Hey guys, I went into my Suzuki dealership's parts department today looking for a new set of jets for my carb. Based on the feedback from this forum I came up with some numbers (132.5, 62.5, 27.5) for the different sizes I needed. When I went into the parts shop though, the guys told me rejetting was a bad idea.
One guy in particular said that his partner "lives" the industry and has seen hundreds of dynonometer runs on all types of Suzuki's, including my '05. He said, that in all of his runs he's never seen a single one come lean from the factory. He said in fact, that if anything, they all come a little rich to protect themselves from different elevations.
Their advice was to simply let it be. They both said that rejetting would add very little, or nothing noticible performance wise, and could very well cause the spark plug to foul out.. As a matter of fact, the one guy said that if I increased the size of the mains anymore, he'd almost guarantee it. I asked about possibly adding in a new K&N air filter, and again they said it might make some little difference, but unlikely not much at all for the $50 it cost to get it.
Now the clincher is this. They said that if I wanted the stuff, they'd go ahead and get it as they had it in stock, but it was their advice not to do the rejet and just save the money. A parts dealership telling me to save my money?? Because of this, I tended to believe them, and wondered if anyone here had any opinions on this.
Added the K & N luchbox filter, and a wileyco exhaust did rejet and I noticed a difference for the good. btw you can get the jets from www.sudco.com they would be cheaper and I think it's USdisel.com that thas the K & N luchbox for real cheap. Then again maybe it was my imagination that it seemed better :icon_mrgreen:
k&N jets and a exaust you can get up to 12 hp or so abot a 25% increase in power over stock. if they came rich from the factory, "to protect themselves" and you rode to a higher elevation whare the air was thinner, then they whould be way rich due to the decreased O2 available in the atsmophere, and whould foul plugs. your dealer is full of asshats, and they just didn''t want to deal with you, because you have a gs and not a gixxer, is what it comes down to. either go find a new dealer or order online and do it yourself. it's not hard, it's all bolt ons with simple hand tools that you can do in a afternoon in a parking lot. so don';t worry about it. and find a new dealer.
i agree with davipu, er karma. its well known and an established peice of knowledge that the bikes are set up to run lean at certain rpms-specifically at certain rpms-the rpms that the bikes are tested for emissions at. magazines talk about this all the time. and there are boatloads of people on this forum alone that know first hand how much rejetting helps.
h6
Quote from: Wrecent_Wryder on May 27, 2006, 12:15:40 AM
+1
Rejetting mine made a huge difference, night and day, not something you could just imagine away. It's just flat-out a much better ride now. The original jetting is apparently what happens when engineering decisions are being made by politicians. In retrospect, I consider the uneven, constantly wavering throttle that the factory jetting caused to be borderline unsafe.
IMHO, the only real question is whether they're trying to decieve themselves and you, or just you.
The dealership was essentially correct. They were telling the OP that no power gains would show up on the dyno after
rejetting. It's true that one can improve throttle response and rideability with minor carb tweaks although the '05 model may have already addressed these issues to some extent with the addition of the mid-main jet. :dunno_white:
The most optimistic gains one can hope for can be found on the GSTwin.com dyno run: http://www.gstwin.com/dyno_run.htm (http://www.gstwin.com/dyno_run.htm)
This is not simply rejetting.
With a drop-in filter, a V&H pipe, and Dynojet kit, this set-up yielded 43.2 HP on the dyno. Most sources have the stock GS500 at about 39.5 RWHP, so if we presume that the 43.2 HP figure for the piped & jetted GS500 is relative and accurate, there is a gain of < 4 HP--or about 9% which may be worthwhile if you can get away with riding around town with a racing pipe (louder than you might think).
However, I did say optimistic because there was no stock run on this dyno with which to make a comparison--results can vary from dyno to dyno--and I've definitely seen lesser numbers posted from similarly modified GS500's. And the recorded gain is peak power; the powerband may well show losses at lower RPM's.
[g
All UK 2001+ models come with 115 mains :) because of strong european emmision control. My dealer also says dont mess with the carbs, because he just lacks knowlegde about it. If it wasn't for gstwins.com i would still be afraid of changing anything on the bike, and thanks to all gurus here i am doing everything myself, even messing with the carbs. The first time i opened them i felt like i was doing it 10th time.
