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Post by ricardoguitars on May 26, 2015 15:23:09 GMT -5
What's the difference between a performance ceramic head with a 59mm BBK vs a 59mm 4 valve BBK with a 4 valves head? Is it worth the extra money? What is the minimum expected performance improvement?  |
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Post by dmartin95 on May 26, 2015 16:38:16 GMT -5
Have you seen my 4 valve thread? I only went up 5cc (155cc) and used a 4 valve head, the power this beast makes is just nuts.... There is no comparison between 2 and 4 valve heads. 4 valve smashes 2, hands down. It is my opinion, a 4 valve head the single best upgrade you can do to one of these scoots. Check out this thread |
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Post by geh3333 on May 26, 2015 19:15:24 GMT -5
Have you seen my 4 valve thread? I only went up 5cc (155cc) and used a 4 valve head, the power this beast makes is just nuts.... There is no comparison between 2 and 4 valve heads. 4 valve smashes 2, hands down. It is my opinion, a 4 valve head the single best upgrade you can do to one of these scoots. Check out this threadI always wondered about the 4 valve head. |
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Post by cyborg on May 26, 2015 23:52:18 GMT -5
Martin wins the prize ,,another forum has a debate going on about this very issue,,,I feel 4 valves are better and the performance difference is night and day,,in my opinion,,,,in favor of four valves,,and almost every manufacturer on the planet uses 3 or 4 valve tech,,,very few modern thought engines have 2 valves
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Post by dmartin95 on May 27, 2015 1:28:58 GMT -5
Have you seen my 4 valve thread? I only went up 5cc (155cc) and used a 4 valve head, the power this beast makes is just nuts.... There is no comparison between 2 and 4 valve heads. 4 valve smashes 2, hands down. It is my opinion, a 4 valve head the single best upgrade you can do to one of these scoots. Check out this threadI always wondered about the 4 valve head. My Yamaha SMAX comes stock with a 155cc, 4 valve head and EFI. I have hit 80+ MPH. That will dust a GY6 150cc. |
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Post by geh3333 on May 27, 2015 19:22:38 GMT -5
I always wondered about the 4 valve head. My Yamaha SMAX comes stock with a 155cc, 4 valve head and EFI. I have hit 80+ MPH. That will dust a GY6 150cc. I remember when I first got my scoot and was on the SD forum . some said , it wasn't worth it and some said it was . I would imagine they would def help with performance. |
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Post by JerryScript on May 27, 2015 23:59:24 GMT -5
@dmartin did you get before and after numbers, such as RPMs at low, cruising, and high speeds, and of course during acceleration? Was it a significant enough difference to need to change the CVT weights or springs? Do you mostly get more torque, mid-range acceleration, or top end?
I plan on upgrading my 150cc one component at a time, including BBK, head, intake and exhaust, and sliders to dial it all in. I'm thinking of doing just the 4 valve head first, with uni intake and some exhaust modifications, then do the BBK later, and tune the CVT with sliders each time if necessary.
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Post by ricardoguitars on May 28, 2015 13:01:37 GMT -5
@dmartin did you get before and after numbers, such as RPMs at low, cruising, and high speeds, and of course during acceleration? Was it a significant enough difference to need to change the CVT weights or springs? Do you mostly get more torque, mid-range acceleration, or top end? I plan on upgrading my 150cc one component at a time, including BBK, head, intake and exhaust, and sliders to dial it all in. I'm thinking of doing just the 4 valve head first, with uni intake and some exhaust modifications, then do the BBK later, and tune the CVT with sliders each time if necessary. Those would be nice stats to know, that's the only thing holding me from finally getting a BBK and stop procrastinating  |
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Post by dmartin95 on May 28, 2015 23:11:59 GMT -5
@dmartin did you get before and after numbers, such as RPMs at low, cruising, and high speeds, and of course during acceleration? Was it a significant enough difference to need to change the CVT weights or springs? Do you mostly get more torque, mid-range acceleration, or top end? I plan on upgrading my 150cc one component at a time, including BBK, head, intake and exhaust, and sliders to dial it all in. I'm thinking of doing just the 4 valve head first, with uni intake and some exhaust modifications, then do the BBK later, and tune the CVT with sliders each time if necessary. Sorry for the late reply. No, I didn't get before and after numbers...I pretty much know what the stock numbers are. I've only taken this new engine out for a few short test runs.... This 4 valve head is taller than the stock head and in addition, the exhaust flange is at a different angle which causes the muffler to both, hit the frame on bumps and stick out about a foot past where it normally rides.... Taida makes a 4 valve muffler, I'm waiting for it to arrive in the mail... I was going to take this