[photocodo]

Ok, so I have already posted on this topic but it has turned in another direction so I am starting another topic. I purchased a set of carbs from Blindstitch a few months ago and finally got around to swapping them out with my old ones a few weeks ago. When I swapped the carbs I also pulled the airbox and replaced it with pod filters. I then took the H-box off and put emgo shorty mufflers on. Then I rejetted to 95/125. I guess my first mistake was making so many changes at once. After I got all of that done the bike was running however the right cylinder was not running until I hit about 3000rpms. For a while I thought it might be the spark plugs but they were working fine until I made all the changes. I decided it might be the carbs (maybe nothing was getting to the right cylinder until I hit 3000rpms). So I just pulled the new carbs off and switched them with the old ones (I also switched the jets). I put everything back together and BAM, fired right up, both cylinders kickin like she just drove off the assembly line. I rode around for about 10min and everything seems to be working great.

This brings me to my question, the problem clearly lies within the carbs somewhere (more specifically the right carb). Does anyone know why or what could be prohibiting the right carb from throwing fuel or air (or both) below 3000rpms, then at the magical 3000, it wants to work. Does a blockage somewhere seem plausible? I dont know too much about the system but I do know that there are different jets or components that control different throttle levels. Has anyone had this problem before? Thanks for all the help

Cody

 

[Ross]

Ok, so I have already posted on this topic but it has turned in another direction so I am starting another topic. I purchased a set of carbs from Blindstitch a few months ago and finally got around to swapping them out with my old ones a few weeks ago. When I swapped the carbs I also pulled the airbox and replaced it with pod filters. I then took the H-box off and put emgo shorty mufflers on. Then I rejetted to 95/125. I guess my first mistake was making so many changes at once. After I got all of that done the bike was running however the right cylinder was not running until I hit about 3000rpms. For a while I thought it might be the spark plugs but they were working fine until I made all the changes. I decided it might be the carbs (maybe nothing was getting to the right cylinder until I hit 3000rpms). So I just pulled the new carbs off and switched them with the old ones (I also switched the jets). I put everything back together and BAM, fired right up, both cylinders kickin like she just drove off the assembly line. I rode around for about 10min and everything seems to be working great.

This brings me to my question, the problem clearly lies within the carbs somewhere (more specifically the right carb). Does anyone know why or what could be prohibiting the right carb from throwing fuel or air (or both) below 3000rpms, then at the magical 3000, it wants to work. Does a blockage somewhere seem plausible? I dont know too much about the system but I do know that there are different jets or components that control different throttle levels. Has anyone had this problem before? Thanks for all the help

Cody

I found that there was a similar issue with mine when I swapped the carbs out a couple of months ago. The main issue was getting the pilot screws set properly. I'm not sure if it went up to 3000, but one side was definately not running at the lower end. An additional problem is that you need the carbs to be balanced before you adjust the pilot screws, but it can be difficult getting them balanced if it won't idle well.



The process is to get it running at 1100rpm, adjust the screws in turn, from 2-2.5 turns out, until the revs rise to a max and then screw them in to lose 100 rpm, reset the idle to 1100 and repeat. I've found that this seems fairly easy to adjust the first carb, but seems a lot harder to achieve for carb 2. I still don't think this part of the setting has been done on mine too well but it works okay. Until the pilot screws are sorted it's difficult to tell if there are other probs.



Hope this helps.

 

[Shep]

Carb balancing can only be done when all other parts of the carburation and ignition are correct and is the,"Icing on the cake".



In this instance it sounds like a blockage in the slow speed idle circuit/venturi in the carburettor and or possibly a fault with the fuel transfer tube.



Another known cause is debris from a decayed Idle mixture O-ring stuck in the recess.There are four parts to the idle mixture screw set in order of assembly Screw/spring/washer/O-ring.If a small part of the of a damaged O-ring is crushed it can be left in the recess.



The fact that you have fitted pod filters and removed the collector/balance box also mean you have affected the engine's performance and it may never be as good as a stock system.



See this thread,



http://cx500forum.com/index.php?/to...0846__hl__collector__fromsearch__1#entry70846









HTH.

 

[photocodo]

Thanks guys. I will keep going with it.

Cody

 

[Ross]

Carb balancing can only be done when all other parts of the carburation and ignition are correct and is the,"Icing on the cake".

I don't mean to argue, but to clarify if I'm wrong and to help Photocodo, I thought that balancing the carbs went before the final mixture adjustments. The Haynes manual shows balancing following mixture, but I don't think this signifies the correct order of tuning. I can't find my copy of the official procedure, but this is the order I've used when fitting new or rebuilt carbs.



Before this you would need to check that ignition and valve clearances are sorted and that there were no leaks between cylinders and throttle butterflies, as well as the other side, and we're also assuming the rest of the system is okay too. The principle is that you're aiming for balanced pressures/air flow in both cylinders (which can be influenced by piston rings, valve sealing issues and volume issues)which needs to be done before finally adjusting mixtures, not after. If you adjust the air flow, this will affect mixture settings, so they will need to be readjusted. However, as I mentioned, the mixture needs to be near correct, in order for the motor to run well enough to get the balance correct first, so it's a bit of a Catch22 situation.



regards



Ross

 

[Shep]

All manuals have faults or are vague in places so I actually make sure my carbs are close to balanced before making any mixture adjustments and then again after bedding in the carbs and the check then again as a soon as I feel the performance go off.



As I use one of these,



http://www.carbtune.com/



It's very easy.



I wouldn't trust a carb balance if there was a fault somewhere else that could affect the vacuum at the intakes like a Faulty plug or plug cap causing bad reduced firing or a carb boot leak.