Freshman Rider
Currently Offline
Posts: 66
Likes: 0
Joined: May 24, 2013 11:00:12 GMT -5
|
Post by kingkaymo on May 24, 2013 11:26:46 GMT -5
Well after owning a few scoots, and now dealing with my 02 honda elite 80 ive realized a few things. for one, ethanol sucks. eats everything. goes bad faster. just dont use it in anything you feel like keeping. secondly, vacuum petcocks suck. Even when they do work right, wide open throttle will keep them from operating, leaving you on the side of the road cranking over your bike just to get some fuel back into the bowl. third, replacing the vacuum petcock for a manual one is great... unless you have a honda elite. there is a panel that covers the bottom of the fuel tank, and if you like to have all your plastics installed as i do, there really isnt a good place to put an inline cutoff either. after much brain squeezing, I've discovered an easy solution to my problems. since there isnt much height between the carb and tank, it doesnt leave much room to run an inline cut off and one would have to cut holes in something to do so. adding extra line and running it to the outside also makes the gravity feed a more difficult prospect. then i realized i was attacking it the wrong way!  the trick is to modify the VACUUM line! cut the existing vacuum line, and install a one way check valve and a T fitting. valve on the intake side, T fitting between check valve and the tank. then run a vacuum line off the T to an easily accessible place (mine is going under the seat) and then attach a manual valve to the end. (like a cheap fuel valve) simply close the valve and crank the bike. the one way valve should hold vacuum on the petock until you open the valve again, releasing the vacuum. this line can also double as a bowl primer, just suck on the open valve to fill your carb's fuel bowl for quick starting (if you drained your bowl after parking) I am going to do this mod and take some pictures for those who have trouble visualizing what im talking about, but its pretty simple and surprised no one else has come up with this yet (trust me i've looked all over for this type of solution! havent found it yet!) anyway let me know what you guys think, and if this helps any of you! if you have an elite 80 its a MUST for high speed riding! (ive gps verified 55 on mine... right before carb ran out of fuel!) |
|
|
|
Post by dragonsparks on May 24, 2013 17:31:31 GMT -5
Looks good on paper. Would like to see it in practical application. If it works as advertised you could sell that set up as a kit.
Dave
|
|
|
|
Post by alleyoop on May 24, 2013 18:05:20 GMT -5
Your better off just putting a cut off valve close to the carbs fuel inlet where you can reach it and not have a vacuum operated valve. What your trying to do is have gas flow all the time due to the low vacuum produced at high speed. It will not hold the vacuum as you expect it too for that long.
The other thing you can do is Adjust the float to fill the bowl more.
Alleyoop
|
|
Freshman Rider
Currently Offline
Posts: 66
Likes: 0
Joined: May 24, 2013 11:00:12 GMT -5
|
Post by kingkaymo on May 24, 2013 19:13:47 GMT -5
indeed at the moment it looks good in theory, but how well it works will have to be determined.
alley- If i can reach it, I will just put a cut off at the inlet of the carb, but im pretty sure its too far up in there to even get to once i put my plastics back on. i am not gonna run it naked, and im not gonna pull the plastic every stop.
i do know what i am trying to do lol and i do know there is little to no vacuum at high speed which is why ive devised this setup in the first place. If the check valve and fuel petcock are in good shape, there isnt any reason that it shouldnt hold vacuum until its been released. my idea is that initial vacuum should be enough to keep it open, but in reality if im riding at high speed, a single dip in throttle should pull strong vacuum and if it doesnt hold as i expect, maybe it will hold long enough till the next time i dip the throttle.
a manual one will of course be best, but this is an alternative for those of us who CANNOT use manual ones, like the CH80
|
|
|
|
Post by larry001964 on May 24, 2013 19:28:45 GMT -5
|
|
Sophomore Rider
Currently Offline
Posts: 239
Likes: 1
Joined: Mar 13, 2013 9:13:17 GMT -5
|
Post by jeffery5568 on May 24, 2013 19:29:48 GMT -5
Do you really lose all of the vacuum at wot?
|
|
Freshman Rider
Currently Offline
Posts: 66
Likes: 0
Joined: May 24, 2013 11:00:12 GMT -5
|
Post by kingkaymo on May 25, 2013 1:45:16 GMT -5
also, alleyoop, why would i raise the float level if the problem is not getting enough fuel at high speed? the problem is not enough fuel in the fuel lines above the needle to fill the bowl because its emptying with the fuel petcock closed from no vacuum...
indeed so. my first scoot was an 08 benelli andretti 150 and it would die out at WOT after the fuel filter and bowl emptied, because there was not enough vacuum to run its vac fuel pump. if i stayed at 7/8ths it would do alright. my elite with its gravity vac petcock seemed fine until you ran it out to 50-55 and it would empty the fuel bowl and filter and not refill thus shutting off. that engine ran lean... now ive got a low mile motor swapped into it.
im using the tank that came with my parts scoot, because i thought the vacuum problem might not be the same, that maybe the diaphragm was bad on the other one, but its worse. i pulled the hose off and applied vacuum manually before i cranked up this motor first time to prime the carb, and it shot gas out and filled the carb and filter pretty fast. ran out of fuel on me after my first downhill after a flat 45+ run. applied vacuum manually again, barely a trickle. can sometimes make it go faster by alternating vacuum and pressure, working the diaphragm like a pump, but im guessing its either trashed up or fubared. didnt give me a mouthful of gas tho so theres that. seemed to even hold vac so maybe just trashed up.
im going to inspect my old petcock and tank thats now empty and dry and swap back to it (mainly cause its stickerless) and do some low speed runs and testing with panels off (so i can watch fuel filter) and then another high speed run to confirm thats the problem. it seems to run excellent at low speed very quick off the line no stumbling idles great.
