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Post by 4950cycle on Aug 29, 2016 22:58:16 GMT -6
While I'm waiting for my fuel pump I'm making a trap door to get to my intake valve easy. I made one years ago to get to the exhaust valve. These Linhia's with receding valve seats (exhaust valve mainly) need valve adjustments often. And since the engine lays down the exhaust valve is accessible from the belly and the intake has to be accessible from under the seat. If you don't make these access doors or holes you would have to take off all the body work just to get to the top and bottom of the cylinder head to adjust the valves. The trick is to make these mods as invisible as possible. We wouldn't want to louse up the beautiful lines of a Reflex clone would we .  |
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Post by 4950cycle on Aug 28, 2016 23:14:49 GMT -6
Thanks for the info, Actually I'm very lucky in that department. Whole fuel system seems do be totally debris free ! Not a darn crumb of anything in tank, Carb, hoses, anywhere. But my first problem was my main jet fell out in the bottom of the float bowl, Holy crap I feel like a total YO Yo. I guess in all the junk I was screwing with that day I forgot to torque the 115 main jet I moved from the new 32 mm carb (trying to get it working) back to the old 30mm carb where the 115 came from. Anyway, I got it running good again except for my float bowl running empty often. Seems this fuel pump I bought off Ebay just isn't enough. I will return it. I don't want to go electric fuel pump like a lot of 250 and up guys do. I got another Vacuum Jin Bo Chinese fuel pump on the way. Hey, The last Jin Bo exactly like it lasted almost 8 years before it quit. That's good enough for me. It is somewhat equivalent to a Mikuni DF 52-21-D fuel pump. But under half the price. I'd like to adjust my valves and pull my cover and mark my variator while I'm waiting for this new Fuel pump. Read more: scooterrebels.proboards.com/thread/2676/miles-hour-257-linhai-jcl#ixzz4IgvWXpdw |
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Post by 4950cycle on Aug 25, 2016 23:14:24 GMT -6
Finally got my old carb back together and got it back in my JCL 257cc. "THEN" I leave the driveway on a test run and something gets sucked up in the main jet I figure . Blasted up the small hill from my driveway entrance. Ran great for 200 + yards got to the top of the hill and started starving and sputtering. All I can figure is the WOT up the hill sucked a piece of debris right up against the bottom of the main jet I guess. I'm starting to get a complex here. Someone doesn't want me to ride I'm starting to think ? I can't get a block down the road without something lousing up on this otherwise good running scoot. Read more: scooterrebels.proboards.com/thread/2676/miles-hour-257-linhai-jcl#ixzz4IPGhinjD |
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Post by 4950cycle on Aug 24, 2016 21:59:52 GMT -6
I went to put on my old carb on today to get ready to do the variator test. What a bitch working through that hole underneath the seat. Especially when I'm not using pod air filter (K&N style). When I finally get it in there and all hooked up I try to start it. Gas started coming out of the overflow tube as fast as the fuel pump would pump it. I guess all that wresting with the carb somehow got the float stuck inside the float bowl is all I could figure. Tomorrow's another day  |
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Post by 4950cycle on Aug 22, 2016 22:54:48 GMT -6
Get this, After all this I put my 115 main out of my old Jap 30 mm carb in the new 32 mm , New carb ran great then ! But no better readings from the tach and speedo than my old carb. I think it had a sleight edge on my old carb in the mid range. But not enough difference to change much. So what that means is if they will take this 32 mm back I want a refund.
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Post by 4950cycle on Aug 22, 2016 22:45:19 GMT -6
Get this, After all this I put my 115 main out of my old Jap 30 mm carb in the new 32 mm , New carb ran great then ! But no better readings from the tach and speedo than my old carb. I think it had a sleight edge on my old carb in the mid range. But not enough difference to change much. So what that means is if they will take this 32 mm back I want a refund.
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Post by 4950cycle on Aug 22, 2016 11:21:17 GMT -6
Please fix this thread for me please. I don't know what happened ?
