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Lou Girardin
19th April 2004, 07:01
My RF's driving me nuts. It's started to miss at idle and pop and sputter on overun, it runs fine elsewhere. I've put in new plugs, cleaned the carbs, checked for air leaks. But it's still the same. It was OK for a while, straight after I cleaned the carbs out, but started playing up after 80 km's or so. I'm starting to think plug leads or coil pack breaking down when they get hot. But that doesn't really make sense.
Anyone had a similar prob?
Lou

Drunken Monkey
19th April 2004, 09:16
Yep - Myself and others have had pretty much the same problem on our old GSX-R's...Every time it was the coils. Checking for spark doesn't work either, as a weak coil can still give a visible spark, without getting to the required voltage to produce clean combustion. I would put $$$ on your problem being the coils.

Posh Tourer :P
19th April 2004, 12:32
As would I.....I had that type of problem on the MZ. Coils were at fault. Another thing to check maybe is the output voltage of the battery.

Also, when you clean up the plugs it takes a while for them to foul up again. Another issue I had was that it was intermittent, as the coil was slightly cracked, with a very small amount of water in it, that shorted it at random times after a while of vibration and capillary action or something. After sitting round I guess the water flowed to somewhere not harmful, so it was ok when i first took off... At one stage, it was so bad, it would only do 6miles before the plug needed changing, or 12miles if I didnt ride with the light on

Eddieb
19th April 2004, 17:17
I'd go for coils as well, had the same problem with my old GSXR250RR, Suzuki coils don't seem to age well and don't like getting hot.

Big Dog
19th April 2004, 18:10
I hate to be the only voice of dissention, but I know nothing about coils and a bit about fuel. Sounds like the problem I had with my old bike after many dollars spent replacing bits, that I didn't know what they did but the bike shop said it was the highest probability, it turned out to be a cracked fuel filter. Allowing pockets of moisture to suck through under pressure causing uneven firing and sometimes backfiring whenever I buttoned off. Because it was only on the down spin the plugs etc were always clean.

Check your coils as that seems to be the consensus and it won't hurt, but if not check your fuel lines and even the gasket to your fuel cap/tank/tap/carb etc.

Jackrat
19th April 2004, 18:38
Big dog may have something there.If as you say it ran ok for a while after cleaning the carbs it may be something geting dragged though from the tank.
My own model of bike is pretty well known for this.
Mind you Iv'e also had the coil thing as well,but that has always come on when the bike was hot and wasn't intermitent.
Good luck with it what ever it is.

Posh Tourer :P
19th April 2004, 19:56
Always check the cheapest, easiest things first..... Good post BigDog, I certainly hadnt heard of that issue before.....Worth having a look...

Lou Girardin
19th April 2004, 20:36
The fuel system is clean now, next step - coils. Bugger$

Big Dog
20th April 2004, 16:46
The fuel system is clean now, next step - coils. Bugger$
Ya, but fuel filter new lines and a swill out of the tank should cost less than $30 and will at the very least increase the availible flow rate (most japanese market fuel filters are more restrictive than NZ manufactured ones). In the Trader I remember reading in their spanner section that this alone can yeild power gains of around 1-2percent, but can require remapping in early fuel injection. Coils can cost upwards of $200 depending on the model. Which is why I said fuel first.

If you are competent with carbs try pulling out the diaphram and checking it for cracks (these can screw up your mix on the down spin, also according to the trader).

If you dont have a diaphram check your jet returns ( I think thats what they are called anyway spring returns that govern the flow rate in non diaphram carbs) as these sometimes stretch when you open up a lot meaning ( :whistle: ) one jet is not returning fully meaning you end up with a really rich mix on the down spin. These were the offenders on a mates suzuki 150 many years ago. after many $ spent trying to resolve the backfire on the down spin problem it turned out to be a $1 part + fitting.

Basically it sounds rich on the down spin to me.

As you feel it is more of an issue after reaching operating temp have your earth ohms checked at temp compared to cold, in theory there should be less resistance but if your lead is deteriorated there will be more. After $800 (trade price parts) spent on replacing every single other part of my ignition on my falcon it turned out the heat sink was coming from a deteriated engine earth. $9 for the genuine bosch part. :brick:

IMHO check every thing that is free or cheap before you spend the big kahuna on something you are not certain about (unless dioagnosed by a pro who will stand behind the work.)

F5 Dave
20th April 2004, 17:19
Yeah I’m doing some sorting out on my RF’s carbs at present though I don’t have those symptoms. (The coil idea is interesting though). Seems a common problem with the carbs is the needle jets wear oval, if you do take the diaphragms out have a look at the needle jets for slight ovality. Another thing is apparently the thermostat is very cold at 76.5 deg, most bikes are 82 ish or higher. I am experimenting with trying a 91 deg one soon. Check out the Factory website, they have a bit of interesting info there.