ive got two other carbs to rebuild for it, so one of them im going to drill the main jet out a hair, port it a little maybe or just k+n drop in with a few more holes in the airbox, along with a 110cc four wheeler muffler. i wont do any of these mods without a set of stock parts though, because honestly im already stoked with the performance of this engine with just my variator mods. 55 mph easy on a downhill and 50+ on flat with no airbox carb or exhaust mods is really plenty on this fairly lightweight frame.
anyway im going camping, wont be able to work on it till i get back! happy memorial day weekend folks
|
|
|
|
Post by tvnacman on May 25, 2013 9:04:57 GMT -5
|
|
|
|
Post by sailracer on May 25, 2013 12:55:07 GMT -5
[replyingto=dragonsparks]dragonsparks[/replyingto]I had this problem on my new jonway. I installed a new vacuum petcock, and same thing! I ordered a manual shutoff valve, but in the meantime, I removed the petcock and carefully cut off the bottom where the vacuum line connects, ran a 5/16" drill through careful not to drill the diaphragm. I pushed the metal spring retainer aside, and with a pair of needle nose. pulled the spring out. this lets fuel flow freely to the carb, ( pinch it with an alligator clip when not in use.) Much to my surprise, it died again after a full throttle run! The gas cap has no vent hole to allow air in! a 1/8" hole solved this. now i will put in the manual valve when it arrives.but Im still able to ride
|
|
|
|
Post by sailracer on May 25, 2013 12:57:03 GMT -5
[replyingto=salracer]salracer[/replyingto]oops! dont forget to block off the vacuum line
|
|
Sophomore Rider
Currently Offline
Posts: 239
Likes: 1
Joined: Mar 13, 2013 9:13:17 GMT -5
|
Post by jeffery5568 on May 25, 2013 13:21:21 GMT -5
Makes me wonder if I could be running lean if I hold wot for a long time. I ride wot for miles sometimes.
|
|
|
|
Post by alleyoop on May 25, 2013 13:25:40 GMT -5
What you did WHY bother having the petcock, just take it off and run the line straight from the tank to a fuel filter then to the carb. Because what you did is eliminate the petcocks function and just makde it free flow.
You should raise the float so that it covers more of the main jet is what you should. It gives more time for the bowl to fill up before it drops below the main jet on long wot runs.
Also if you have a gravity fed system the fuel line from the tank to the carb fuel inlet should not have any dips in the line going to the carbs fuel inlet. Make it so it is the shortest way to the carbs fuel inlet, Many have the petcock bolted to the side of the frame then a long stretch of hose going to a fuel filter then to the carb.
Alleyoop
Alleyoop
|
|
|
|
Post by sailracer on May 25, 2013 17:30:54 GMT -5
[replyingto=alleyoop]alleyoop[/replyingto]yeah good idea. the only reason I did that, was that I had no fittings. otherwise I would have just used the hose (temporarily). The manual petcock arrived today ,so after I install it, we'll see how it behaves. Right now with the freeflow, Its great. I just sometimes forget to pinch off the line ,so not to ruin the float valve. Have to remember to shut off the petcock when done riding though.
|
|
|
|
Post by alleyoop on May 25, 2013 20:23:01 GMT -5
Great, yea sometimes if you forget to shut fuel valve off IF there is enough pressure after shut down it will push down the plunger and allow more fuel to get into the bowl and sometimes it will overflow but you will know if you find gas on the floor. But usually that happens over a couple hours because it is SIPPING in not really a full flow.
Alleyoop
|
|
Freshman Rider
Currently Offline
Posts: 66
Likes: 0
Joined: May 24, 2013 11:00:12 GMT -5
|
Post by kingkaymo on May 28, 2013 0:23:00 GMT -5
tvnacman: obviously you didnt read my post. here lets try that again third, replacing the vacuum petcock for a manual one is great... unless you have a honda elite. there is a panel that covers the bottom of the fuel tank, and if you like to have all your plastics installed as i do, there really isnt a good place to put an inline cutoff either. there is no way for me to install that valve and use it without leaving off a bunch of panels which i simply will not do. sailracer: i doubt you have the same problem. as alley said, you have eliminated the petcock entirely, and replaced it with a clamp pinching the fuel line... not the type of rigging im into, nor would it work for me anyway since with my plastics on I CANT REACH MY FUEL LINES. seriously guys if you dont understand what im doing or why im doing it, you should just ask. im not a noob to scoots or mechanics, i know manual petcocks exist and i know how to break a petcock all by myself. this is an uncommon problem, having a unaccessable tank bottom, and it requires a different solution. i posted here in case any other elite'rs could chime in or get some use from my idea, which i will be implementing now that im back from my camping trip. Alley: my entire problem is a lack of fuel flow TO the carb. I have ZERO running issues besides this. the only reason i have a problem with WOT runs is the lack of flow at WOT because of no vacuum, so how is changing the float going to let me have more fuel if there is no fuel in the lines to flow past the needle? the needle is already open because the bowl is empty! there is simply no fuel! now if i had a lean condition on WOT runs AFTER i fix the petcock problem, your advice might be applicable... but its just not here. yes its a gravity feed system, and ive got no place i could attach a remote petock to the frame- there is simply no place where it could be installed and accessed without cutting an access hole in the plastic period. ive already got the lines quite short with no dips. there is no problem with the path of travel- the fuel can flow just fine IF there is vacuum on the petcock. the lack of vacuum is the problem. and whoever had the idea of a vacuum pump- would be a good idea if a vacuum pump wasnt the most complex solution. im low on space as it is, and no electricicals to spare either. if the solution isnt simple and halfway decent looking, its not the right answer IMO
|
|
the trick is to modify the VACUUM line! 
..BAD TO THE BONE..
jet