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Post by dmartin95 on Nov 5, 2014 1:59:48 GMT -5
Mr Martin Just to make sure - here is what we are talking about. When you get a BBK, you get a set of parts including a jug (cylinder liner), a cylinder head (where the valves go), a piston, etc. : The jug - the part housing the piston when it travels up and down (driven by the crankshaft and connecting rod that are inside the crankcase - is the part that must fit inside a hole in the crankcase. The problem is the hole that is standard in a GY6 engine is pretty small, and most serious Big Bore kits will not fit into it: So the hole must be enlarged so the BBK jugs can fit in the hole. THAT's what is meant by "bore".When you buy a BBK you get a cylinder lining (jug) and piston that are already the correct size for what you buy. You do not need to do anything to the jug you buy other than install it ..... presuming the hole in the crankcase is large enough (bored out, if you are getting anything larger than a 60mm BBK). You don't need to bore the jug. Hope this helps. Yes, that is quite helpful..... Is the only way to get a bigger piston is by purchasing a BBK? Is it possible to get a new jug for my existing cylinder? I was thinking I would just bore out my existing cylinder (jug), but apparently that's not how it's done....?? To further expand on this topic, if I decide to go with a stroker kit - do you know if they sell tall cylinders for A-case scooters (54mm stud spacing)? The stroker Kits I have seen come with spacers.... I have seen some BBK's listed as "tall cylinder", eliminating the need for spacers.... However, the only tall ones I've seen have been for the B-case (57mm stud spacing)..... My ideal find would be a 63mm, water cooled "tall" BBK..... |
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Post by dmartin95 on Nov 4, 2014 17:35:43 GMT -5
Do these things work for the crankcase and the cylinder?
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Post by dmartin95 on Nov 4, 2014 10:54:00 GMT -5
These pumps we have on our scoots operate on pulses. Every time your intake sucks in air, the pump's diaphragm is pulled and afterwards released, thousands of times per minute. As you saw in my gauge testing results, a smaller 3 inches of vacuum at 7,000 RPM produces much more fuel pressure than a much larger 11 inches of vacuum at only 4,500 RPM. More small pulses is better than fewer big pulses. I wonder why these scooters are cutting out at WOT....!?! If it's getting the best fuel pressure at higher RPMs, then what do you think is the cause of these scooters cutting out at WOT? I really want to get to the root cause of why all these scooters "cut out at WOT"... It seem to be the case that these particular scoots (turtle shells as shannen calls 'em  ) with the tank in the bottom have this particular issue.... Xyshannen, Katastroff, Me, rcq and the list just goes on.... But, like Alleyoop said, thousands of these scoots with the same design operate just fine.... Perhaps it's the case that some of the fuel pumps had a bad batch of diaphragms or something odd like that.... As to the root cause of the scoots cutting out at WOT, your post has confused me more than helped.... |
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Post by dmartin95 on Nov 4, 2014 1:20:01 GMT -5
It's used as a power port for charging cell phone, GPS, etc.... That is how I plan on mounting it.... it will only be inches away from the the fuel tank..... Here's a video I made while back showing the scooters fuel system layout:
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Post by dmartin95 on Nov 4, 2014 0:48:28 GMT -5
OK, about placement of the pump Placement of the pump shouldn't be an issue with mine. In addition to it being a self priming pump, it also has a 24" head and a check valve to keep the system pressurized when turned off. I know you said you didn't want to hear about wiring, but a few more cents. It's not that I don't want to hear about wiring, it's just that I already have a 12volt relay installed that I have dedicated to my aux power port (cigarette lighter)...... I'm just going to tap into that. |
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Post by dmartin95 on Nov 4, 2014 0:34:03 GMT -5
Hi Mr. Martin! You asked about the PRESSURE in psi (completely different than volume in (gal/hr). Again, i don't think you will find a pump that provides too LOW a pressure - but your question about "too HIGH" is legitimate! The reason I asked about PSI and gal/hr is because that is how K&N list the specs of my PUMP: Engineered to pump 15 gallons per hour between 1 and 2 psi"Scooter" did some pressure measurements on his vacuum (OEM) pump and found the psi to be from 1.5psi to 4psi. So, anything in that range is fine since it simply duplicates what the OEM vacuum pump provides. His reading was of fuel vacuum pressure, not the pressure of the fuel pump outlet.... I guess I didn't realize they would be the same...However, the vacuum pump's psi drops off as engine RPM increases, while the electric pump is constant at all engine speeds (a plus). This is the problem on this particular scooter I'm trying to fix.  The carburetor does NOT regulate pressure - only volume. The gas flows through a needle valve into the carb bowl. -------------------- SO~~~~ the PRESSURE going into the carb isn't important (assuming it's "enough" - say, 1psi) AS LONG AS IT IS NOT SO HIGH IT OVERWHELMS THE NEEDLE VALE AND FORCES GAS IN WHETHER MORE GAS IS NEEDED OR NOT. Hope this is helpful and not just boring. That is the exact information I was looking for.... Absolutely not. It is not boring. Thank you very for much for taking the time to share the info,..... |