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Post by 4950cycle on Aug 22, 2016 10:54:13 GMT -6
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Post by 4950cycle on Aug 22, 2016 9:43:16 GMT -6
Aug 9 2016 at 6:10pm jct842 said: First thing I would look at is the rpm at the top speed you get now. Depending on if it is wound out or not to decide on what weights you have and what you need to go to. If you don't have a tach get one on there. If you are a whole lot under red line you need to go lighter in weights which is what I would suspect. Doubt if you will be happy with a larger carb with out doing other mods to go with it. Jetting is usually all that is needed. Folks, Take jct842's post to heart ! And do not buy a 32mm (BS) more like 31mm racing carb they call it.  The one I got has at least a 125 main jet which is way to big unless you are gonna mod the rest of the breathing system and maybe even port and cam it. Just do what he says. Don't be a Hard head like me. Read more: scooterdoc.proboards.com/thread/13008/mph-more-top-speed-mp250a#ixzz4I4lXi1wE |
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Post by 4950cycle on Aug 22, 2016 9:32:49 GMT -6
First thing I would look at is the rpm at the top speed you get now. Depending on if it is wound out or not to decide on what weights you have and what you need to go to. If you don't have a tach get one on there. If you are a whole lot under red line you need to go lighter in weights which is what I would suspect. Doubt if you will be happy with a larger carb with out doing other mods to go with it. Jetting is usually all that is needed. Folks, Take jct842's post to heart ! And do not buy a 32mm (BS) more like 31mm racing carb they call it. The one I got has at least a 125 main jet which is way to big unless you are gonna mod the rest of the breathing system and maybe even port and cam it. Just do what he says. Don't be a Hard head like me. |
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Post by 4950cycle on Aug 21, 2016 20:23:38 GMT -6
Well, I put in the 32 mm carb today. Lost some acceleration and gained ZIP / nodda on the top end. It has a main jet the size between a #56 and 57 drill bit. I know because I checked. The seller said it is a 125 main jet (no markings) I think I will at least have to back off to a 115 Main jet. I would bet money I'm running rich. Havn't checked the plug yet. Got dark on me. BTW I bet this 32mm carb is no more than a mm bigger than the Japanese made stock carb measured it. Definitely do not buy one of these. Just mod your stock unit like Jct842 said . Save $100
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Post by 4950cycle on Aug 20, 2016 22:25:41 GMT -6
Got detoured on this project. The fuel pump quit so i ordered and installed another one. New fuel pump would starve out the motor at about sustained 60 mph running. I can't understand why because when I pulled the hose off the carb so I could turn the motor over and see how much fuel it pumps with each engine vacuum pulse it pumped plenty to run a 250. Hell, It looked like enough to run a car ! So anyway I put another new fuel pump I have on the scooter, Adjusted the exhaust valve while I was right in the area of the belly. Started her up with no issues. In a tuck it will get my 260 lbs butt up to about 71. But still couldn't go any faster than 64-68 while sitting natural top speed. I may put that 32mm carb I got in the mail today on tomorrow. I hope it won't become a nightmare to make run right. Read more: scooterrebels.proboards.com/thread/2676/miles-hour-257-linhai-jcl#ixzz4Hw8ffDzv |
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Post by 4950cycle on Aug 19, 2016 22:38:46 GMT -6
I'm not familiar with every Jonway 250 model #. But, If its anything like my JCL MP250A your spark plug and fuel pump are accessed from the plastic belly pan. I have a trap door I made for mine. This way every time any itsy bitsy thing goes wrong I don't usually have to rip my entire scooter apart now. Also, I noticed you said you smelled gas. First, make sure no fuel lines are not damaged or pulled off, if not. Then If you can somehow give the float bowl on your carburetor a few sharp wraps to shake your float loose in case it is stuck. If the carb float is stuck open it will super flood. Leaving it hard to clear all the liquid gas out of the cylinder even. The carb float bowl is kind of hard to access on my 257cc Linhai drivetrain. I think the CN 250s drivetrains are easier to get at the carb float bowl from the top (Under the seat).
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Post by 4950cycle on Aug 18, 2016 23:23:27 GMT -6
I wish I could help you. Your scoot looks like a Majesty copy to me. The windsheilds you picked look like they would be correct for your scooter to me in name and design. I liked the windshield nuts you found to. I need a set of those myself. Just hav to figure out what size I need.
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Post by 4950cycle on Aug 18, 2016 20:35:40 GMT -6
First of all what is the rpm at top speed? Do you have any big hills or are you riding in pretty flat territory? Any Idea what the weights are in your variator? Is your belt fairly new and good condition? If you go lighter with weights/sliders it is like going to a lower gear. Heavy weights similar to shifting from 4th to 5th gear. You only have so much power and if geared to high you can go slower. Geared to low and you run out of rpms before you get to the speed you want. Open up the variator and find what their weights are. Clean it out and then take a ride and note the rpms at top speed and get back here with results. If it is gunked up you may be surprised. Put my scooter up on the center stand and took it up to the rev limiter a couple times to find out where it topped out. The RPM went up to about 8400 without breaking up at all. Any higher and the RPM was unstable. But it would go up to about 8700 as indicated on the not so precise scooter tach. What that means is I might get my 5 mph on top if my variator isn't maxing out already. And 16.7 HP will haul my 260 lbs any faster than it already will go. While I've got the belly and side exposed I am gonna do a much needed valve adjustment. " Again " About the 4 th one I've done. "THEN" next on the agenda will be that Marking the inside of the variator test we talked about Read more: scooterdoc.proboards.com/post/118208/quote/13008#ixzz4Hk2ULsNU |
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The one I got has at least a 125 main jet which is way to big unless you are gonna mod the rest of the breathing system and maybe even port and cam it. Just do what he says. Don't be a Hard head like me. 