Re: GS not revving over 6000 rpm FIXED

[xlayn]

First than nothing, hello everyone, this is my first post, but the second use of my account, first one was to buy The Buddha jet kit.
Second, please pardon my English.... second language
Story:
So let's start with the story... my first intention with changing the jets on my GS where to try to fix a situation in which the bike seemed to run out of gas, if you brought the machine closer to sea level, around 400 mts if would run like hell, I live around 1500 mts and it runs meh but if you go to 2000, 2200 mts bike will run like shut a couple of times some 150cc Chinese motorcycle left me in the dust; I do understand that it's close to impossible to make the bike run at every altitude.
Bike had a lot of of explosions under deceleration.
So I started my project to change a lot of parts, including new springs for the forks, braided lines, rear r6 shock, bla, and when I finish putting everthing back I ran into the issue

Some hard data:
gs500 2000, around 18k miles (previous owner crashed it and destroyed the odo, it had 8k miles when I bought it and I have perform 8 oil changes at religiously 2000k miles including oil filter), before doing jet swap it had a 37.5 pilot and 117.5 main (yes, 117.5), stock air filter, slip on, switch over to 40 pilot 125 main, dpr7ea spark plugs

the problem, now that I finish the changes I cannot rev the machine past 6k rpm I have:
-cleaned the carbs as carefully as I could, clean every hole and make sure it was clean prior to put together the carbs again.
-clean the air filter, clean all the fuel and air lines and make sure they are free and you can blow air easily through them
-check coil ohm resistance, they are in spec
-voltage at idle 12.7, 14 @ 4k rpm
-new fresh fuel with cleaning carbs additive
-check by throwing water to exhaust pipes that both are working
-rev the machine with one spark plug off, then the other and both fall to the same rpm
-balance carburetors
-check choke is free
-check acceleration cable is free and snaps back when let it off
-check the spark with a spare spark plug revving on one cylinder and I got spark on both cylinders
-starts and idles without a hitch
-clean the petcock
-run the machine on prime
-blow through the air breather on the gas tank cap and it's working (but I have not ride it with the tank open)
-spray wd40 and carburetor cleaner around carbs, no increase on revs
-close tank valve, switch to on and open the carbs to leak the fuel, 31 seconds to dry up on both carburetors
-no deposits on the fuel system on my way cleaning it
-three fuel filters, the one on the tank and one on the main and one on the reserve lines
-oil a little bit over the max, quaker state 10w40
-spark plugs looks a ok
-revs with hiccups to 9k without load

any idea?


Edit:
-also verified that both diaphragms are ok
-needles on the diaphragm are from a dynojet, not sure why, clip on second line from the top
-check that the air vacum from the left carb doesn't have any leak

[xlayn]

Will try:
-Change the filter on reserve and blow back to gas tank, maybe lines are clogged, run on prime
-Take out the filter on reserve, switch to prime
-Run the machine with the tank open
-put new spark plugs d7ea9 will be

two set of different sparks (I did also throw a couple of iridium )
d7ea on the left, dpr7ea9 on the right on the first two photos, last one upside down




[attachment deleted by admin]

[radodrill]

-three fuel filters, the one on the tank and one on the main and one on the reserve lines

This could very well be your problem.  The GS doesn't need inline fuel filters (the one inside the tank is sufficient) and there have been multiple reported issues with inline filters; these include running lean and lack of power/performance.

[xlayn]

Ok, brand new DPR7EA plugs, removed main line fuel filter, changed the reserve\prime fuel line totally, run with the tank cap open... and the same...

just came from my small test ride and try the coil resistance as per

http://gstwins.com/gsboard/index.php?topic=19546.0

update: bad measurement
primary is 5.6 for both for secondary it's infinite for both... I will update once everything is cold as it seems heat make electric stuff to show their problems...

I initially thought that for some reason I was not reading correctly as the value first appeared to be 9k and the infinite... then 12 then infinite... but I went and "test" my tester with some 9k resistance parallel, serial and got 4.5k and 18k

coils ordered and in their way

not sure if  because I found the defective part or  because I found defective part

[The Buddha]

If you have the thing run when hot - your coils are fine.
6k - well, is it 6k in all gears or 6k in 6th, but 7k in 5th, 8k in 4th etc etc ...

If its not fuel flow, its likely carbs.
6k isn't likely to be electrical.

Your coil probably were fine. Those multimeters are erratic at best. I've seen all sorts of crap from 2 different meters.

Cool.
Buddha.

[xlayn]

Edit: you are right Buddha I did a bad measurement, coils are in spec...