PS: don’t know the float height do you? Mine was at about 20mm & it didn’t like running uphill. I raised the level a bit & it got better but still a bit dodgy sometimes.

Big Dog
20th April 2004, 17:45
PS: don’t know the float height do you? Mine was at about 20mm & it didn’t like running uphill. I raised the level a bit & it got better but still a bit dodgy sometimes.
Nope. Not a mechanic, just can't afford one.

If you still have your manual it may be in there on the servicing page along with gaps etc.

If not try and find out from other owners of your model I found out all sorts of $H!% by doing a MSN / google on my specific model (just used the gsx1100f and hit search). It came up with 11000 matches, mostly websites or pages created by enthusiasts, often pages and pages of the most unlikely details.

Lou Girardin
20th April 2004, 21:09
PS: don’t know the float height do you? Mine was at about 20mm & it didn’t like running uphill. I raised the level a bit & it got better but still a bit dodgy sometimes.

Float height is 6.9mm +/- 1mm. Measured with the carbs inverted, from the top of the float to a line level with the main jet. Hope that's clear.
What's the factory site address?
Lou

F5 Dave
21st April 2004, 09:02
Cheers, was of course measuring from gskt face to get that measurment but will look at Mainjet mark.

http://www.factorypro.com/

Have to look around a bit to find all the info there.

Still have the manual?!? How many 2nd hand bikes have you bought that you got the manual? Or the toolkit for that matter. Besides the ones you get from new just tell you to : ‘See your authorised Dealer’ if you want to fill the petrol tank up.

speedpro
21st April 2004, 09:13
Cheers, was of course measuring from gskt face to get that measurment but will look at Mainjet mark.

http://www.factorypro.com/

Have to look around a bit to find all the info there.

Still have the manual?!? How many 2nd hand bikes have you bought that you got the manual? Or the toolkit for that matter. Besides the ones you get from new just tell you to : ‘See your authorised Dealer’ if you want to fill the petrol tank up.

Last year I bought a MB100 with the original toolkit still in it's plastic tube. No signs of use. Probably because you needed a screwdriver to get the sidepanel off to get the tools :brick:

F5 Dave
21st April 2004, 09:16
I think the key is supposed to work

Yeah MY YZF needed a substantial screwdriver to access the toolkit

PS email me your postal address.

MacD
21st April 2004, 12:06
Another thing is apparently the thermostat is very cold at 76.5 deg, most bikes are 82 ish or higher. I am experimenting with trying a 91 deg one soon.

I'll be interested to hear how you go with this experiment. When I first got my RF900 it was running so cool I wondered if either the thermostat was stuck open or missing so I pulled the housing apart to check. Sure enough there was a perfectly functional thermostat in place. On the open road the bike tends to cool down a lot. The only time the temperature seems to rise is when I'm sitting in traffic.

I also developed a problem with it missing on idle during all that rain in February (I commute on the bike) which I fixed by spraying the coils with lots of CRC. I noticed one of my coils had been replaced too.

:raghead:

F5 Dave
21st April 2004, 12:43
Yeah 76.5 degrees with FIVE holes drilled in it is hardly operational eh?

Will let you know how it goes after the weekend hopefully.

ManDownUnder
21st April 2004, 13:04
Lou,

I don't know how to fix the prob but coil sounds like a likely start. I have the manual for all RF900s 94 through 99 (I think)... complete with parts listing if that helps. You're welcome to borrow them and I'll drop them by the shop if needed.

They are a faxed and scanned page so the quality isn't 100% (ok, close to 30% at times) but the words are all there.

I had problems with mine after sitting outside for a while - the number4 plug had the top thread rusting (I guess the hollow it sits in must have filled with water at some point!?!). Not good... just spent 500 on it getting a B Schedule service at Red Baron and it purs now! 110ps on the dyno which is ok (or really good?) I dunno.

It's still heaps fast enough to put be into the roadside shrubbery

MDU

Big Dog
21st April 2004, 17:11
just spent 500 on it getting a B Schedule service at Red Baron and it purs now! 110ps on the dyno which is ok (or really good?) I dunno.
MMMM difference between before and after for mine was like satin and silk. It was good and smooth before but its seamless now!