So trust the guys here more than your dealer or some car mechanic.
im going to be playing with my jets tomorrow.
I am running 20, 62.5 and 145's i believe.. but its still lean on the top end... with teh K&N.. i can feel it bog down a bit at 80mph.. so i am going to shim the needles tomorrow and see how it does.
Greetings all,
New 05 500f owner here. Had the bike about a month and really like it. Alot better than the Rebel 250's we rode in the safety class.
Anywho; As I was saying, It's an 05 with about 200 miles on it and I must say that it runs really rich all the time. It loads up bad while idleing and stutters on take off. On deceleration (engine breaking) it will sputter and backfire a bit. My dealer suggested to try the K&N to lean it out before messing with the carbs. Any thoughts out there on this?
If rejetting and K&N will cure the throttle jerks and the rich running issues which seems to be what all are saying then this is what I need to do. Right?
i like my bike just the way it is . i'm just waiting to get the money so i can get my jarden exaust ,k&N and rejet ( i go to the local mom and pop cycle shop :) i like to sport them better then the stealers ) i know the owns son pretty well . we go riding all the time ( he has a 94 CBR 900RR ) he was telling me the same thing rejet . with the power to weight ratio just about any hp gain is noticable and will make the bike feel like a new beast :)
I rejetted my 05 F a couple of months ago, and well I'm very pleased with the outcome.
I also added a K&N lunchbox filter. It went from a tame little motorbike to one that has a slightly larger stones. :cheers:
It has better top end and is quicker to throttle up then ever before.
I do not who told not to waste your money but it's your bike, do what you want to make it better then factory stock.
By the way the new K&N lets you hear the motor, sounds like an engine not a sewing machine. :thumb:
Quote from: Firegod42 on May 27, 2006, 08:46:35 AM
Greetings all,
New 05 500f owner here. Had the bike about a month and really like it. Alot better than the Rebel 250's we rode in the safety class.
Anywho; As I was saying, It's an 05 with about 200 miles on it and I must say that it runs really rich all the time. It loads up bad while idleing and stutters on take off. On deceleration (engine breaking) it will sputter and backfire a bit. My dealer suggested to try the K&N to lean it out before messing with the carbs. Any thoughts out there on this?
If rejetting and K&N will cure the throttle jerks and the rich running issues which seems to be what all are saying then this is what I need to do. Right?
A brand new bike (200 miles), should not be loading up. The jerky throttle is most likely a lean condition. If it is loading up after it warms up and with the choke off, I would take it back to where you bought it. Something is not right. New bikes are never, ever, rich, right from the factory. Emissions laws won't allow. it.
ok... size 12... where di you get those numbers for a rejet???? thats not quite what I would recommend.
BYpass the stealers... they DO come lean from the factory and that is all there is to it...
You can find the K&N's online for 30 bucks... if you order from a mom and pops shop or just go to the service dept. at yoru local stealer adn ask for 127.5-132 main jets for a mikuni carb and 40 pilots (no bigger... if at alll just one step up) It should cost all of 10-15 bucks. If you order online you'll pay shipping. Go to lowes and buy some #4 washers and install it on your own. Its really easy and If you want I'll talk you through it via phone.... i'm sure there are some gs'ers here that live near you... where are you at?
Plus... those sized are way off if you're wanting a stock bike... (ie no filter or pipe.) PM me if you want specific ?'s answereed
I got those numbers from this reply (http://gstwins.com/gsboard/index.php?topic=12930.0) by Roadstergal about rejetting the '04+ models. I made a mistake on the OP. It was 22.5 pilots (one step up) not 27.5. I basically took all three jets and went one step up on them, as I will be adding a new air box at the same tme.
Anyways, I've already had the carbs apart, and removed the stock jets, as I brought them into the dealership with me. I do appreciate the offer for a walkthrough though :cheers: that was cool of you. From what I'm reading here though, it sounds like people ARE noticing a smoother powerband with the new jets. So regardless of what the dyno guy says, I think I'm going to go ahead and rejet.
