|
|
Post by rockynv on Aug 18, 2016 3:52:27 GMT -5
One danger with the sliders is that on some bikes the belt may ride far enough past the rim of the variator to pull any oil sump gaskets it comes close to out. Not sure about the Yamaha design however on a number of dry sump engines this has been an issue. Simply trimming any excess gasket material sticking out into the belt path off with a razor will many times be all thats required to prevent this.
|
|
Sophomore Rider
Currently Offline
Posts: 183
Likes: 4
Joined: Mar 4, 2013 19:49:04 GMT -5
|
Post by 4950cycle on Aug 21, 2016 0:51:39 GMT -5
One danger with the sliders is that on some bikes the belt may ride far enough past the rim of the variator to pull any oil sump gaskets it comes close to out. Not sure about the Yamaha design however on a number of dry sump engines this has been an issue. Simply trimming any excess gasket material sticking out into the belt path off with a razor will many times be all thats required to prevent this. I will check my CVT housing once I open her up for any oil sump gaskets. I was slowed down by a defective fuel pump replacement. 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. , 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 one up top speed. I may put that 32mm carb I got in the mail today on tomorrow. I hope it's won't become a nightmare to make run right. Read more: scooterrebels.proboards.com/thread/2676/miles-hour-257-linhai-jcl#ixzz4Hw8ffDzv |
|
|
|
Post by rockynv on Aug 21, 2016 8:09:29 GMT -5
You really need to adjust both valves with the engine cold for 24 hours before going too crazy on this. A vacuum fuel pump relies upon the pulse of the intake in order to work effectively and if the valves are not adjusted correctly the pulse will not be sufficient at high speed to keep up so your float bowl can start running low causing your engine to run lean and hot. When that happens you increase your chances of burning a valve or a hole in the piston top.
There is also a chance if the bike had been sitting unused for a lengthy period of time that the ethanol evaporated to the level of the high speed jet and clogged it with floating scum. If the needle valve seat has swelled from the ethanol then your float level can now be so low that the high speed jet may no longer be fully submerged in fuel and sucking air instead also limiting top speed.
Before adjusting the carb both valves need to be adjusted precisely followed by carburetor cleaning/float adjustment along with the very often overlooked throttle cable adjustment. Many skip checking the throttle cable adjustment check however as they wear in they become slack and no longer pull the throttle fully open limiting top speed. Adjusting the throttle at the grip is a standard maintenance check for any motorcycle that should be done at least annually however it is overlooked by many and it can reduce top speed by 5/10/15 or more mph if there is slack in it.
|
|
|
|
Post by ricardoguitars on Aug 21, 2016 8:36:47 GMT -5
A bigger carb has to go with bigger ports, bigger valves, and bigger exhaust; otherwise you are just waisting fuel.
|
|
Sophomore Rider
Currently Offline
Posts: 183
Likes: 4
Joined: Mar 4, 2013 19:49:04 GMT -5
|
Post by 4950cycle on Aug 21, 2016 22:17:08 GMT -5
Well, I put in the 32 mm supposed performance carb today I got from Ebay . Lost some acceleration and gained ZIP / nodda on the top end which is what I was looking for. It has a main jet the size between a #56 and 57 drill bit. I know because I checked. The Chinese 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 have learned from another 32 mm carb advertisement . I would bet money I'm running rich. Just for now no air filter, Still stock muffler. Havn't checked the plug yet. Got dark on me. BTW I bet this 32mm carb is no more than a measured 1 mm bigger than the Japanese made stock carb. Definitely do not buy one of these. Just mod your own. Save $100 Again, Mod your stock carb and save your $100 IMO. Any suggestions Read more: thescooterprofessor.proboards.com/thread/4573/linhai-257-32mm-performance-carb#ixzz4I1jocbiV |
|
Sophomore Rider
Currently Offline
Posts: 183
Likes: 4
Joined: Mar 4, 2013 19:49:04 GMT -5
|
Post by 4950cycle on Aug 21, 2016 22:54:26 GMT -5
Rock, Clean new carb, Adjusted valves. As far as recardoguitars , New carb only 1 mm bigger. Very , Very little difference in size actually. Not enough difference to need anything different to function properly I wouldn't think. Pretty much a big waste of my $ and time. Should just stay with my higher quality stock carb . Thanks for the input though. PS the cable adjustment thing has happened to me before , keeping me from WOT
|
|
Sophomore Rider
Currently Offline
Posts: 183
Likes: 4
Joined: Mar 4, 2013 19:49:04 GMT -5
|
Post by 4950cycle on Aug 22, 2016 11:32:07 GMT -5
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/13015/gram-sliders-linhia-257cc-260#ixzz4I4zAryxk |
|
Sophomore Rider
Currently Offline
Posts: 183
Likes: 4
Joined: Mar 4, 2013 19:49:04 GMT -5
|
Post by 4950cycle on Aug 23, 2016 0:56:24 GMT -5
I feel I should cap this 32 mm carb fiasco off with this. 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. And the old Jap 30 mm goes right back on with no more than one jet size higher or lower than stock. , It might even run the best with this 115 main jet it came with. Now off to the slider subject I guess .
