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Post by dmartin95 on Oct 12, 2014 10:50:46 GMT -5
At any case, works or doesn't work, the combined cost of the 2 are cheap enough that it's well worth a try, and a of a lot easier than adding a second tank. Yeah, an electronic fuel was my first thought as well and would still like to go that route, I just have no idea how to proceed. After reading TVnacmans post, the upper fuel tank is starting to sound discouraging. I didn't know that some scooters come with a vacuum fuel pump and an upper tank. I thought it was either or, pump w/tank on bottom or tank up top w/manual petcock... I came across this thread on scootdawgs forum with the exact same problem as we're having. It was suggested to buy a Mikuni fuel pump.... The poster said he bought 2 of them and then never followed through with the thread to let readers know if it fixed the problem or not... At $25.00, I may just buy one to try it before attempt a second tank... |
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Post by xyshannen on Oct 12, 2014 10:59:07 GMT -5
At any case, works or doesn't work, the combined cost of the 2 are cheap enough that it's well worth a try, and a of a lot easier than adding a second tank. Yeah, an electronic fuel was my first thought as well and would still like to go that route, I just have no idea how to proceed. After reading TVnacmans post, the upper fuel tank is starting to sound discouraging. I didn't know that some scooters come with a vacuum fuel pump and an upper tank. I thought it was either or, pump w/tank on bottom or tank up top w/manual petcock... I came across this thread on scootdawgs forum with the exact same problem as we're having. It was suggested to buy a Mikuni fuel pump.... The poster said he bought 2 of them and then never followed through with the thread to let readers know if it fixed the problem or not... At $25.00, I may just buy one to try it before attempt a second tank... That's what I love about these little engines. Parts are cheap enough that experimenting is pretty much a no brainer. It's not like building a chevy small block where little choices make the difference of loosing several hundred bucks in a go. |
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Post by xyshannen on Oct 12, 2014 11:26:03 GMT -5
I agree with fuel starvation at wot , I differ from you guys as my tank is above my carb . However mine has the vac operated fuel valve . As mentioned above it starves for fuel at wot , I find if I back off a drop its better without breaking up. I have thought of putting the manual fuel valve . So I went and bought a vac gauge in an effort to get my carb dialed in . Everything your saying (Xys) I saw with the vac gauge . I have done the 11pole stator and sell them . When I tested them I found at about 125w load it stayed 13.3vdc maybe I could have added some more load and been ok . From a sales standpoint I would rather down play the numbers and be safe then up play them and disappoint the buyer . I really like the EFI idea , however the cost I can not bring myself to part with the coin . I have been looking for a wrecked vespa to do the conversion . John Sorry John, I totally missed seeing your post. As far as the 11 pole goes, I'm eventually wanting to add more lights and a few other electric things, like maybe a stereo. Mu scoots rear trunck has a fake antenna mounted on it, and as dumb as a stereo on a scooter sounds, it kinda bugs me to have anything "fake" on my ride. So I can see an 11 pole def being something I'll need one way or another. |
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Post by xyshannen on Oct 12, 2014 13:53:37 GMT -5
dmartin95 I just had a look at that Mikuni fuel pump you listed... Wile it's cheap enough to be worth trying. I don't think it's going to solve our problem. It's operation still relies on vacuum and our problem stems from loosing vacuum at WOT. Now if someone would chime in on a way to fix the root of the cause "loss of vacuum" that would be great. But thus far I haven't read any suggestions other than going back to stock carb, intake, and air box. Sorry to me that's not an option. Not to mention I still had this problem with all the stock equipment and upgrading has helped because my engine can now run at higher speeds with less throttle, helping me to run at a lower throttle before reaching WOT and loosing the vacuum.