I don't know of any Mom & Pop places around here that do any bike business, so I guess that leaves an online wholesaler. I'm from Michigan btw, Lansing area. Home of the broken asphalt, tar snakes, and 100 mile straightaways. :thumb:
good on ya, stuff those gits, glamourised parts changers :icon_mrgreen:
Quote from: badkarma506 on May 26, 2006, 09:54:27 PM
k&N jets and a exaust you can get up to 12 hp or so abot a 25% increase in power over stock
I want to see that improvement, drunk karma....3-5 HP max about 10 % in real world
hi dave
add a comma and a period in there.
a exaust you can get up to 1,2 hp or so abot a 2.5% increase
Quote from: badkarma506 on May 26, 2006, 09:54:27 PM
k&N jets and a exaust you can get up to 12 hp or so abot a 25% increase in power over stock.
I've got dyno sheets that say otherwise, 50 horses at the wheel is a huge improvement. My '01 with individual pods, Jardine full exhaust, V&H advancer, and two hours on the dyno netted 45 at the wheel (albeit at 4500ft elevation). The next 5 horsepower are going to be tougher and moer expensive to get.
Quote from: aplitz on May 27, 2006, 06:41:29 PM
Quote from: badkarma506 on May 26, 2006, 09:54:27 PM
k&N jets and a exaust you can get up to 12 hp or so abot a 25% increase in power over stock.
I've got dyno sheets that say otherwise, 50 horses at the wheel is a huge improvement. My '01 with individual pods, Jardine full exhaust, V&H advancer, and two hours on the dyno netted 45 at the wheel (albeit at 4500ft elevation). The next 5 horsepower are going to be tougher and moer expensive to get.
just curious what jets your running with the individual pods?
sorry im busting in on this thread :icon_mrgreen:
Quote from: hmmmnz on May 28, 2006, 01:28:18 AM
just curious what jets your running with the individual pods?
sorry im busting in on this thread :icon_mrgreen:
Sorry bro, I never got those numbers. They did numerous jet changes during the two hours on the dyno, and we were just stoked to see a good curve and good hp numbers.
No Power gains ... rich from factory ...
WTF ... rejet it and do it right ... you will swear its a different bike ... Add a pipe and the filter you like and set it to that and trust me it will be a different bike.
Cool.
Srinath.
gonna bust in here with another q'n... :icon_mrgreen:
with my bike getting the unifilter pods and the remus exhaust, i was wondering if the dynojet kit will have enough for the 05...
Do a mikuni DIY jetting. That way you have plenty of room to go up or down if needed.
Cool.
Srinath.
The likelihood of the hotdoggers on this forum out-engineering Suzuki and Honda engineers is just laughable. No, it's hysterical. No, it's gut-wrenchingly silly. After 26 years on a Suzuki GS400, the 2 years on a 2001 GS500 that runs perfectly and gets 70+mpg, all I can say is, don't fuc* with the carbs. Unless you just like to needlessly screw around with stuff.
Cheers,
Let me add a little bit to my last rant. The GS500 engine is nearly identical to the old GS400-425-450, which also used the twin Mikuni carbs, starting up in 1977. What I like best about the new GS500 (I have a 2001) is the electronic ignition, and the fact that it gets up to 75mpg, which beats the old 400 which got maybe 50 mpg.
So here we have a twin Suzuki motor virtually unchanged for about 30 years, giving Suzuki's engineers plenty of time to tweak the carbs, ignition and other components. Everything is in balance. The Japanese are not fools. Their automotive and other engine technology is second to no other. Why in the world would they market a motorcycle that delivers less than the best possible worlds of economy, reliability and performance? A clean-burning, low emmissions vehicle is not running lean, it's running just right. Just ask the folks at Honda who make the cleanest, most fuel-efficient and most reliable vehicles on the planet. The Suzuki dealer who told you to leave the carbs alone is giving you sound advice. Ignore these hot dog wrench-benders who haven't a clue.
Cheers,
Quote from: ballyhoo on May 30, 2006, 08:19:55 AM
The likelihood of the hotdoggers on this forum out-engineering Suzuki and Honda engineers is just laughable. No, it's hysterical. No, it's gut-wrenchingly silly.
