81 GS650 tuning help Dynojet stage 3

[Gsnoob]

Oh really that's all they wanted me to do lol okay so how will that affect my tuning will I have to retune idle and will that affect my W.O.T

Just take the vent hoses off and leave the T's open

[UncleBen]

It shouldn't effect much. I didn't notice much of a difference when I finally took mine off.

[Gsnoob]

lol I was hoping youd say yeah that might just straighten out your W.O.T. I actually rode it to work yesterday to get a real test ride and its only like 7 miles

It runs fairly smooth actually the bog is non existant in 1-3 and 4th is very very minimal and only at high rpms however 5th still has big issue past half to 3/4 sputters and bogs down till let off it cruises at 55mph okay with a minor what i would describe as a bog or chug here and there i dont know what else to call it you can just feel a little chug in the bike here and there at 55 but we are talking few and far between the chugs

Still im open to any suggestions before ordering another set of mains.

Like i said needle clip still in top notch with washer below it.

Was gona ride it again today after removing vent tubes but its raining and dont wanna get stuck on side road in pouring rain

It shouldn't effect much. I didn't notice much of a difference when I finally took mine off.

[UncleBen]

Well, it may just make a difference. Try and see. Have you done any more plug chops to see what's going on with that stumble?

If it's still rich, do you have room left for a washer above the clip? That would lower the needle one final half notch.

[Gsnoob]

Yeah I chopped it lastnight on way home in 5th during the W.O.T stumble and plugs wernt black but were much darker then should be so yeah shes still rich at w.o.t. in 5th and little in 4th at around like i said 7kish

As far as needle clip I could prolly move the washe that there from bottoom of clip to top but i dont know that the little plastic washer that sits ontop needle would stay but i can surely remove the little silver washer from bottom of clipi think that would let it fall maybe another half notch.

Well, it may just make a difference. Try and see. Have you done any more plug chops to see what's going on with that stumble?

If it's still rich, do you have room left for a washer above the clip? That would lower the needle one final half notch.

[UncleBen]

Removing the washer from under the clip won't lower the needle any. It will just effect the pre-load on the spring.

[Gsnoob]

Well I pulled my tubes lol oh i wish i would have done that from the get go like the install sheet told me to. FINALLY I have W.O.T through all gears 5th has no bog at all after removing the tubes. Could hold her open all way to top speed i bet.

Makes me wonder if i had pulled the tubes from get go if i woulda been able to stay on the 160 mains. But oh well like a week or two left of riding anyway up here in MN after Oct 1st snow could fly anytime, maybe in the spring ill through the 160s back in when i do my V&H 4-1 just to see if i can get her tuned right on them. Now that ive pulled it apart a million times lol I feel pretty comfortable with the carbs

My question now is being that I have my idle and W.O.T going shoudl i make any other adjustments or leave it alone and ride it cause it feels pretty smooth now I will do some chops on way home tonght to find out how shes really running make sure didnt lean it out or something when i pulled the tubes.

Removing the washer from under the clip won't lower the needle any. It will just effect the pre-load on the spring.

[trippivot]

yep .. like to hear some positive news

Remember this is the best air of the whole year -- late cool summer and all the leaves making all that oxygen.. Your bike is going to eat as much gas as you throw at it

spring and summer = not many leaves and hot-humid... less "air" cause of water- ok? so you get it tip top now and next year it is going to too rich. Next year about Memorial day you may lean it out a touch.


but I'd make a 2 groove change and chase the power (bad ~good) until it runs the way you like it.

Once you get idle and WOT with a plug color you like, the rest is micro changes - that is why I go 2 so I know where too far is, and come back at it.

[Gsnoob]

Thanks trip ill make the micros now but ill have to retune next spring anyway because im 100% sure im putting a 4-1 on this bike cause its LOUD with these straights. lol Dont get me wrong it sounds mean and wicked and she turns the heads of even the Harley guys around here but my god im gonna go deaf lol and im only 25. Plus the 4-1s looks pretty nice on these bikes. I really like that cafe look I think some clubman bars a 4-1 and maybe some paint changes with the new pods shes gonna look sweet and very unique for what you see around here.

Well im pretty sure at this point my micro carb adjustments will go well specially with all the advice to look back on so I dont know how much i will still be posting to this thread. So i wanted to take sec and thank all of you who have given advice and helped me through getting my bike running! Im sure youll see me again on future projects wiht this bike or problems lol lets hope projects vs problems. Once again THANK YOU to all.

yep .. like to hear some positive news

Remember this is the best air of the whole year -- late cool summer and all the leaves making all that oxygen.. Your bike is going to eat as much gas as you throw at it

spring and summer = not many leaves and hot-humid... less "air" cause of water- ok? so you get it tip top now and next year it is going to too rich. Next year about Memorial day you may lean it out a touch.


but I'd make a 2 groove change and chase the power (bad ~good) until it runs the way you like it.

Once you get idle and WOT with a plug color you like, the rest is micro changes - that is why I go 2 so I know where too far is, and come back at it.

