Scorpa, Airflow / Carb Questions

[nitjay - hrc]

Today i rode my Scorpa for a bit of a practice, however after about 20mins i noticed that on huge revs (something ive never really needed to use on this before) it was coughing and spluttering like crazy.

I spoke to someone who said (as i thought was likely) there could be water in the float bowl, but as i couldnt take the carb out at the practice i thought id have a look at the airfilter to check it was in correctly.

It turned out the airfilter wasnt fitted properly, this was because the whole airfilter is foam, with no little rubber bit on the top, i managed to open it out and it felt better until later on when it started doing it again. I was wondering perhaps if i could have over oiled my filter. I will get a new airfilter as i have an old one lying around which has the rubber bit on the top and the gap which the air flows through is much larger. I wondered if this was likely to be my problem - lack of airflow. (i read someone had this problem in another post)

However ive just taken the carb out and looked in and sure enough there was a couple of tiny "bubbles" of water in the float boal, i was wondering how much water in the carb it takes for it to cause problems and was this likely to be what was wrong? I also cleaned the Jet which had a very small piece of dirt in. The reason im asking is because i cant tell if its fixed or not as i cant REv it up as much as it needs revving to see if the problem still exists (due to neighbours), and i dont really want to go to the next trial and it start doing it again, so i was wondering if there was anything else i should check - i checked the rubber bits that connect the carb to the engine and aibox and they are fine. Also the spark plug is brand new.

One last point there are three tubes coming from the carb, two i gather were for atmospherics or something, and the third i wasnt quite sure what did, however this third tube has a small hole in this, is it vital i replace it?

Also have you any tips for excellent carb setup on a Scorpa to get it to rev nice and cleanly, as i rode an 03 SY and it felt a lot cleaner.

Thanks for reading!

Edited May 20, 2006 by Nitjay - HRC

[boofont]

My guess would be the bit of dirt in the main jet. When the engine is working hard it's the main jet that's giving it it's fuel. I too had a simliar problem once at a trial. Couldn't get the bike to rev clean on a long hill climb, it kept spluttering etc. Sure enough, a small bit of dirt was blocking the jet.

Not saying this is what's up with yours but if you've found some dirt then I think you may of sorted it.

[eric23]

My local dealer ran out of the aerosal spray filter oil so I bought the bottled variety. At first I kind of drizzled it on and spread out with my hands. Later on I switch to dunking the filter in the oil and wringing it out. That proceedure over oiled the filter. The bike ran very much like yours. My dual sport bike had the same problem and wouldn't pass the the MVD emissions test. I've since cleaned the filters with PJ1 spray filter cleaner and bought a can of spray oil. So far so good. While you have the carb apart go through all the jets and openings with some compressed air, never hurts.

[ham2]

Nitjay..I hear what you say about your neighbours so when you've got your water logged bike at a trial try this---(those of you who are squeamish or may have some mechanical sympathy, turn away now):-

Engine switched OFF/fuel tap ON---lean your bike over on one side flat for about 10 secs.

Then lay it flat on the other side for 10 secs.

You should now be smelling petrol.--put out your cigarette.

Start bike and see how she runs...if that is still no good (disclaimer time);-

Engine ON/ fuel tap OFF----Blip the revs(use up the fuel in the bowl)until you detect the bike reving up by itself..then quickly hold the throttle wide open until she runs dry and quits.

Not nice or quiet I know but I have had some success with this procedure in the field.

This brutal procedure is better than coming down a hill climb backwards.