I don't think anyone's saying that Suzuki engineers suck. Just that they've been put in a difficult position and were forced to make compromises that riders don't agree with. People on this forum are pretty quick to cut through the BS, and I haven't seen anyone yet say that the emperor has no clothes (in this case "I did a rejet and it sucks.") I'm sorry, but if I hold up your firmly held (seemingly untested) belief against the experience of a dozen or so people who have done it and seen the benefits, I have to believe the dozen or so. And they can rejet without insulting the honor of the engineers who designed the bikes that we love so.
........"So regardless of what the dyno guy says, I think I'm going to go ahead and rejet."...................
I say go for it!! In the worst case scenerio you can always put the stock jets back in. Either way, it'll be a great learning experience working on your bike.
Chris
I like my bike a lot, and I also appreciate the work of the good engineers who designed the GS500 and its predecessors. I also think of the GS500 as (in it's way) a lot like the 1967 VW Beetle I owned. It was a great car, one that ran fine, was economical, reliable (do the maintenance!) and fun to drive. I suppose there were a handful of afficianados who attempted to hot-rod the 1967 Beetle. Do you suppose they believed the VW engineers were "making compromises that drivers don't agree with?" Granted, the post-1967 Beetled suffered a bit from the imposition of anti pollution fixes, but the 2001 Suzuki GS500 doesn't have that stuff. Unless you count the crankcase vent back to the airbox.
My beliefs are nothing compared to those of the folks on this discussion group. I just go with what makes sense for my bike. The last one I had lasted 27 years and the jets were never altered. I did have to unclog a stuck float needle a couple of times.
Cheers,
engineers didn't design these bikes, accountants did. engineers just fixed the most blatent fuckups. why do you think it took them 5 years to figure out that the heads were crap and that they needed to fix them, or 11 years to go to a three jet carb?
it's all about costs at the factory.
Quote from: ballyhoo on May 30, 2006, 11:54:38 AM
I suppose there were a handful of afficianados who attempted to hot-rod the 1967 Beetle. Do you suppose they believed the VW engineers were "making compromises that drivers don't agree with?"
Absolutely yes. I suppose the engineers compromised a bit of performance for better reliability and durablility. As an engineer (software, not cars) I do this all the time, and I would expect the car guys to do the same. Engineering is balancing a number of conflicting factors to create a product. If you have a different opinion about the importance of those factors that changes the resulting engineering.
If you bore out a cylinder, for example, you know you're changing the way it will handle heat and stress, but you do it to increase performance. This is something I know first hand that a lot of reasonable people did on that era Beetle. If these are your priorities and this is what you decide to do, then way to go. This is not defiling the engineers' perfection, this is saying "I want something slightly different" and doing it.
Quote from: badkarma506 on May 30, 2006, 12:00:23 PM
engineers didn't design these bikes, accountants did.
Okay, I could have saved a lot of typing. That's what I was getting at.
67 beetle - very very good ... BTW they made the beetle since 53 ... why the 67 in your argument.
BTW the heads are total crap in the 67 and 68 and the 69 and the 70 even ... when did they go to the 2 letter prefix ... That was the first decent ones.
BTW in the case of the GS ... it does have EPA crap ... its the way the carbs are jetted. They put diffeferent jets in Canada vs US bikes. US being leaner - one of those is a mistake, they put different advancers in the 49 state bike vs the CA bike ... one of those is a mistake ...
Your bike may be running great and giving you great gas mileage, but these were made with such loose tolerances ... Someone else's ... most other people's bikes behave completely differently. BTW how many miles on yours ... you are that lean, it may be running much hotter than the average and hence have effects related to that in terms of life.
You'd rejet mainly to lower operating temp ... aka rich enough to run fine on the hottest day but other than that use up as much gas as possible ... OK OK sounds horrible, but you're still talking under 3-4 mpg max. A real lean bike once hot will actually make more power ... you'd pay for it in longevity ... but power will be there ...
I jet mine always on the coldest day ... and if it runs fine on the hottest day i am happy.
Cool.
Srinath.
