Today i phoned my suzuki dealer, needed to book my quad in for a service. Over the service i just mentioned that i was goin to be putting on a new exhaust, just the slip-on. I said i was looking at the HMF slip-on. I told the guy from the dealer that i was going to install the exhaust, remove the air box lid and then rejet.

The guy then told me that rejetting isn't necessary, i was confused here.
He then told me that romoving the air box lid will completely mess up my engine and eventually destroy it.

This is confusing me, this guy can't be right, can he ? Or doesn't this guy know what he's talking about, and is completely wrong ?? I've always heard that what i wanted to do to my quad is ok.

Any info or comments on this very much appreciated.

 

Anytime you change the intake or exhaust and it alters airflow significantly, you will need to rejet. That guy at the dealership doesn't know what he is talking about. As for removing the airbox lid, that CAN definately lead to engine trouble down the road. You will need to step up your filter maintenance routine, because it will become dirty much quicker. In addition, you will have to be more careful of any water crossings, mud runs, or other nasty conditions. The filter can only hold back so much for so long before nasty stuff gets sucked down the intake. If you only ride dunes then it may not be as big of a concern, but the crap I get into from time to time doesn't go along well with no lid[img]i/expressions/face-icon-small-wink.gif[/img]

 

the motor may or may not need re-jetted. Most do. The removal of the air box lid is what will make you re-jet as there will be much less restriction.

I've never had a air box lid ion my R. I don't see a problem.
The previous poster is correct about maint. AND high water. [img]i/expressions/face-icon-small-happy.gif[/img]
Get a K&N with a Sparks foam pre-filter and you'll be fine.

I hope your going to get a quiet exhaust. [img]i/expressions/face-icon-small-smile.gif[/img]

 

Well here is the scrub........

He's right about the lid.... unless you ride in perfect conditions with no water, no dust, and no debris taking off your lid is NOT a smart idea. The last thing you want to do is suck anything but air into that part of the system....I'm an Upstate NY rider too like Scooter86 and we probably ride in the same kind of often nasty conditions....I would never take off my air-box........... besides the gains are minimal anyway......

As far as re-jetting goes, there seems to be two lines of thinking here. I have been told by people that just a slip-on will NOT require a re-jet....others say you do but here is the reality................

Changing the header pipe, tail pipe and running a racing air box absolutely requires a re-jet......

However just a slip-on alone with no other mods should NOT require a reject because you are not changing the air-fuel mixture, you are only reducing back pressure which is a after effect of combustion....

The only reason to re-jet is if you change the air-to-fuel ratio mixture. Opening the air-box up or putting on a racing box will allow more air to enter the system. In turn you need more fuel or the mixture will have too much air and you will run lean.... Just a slip on will not alter that ratio at all and thus there is no need to re-jet.....

However your gains will be minimal with just a slip on. You might notice a slightly quicker revving condition and perhaps a little more low end throttle response but you are not going to see any large gains.

 

When I put the hmf on my ds650 I had to rejet it didnt run right good at all. Prior to the hmf all I had was the k&n airfilter and it ran great but once I put the hmf on I had to rejet it. I also tried it with the stock filter just to see if it would run good and it would not. So I would think depending on the machine possibly you would have to rejet.