Honda Shadow Forums banner

1 - 6 of 6 Posts

·
Registered
Joined
·
688 Posts
Discussion Starter #1
I have an '02 SS 750. The previous owner put cobra drag pipes on (which I really like). I asked my local dealer if the previous owner had to rejet when he put the Cobra's on the bike. He said most likely he did. Then he asked how the bike runs. I told him it runs very good, runs smooth, no hesitation, but it has a good bit of decel popping. He said that is another indication that the previous owner rejetted. He also said that another indication would be if the pipes and plugs are showing a rich mixture. So all indications are that the carb was rejetted for the Cobra drag pipes.

Now here's the question. IF I put a K & N filter on do I need to rejet again? If I am presently running rich and getting decel popping I would think that a K & N would lean out the mixture. Perhaps simple adjustments of the mixture would be enough.

If I can go to a K & N without having to rejet I'd do it tomorrow.

Pastor Ron
 

·
Registered
Joined
·
119 Posts
I'm no expert, but popping on decel is usually a lean mixture. I know mine started a little (only when cold outside temps) when I did the hole saw mod. You should be able to richen the idle mixture by adjusting the jets. Pretty easy from what I have heard, but I haven't messed with mine yet as it only does it when cold, and only once in a while.

Definitely check the plugs for signs of a lean mixture. Doing the filter upgrade will lean it more and more than likely you would need to re-jet again...

For those who wonder how restrictive the stock air filter is, try taking it out and start the bike up.... Rev it a few times, you will see....
 

·
Registered
Joined
·
327 Posts
If I may ask wiithout hijacking the thread, I have stock pipes with the rear baffles drilled out to 1/4". I'd like to go to K&N also. Would I need to rejet? I really don't feel like getting into a rejet for an air filter, but I also hate paying $20+ for throw away filters.
 

·
Registered
Joined
·
688 Posts
Discussion Starter #4
rejet

OK, I pulled my plugs and they were a little on the black side, a slight black carbon, nothing serious but definately on the black side. The inside of the pipes have a slight black carbon soot, kind of like charcoal chalk dust. The bike and plugs have 14,000 miles on them. Am I correct in thinking that carbon build up is evidence of the mixture being a little rich? :?
I also thought that decel popping (backfiring) was unburned fuel firing back through the pipes and can possibly be from a rich mixture! I could be wrong... one thing I am... willing to learn!

Ron
 

·
Registered
Joined
·
628 Posts
My opinion, it's worth what you're paying for it... :)

Your bike may have been rejetted, or maybe only the mixture screws were backed off. The only way to know for sure is to open the carbs. As was posted above, popping on decel is usually caused by being lean.

I think your bike will run fine with the K&N filter, without any additional jetting work.

(re-read first line.. :))

A question: Why do you want the K&N? (unless you think it will help your bike run better...) A K&N costs ~$50. A cleaning kit costs I think around $15. There's $65 invested. An OEM filter lasts what, 2 years? I'm not sure what they cost, but say $25. That $65 will supply your bike with >5 years worth of OEM filters. You will have to keep the bike >5 years before the K&N will be cost effective. Most people (not all) do not keep a bike 5 years.

Disclaimer: I have the K&N, and purchased the cleaning kit. :D Would I do it again? No.
 

·
Registered
Joined
·
369 Posts
K&N Filter

If you are currently rich adding the K&N will increase the potential air flow and possibly cause a leaner mixture. Notice I say "possibly". An engine can only take in as much air as it can exhaust and an engine can only exhaust as much air as it can intake. Fuel air mixture is greatly affected by the flow dynamics of the intake, combustion chamber, valve size and exhaust.

From pesonal experience, the K&N wil increase air flow potential and, depending on exhaust restriction, increasing the air factor in the air to fuel mixture ratio thus leaning out the mixture. I would bet you will still be slightly rich, but better to be slightly rich than lean. Slightly rich engines run cooler.

I put K&N air filters in every one of my cars, bikes and boat the 1st time they need a filter.
 
1 - 6 of 6 Posts
Top