Kawasaki Vulcan Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
I've had my "09 900 Classic since April 20, 2010. I bought the bike new it has 1400 miles on it. I was using 91 octane fuel for a while. But recently I switched gas stations. The new place I go does not offer 91 octane, they have 93 octane. Since switching, I've noticed a throttle body backfire that happens on quick throttle input (feels like the air cleaner is gonna blow off!!!). Dealer had nothing. Does anybody else have this. Is it just the higher octane....or something else? Just wondering.
 

·
Registered
Joined
·
657 Posts
Sounds like you're running a bit rich with your fuel/air mixture. You may need an adjustment or a fuel management device....
 

·
Registered
Joined
·
719 Posts
The engine won't loosen up until around 3000 miles and at least mine got a lot better around 5000 miles. I think you're dumping fuel faster than the engine can use it since it's still tight. Go slower with the throttle or one time it's going to stall just when you wish it wouldn't.
 

·
Registered
Joined
·
343 Posts
I would try using the lowest octane see if that helps.I just switched to 87 after reading the long thread on here about octane.Bike runs great on it feels like it pulls harder.
Someone else just started a thread about this & I,m wondering if changing the throttle position sensor on these bikes that do it would help this to get the timing better.I know my bike never does it.
 

·
Registered
Joined
·
719 Posts
Changing the TPS setting is an old trick used on late 90's Dodge Dakota's to prevent stalling when stepping on the gas prior to being completely warmed up. I haven't had a need yet to my service manual on whether or not it can be easily done on a 900. On most cages it usually means just drilling out a brass insert around the attaching screw and the few thousandths gained is all that's needed. You need to probe the TPS wires to set it properly but I don't yet know the voltage on the 900.
 

·
Registered
Joined
·
60 Posts
I mentioned that I have this problem if I snap the throttle quick to match revs when down shifting. This happens when the RPMs are down low.

Related? Baitis mentioned a secondary throttle plate. He said he removed his. I just decided to be more gingerly with my throttle inputs.
 

·
Registered
Joined
·
5 Posts
Discussion Starter #7
Just filled with 89 octane. Low fuel light was on. Took 4 gallons. One mile out of the station, noticed the difference. Definate better throttle response. time will tell. Thanks fellow Vulcanites.
 

·
Registered
Joined
·
719 Posts
Higher octane is harder to ignite so I would expect more frequent backfiring using 87 or 89 fuel. A different gas station may help since E10 fuel is a problem at stations that don't monitor the tanks like they should.
 

·
Registered
Joined
·
343 Posts
Yes,using lower octane is like advancing the timing,because it burns quicker
 

·
Registered
Joined
·
5 Posts
Discussion Starter #10
Well, 89 octane did reduce it for sure. But it still does it. That said, I can say, there was a marked improvement in throttle response. I'm starting to think it's the overall fuel volatility from that gas station.
 

·
Registered
Joined
·
245 Posts
i just bought a 2008 with 1220 miles on it, the owner i bought it from said he only put in high octane, could this possibly have harmed the engine considering the engine was fresh. i plan on sticking to 87 because its cheaper and that's all the bike needs, and apparently runs better on it. Is there anything i should look at or inspect?

thanks sean.
 
1 - 11 of 11 Posts
Top