myffler and have it bent, but decided against it cause I need the muffler for when I test other engines.... This is what I can tell you... On dirt, with my feet on the floorboard, I can goose the throttle and literally peel out.... On one of my test rides, I hit 67 MPH and still had a couple 1000 RPM's left. It does not slow down on hills..... I'm using the stock gears and they are for sure limiting me... I'm expecting 70, maybe even 75MPH top end with the right gears..... And remember, this is a no bore upgrade... I only went up to a 155cc (58.5mm). I also have a Taida 232cc that's 4 valve. But you have to remember, this is a brand new engine and It's still in the break in period. I haven't really got into it yet... Not to mention, I have about 10 builds going on right now.... I will update you guys more with better results with some time..... My initial performance assessment is for $$$ it cost, it's well worth it. I will put my 58.5mm 4 valve, against any other 58.5mm 2 valve out there. |
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Post by geh3333 on May 29, 2015 0:42:54 GMT -5
@dmartin did you get before and after numbers, such as RPMs at low, cruising, and high speeds, and of course during acceleration? Was it a significant enough difference to need to change the CVT weights or springs? Do you mostly get more torque, mid-range acceleration, or top end? I plan on upgrading my 150cc one component at a time, including BBK, head, intake and exhaust, and sliders to dial it all in. I'm thinking of doing just the 4 valve head first, with uni intake and some exhaust modifications, then do the BBK later, and tune the CVT with sliders each time if necessary. Sorry for the late reply. No, I didn't get before and after numbers...I pretty much know what the stock numbers are. I've only taken this new engine out for a few short test runs.... This 4 valve head is taller than the stock head and in addition, the exhaust flange is at a different angle which causes the muffler to both, hit the frame on bumps and stick out about a foot past where it normally rides.... Taida makes a 4 valve muffler, I'm waiting for it to arrive in the mail... I was going to take this myffler and have it bent, but decided against it cause I need the muffler for when I test other engines.... This is what I can tell you... On dirt, with my feet on the floorboard, I can goose the throttle and literally peel out.... On one of my test rides, I hit 67 MPH and still had a couple 1000 RPM's left. It does not slow down on hills..... I'm using the stock gears and they are for sure limiting me... I'm expecting 70, maybe even 75MPH top end with the right gears..... And remember, this is a no bore upgrade... I only went up to a 155cc (58.5mm). I also have a Taida 232cc that's 4 valve. But you have to remember, this is a brand new engine and It's still in the break in period. I haven't really got into it yet... Not to mention, I have about 10 builds going on right now.... I will update you guys more with better results with some time..... My initial performance assessment is for $$$ it cost, it's well worth it. I will put my 58.5mm 4 valve, against any other 58.5mm 2 valve out there. Did you say you have the efi on the scoot also ? Is that with the 58.5 ? The efi makes a big difference also . at the same time , I try to express that you really don't need to go that big when it comes to a big bore kit to reach the 65mph range . even without efi. Im really impressed with the 58.5 kit that I have. I know I've said this before , but I know of many with bigger kits that do not have the top end I have. I can say its because of this or that , but unless I actually went through and did whole load of tests I really don't know the actually reason for this. I also have no clue what cam I'm using ! I wish I did. The cam I am using makes a night and day difference in performance from the stock cams . funny thing is that the stock cam that can with my scoot and the stock cam that can with the new engine are noticeably different " lobe height" which was kind of strange. |
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Post by geh3333 on May 29, 2015 0:49:50 GMT -5
I see , it was the Yamaha with the efi . I like to see others with great results with just a 58.5 kit.
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Post by steve on May 29, 2015 9:21:59 GMT -5
Do ya'll know if they make a 4 valve head for a 50cc?
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Post by JerryScript on May 29, 2015 20:15:49 GMT -5
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Freshman Rider
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Post by hunter on May 31, 2015 12:36:28 GMT -5
After reading this thread and looking around and pricing some 4 valve heads, is anything else required for the installation besides what would come in the kit? (head, cam, rockers, gaskets, etc.) I saw 4 valve bores also listed. This is what I was wondering if it was necessary.
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Post by JerryScript on May 31, 2015 14:32:42 GMT -5
In some builds, you need a piston with valve hollows for the four valves. You can use modeling clay to determine if your piston needs modding, a dremel is enough to do the job.
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