Back firing and spudder

[boomer91]

Hey everyone, I just went on my first somewhat long ride on my 81 and it did great shifted perfectly, brakes were great. When i got back to my crib i left the bike running for a few mins and noticed that it was doing a kind of back fire/spuddering thing. I took it for another ride and all good, had plenty of power with no struggle. So i pulled the plugs after the second ride and they looked good, no blackness or anything. Not sure if this is due to needing a valve adjustment or maybe bad fuel??? Any input on this would be great.

 

[bcware]

Ride the crap out of it and see if you can recreate the same thing. If it only happened once and seems to perform fine I would just keep riding it for a bit and see if you can really pin it down.

 

[boomer91]

Is there a way to post videos? I took one after the second ride...

 

[bcware]

Throw it up on youtube and link it here.

 

[boomer91]

Kinda hard to hear it...

 

[bcware]

Intake leak or carb boot leak.

 

[boomer91]

Ok cool i'll inspect the boots for tears or looseness tomorrow. Thanks!

 

[bcware]

Look at your intake and air filters too. Loose clamps or cracks, etc.

 

[xschris]

Also it would be good to sync the carbs

 

[boomer91]

Ok so I went out and pulled the air filters off and checked to rubber boots that attach to them, couldnt find any cracks or tears. Then I looked at the other side of the carbs and found this....

 

[willem]

go buy some new ones

 

[boomer91]

Know a good online store that sells new ones?

 

[willem]

not really but my first guess would be ebay or mikesxs

 

[boomer91]

found these but they say for a specialII. Is there a difference?


http://www.ebay.com/itm/Yamaha-XS40...amaha|Model:XS400&hash=item5af9a960e9&vxp=mtr

 

[xschris]

Ebay has them for cheap around $40 with gaskets.

 

[xschris]

http://www.ebay.com/itm/NEW-77-81-Y...Parts_Accessories&hash=item2ecf9f6f30&vxp=mtr They will work but I found this guy also. A few dollars more but has a better feedback score