Quote from: ballyhoo on May 30, 2006, 08:37:14 AM
Let me add a little bit to my last rant. The GS500 engine is nearly identical to the old GS400-425-450, which also used the twin Mikuni carbs, starting up in 1977. What I like best about the new GS500 (I have a 2001) is the electronic ignition, and the fact that it gets up to 75mpg, which beats the old 400 which got maybe 50 mpg.
So here we have a twin Suzuki motor virtually unchanged for about 30 years, giving Suzuki's engineers plenty of time to tweak the carbs, ignition and other components. Everything is in balance. The Japanese are not fools. Their automotive and other engine technology is second to no other. Why in the world would they market a motorcycle that delivers less than the best possible worlds of economy, reliability and performance? A clean-burning, low emmissions vehicle is not running lean, it's running just right. Just ask the folks at Honda who make the cleanest, most fuel-efficient and most reliable vehicles on the planet. The Suzuki dealer who told you to leave the carbs alone is giving you sound advice. Ignore these hot dog wrench-benders who haven't a clue.
Cheers,
alright maybe you like the gas millage but we dont care as much as you do...... we want to add a lil bit of power in case you didnt realize what were trying to do!!!! and yes they know what their doin but they have restrictions and now we dont so were puting are bikes to how we want it to be
2001 GS500 comes stock in US with 127.5 main jets, and in United Kingdom with 115 jets. And they put in such small jets not because they tried to design GS perfectly :). Poor engineers are strangled by men in suits. I bet none of suzuki engineers who ride motorcycle dont ride it stock.
They also designed front forks perfectly :)
And the back shock ... and tires ... and the tank that rusted and turned into a seive after 3-4 years ... yea ... :thumb: ...
Cool.
Srinath.
Everything is a compromise.
The GS500, is a compromise.
The great designers quote is....
you can have it either cheap, perfect or quickly. Pick Two!
Cars have quiet exhausts, because the have noise limits to pass, and most people don't like loud exhausts. This is done at the compromise of flow. It really depends what you are looking for.
Designers and Engineers try to please the highest common denominator. Buyes may be turned off by a polluting gas guzzling bike, but they know performance tinkerers will be happy buying the fuel efficient, clean running bike and modify it to get better performance.
i agree cause its eazyer to put performance parts and..... most people care about gas consomption...noise....reliability.....and then a lil bit of performance...... in the end they cant satisfy everyone.... if they could then it wouldnt be cheap to by a gs500 any more
Just as an update, I went ahead and did the rejet. I have an '05 GS500F.
- K and N Lunchbox Filter
- 20 Pilots (Up from 17.5 stock)
- 60 mid mains (60 stock no change)
- 132.5 mains (Up from 130 stock)
This is like a totally new bike. It's unbelievable. :icon_lol: It sounds meaner, runs much better in the low rpm range, and takes off from stops without a stutter.
I just want to thank everyone on here who recommended this adjustment. If I had followed the advice from my dealer, I would not have done this, and would have missed out on a valuable performance upgrade. Anyone thinking about doing this to their bikes, I'd strongly reccommed it, regardless of what you might hear from other sources. Trust the people that have seen it and done it. It's worth it.
Quote from: Size_Twelve on June 16, 2006, 04:14:59 PM
Just as an update, I went ahead and did the rejet. I have an '05 GS500F.
- K and N Lunchbox Filter
- 20 Pilots (Up from 17.5 stock)
- 60 mid mains (60 stock no change)
- 132.5 mains (Up from 130 stock)
This is like a totally new bike. It's unbelievable. :icon_lol: It sounds meaner, runs much better in the low rpm range, and takes off from stops without a stutter.
I just want to thank everyone on here who recommended this adjustment. If I had followed the advice from my dealer, I would not have done this, and would have missed out on a valuable performance upgrade. Anyone thinking about doing this to their bikes, I'd strongly reccommed it, regardless of what you might hear from other sources. Trust the people that have seen it and done it. It's worth it.
You're probably going to find that it runs lean and will get hot. I have the exact same mod and it took me literally DOZENS of carb pulls to get it right. My plugs were white before and now they are brown. I think I'm still a little lean on top, but not much.
22.5 pilots/65 mid-mains/137.5 mains