[trippivot]

zoom - zoom -- I like quiet street bikes these days. My V&H megaphone is packed and I have a set of 36mm CV's peak tuned for smoothness..I haven't touched mine in 2 years 1150cc~36 mpg.

need help anytime just ask

[keman]

This has been a very informative thread. I learned a bunch and it's not even my thread!!

[IanDMacDonald]

Noob-

Reading through this whole thread, my first thought was that the mains were too large for running your bike without the pods! You were running way too rich, causing the fouling of the plugs. I'm glad you put the pods on. I have posted a couple of guidelines on here from my XS forums I belong to for CV carbs. I have the Mikuni MKII's on my Yammie, which are very similar to the BS32SS'. My main jet (stock) was 132.5, and I have a 135 in there and she runs like a raped ape in a cage. Mikuni main jets go up in 2.5 size increments.

My suggestion is when working with stock stuff (airbox, pipes, etc.), stay stock sizing in jets. Sometimes something is overlooked that causes a condition most attribute to poor jetting characteristics, such as a poorly sealed air box, cracked boots, fouled plugs, etc.

When switching to pods, 3/4-1 exhaust, main jets should not have to go up in size not much more than a couple of sizes, with a pilot jet size for every two main jet changes.

I've thought about using dynojets over the years, but, found that studying cv carb fundamentals and really knowing how they should run helps you jet properly without the use of dyno kits.

[TheCafeKid]

Noob-

Reading through this whole thread, my first thought was that the mains were too large for running your bike without the pods! You were running way too rich, causing the fouling of the plugs. I'm glad you put the pods on. I have posted a couple of guidelines on here from my XS forums I belong to for CV carbs. I have the Mikuni MKII's on my Yammie, which are very similar to the BS32SS'. My main jet (stock) was 132.5, and I have a 135 in there and she runs like a raped ape in a cage. Mikuni main jets go up in 2.5 size increments.

My suggestion is when working with stock stuff (airbox, pipes, etc.), stay stock sizing in jets. Sometimes something is overlooked that causes a condition most attribute to poor jetting characteristics, such as a poorly sealed air box, cracked boots, fouled plugs, etc.

When switching to pods, 3/4-1 exhaust, main jets should not have to go up in size not much more than a couple of sizes, with a pilot jet size for every two main jet changes.

I've thought about using dynojets over the years, but, found that studying cv carb fundamentals and really knowing how they should run helps you jet properly without the use of dyno kits.

Ian, not trying to make you out to be an idiot or anything but a dynojet kit isn't about the jets. It's about the needles.

The needles in a set of stock GS CV type carbs are not designed to feed the necessary amount of fuel to the engine with a pods/pipe setup.
The tapper is not fast enough. To compensate for this people often stick massive main jets and too large pilots in the carbs. What ends up happening is a bike that is wet and sloggy in some places, and dry and hot and lean in others. The bike is not running to it's potential. I've never dealt with XS carbs, though I'm sure they're similar in design, but I can tell you and anyone else that trying to rejet CV carbs by hand without changing the design of the needle is a futile, time consuming wasted effort.
Even if you were able to turn down your own needles out of Alu, it would either require copying someone elses tried and tested design or a lot of trial and error.
$120 or so may seem like a lot of money for some needles and jets but you're paying for the R&D that went into them. They've been tested and found to optimize fuel/air delivery at all throttle openings for a full stage three set up.
Even still most find that the suggested setting for the needle clip on the lean side and have to move the clip a whole or half step to dial it in just right.

I wholeheartedly beleive that if your were to install a DJ kit on your yamaha, you'd find a whole new level of power out of that bike. I'd be willing to bet quite a bit of money on it.

I tried for many months to jet a set of GS CV carbs myself. The needles simply do not work. I even had Canada spec adjustable needles.

[IanDMacDonald]

You are absolutely right! I keep forgetting that the GS carbs have a non-adjustable needle! The MKII's came with an adjustable needle, which rarely needed a notch moving unless you modified in some sort of way.

[TheCafeKid]

You are absolutely right! I keep forgetting that the GS carbs have a non-adjustable needle! The MKII's came with an adjustable needle, which rarely needed a notch moving unless you modified in some sort of way.

Like I said, never cracked a set of XS carbs. id be interested to see the shape of the needles as well.

And, don't think I'm a Dynojet fanboy or anything. There are other companies that make kits that are just as if not more effective for different models.
Currently in my ZRX I have a dynojet kit and I'm not a fan of it. The needles in that kit stop metering far to early at the top end and the bike starts to drown a bit. There are other, reportedly more effective kits on the market, such as Holeshot, Factory Pro, and supposedly the best, Ivans kit. I'll be giving te Ivans kit a try this coming season. I feel like the bike is leaving a little on the table just by the seat of the pants dyno. Actual numbers say 127rwhp and 82 lb.-ft of torque but some guys with roughly the same set up are seeing 135 and 85.. And with the feel at the top end, (sometimes I have to back out of the throttle to get it to spin up more or it falters a little) I think they're probably right.

Anyway, like Tripp said...its part science, part art, and mostly voodoo.