No acceleration after bike fall By scootro (Read 1,276 times)

[scootro]

I couldn't get to the rollers as have no torque wrench. did remove the cover and did not notice any movement of the belt at the variator end. On the stand it revs very high.

with the engine off and turning the variator manually it did feel like at one part of the rotation there was some restriction.

I think the video idea is excellent. will try to do and upload 2moro.

Also yes the fuel/air mixture needed quite a change after the new air filter. needed to be richer by quite a bit too.

thank you so much for your help. just about everything that can go wrong is going wrong at the mo (not just the bike). it's very nice to have some help

[Alleyoop]

Q1.
So you took the CVT cover off and started the motor and gave it some gas and the BELT DID NOT MOVE UP THE VARIATOR???

Q2.
Turning the Variator by hand at one point some restriction.
A2. That is normal the restriction is because it is on the COMPRESSION STROKE.

And with the FREE FLOW FILTER more AIR SO YES you would have to RICHEN the Mixture up.

Here is how to adjust the CARB CORRECTLY:
Alleyoop

Follow this procedure to tune the carb: Take your time 1/4 turn to much in either direction makes a big difference.


ADJUSTING YOUR FUEL RATIO MIXTURE:

YOU WANT THE HIGHEST RPMS OUT OF THE AIR RATIO MIXTURE SCREW:

Start your scoot and Get The Engine Nice and Hot about 5 minutes so that the Enricher IF it has one is no longer Allowing Extra Fuel to come in. Then do the following to fine tune the Fuel Ratio Mixture:

FUEL RATIO SCREW:

FIRST TRY RICHENNG THE FUEL MIXTURE FROM ITS CURRENT SETTING:


RICHEN THE FUEL RATIO MIXTURE:

1. Turn the Fuel Mixture Screw COUNTER CLOCKWISE 1/4 of a turn and wait 10 seconds to let the engine catch up with the new setting.

a. If the RPMS go up REPEAT #1 UNTIL the RPMS GO DOWN OR NO CHANGE(then go to b).
b. TURN the Fuel Ratio Mixture Screw CLOCKWISE 1/8 and that should be your highest Fuel Ratio Mixture setting—GO TO #3.

******If on the FIRST 1/4 TURN from the STARTING Position IN #1 ABOVE the RPMS GO DOWN OR NO CHANGE , turn the Fuel Ratio Mixture Screw Back the 1/4 turn to the Starting position and wait 10 seconds until the engine catches up -- GO TO #2 ******


LEAN THE FUEL RATIO MIXTURE:

2. Turn the Fuel Mixture Screw CLOCKWISE 1/4 of a turn and wait 10 seconds to let the engine catch up with the new setting.

a. If the RPMS go up REPEAT #2 UNTIL the RPMS GO DOWN OR NO CHANGE(then go to b).
b. TURN the Fuel Mixture Screw COUNTER CLOCKWISE 1/8 and that should be your highest Fuel Ratio Mixture setting—GO TO #3.

IF YOU GOT TO THIS POINT AND NOT INSTRUCTED TO GO TO #3 THAT MEANS THERE WAS NO CHANGE IN RPMS FROM DOING #1 or #2 ABOVE, IT IS TIME TO CLEAN THE CARB:
YOU NEED TO CLEAN YOUR PILOT JET AND PASSAGE AND AIR PASSAGES AND THEN START FROM #1 AGAIN.

IDLE SPEED SCREW:

The Idle Speed Screw on a Carb that are on most 4Ts you will find on the right side on the THROTTLE CONTROL WHEEL. It is the screw with a SPRING on it.

To Lower the IDLE you turn it COUNTER CLOCKWISE to Raise the IDLE you turn it CLOCKWISE.

3. If after adjusting your Fuel Ratio Mixture your idle is to fast Turn the IDLE SPEED SCREW COUNTER CLOCKWISE. For the 50s-150s they like to idle around 1500-1800rpms, for the 250s+ they like to idle from 1800-2000 rpms, pick the smoothest idle with the rear wheel not spinning ---GO TO #4.

TEST YOUR ADJUSTMENTS:

4. Now give the Throttle a QUICK twist and the RPMS should climb up quickly without hesitation or bogging and come down to where you set your Idle at---GO TO #5.

5. NOW take a ride and try it out, the Fuel Ratio mixture may need a tweak in either direction now that the motor has a load on it.

The tweak will be minor maybe a ¼ turn richer or leaner IF it acts up with a load---GO TO #6

6. When it acts up BACK OFF the throttle about ¼ of an INCH AND HOLD IT THERE:
a. If the motor speeds up it is LEAN you need to richen it up a little.
b. If the motor settles down and or stumbles and then settles down it is RICH you need to LEAN it out a little.
GO TO #5 AGAIN.

Problems with the IDLE:

1. Give the throttle a quick twist:
A. If the rpms drop below idle speed, then recovers (or stalls), it is RICH —Turn the Fuel Mixture Screw Clockwise ¼ turns at a time and go to #1.
B. If the rpms do not drop quickly to the idle speed but hang and drop slowly it is LEAN —Turn the Fuel Mixture Screw Counter Clockwise ¼ turns at a time and go to #1.

[scootro]

Dear Alleyoop,

Thank you again Sir. Here is the link to the video of the variator which seems to my inexperience to be working correctly?

www.dropbox.com/sh/mv0smt5kkvojzmx/QpTVmVLaR4

I have not yet been able to apply those greatly detailed tecniques for tuning fuel/air but will do so asap - thanks for the details am looking forwards to applying them.

[Alleyoop]

Well your variator and clutch are working good no problems there.
Alleyoop

[scootro]

Last night acceleration and power was back on for about 30mins after making no changes. today back to slow as anything up hills.

Any ideas?

It's almost like anything above 3/4 throttle just doesn't exist.

totally at a loss here

(add:) worth noting the scooter had not been used for a couple of days and was an unusually wet and cold night - when it ran strongly last night.

[justbuggin]

you may need to reset the float level in the carb when the bike fell the impact could have messed the float level up

[Alleyoop]

If it ran good when it was COLD and wet means it was running leaner. 4Ts love cooler and wet weather even cars tear up the aslphalt when it is cool. So basically your probably running to rich.
So adjust the carb like I said. Once you get it to that point all it takes is around 1/2-1 full turn from HOT TO COLD weather.
Alleyoop

[dent42]

Feb 6, 2013 22:37:44 GMT -6 scootro said:

Ok I've cut away the stock air box leaving the curved tubed where i have attached an after market filter. I figured taping up and cracked air box was just too prone to fault again. I'm sure its running a little better but still no acceleration. top speed is good but really slow getting there.

It's as if the throttle wont go above 3/4. Again the carb is clean and needles/jets look perfect to my eye.

notably with the the bike on the stand it revs like anything albeit with a hesitation. apply torque by putting tyres on the road and back to slow sally.

If you remove the stock air box you have to re-jet the carb or it will run worse. The engine is designed to operate as it came from the factory and you can not change 1 thing without change other things to compensate.