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Post by dmartin95 on Nov 4, 2014 0:14:04 GMT -5
With this kit you get to choose what cam you get. Wile I like the A11 I have, I would really like to try the A8. Since I'm like you and not worried about top speed, it should have better power at lower RPMs, always being at 6500 get's annoying at slower speeds. I had 10 ounce rollers in and it had the motor operating in the perfect power band starting dead at 6500 to 8000. I put the stock 12 grams back in and it doesn't hit the power band until I'm almost running 40. But will still hit 60 and has plenty of power to go at only 7200 RPMs. Are you saying the lowest RPM your scooter runs at is 6500? What does the numbers for the cam mean? What is the difference between an A11 and an A8? That's something else I don't know about yet is how the cvt, rollers and clutch all work together.. I would have no idea what to select...... |
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Post by dmartin95 on Nov 2, 2014 21:25:30 GMT -5
What usually burns them up is when they are running with no liquid for them to pump they get really hot. The K&N pump that I selected shouldn't be dry but once, and that should be the first prime.... The unique thing about the one I selected is that it has has an internal check valve, to help keep the fuel system primed when powered off . In addition, it's a self priming pump.... Hopefully it will not be getting hot and running dry.... They are specifically designed for ATV, Motorcycles and Scoots..... I dropped $56.00 on this puppy going for K&N quality.....Fingers are crossed that it will outlast the life of the scooter. Thanks for the feedback, but wiring it and powering it isn't what I need help with.... I would like to know how the fuel is regulated in a stock GY6... In Detail.... For example. How much PSI can the regulator resist before its overwhelmed. |
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Post by dmartin95 on Nov 2, 2014 18:46:13 GMT -5
All wife's tale, thousand of scoots are running WOT and not a problem with Vacuum operated fuel pumps even your 250s and 300s, people just don't know how this stuff works. I think I mentioned several times what the problem is on the scoots that are having a problem at wot but it fell on deaf ears. There is a saying you can lead a horse to water but you cannot make him drink. Tip for you guys that are going to put on a electric pump and do ride a good distance from where you live. Take the Vacuum pump and vacuum hoses as spares, just in case the battery goes south or the pump burns up.  Alleyoop Care to elaborate? Your suggestion did not fall upon deaf ears, I just don't don't see how relocating the pump and porting the gas tank lower will solve the problem..... On one hand you say thousands of scoots have the vacuum operated pumps and work fine, but then you still proceed to offer up a solution..... Irregardless of how many thousand work, mine isn't.... I'm not trying to argue with anyone, especially when no doubt you know way more about this stuff than me....... I just want to fix my wifes scooter.... That's it... A bunch of people have suggested an electronic fuel pump..... Why do you feel the pump will fail? It has a 5 year warranty backed by K&N direct. Anyhow, all that aside, fix or no fix, I'm committed now as I've already paid for the pump.... Now I just need advice on the proper way to hook it up.... Do you have any of the info I'm requesting? Can you help me? You know how the fuel is regulated and what its tolerances are? At what point does it stop regulating due to too much PSI? Rather than telling me it will fail, I hope you'll help me figure out how to hook it up properly. |
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Post by dmartin95 on Nov 2, 2014 18:10:59 GMT -5
Sounds sweet, can't wait to see the results. I forgot to mention a while back that after I fixed the vacuum line running from the carb, to the "Tee", before fuel pump, the results..... I took the scoot out for a 18 mile ride and it never cut out at WOT... A few days later, me and wife were riding and she's got about 100lbs on me, it cut out on her just as if I never fixed anything...... I never installed that Mikuni pump yet.... Even though it's a Vacuum operated pump, it doesn't require constant vacuum and is pulse vacuum operated, meaning it needs less vacuum..... I didn't select it just because it's higher quality... It operates differently...... However, I think an electronic pump is the better way to go so I'm not going to have any vacuum operated fuel pumps..... I just need to figure out the whole fuel regulation thing...... |
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Post by dmartin95 on Nov 2, 2014 18:02:06 GMT -5
