JCL MP250A Runs Poorly 0-40 MPH & No Front Brakes By bob123456789 (Read 3,979 times)

[Alleyoop]

I cannot tell you which side is easier to get at the screw that will be up to you and what is in the way on both sides. Remember I do not have your scoot but I do know how all of them work and they all work the same way 50s, 150, 250s 300, 400s etc.. If you can work on one you can work on any of them the parts may be a little different but the same principal works for all.
Alleyoop

[bobf]

While on the full stand, not the kick stand, I have adjusted my idle to where it runs best for me and my engine. My dash instruments are not usually real stable so my numbers may not be as true as some add on instruments might be.

I start from a cold engine and watch as my engine will climb up into the 2,000 rpm plus some more to about 2,500 rpm. Then at about a minute it will start to slow down and finally end up on about 1,200 rpm or 1,500 rpm. All done in about a minute and a half.

I am still working on my scoot, I believe it is the same as yours, has been going on for a long long time. I was asked to change the mixture screw also but on my scoot I could not find a way to do so as no access for finding the screw on the bottom of the carb.

So now I am slowly tweaking the carb when I have time. I am tweaking to avoid the mess I recently got away from. The engine would start from cold and go straight up to about 3,500 rpm showing. So I have had to slow down the idle to the 1,000 rpm level then the cold starts would be into the 2,000 rpm levels. Now I try to reset the idle while warm and on the stand to be in the mid level, about 1,500 rpm area and not pulling the wheel. My problem being that just a minor tweak on the throttle and the rear wheel starts to turn. I do have the throttle cable set to allow about a quarter inch turn on the outer edge of the grip.

I think the final rpm will depend on the engine and how it is set up with the valves, air system, fuel used, instrumentation, whatever. No two engines will be exact the same so for me getting it to run good is the secret. Exact would be the intended goal.

Hope it works for you, and have a good ride.

[bob123456789]

On the 4T sheet I have the second carb with the long black enricher on top. I have attached your pic again. Your pic shows where the A/F adjustment screw is.

I am attaching a pic of the bottom of my carb. Is the rust colored cylinder related to the A/F screw? The cylinder is right next to the hose clamp from the intake manifold. I am having difficulty identifying the a/f screw on my carb.

Not a fun place to get to period. Especially with the engine running to adjust it.

[bob123456789]

I just pulled the front caliper. I used a couple of boards and a C clamp to compress the pistons using the brake pads. Even with the pistons pushed back there is no brake fluid showing up in the window on the master cylinder.

My first guess is that everything may work, it just needs fluid. The problem is that I had previously tried to add fluid. When I tried to unscrew the Phillips screws holding the cover on the didn't budge and stripped a bit.

How do I open the master cylinder so I can add fluid without damaging anything?

This leaves an obvious question which is where did the fluid go?

[Alleyoop]

Yours has a CAP on it take the cap off to get at the screw.



To get rusted screws or hard to get screws out you need an impact screwdriver they work like a charm.
You can set it to turn in either direction left LOOSEY or right TIGHTY and just give it a nice little whack on top NOT TO HARD just a nice little whack. I had to use it on one of my master cylinder covers to fill it with fluid.

www.harborfreight.com/impact-screwdriver-set-with-case-37530.html
Alleyoop

[bob123456789]

Here is an update.

After removing the cap from the a/f screw I can get to the screw with a ratcheting screwdriver. I have gone a fair ways clockwise and it hasn't made any difference. I am working my way back counterclockwise. I still haven't hit a point that when I turn the screw it impact the idle speed. I have had to modify your steps Alley. I am changing the A/F screw when the engine isn't running. So after a change I let is warm up again for 3-4 minutes before checking the idle. This slows the process down, but my hands are glad they aren't up there when it is running.

The front brake. Using a hammer screwdriver I was able to remove one of the screws. I still need to figure out how to get the other out.

Alley can you take a listen to a video of the CVT so you can tell me if a noise is normal or not. I am hearing that noise and hope the CVT is functioning properly and not impacting me trying to change the idle using the A/F screw on the carb.

View My Video

[Alleyoop]

WOW!! something is not right in your CVT that is making a lot of noise and I see that the wheel turns at those low rpms.
To pinpoint where the noise is coming from take a SCREWDRIVER and touch the cover by the CLUTCH and by the Variator cover and the noise will emit to the handle of the screwdriver and that will tell you where the noise is coming from.

But you need to take the CVT cover off and VIDEO it again without the cover on it and running.
And give it some throttle want to see how the belt moves in the Variator and the Clutch pulley.

Sorry to say but you do have a problem in the CVT.
Alleyoop

[bob123456789]

Alley.

Hopefully you had a nice sunny day and some time to take that nice trike of yours for a ride yesterday.

I have a mechanics stethoscope and listened to the CVT cover. The noise was coming from the back half of the cover. I pulled the cover and found that the nut holding the clutch on was loose. I'm glad I caught that quickly! I am off to buy a torque wrench from Harbor Freight. What torque should it be set to? I am also going to buy some removable Loctite to use on the nut when I put it back together.

I sanded the clutch pads lightly with 400 wet/dry paper since I have it apart and didn't do that last time. There don't appear to be any unusual marks on the clutch pads or the bell where they grab.

Is there anything else I should be doing to fix this?

I have put adjusting the A/F mixture on hold until I get the CVT back together.

Is there any point in me videoing the CVT while it is apart or have we got the issue identified?

[bob123456789]

Anyone know the correct torque to tighten the nut on the clutch to?

I have some removable Loctite I am planning on using. Is that what I should be doing?

I have both a torque wrench and an electric impact wrench to use.

[cyborg]

40 ft/pounds will do it,,,and a drop or two of blue locktite

[bob123456789]

Thanks Cyborg.

[bob123456789]

On the front master cylinder I was able to use the hammer screw tool Alley suggested to remove one of the two screws. I still can't get the second one. Any suggestions on how to get it to crack?

[cyborg]

Soak it with penetrating oil,,,,or just replace the whole thing they are very inexpensive,,,you must have a leak somewhere,,,to be that dry it has to be,,,I hate to put you thru it but I'd be looking at replacement of master/brake line and caliper as well,,,start fresh,,,it's less expensive and less painful to do that than have an accident ,,I never take any chances with braking systems,,,

[bob123456789]

Cyborg.

Tried the penetrating oil thing. I let it soak an hour. Still not able to get it to crack loose. I am only able to put the oil on the top and the threads are down a ways. I am guessing that the oil isn't getting all the way down to the threads.

Any other suggestions to help fix it?

Also, any recommendations for where to look to find the correct one at a reasonable price? Roketa wants $90 here:

www.roketa.com/product/parts_detail.jsp?partId=31021&partName=STEERING ASSEMBLY(5)

[thecableguy]

Bob, Isn't all you need is the master cylinder? Scrappy has one with the lever for $25.

Go to this page and scroll almost to the bottom Gy6 right master cylinder with lever