105ps + or - = 78KW /107hp according to the exchange rate listed in a old Superbike mag, I remember it cos mine is 105. :msn-wink:

Lou Girardin
22nd April 2004, 06:52
Thanks MDU, I've got a manual. I've been told how to drill out the pilot screw blanking plugs and adjust the idle mixture, so I'll try that too.
110ps sounds healthy.
Lou

Motu
22nd April 2004, 08:07
Geez,it's still got blanking plugs on the mixture screws? Everything,car or bike was made to run super lean after about 1980 with blanks or tamper proof adjusters.Any wear or aging and it all goes to shit - we hate carbs now,we can't fix them.We just plead ignorance and tell them to go to a real mechanic.Popping on the overrun means it's running lean,gives a crap idle too - do an idle mixture adjustment.Bear in mind the mixture scew only controls a small portion of the idle mixture,you might not be able to tune it out.

My XLV750 snap crackles and pops something fearful - I like it.

ManDownUnder
22nd April 2004, 08:55
Thanks MDU, I've got a manual. I've been told how to drill out the pilot screw blanking plugs and adjust the idle mixture, so I'll try that too.
110ps sounds healthy.
Lou

No worries, I figured you'd have access to all the books and bits you'd need at work ...

Not sure how 110ps rates but I know the thing idles smooth as baby's bum even when cold now all the carbies are balanced up (and no - you can't have mine...)

MDU

F5 Dave
22nd April 2004, 09:27
I've posted my thermostat experiment

http://www.kiwibiker.co.nz/forums/showthread.php?p=40739#post40739

Lou Girardin
26th April 2004, 07:05
Cracked it! Jeez. I feel stupid, when I cleaned the carbs the first time, I blew out the needle valve jets but didn't strip them. This time I did, there was some type of fibrous material clogging the two outer carbs and starving it for gas at certain times.
Whatever this stuff is, it got past the two lots of filters.

Posh Tourer :P
26th April 2004, 16:52
Well done :) I take it you've run it and tested that cleaning that out worked.....

F5 Dave
26th April 2004, 17:08
Hmm, [puts on suspicious hat]. I wonder if at some stage someone has tried to resin the tank to prevent rusting tank syndrome? a common Suzuki ailment.

Lou Girardin
26th April 2004, 20:28
The techs at work say that it is sediment from dirty gas station tanks. Considering that I only fill at 2 gas stations, it looks like a change is due.
Lou

FROSTY
26th April 2004, 21:12
Ok but has it worked ??
:calm:

Posh Tourer :P
27th April 2004, 13:36
Go to the newest, nicest stations... The older ones are likely to have cracked storage tanks etc, letting in water and perhaps sediment

Big Dog
3rd May 2004, 19:07
Go to the newest, nicest stations... The older ones are likely to have cracked storage tanks etc, letting in water and perhaps sediment
You are morte likely to get sediment at your low volume servos. Aim for a busy one.

Big Dog
3rd May 2004, 19:08
The techs at work say that it is sediment from dirty gas station tanks. Considering that I only fill at 2 gas stations, it looks like a change is due.
Lou
Any names? Where should we avoid?

Lou Girardin
3rd May 2004, 20:47
Any names? Where should we avoid?

Chicken disclaimer - I have no evidence that any of these servos caused the problem, blah, blah, blah.
But I fill at Caltex on Mokoia Rd and the Gull stations at Otara and Takanini.
Lou

Big Dog
4th May 2004, 18:25
Chicken disclaimer - I have no evidence that any of these servos caused the problem, blah, blah, blah.
But I fill at Caltex on Mokoia Rd and the Gull stations at Otara and Takanini.
Lou
Do you park mostly inside or outside?
Do you normally fill up or put x dollars in?
How old were said filters?

When you fill right up every time you get less moisture in your fuel tank as the fuel naturally pressurises as you use the juice (less true the more air you had in there to start with). Then when your engine cools down the tank drops a couple of degrees as well this causes any oxygen to contract and attach to the hydrogen samples in the fuel creating water , and oxides to form(from the additives in all fuels), creating the sludge to which you appear to be refering. Parking outside exacerbates this.

If you were on the stock filters they have probably held back the same sludge for many years and just gave up.

Most fueling problems can be traced back to either not filling right up each time or faulty filters, or both.

Having said that avoid gas stations where their physical location is prone to flooding, for the first couple of weeks after heavy rain.

Gas stations are required to test regulary for water in their tanks. Sadly silt forms for the same reasons as above filling temp changes etc but there is no requirement to test for it unless you mention it to them.

I don't reccommend putting half a tank of one company and a half of aanother either as some companies additives will react negatively with anothers.

Not a problem on a cage, due to the increased diameters of the jets. Apparently they can bond with each other as each tries to remove the other from the fuel creating, you guessed it, sludge. I only use Caltex due to my fuel card and only use other companies when it is already in the red.

When I fill up with anything else while my tank already has a half of caltex it backfires or runs rough.

Synopsis: Buy a whole tank at a time and replace your fuel filters if you have not already.