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Post by humanshield on May 21, 2015 13:37:22 GMT -5
Jamie,
check your compression. Make sure it's at least 150psi.
Mine has to go back. 80 psi max. No good.
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Post by Silar on May 21, 2015 15:12:32 GMT -5
Just requires a simple valve lapping..
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Post by humanshield on May 21, 2015 15:46:56 GMT -5
Just requires a simple valve lapping.. I don't want to mess with the seats in case it doesn't work. Could void the warranty |
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Post by humanshield on May 22, 2015 17:30:23 GMT -5
Hey Jamie,
Could you check your compression and let me know what yours is?
I have a slight suspicion yours might be lower than you think. These scooters really shine with 150psi or higher compression. WORLD of difference. So big that my scoot with the BVH at 115psi is still out-performed by the 160psi stock head.
I corrected the valve situation and did a thorough leak test to make sure the valves were sealing.
At first they were leaking and could only get 80psi. Now they are not and can still only get 115psi. I used the thin metal gasket...you did as well right?
I could understand the 115 if they were leaking, but again I verified after correcting the seats and they are no longer leaking.
Knowing your compression would be a stellar piece of information.
Thanks!
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Post by humanshield on May 22, 2015 21:14:05 GMT -5
Remember.. I'm running with an 18mm carb. It's only going to take what that carb can give it. This may be the reason I need to go to a larger carb to gain any performance increase from where I am. 2007 Chinese GY6 139QMB 50cc (Bumblebee) - 100cc Big Bore Kit - Big Valve Head (23mm & 20mm Valves) - A9 Performance Cam - Performance Racing CDI (Blue) - 18mm Kei-Hin Carb - #90 Main Jet - K&N Style POD Air Filter - Gates Powerlink Belt - 8 gram rollers An FYI - You don't always need a bigger carb to get better performance! Of course you don't.....if you're going with this  or this   |
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Post by Silar on May 22, 2015 22:02:52 GMT -5
Funny man.. Funny man!  |
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Post by 90GTVert on May 23, 2015 7:29:49 GMT -5
You could check your clearances and see if you can get away with running without a base gasket and just some sealant. Usually the big bore 4T guys report the opposite and use 2 gaskets to lower compression, but kit quality and design varies so maybe your deck height is off.
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Post by Silar on May 23, 2015 21:44:00 GMT -5
Got my 6 gram rollers put in today and took it for a spin. From takeoff at WOT, it was right around 9k rpm. about 1 to 1.5k more than with the 8 gram rollers. Launch is ridiculous and I'm up to 30 mph at the blink of an eye. I really need to get some kind of a phone mount so I don't have to hold my phone in my hand looking at the GPS speed.
I like my setup with the 6 gram rollers. I'm also running a Hoca 1k RPM contra spring. Acceleration is everything I was hoping for and climbing hills is a hell of a lot easier. It does make me wonder what a 1.5k contra spring would be like or if I staggered the 8 gram and 6 gram rollers..
I found a nice long straight stretch and had the scooter right at 50 mph today GPS verified and let off the throttle. I've got 10" wheels and it was way too scary for me. Don't know how you guys do it. Like I've said before, I'm not really going for speed. I Just want the power to get over these hills.
Still plan on taking the head off sometime in the near future and port matching.
I'm pretty satisfied at this point so I think now it's time to concentrate on the body panels!
I think with the POD filter on the 18mm carb, it allows enough airflow through the engine and with the #90 main jet, it happens to be such a magic combination on my scooter.
Edited to include my current equipment:
100cc (83cc) Big Bore Kit
Big Valve Head with 20mm & 23mm valves
Both Valves at .003
A9 Performance Cam
Stock Crank
Blue Performance Racing CDI
18mm KeiHin carb
#90 Jet
1.5 turns out on the idle/fuel screw
Needle clip set to mid position
POD Filter
6 Gram Rollers
1k Contra Spring
15w40 Rotella T6
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Post by humanshield on May 24, 2015 7:05:21 GMT -5
You could check your clearances and see if you can get away with running without a base gasket and just some sealant. Usually the big bore 4T guys report the opposite and use 2 gaskets to lower compression, but kit quality and design varies so maybe your deck height is off. Good idea. Thank you sir. I agree and I do find it odd the compression is down so much with the BVH. Unless it has some other odd defect. The compression was WAY up with the BBK and stock head. Was also thinking that if I came back with a low compression number with the replacement head, I might need to have the head flycut to raise the compression? Hopefully a replacement head will resolve it. I'm thinking so. All in good fun. Soon I'll be posting how great it's running again. Never knew scootering could be this much fun. I'm addicted |
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Post by humanshield on May 24, 2015 8:16:41 GMT -5
Got my 6 gram rollers put in today and took it for a spin. From takeoff at WOT, it was right around 9k rpm. about 1 to 1.5k more than with the 8 gram rollers. Launch is ridiculous and I'm up to 30 mph at the blink of an eye. I really need to get some kind of a phone mount so I don't have to hold my phone in my hand looking at the GPS speed. I like my setup with the 6 gram rollers. I'm also running a Hoca 1k RPM contra spring. Acceleration is everything I was hoping for and climbing hills is a hell of a lot easier. It does make me wonder what a 1.5k contra spring would be like or if I staggered the 8 gram and 6 gram rollers.. I found a nice long straight stretch and had the scooter right at 50 mph today GPS verified and let off the throttle. I've got 10" wheels and it was way too scary for me. Don't know how you guys do it. Like I've said before, I'm not really going for speed. I Just want the power to get over these hills. Still plan on taking the head off sometime in the near future and port matching. I'm pretty satisfied at this point so I think now it's time to concentrate on the body panels! I think with the POD filter on the 18mm carb, it allows enough airflow through the engine and with the #90 main jet, it happens to be such a magic combination on my scooter. Sounds good. Glad you got it where you want it. That's the name of the game  I kinda felt that way about mine last month....then the thought of just a "little" more crept in. I have taller wheels so my 0 - 30 will be a bit slower, but top end better. Probably why I'm hitting 50 without the BVH. If you're happy as is, there is absolutely no reason to upsize the carb on your scoot  |
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Post by Silar on May 24, 2015 11:41:41 GMT -5
I'll try to get a video today of a WOT takeoff.. It may not look as dramatic as it feels when on the scooter, but still it's pretty impressive.. |
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