RX-1 Exhaust donut

[glas0233]

Hey everyone,

I just finished replacing the exhaust donuts in my 2003 RX-1 with copper ones. What a pain, I can't believe Yamaha thought it was a good idea to use allen heads.... My question is, the left exhaust has a slight backfire at idle. what could be the cause of this? thanks for the help!

 

[AftonJay]

Try holding a gloved hand or something over both exhaust tips and see if it wants to stall. I guess it is not uncommon to have the header crack also which may be what is happening, I doubt you burnt through since it is an 03, those are the steel not Ti. Did you replace the other two fiber like gaskets where the headers meet the pipes attached to the muffler?

 

[glas0233]

Try holding a gloved hand or something over both exhaust tips and see if it wants to stall. I guess it is not uncommon to have the header crack also which may be what is happening, I doubt you burnt through since it is an 03, those are the steel not Ti. Did you replace the other two fiber like gaskets where the headers meet the pipes attached to the muffler?

Hey Jay, thanks for the reply! To replace the donuts I did not need to separate the pipes from the muffler. I will plug the exhaust this afternoon and see if it stalls. From my limited visual inspection it didn't look like anything was cracked.

 

[glas0233]

Hey Jay,

I plugged the exhaust and it wants to stall almost immediately which I assumes means the exhaust is intact and the donuts are working as intended. I also just got the carburetors cleaned. could the backfire be caused by carbs that are not synced correctly?

 

[AftonJay]

That's a good sign and it sounds like the exhaust is solid. With the back fire occurring at idle it could be carb sync but you may want to double check the cleaning, those idle jets are pretty small as you know. I have heard of guys on here cleaning them two and three times but since you already did it I would go with the sync first if you have the equipment. Does it rev good? Does the backfire get worse on deceleration after revving?

 

[glas0233]

That's a good sign and it sounds like the exhaust is solid. With the back fire occurring at idle it could be carb sync but you may want to double check the cleaning, those idle jets are pretty small as you know. I have heard of guys on here cleaning them two and three times but since you already did it I would go with the sync first if you have the equipment. Does it rev good? Does the backfire get worse on deceleration after revving?

Hey Jay,

Yeah it revs good and when I give it some throttle the backfire becomes less noticeable. I am going to check the coils and if that checks out I will pull the carbs again. Thanks for your help!

 

[blkhwkbob]

It almost seems like when you do your donuts, you loosen up crap in your fuel system, and the carbs need almost two cleanings. I could be imagining this, of course, but I speak from a lot of experience.

 

[glas0233]

It almost seems like when you do your donuts, you loosen up crap in your fuel system, and the carbs need almost two cleanings. I could be imagining this, of course, but I speak from a lot of experience.

Thanks for the response! I did make the mistake of cleaning the carbs and synchronizing them before I changed the donuts. I am thinking now that the exhaust is not leaking anymore the carbs are out of sync?