Is it just me and my Rev3? I've noticed that when dropping down steep / long inclines my Beta acts like its trying to load up - kind of burbles a bit making me want to blip the throttle to clean it out (doesn't want to idle very well till the terrain flattens out).

Is this only my bike, a Beta trait (raw gas getting dumped in the inlet tract when the carb throat is pointing toward middle earth), or something that happens on all bikes?

Hiya...Sorry, I can't be of any technical help...all I can say is it doesn't happen on my 2002 Rev 3 250. Good luck sorting it!

I encountered this on an '02 Scorpa.

It was actually a bad carburetor...machined incorrectly. A rare occurrence, I guess, but maybe worth mentioning.

The bike would actually die if the back wheel got more than a couple feet above the front. No amount of tweaking would help.

A new carb cleared it right up.

I naturally pull in the clustch and give the bike a blip when going down stuff, so i haven't noticed anything.

Go to the Billy T. Mikuni carb set up on this BB. http://www.trialscentral.com/forums/index.php?showtopic=310 My float tang was put on upside down form factory? Any way I hadn

Don't get this problem exactly, but I find that if I leave my bike ('01 Rev3) parked up facing downhill so the front is lower than the back, I sometimes have a nightmare getting it fired up again. It seems to flood very easily. I didn't have the same problem with my Techno

I've experienced the petrol-urination problem, fixed it, then when my bike went into the dealer for a service, they unfixed if for me!!!

So now, whenever I park facing downhill, I turn the fuel off. And then halfway through the next section I run dry cos I forgot to turn it back on again......

As always, BillyT is your man for this kind of stuff...

KB.

Who's Mr. unibrow?

In keeping with the theme, I had a girlfriend once that had a uinbrow. Her head movements were similar at times as well. Darned if she too did'nt p*** all over the place when the back end was raised higher than the front. Think that's why I got rid o'her.

Just a thought but how much petrol do you have in your tank when you go down this incline?

This happens to me and my m8's sometimes, we go out for a ride then on the way back we always try the mother of all climbs.

Coming back down it is so steep that obviously the fuel is at the front of the tank (lowest point) whereas the feed tap is at the back/highest point *(EDITED)* and we almost always have to coast back down as the bike cuts out.

I'm surprised this has not been mentioned in any of the above posts as its the first thing that should've been thought of.

Also when coasting or doing long downhills its recommended to pull in the clutch and give a blip of the throttle now and again just to get some fresh fuel mix into the barrel.

Edited January 23, 200422 yr by superflytx270

Also when coasting or doing long downhills its recommended to pull in the clutch and give a blip of the throttle now and again just to get some fresh fuel mix into the barrel.

Superfly, good call I had to reread the original post and it did say steep / long inclines. Blipping the throttle is a must to keep the cylinder lubricated since the oil is in the gas!

Copemech, got her phone #? Sounds like we have allot in common! Head movements are from a nervous tic; hopefully hers aren

Suprflytx wrote.

"Coming back down it is so steep that obviously the fuel is at the front of the tank whereas the feed tap is at the back/lowest point and we almost always have to coast back down as the bike cuts out."

Mmmm I guess you missed physics class that day.

Think about what you are saying/proposing.

I have heard this before and it holds no credabilty as the fuel will always seek a level of the earth not the hill. Sceptical !!! Take a cup of water 3/4 full, turn the cup heavly to one side. Did the water follow the cup or did it stay parrallel with the ground.? Meaning with the cup held at right angles to the ground the water is parrallel to the rim of the cup, tilt the cup and the water is no longer parrallel with the rim but rather stays at the same plane to the ground. It stayed at the same plan as the ground and so does the gas in the tank.

The amount of gas in the tank would always spalsh around trying to go through the fuel spigot.

It would always try to seek the lowest point in the tank, that is why the spigot is at the lowest point. If you are telling me that the spigot is higher then the gas in the tank then we have some other more serous problems.

There would still be gas in the float bowl. If you were coming down a hill one would presume that you were running on the idle circut (no throttle or very little) as the hill is very steep, on the idle circut the amount of gas in the float bowl is more than sufficent to keep the bike feed for fuel in this scenario.

More of a problem is that the gas level moves away from the jets cuasing it to suck in some air. This is a documented problem and can be remided by setting the float level higher for more fuel. It also trys to go into some other jets that it should not (too hard to explain at this time of night).

Not trying to bash your theory, but been there done, that heard that.....

I do however agree about blipping the gas to keep things cleaned up.

Yer na a braw we loon, but ma heids nipping wae aw this techincal patter.

BillyT

BillyT

I did not miss physics

i re-read my previous post and have edited it accordingly.

Your theory is correct but bear in mind this is at the end of a ride when we tackle this climb hence not much petrol left after 3 hours riding!!

The hill is that steep that the spigot is at a guess (and i mean a guess) 2 - 3 inches higher than the fuel level hence starvation.

Any bike will cut out in that scenario i would have thought???????????

Please excuse the crudity of the attached drawing.

The fuel will not always splash around and find its way specifically to the tap.

This happens to 6 bikes are you suggesting we all have serious problems because the spigot is higher than the fuel in the tank and all at the same time.

Another option is that if the float bowl is indeed full then at such angles maybe all that fuel is being tipped up into the main body of the carb hence flooding ?

The answer is - do your steep drop offs when you've plenty of fuel in the tank then see what happens.

Edited January 23, 200422 yr by superflytx270

Or an even better diagram which proves my point :

Edited January 23, 200422 yr by superflytx270

Actually I understand your first post Superfly However, the float bowl holds sufficient fuel for fairly long runs at idle speeds. If you want proof, shut off your gas petcock and leave the bike idle...it will sit there idling for quite a while. Now granted if the steep drop is longer than that, yes you will have a problem (we out here in Eastern Canada don't have to worry about hills that long ). Now, the carb drawing from the float, that can be another problem.

Blipping the throttle will only make this situation worse though, as you are using up more of that fuel in the float bowl...although still a good idea regardless.

Spoke to a handy beta rider today who confirmed this fault on his 03. Beta do a specific part which I think goes on the bottom of the float bowl, gives extra capacity and solves the problem. As it is a beta part best to buy from John Lampkin.