|
|
Sophomore Rider
Currently Offline
Posts: 183
Likes: 4
Joined: Mar 4, 2013 19:49:04 GMT -5
|
Post by 4950cycle on Aug 24, 2016 23:13:30 GMT -5
I went to put on my old carb on today to get ready to do the variator test. What a BEACH 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  Read more: scooterdoc.proboards.com/thread/13008/mph-more-top-speed-mp250a#ixzz4IJVfHYMq |
|
Sophomore Rider
Currently Offline
Posts: 183
Likes: 4
Joined: Mar 4, 2013 19:49:04 GMT -5
|
Post by 4950cycle on Aug 26, 2016 0:44:42 GMT -5
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 |
|
|
|
Post by ricardoguitars on Aug 26, 2016 7:11:49 GMT -5
Did you made that run with our without the air filter on? If the filter was off, it probably is sucking too much air, get the filter on; if the filter was on, probably too much fuel, if you changed the jet, you have to trial and error with the jets and the air/fuel mixture screw to get to the right setting.
|
|
Sophomore Rider
Currently Offline
Posts: 183
Likes: 4
Joined: Mar 4, 2013 19:49:04 GMT -5
|
Post by 4950cycle on Aug 29, 2016 0:50:45 GMT -5
I thought you said this 32 mm carb wasn't going to work ? Now I take it off and go back to stock carb, stock 115 main jet now you tell me I should have experimented with the 32mm carb. After you said that I didn't want to waste my time trying to tweak something that wouldn't tweak. And I am still having a hard time trying to find a vacuum fuel pump that will pump sufficient fuel. My float bowl keeps running empty. I finally got a Chinese Jin Bo brand vacuum fuel pump just like the one that just lasted 7 + yrs. on it. Ordered it on Ebay tonight.
|
|
|
|
Post by ricardoguitars on Aug 29, 2016 7:13:58 GMT -5
It should work, if tuned right, but you won't get any benefit out of it, just wasted fuel compared with the stock carb.
|
|
|
|
Post by rockynv on Aug 29, 2016 7:29:54 GMT -5
Something to watch out for is which vacuum port you have the fuel pump connected to. Some people switch them around and accidentally hook them to one on the carb instead of the unrestricted port on the intake manifold between the carb and the head. Sometimes the port gets partially clogged with hose debris which won't allow even the best fuel pump available to work properly and keep up at higher speeds. If its connected to a vacuum port between the slide an the air filter then it would be amazing that the bike would run at all however some have been run like that too albeit not running well or very fast.
|
|
Sophomore Rider
Currently Offline
Posts: 183
Likes: 4
Joined: Mar 4, 2013 19:49:04 GMT -5
|
Post by 4950cycle on Aug 30, 2016 1:09:57 GMT -5
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 . And yes I am on the correct vac port fitting. But now that you mention it the vac power is on the weak side. I touched the hose to my tounge.
|
|