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Post by tvnacman on Oct 12, 2014 14:14:21 GMT -5
At any case, works or doesn't work, the combined cost of the 2 are cheap enough that it's well worth a try, and a of a lot easier than adding a second tank. Yeah, an electronic fuel was my first thought as well and would still like to go that route, I just have no idea how to proceed. After reading TVnacmans post, the upper fuel tank is starting to sound discouraging. I didn't know that some scooters come with a vacuum fuel pump and an upper tank. I thought it was either or, pump w/tank on bottom or tank up top w/manual petcock... I came across this thread on scootdawgs forum with the exact same problem as we're having. It was suggested to buy a Mikuni fuel pump.... The poster said he bought 2 of them and then never followed through with the thread to let readers know if it fixed the problem or not... At $25.00, I may just buy one to try it before attempt a second tank... DM this is a vac actuated fuel valve it is only opened when there is vac to pull the diaphragm and allow fuel flow . The auto one is the one under my tank and is very common . I have seen this under the tank in absent of the vac valve , but still mounted above the carb . I don't think the little pump has the umph to push furl up to the carb when the tank is below the carb . As for pumps and pressure pumps do not make pressure , they create flow . Restriction to flow create pressure . The pressure regulator is variable restriction . John |
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Post by dmartin95 on Oct 12, 2014 18:59:45 GMT -5
dmartin95 It's operation still relies on vacuum and our problem stems from loosing vacuum at WOT. Now if someone would chime in on a way to fix the root of the cause "loss of vacuum" that would be great. "loss of vacuum" could imply many things. A leak in the air hose, a bad clamp, faulty petcock, clogged evap canister, etc etc...... I have started to think the loss of vacuum is not carb/air intake/etc etc.... related I think there is a design flaw in these specific Retro style scoots with the tank on the bottom.... I've seen too many threads on these types of forums, all with the same problem... They lose power at WOT.. I start to see a pattern, or commonality if you will..... Now, as to where that loss of vacuum is coming from, I think it's this specific part:  ------------------------------------------------- Of course, I am just guessing by trying to find the common denominator ... I have been seeking a thread where someone with this specific issue chimes in and says; I fixed it by doing X. The thread that I linked to, the guy suggesting the Mikuni Pump seemed like he had seen the issue before and that our type of pump maybe the culprit.... I can't find the link, but I saw it another thread as well..... Do you have a guess as to why it losses vacuum at WOT? ------------------------------------------------ Alley -- I will get pictures of my scoots fuel layout... I have it up on the lift but went to do it and realized my wife had her saddlebags secured with like 50 knots... Normally the seat compartment has 4 bolts and comes off in about 30 seconds... I guess I discovered one down-side to saddle bags.... |
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Post by dmartin95 on Oct 12, 2014 19:03:40 GMT -5
DM this is a vac actuated fuel valve it is only opened when there is vac to pull the diaphragm and allow fuel flow . The auto one is the one under my tank and is very common . I have seen this under the tank in absent of the vac valve , but still mounted above the carb . I don't think the little pump has the umph to push furl up to the carb when the tank is below the carb . John Your first link isn't working... It just opens a Shopping cart.... Are you linking to one like this (first link):  |
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Post by tvnacman on Oct 12, 2014 19:07:16 GMT -5
DM this is a vac actuated fuel valve it is only opened when there is vac to pull the diaphragm and allow fuel flow . The auto one is the one under my tank and is very common . I have seen this under the tank in absent of the vac valve , but still mounted above the carb . I don't think the little pump has the umph to push furl up to the carb when the tank is below the carb . John Your first link isn't working... It just opens a Shopping cart.... Are you linking to one like this (first link): Yes John |
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Post by xyshannen on Oct 12, 2014 19:36:20 GMT -5
All I can say is in my case I've replaced every component possible in regards to the engine and still have the problem so you might be on to something.
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Post by katastroff on Oct 13, 2014 6:01:00 GMT -5
Mikuni pumps are great, get one.  |
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Post by dmartin95 on Oct 13, 2014 9:26:20 GMT -5
All I can say is in my case I've replaced every component possible in regards to the engine and still have the problem so you might be on to something. Luckily, Katastroff is a member here as well scootdawg... I was able to track him down through the Personal Message system of this board. He replied last night and said the Mikuni fuel pump did fix his problem.... At only 25~30 bucks, I'm ordering one today. Here's a video on the installation of the Mikuni pump: |
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Post by xyshannen on Oct 13, 2014 11:14:11 GMT -5
That's great news! I'll order one next month as well... Do report back, or heck make a FYI thread about it! dmartin95 Coffee is kicking in...So the thinking is that our crap fuel pumps are causing the loss of vacuum? Just out of curiosity..with your vacuum gauge, have you seen the vacuum drop to zero? |
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Post by dmartin95 on Oct 14, 2014 12:15:37 GMT -5
Just out of curiosity..with your vacuum gauge, have you seen the vacuum drop to zero? It's my wife's Retro Style Scoot (BMS Heritage) that cuts out at WOT, not my Bintelli Havoc. I do not have a vacuum gauge installed on her scooter, yet. I did however pick one up for her scoot (12 bucks is hard to resist) and will eventually get around to installing on her scoot... Here in Michigan we have some pretty long and cold winters, I'll have plenty of time to wrench on all my scoots then. |
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Post by xyshannen on Oct 14, 2014 13:55:14 GMT -5
That's right, I'm sorry I forgot it's that Havoc with all the kewl gauges. Still would be interesting to see what you get. Is your season over already? I forget that you snow birds can't ride year round. Heck even here in North Florida we only get really cold a few days out of two months. Once in a wile we will have a months worth of consecutive really cold days. Even then freezing temps are rare and only at night. It's in the mid 90s today..  |
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Post by dmartin95 on Oct 14, 2014 15:46:45 GMT -5
No, the season isn't over just yet... But it's getting close. It's been raining a lot lately and I haven't been able to ride though... Kind of Bummed too because I wanted to test out some mods.
If I can squeeze in the time, I'll install the vac gauge and fill ya in the results... If I can get to it, before the snow flies that is....
I discovered a damaged vacuum line when I went to take some pics on my wifes BMS heritage... It's a line that runs to the fuel pump from the carb.... I'll get pics later but I really wanna get out and ride this thing and see if it helped, or maybe even fixed the problem.
However, I'm still going to order the Mikuni Pulse pump because it's a better pump.
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