6k all gears
will try with another multimeter to be double sure it's not the multimeter and measure directly in the coil to discard cables.

I spent good 3.5 hours cleaning the carbs.... the third time... and I did not find anything blocking or dirty, make sure every hole were not clogged, check the air lines...

but as I read somewhere, constant velocity carbs are never clean enough... any recommendation on what to check especifically?

also it does not rev to 9k without load anymore and it has a lot of hiccups accelerating that way

next task:
-check regulator, rectifier voltage....
-take away the filter, check that diaphragms are working
-check that valves are in spec
-check signal generator

[xlayn]

-charging system ok
-regulator/rectifier ok
-took away the spark plugs and replace for the NGK recommended DPR8EA9 and the ones in place for one day were in the ultra lean side....

back to carburetor, something needs to be clean

next task
-re-clean carburetor
-compare the actual filter against the stock OEM, could be an aftermarket one (and thus making more lean the mixture)
-check sliders are working.

[bmf]

Hi, what air filter do you have? Is it clean/ letting air through?


Sent from my iPhone using Tapatalk

[xlayn]

Air filter is clean, right now the situation is that mixture is extreamly lean, know that you mention it, I will try to cover a little bit the air intake in order to enrich the mixture.
But as you mention I'll check the air filter again.
Thanks!

[The Buddha]

-check sliders are working.

That is my next stop.
Cool.
Buddha.

[xlayn]

Hey there everyone, it's been sometime, long story short today I got the GS to start... on stequiometric fuel-air ratio mixture... on FI, long story short I decided to take on the project, see if I were able to make it works.... and guess what I did.
Added a lambda sensor, system running on closed loop, I'll post the youtube link soon, I still have to edit it.

[The Buddha]

Oh ... why you using that 7 ea plug. You do know the original plug on a gs is 8 right.
A 7 plug runs hotter than a 8 plug. No, that doesn't mean it sparks @ higher voltage, it means that it reaches a higher temperature cos it has less conduction path to the threads for heat.
It nicely cleans itself of the carbon faster.

Cool.
Buddha.

[xlayn]

You are totally right but DPR7EA9 it's the only one I found, DPR8EA9 are harder to get.
Thanks!

[The Buddha]

What ?? where are you ? Iceland ?
You never heard of autoparts store ?
Cool.
Buddha.

[DevilDesire]

I'm also a little shocked... I live in Bulgaria and even here you can find those sparg plugs in almost every shop that offers motorcycle parts. I bought mine for 14 BGN which equals 8.89$

[bombsquad83]

Well, glad to see you are tackling the FI project.  That's pretty neat.  I think that your carbs were probably just running rich due to bad needle valves.  Had the same problem on my bike.  Replaced the needle valves with new OEM and verified gas level with the clear U tube test. That was the main key to my issues.

[xlayn]

"What ?? where are you ? Iceland ?"
maybe even in iceland you can get them...

"I think that your carbs were probably just running rich due to bad needle valves"
you are right... in fact once I put the lambda probe I discover the 40 pilot is perfect as it makes the machine start in stequiometric air-fuel relationship but once you give it more fuel and it rev up it was running extremely rich.... on one cylinder the other was lean.

"glad to see you are tackling the FI project"
indeed, a project it is, I still have all the parts and everything has been bolt on so I can always go back, I'm not going to lie, I looking forward to see if I can get some kind of financing from other people who would like the project to continue, plans include to make the module an arduino shield, which I already designed and send to build, I just have to wait for it to come, another for the lambda module and a third one for the Obsessive-Compulsive on us who would love to have information, lots of it, right now I have the following information
-rpm
-fuel pump working status
-air-fuel ratio
-injectors timings

but I'm planning to add the barometer information and the temperature... why?
Turbo... electronic controlled turbo, with selectable power mappings.
Machine already started and rev up to 8k on perfect air-fuel ratio, process is auto adjustable so adding the turbo shouldn't (notice the proper use of the word should not) be that hard....

why?
geek with spare time... and maybe I can make this my way of living

[xlayn]

https://www.youtube.com/watch?v=8Sg9a1tRCu0

video of the machine running

[xlayn]

It's been some time, I fitted back the carburetors for the summer, the project now it's on printed boards as shields for arduino, way more cleaner.

About the bike not revving the culprit was that the mixture was way to rich, I took the pod filters I had for the EFI setup and the bike ran a bit lean, I like the way it handles now but I hit some already know problems, fuel starvation if the tank is not completely full.

So I guess we can close this topic, I'll start another thread for the EFI project once I fix a problem with the starter.
Thanks to all!!