of compression.now that it up to par.
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Post by 90GTVert on Feb 13, 2015 10:25:15 GMT -5
Possibly the battery is not in great condition. They struggle to start much more in very cold weather. I have to kick start mine most of the time in the cold. The starter will crank it over, but not fast enough to start it usually.
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Post by lansingscootguy on Feb 14, 2015 8:47:19 GMT -5
Ok guess I better fix the kick start then LoL.
Anyone have a site that has a upgraded starter for a reasonable price?
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Post by humanshield on Feb 14, 2015 18:38:30 GMT -5
I still think the 83cc (50mm piston) BBK simply tries to push too much air through the engine.
I'd like to hear from someone who has the 50mm piston AND the Big Valve Head.
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Post by blaq on Feb 15, 2015 8:18:10 GMT -5
I have but no compression tester to tell you the readings
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