So i was looking on the gs wiki at air filter upgrades as the stock air box is always a pain in the ass to get back on, im tempted to go for the k&N lunchbox filter as it seems to leave alot of space between the battery housing and the end of the filter, making it look like its quite easy to take on off etc.
I was wondering whther the K&N lunchbox filter (RU-2970) would fit on a k4 gs500. All the photos show it on a GS500e with the old style carbs. Does anyone know whther the new style carbs with the vacuum hoses etc on them have different spacing between the intakes on the carbs.
Also does anyone from the UK know of any good places to buy the filter? Amazon has it for £44.
And is there any reason i shouldnt go for the K&N lunchbox filter, are the individual pods better? Or equally as good?
And lastly i was wondering whether anyone had any good jetting for a 2004 gs500 with stock exhaust and a K&N lunchbox filter. Thanks alot for the help!
The filter will fit your bike.Lay it in the sun if there's any around or use a hair dryer to heat the air filter carb boots.It's easier to get the jetting correct if you do an exhaust upgrade at the same time as the filter.This way you only rejet once and get maximum gain from the filter and rejet.All my bikes are early models so I can't advise on jetting.
okay thanks, can you recommend any exhausts?
Quote from: DaielHancock on June 08, 2011, 11:02:09 AM
okay thanks, can you recommend any exhausts?
I am in the US and there is a bigger following for the GS in the UK.I'd have a search there for an exhaust.I have a custom exhaust on my 89 and my other 3 bikes are running stock exhaust and air filters.Check this out.It may help you decided. http://wiki.gstwins.com/index.php?n=Upgrades.Exhaust
The lunchbox will fit no problem - I've never even had to heat mine up to get it on my '05. It slides on with no effort every time.
I only have a lunchbox now and use the jetting in my sig. I think it may be a hair on the lean side, but other than the rare backfire on deaccel, I haven't had any other issues. Power delivery is smooth through red line, throttle response is quick and consistent, and no signs of detonation using regular pump gas.
I highly recommend it, not just because the performance gains and ease of service, but it also adds a very nice sound.
£44 is kind of steep - they're about $30 USD on Amazon here in the States, so you'd be paying more than double. I guess that's the price you pay for buying American goods, but please feel free to do your part to help balance our trade deficit!
I really don't know if there is any benefit over using individual pods or vice-versa.
Quote from: LimaXray on June 08, 2011, 11:26:30 AM
The lunchbox will fit no problem - I've never even had to heat mine up to get it on my '05. It slides on with no effort every time.
I only have a lunchbox now and use the jetting in my sig. I think it may be a hair on the lean side, but other than the rare backfire on deaccel, I haven't had any other issues. Power delivery is smooth through red line, throttle response is quick and consistent, and no signs of detonation using regular pump gas.
I highly recommend it, not just because the performance gains and ease of service, but it also adds a very nice sound.
£44 is kind of steep - they're about $30 USD on Amazon here in the States, so you'd be paying more than double. I guess that's the price you pay for buying American goods, but please feel free to do your part to help balance our trade deficit!
I really don't know if there is any benefit over using individual pods or vice-versa.
Thanks for the reply, it was very helpful. So you think you have yours jetted a little lean, on the wiki it says 20/65/142.5, for just the lunchbox, would you say thats probably to rich then?
Also does anyone know a good UK place to get a K&N RU-2970 " lunchbox "?
Quote from: DaielHancock on June 08, 2011, 01:42:19 PM
Thanks for the reply, it was very helpful. So you think you have yours jetted a little lean, on the wiki it says 20/65/142.5, for just the lunchbox, would you say thats probably to rich then?
I'm glad to help. I can't really say - I've only ever tried the jetting with what I have now and have been happy with it enough to not bother changing it. It's not bad lean, no more lean than stock at least.
I suppose if I were to want to mess with it, I would try 20/65/140 . The deaccel backfires are caused by a lean pilot circuit, so I would probably play with pilot screws and maybe go up to 22.5 on the pilots. I think just backing out the pilot screws a little bit more would be enough though. Unfortunately, I don't remember how many turns out there are now.
Back firing through the exhaust on deceleration is a sign that unburnt fuel is passing through,into the exhaust,and firing off inside the hot header pipes.
Quote from: ben2go on June 08, 2011, 03:25:02 PM
Back firing through the exhaust on deceleration is a sign that unburnt fuel is passing through,into the exhaust,and firing off inside the hot header pipes.
Yup, and this is usually caused by an incomplete burn due to a lean mixture or too advanced ignition timing. It only happens to me when the engine and the air is cold, and since I avoid these conditions anyway, I don't worry about it.
Quote from: LimaXray on June 08, 2011, 03:42:59 PM
Quote from: ben2go on June 08, 2011, 03:25:02 PM
Back firing through the exhaust on deceleration is a sign that unburnt fuel is passing through,into the exhaust,and firing off inside the hot header pipes.
Yup, and this is usually caused by an incomplete burn due to a lean mixture or too advanced ignition timing. It only happens to me when the engine and the air is cold, and since I avoid these conditions anyway, I don't worry about it.
A lean mixture is not enough fuel getting burnt to produce max power.A rich mixture is to much unburnt fuel passing through into the exhaust.
Quote from: ben2go on June 08, 2011, 03:54:51 PM
A lean mixture is not enough fuel getting burnt to produce max power.A rich mixture is to much unburnt fuel passing through into the exhaust.
Yeah a rich mixture can cause it too, but that's certainly not the case for me - my plugs tell me its stoich/lean. In order for gasoline to burn entirely, you need to be pretty close stoichiometric. Too lean or too right you get an incomplete burn.
With carburetors, deceleration backfires are almost always caused by a lean condition. EFI engines fix this by cutting the fuel entirely on decel.
Not that it matters, but CV carbs are notorious for popping on decel. With the throttle closed (butterfly valve) there's very little air/gas going into the combustion chamber. Hence, the lean condition.
I have a lunchbox and I have trouble not having Back firing when closing the throttle. Yet my plug are showing no sign of lean mixture and otherwise the bike run PERFECTLY, great accelerations. >:(
I have just been reading the gs wiki and it talks about clip position and washers on the needle when it comes to jetting. Can someone explain this to me? i remember there being a small clip on the needle does it just mean the position of that?
Quote from: DaielHancock on June 09, 2011, 10:11:37 AM
I have just been reading the gs wiki and it talks about clip position and washers on the needle when it comes to jetting. Can someone explain this to me? i remember there being a small clip on the needle does it just mean the position of that?
US bikes only have one clip position on the needles,so we compensate by adding #4 washers.Most other countries get bikes that have four clip positions on the needles.The needles help richen the mixture at full throttle and when the slides start to rise.Each washer or clip position that raises the needle adds more fuel into the mix.
I think this link will help you understand a little better.
http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html