Right exhaust is slightly louder/has more back pressure than the left

[Dashiznit1]

Could this be jetting or bad synchronization, or am I looking at something worse? When the bike is cold its a lot more obvious, but when its warm its still the same; I have factory headers with a 4-2 supertrapp open ended exhaust and the right side pipe has more back pressure/is louder than the left.

 

[MaxMidnight]

Whilst it is reasonable to assume that both silencers are identical internally this may not be the case due to manufacturing differences or cock-ups.

By 'back pressure' what do you mean. I interpret this as the pressure waves reflected up and down the exhaust but I suspect you mean something else?

Lets start by reminding ourselves of the basic needs of a motor .
1) It need fuel mixed with air at the correct ratio.
2) It need a spark to occur at the correct time
3) It needs the inlet charge to be compressed before ignition.

Any one of the above may give the symptoms you describe.

I would assume that you have:

• Synchronised the carbs
• If the tamper proof plugs have been removed that the idle mixture screws are roughly set the same.
• With the motor at operating temperature and at idle turn the idle mixture screws to see if the idle speed alters (having noted their position from the check above). If one or more don't have an effect this would suggest a partial or fully plugged idle circuit. Try a carb cleaner first then do 'The shotgun'.
• Checked float heights.
• Checked for air leaks.
• Checked that all the jets are the same.
  
  
  
• Replace the spark plugs.
• Checked the condition of the ignition system and replaced old leads and plug caps.
• Run the bike in a dark but not enclosed space and look/ listen for signs of arcing from the HT system. A favorite place is the LH front cylinder arcing to the coolant hose clip.
  
  
  
• Check and adjust valve clearances.
• Perform a cylinder leakage test.
  

I'm sure there are a few things I have forgotten and that others will chime in with them.

Bottom line though (IMHO) is 'does the bike perform as expected?' If it does then surely your concern is academic?

Should you want to pursue this then any diagnosis here would be guesswork and I'm afraid you will need to get your hands dirty to find the answer.

 

[adambweird]

Mines been like that the entire time ive owned it. It runs great so i dont worry about it.

 

[Dashiznit1]

Whilst it is reasonable to assume that both silencers are identical internally this may not be the case due to manufacturing differences or cock-ups.

By 'back pressure' what do you mean. I interpret this as the pressure waves reflected up and down the exhaust but I suspect you mean something else?

Lets start by reminding ourselves of the basic needs of a motor .
1) It need fuel mixed with air at the correct ratio.
2) It need a spark to occur at the correct time
3) It needs the inlet charge to be compressed before ignition.

Any one of the above may give the symptoms you describe.

I would assume that you have:

• Synchronised the carbs
• If the tamper proof plugs have been removed that the idle mixture screws are roughly set the same.
• With the motor at operating temperature and at idle turn the idle mixture screws to see if the idle speed alters (having noted their position from the check above). If one or more don't have an effect this would suggest a partial or fully plugged idle circuit. Try a carb cleaner first then do 'The shotgun'.
• Checked float heights.
• Checked for air leaks.
• Checked that all the jets are the same.
  
  
  
• Replace the spark plugs.
• Checked the condition of the ignition system and replaced old leads and plug caps.
• Run the bike in a dark but not enclosed space and look/ listen for signs of arcing from the HT system. A favorite place is the LH front cylinder arcing to the coolant hose clip.
  
  
  
• Check and adjust valve clearances.
• Perform a cylinder leakage test.
  

I'm sure there are a few things I have forgotten and that others will chime in with them.

Bottom line though (IMHO) is 'does the bike perform as expected?' If it does then surely your concern is academic?

Should you want to pursue this then any diagnosis here would be guesswork and I'm afraid you will need to get your hands dirty to find the answer.

Sorry, it was late when I wrote that. By back pressure (I know its the incorrect term), I meant the velocity of the exhaust exiting the pipe, i.e. how hard the exhaust puffs hit your hand if you put it directly behind the pipe.

Just going by feel, I can tell exhaust is exiting faster/harder on the right pipe than the left. And yes its academic but at the same time I am very OCD and feel like the exit exhaust pressure on each pipe should be the same given the symmetrical exhaust design.

Also, I just picked the bike up a few days ago and haven't taken it apart yet, so I am not sure about the carb settings or synchronization. It feels like it should probably have a little more power and throttle response, but its not necessarily a dog per se.

 

[Dragmaxster]

I agree with maxmidnight that your best bet is syncing carbs although setting a/f screws "roughly the same" when you have 2 cylinders behind 2 cylinders then it is doubtful they will be need to be set the same. There are different way to set them. Float height is important and air leaks will send rpms' way up. Replacing old leads and plug caps is a bit antiquated as cops are an upgrade that have been around for years. Cheaper too.
Check the valve adjustments if you are over 25k and cylinder pressure also. You are not running a tuned header so most likely it is just a good sync that is in order.

 

[MaxMidnight]

...although setting a/f screws "roughly the same" when you have 2 cylinders behind 2 cylinders then it is doubtful they will be need to be set the same. There are different way to set them.

I agree but what I intended to convey was that one wasn't set at 1 turn out compared with the others at 3.
Ideally each cylinder's CO would be set individually but I have never seen published data as to what this should be.
It is also doubtful if Mr Dashiznit1 has the CO meter that will be needed if he is to adjust to idle mixture correctly.
Perhaps you could elaborate on how best to do this?

 

[thor_eyerdhal]

Probably a bad sync, check the exhaust primaries temp, one on the left should be cold or mild...