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2012 Beta 125 revs increase on incline


gazzaecowarrior
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Hi there. My bikes revs dramatically increase when bike is on an incline (front higher than rear). Even an incline as little as 10 %. I've checked floats and they are set properly and appear to cut off when perfectly horizontal.

This has been a long running occurance. This weekend I have stripped and cleaned carb, decoked front pipe, cleaned and repacked silencer, cleaned air filter, new plug and changed premix to Castrol power 1 racing. Running 50:1. I'm going to have a play with the air screw and get that set properly as I think it's running rich.

Any idea what could be causing this ? Obviously it was like this before I carried out the weekend maintenance.  I just wanted to check everything was clean and functioning before I started looking for a reason for this increase in revs. I find if I stop for any reason on an incline I have to kill the engine as the revs pick up so much it annoys me. Bike runs perfectly albeit a blackish plug.

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What happens if you start it up in neutral and lift the front wheel? Just to confirm that the bike being inclined is the cause, because to be honest it's baffling.

The oil choice and ratio isn't ideal, but it also isn't part of the problem, I just think you'll get spooge using a high ratio of oil that's meant for sustained high rev usage.

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7 minutes ago, totty79 said:

What happens if you start it up in neutral and lift the front wheel? Just to confirm that the bike being inclined is the cause, because to be honest it's baffling.

The oil choice and ratio isn't ideal, but it also isn't part of the problem, I just think you'll get spooge using a high ratio of oil that's meant for sustained high rev usage.

It happens when in neutral. I don't tend to notice it when I'm riding.

I had been using putolene strawberry but had been recommended the Castrol so I thought I'd give it a go.

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6 hours ago, rcgods said:

The floats should not be horizontal. They should be parallel to the carb body when held at a certain angle


Follow the instructions here

 

 

Thanks for the info. I meant parallel not horizontal. However I had also set my floats like picture 3 rather than 2. Could be worth a look. Thanks

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6 hours ago, dan williams said:

The routing of Beta throttle cables isn’t the greatest. Are you bumping up against the cable? Is there any play in the cable? Do you pull the throttle full on before you start the bike to make sure the cable housing is seated? 

No there is zero play on my cable. Revs do not increase however whatever position my handlebar is put in on either side of the opposite locks. No adjustments are possible to loosen and increase throttle cable play as all adjusters on throttle, cable and carb are round right in. No I don't pull throttle to seat it before starting. I will try it though thanks.

Any opinion on Castrol power 1 racing fuel mix ratio ? Container says no leaner than 50:1.

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My money is on the throttle cable, zero play with adjusters wound right in is not normal, I can't think of any way in which being on an incline would pull the throttle though. I was part thinking of this when I asked about lifting the front as it rules out the rider pressing on the cable but it sounds like that isn't the cause anyway.

 

80:1 is the norm, 1.5% is the figure from the Beta manual for synthetic oils, 4% for mineral.

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1 hour ago, totty79 said:

My money is on the throttle cable, zero play with adjusters wound right in is not normal, I can't think of any way in which being on an incline would pull the throttle though. I was part thinking of this when I asked about lifting the front as it rules out the rider pressing on the cable but it sounds like that isn't the cause anyway.

 

80:1 is the norm, 1.5% is the figure from the Beta manual for synthetic oils, 4% for mineral.

Thanks for the oil info. I may lean mine out. Just mixed 5 litres at 50:1 with some in bike already so I will measure out remaining fuel in can and recalculate. 

Although I agree there should always be some play in the throttle cable. I can't see how not having it would affect the revs on an incline. The geometry of the bike is not being altered and nothing is being pressed or squeezed.  Even when on a paddack stand and I manipulate the incline the revs increase. The cable looks standard into a standard beta throttle housing. However for the sake of £15 it is well worth trying a new throttle cable. I will measure out my cable when I remove carb to do float check and compare length to new one.

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The float is the only thing that should be affected by angle, but you started with it. Any other cause will be something odd and unexpected, but it still has to be something that can raise the revs so; throttle, enrichment/choke, ignition advance, or an air leak.

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2 minutes ago, b40rt said:

If you are very careful you can shorten the outer cable, which effectively give some slack for the inner.

Agreed. If you have a dremel handy (if not, check Lidl/Aldi this week) you can mark and cut the outer and with some finesse, leave the inner intact.

 

Alternatively grab a ‘cable repair kit’ set like Oxford sell. You cut the old cable out, ideally at the throttle end. Fit the new (repair) inner cable, and cut some cm’s longer than the original. Then you attach a barrel end to the throttle side, and with the adjusters, work out how much slack you want before cutting (and ideally soldering) the excess.


The second option is what I did with my Sherco, as I didn’t like the look of this kink in the outer when I bought the bike used. I actually cut a whole length of bicycle brake outer, added ends and fitted a new cable. It was cheaper than purchasing as I had all the parts laying around.

7C8FDF1B-94AA-49D6-A83F-0BEB3EACE292.jpeg

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1 hour ago, totty79 said:

The float is the only thing that should be affected by angle, but you started with it. Any other cause will be something odd and unexpected, but it still has to be something that can raise the revs so; throttle, enrichment/choke, ignition advance, or an air leak.

Im going to re-examine the floats again this weekend. I will check them as described in picture 2 of that link rather than picture 3 as I did. It's worth a look.

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