Nice~! I prefer a standard electrical solenoid energized by a wire that gets +12v when the switch is turned on. the upside is there is no long starter run just to get gas pumped into the fuel bowl - the scooter is charged and ready to go from the first instant. The downside (as mentioned) is the pump runs at all times when the key is "on". As for me I do not mind that - have a radio on my scoot, but have not had it running w/o the scoot running. Anyway, I'm sure a "kill switch" would be easy to de-energize the relay if you wanted to do so manually ... but have not had any reason yet to want that. My 2 cents. Do you have 2 more cents? I need advice on the fuel regulation. This new (K&N) pump does up to 15 gallons per hour, but the scooters stock fuel consumption is only about 1 gallon per hour (if even that)....... I've been told the scooter has a fuel pressure regulator.... Does anyone know how much PSI before it overwhelms this regulator? However, what about the scooter fuel pump itself..... Is it a constant pressure pump? Do you or anyone else know the PSI at fuel pump outlet? This is the info I am desperately seeking..... From what I understand so far about engine vacuum is that the more work your engine is doing, it starts to lose vacuum..... Once you're at WOT, there isn't enough vacuum for the fuel pump to keep working.... |
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Post by dmartin95 on Nov 2, 2014 17:39:52 GMT -5
A belt is something I forgot to add to my list and is an excellent suggestion! For those who have problems with the belt area getting hot, there is a good article on the cause and effect on scrappydogs website in the tech talk with mo area.... Here it is quoted: Belts breaking all the time! Here is a reverse MO! question answer. This time it was MO! calling out to all those scootdawgs out there who might know why so many belts are broken on certain scooters. This was a reply from someone who kept breaking belt after belt, and seemed to try everything, then after he changed the rear clutch/pulley assembly, he wrote back this reply below. It seems that the inner bearing would pit and run rough, causing excessive heat, and transfering heat to the belt through the rear sheaves of the pulley. Heat and rubber don't do well together for long!MO! It (rear clutch/pulley) was causing all the heat (a bad needle bearing in the clutch), and I have about 500 miles on my scooter since replacing the clutch with the one I purchased on your site, and it's running great, so you my want to advise people to pull the clutch as part of their normal maintenance routine (every 1,500 – 2,000 miles should suffice), and feel if the bearing has any rough spots in it; this can easily be done by inserting your index finger into the bearing and spinning the clutch on your finger, and if the bearing does not roll freely, or you can feel any rough spots in it, it’s probably getting close to time to change the bearing (if you can find one), or the clutch, because you can warn them if they don’t, they’ll probably be pushing their scooter home from wherever they are when the heat from the bad bearing, melts the belt. -helpful scootdawg no longer changing belts all the time! Source |
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Post by dmartin95 on Nov 2, 2014 12:24:19 GMT -5
Got a link?
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Post by dmartin95 on Nov 2, 2014 12:14:06 GMT -5
Can you link me to this CC graph you found? Yeah, Here's the link . It's the second post in that thread. As of right now, I don't really have a plan.... I'm not sure if I'm going to do a BBK or not.... I would like to have a little more power, not speed.... I have added saddlebags, extra large trunk and carry tools.... All my extras are about 50lbs.... In addition, I'm adding a windshield and the wind resistance will no doubt slow me further. The fastest my scooter ever went on level terrain was 62MPH stock.... Right now, she maxes out 58~59MPH and the windshield will push that down further. If I could get to a steady 65MPH and more power I would be one happy camper! |
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Post by dmartin95 on Nov 2, 2014 11:45:17 GMT -5
Ok, I just ordered a K&N fuel pump. I know a lot of people have linked to the little no name brand fuel pump for under $15.00, but I do not trust no name brand items. This was expensive for an electronic pump of this size. I paid $56.00.... K&N has 4 different mini pump/filter combos. I will list them and provide the link K&N Universal Inline Fuel Pumps K&N Inline Fuel Pump Compatible with diesel, biodiesel, gasoline, E85, methanol, ethanol, alcohol and other fuels Universal design fits most applications Self-priming design provides a quiet running volume Eliminates vapor lock and flooding Fuel filter and installation hardware is included Inline Fuel Pumps K&N Inline Fuel Pumps provide premium quality fuel system hardware with a universal design that fits a wide variety of applications. Compatible with most fuels, this self-regulating 12-volt pump helps prevent vapor lock and flooding. K&N Inline Fuel Pump 81-0400
K&N 81-0400 is a universal inline fuel pump engineered to pump 15 gallons per hour between 1 and 2 psi.K&N Inline Fuel Pump 81-0401 K&N 81-0401 is a universal inline fuel pump engineered to pump 25 gallons per hour between 1.5 and 4 psi. K&N Inline Fuel Pump 81-0402 K&N 81-0402 is a universal inline fuel pump engineered to pump 32 gallons per hour between 4 and 7 psi. K&N Inline Fuel Pump 81-0403 K&N 81-0403 is a universal inline fuel pump engineered to pump 34 gallons per hour between 7 and 10 psi. ----------------------------- I chose the 81-0400 because it's the smallest coming in at only 1~2PSI and upto 15GPH. It was the smallest name brand pump I could find.. Also, the 81-0400 has an internal check valve to help keep the fuel system primed when powered off. 0401 and 0402 do not have the check valve. In addition, you can install the 0400 up to 24" above the tank, the others are only 12. Now, I need to figure out how I'm going to hook this thing up.... |
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