Choking in mid-range

ChildOf*RGV · 13-06-2008, 12:46 AM

Hi all - look i know this may be a silly question, but i prefer to thrash em than fuck around with the bits that make em work...
My RGV250 usually rides quite smoothly up to the 'band, but i got home last r&r (it sits for 4 weeks at a time while i work), took her out for a loving ass-caning and it seems to have developed some sort of flatspot where it chugs and carries on... This happens at about 6000rpm then it clears its throat and once it hits band all is smooth delivery again! I changed the plugs (bout the limit of my knowledge lol) but it still seems to be doing it... Getting VERY fucking annoying rolling 2nd gear on and off uphill round the local mountain! Anyway its probably easyfixed (i hope) but im too retarded to know whats wrong... Any ideas to help me out, or am i just gonna hafta punish the bitch till it dies?

Cheers.

jules_1972 · 13-06-2008, 05:19 AM

Power valves???

chief wiggum · 13-06-2008, 06:48 AM

my first thought when i saw the choking issue was to say remove the dockers sticker......but then noticed you're in qld and prolly dont know who they are.

yeah, powervalves

rgvlee · 13-06-2008, 07:31 AM

nah powervalves won't be an issue until later on in rpm even if not configured properly. I'd start with cleaning the carbs and blowing out the jets with compressed air.

smeghead · 13-06-2008, 10:38 AM

^^^WLS

Sounds like a carbie float thang to me. Clean & reset carbs to spec should sort it

ChildOf*RGV · 13-06-2008, 12:06 PM

yeah, it had a sticking float at one point while i was away at work - got home to a spannie FULL of fuel lol! I gave the carb a good ol tappity-tap with a screwie and *hey presto* she was apples... So you might be on the right track eh? Being a novice tinkerer, ive been too scared to touch the carbs, let alone pull em apart - got any advice, or know where to find a step-by-step guide etc..? I can see it now, 2 carbs in about 50 billion bits and me sat there with a *fuck im just gunna smash this* look on me face... To add some detail though, i just cleaned air filter and went for a midday blast not 10mins ago.. Went like all hell, real strong, for about 25mins (just enuf time to get out to Samford - the fucken bush!) and then the spluttering started to the point that i was jerkin all over the place and just makin it up hills etc. I pulled over had a smoke for 10mins then when i finally kicked it over (it didnt want to - not normal) it ran fucken hard all the way home, to the disgust of many many commuters! Sound like carbs?

Btw - dockers are those guys that lop the tails off sheep arent they??

frazcat · 13-06-2008, 12:15 PM

Quote:

Originally Posted by ChildOf*RGV

Btw - dockers are those guys that lop the tails off sheep arent they??

hahahaha, yeah pretty much!

chief wiggum · 13-06-2008, 12:22 PM

Quote:

Originally Posted by ChildOf*RGV

Btw - dockers are those guys that lop the tails off sheep arent they??

no. better description would be freo chokers, a team that pretends to play afl over here

ChildOf*RGV · 13-06-2008, 12:25 PM

yeaaaah footbawl... i'd rather ride methinks

rgvlee · 13-06-2008, 12:26 PM

They sound like two different symptoms.

The lag at 6k sounds like a jet issue. If the floats were not set correctly it would not get better as the revs increase, it would get worse.

The spluttering and not recovering until you've stopped for a few mins sounds like a float issue. The hard to start also sounds like it took a little bit for the float chamber to fill again.

The carbs are not complicated. Things to watch out for are the solenoid hoses, take a photo beforehand so you remember how to hook them back up. The other trap is the pilot air and main air jets, easy to mix them up. Pull one apart at a time and if you get stuck use the other carb which will still be in one piece as a guide.

I thought the carbs on my wifes rs250 were pretty clean. I stripped, cleaned and set them up properly and it made a big difference.

There are other things, like blocked fuel tank drain vents, that can cause similar symptoms. Is the bike running hot? You mention it didn't happen straight away. Normally an incorrect float will cause problems when your on the hammer for a bit as the float chambers don't have a chance to fill again.

HTH

ChildOf*RGV · 13-06-2008, 02:04 PM

I was looking today, and it probably starts chuggin' at closer to 7-8 grand than to 6... But i'm splittin hairs i guess.. So, if i pull these suckers apart, and DONT mess with any settings/screws/etc - when i put them back together they should still be in the same state of tune as they were beforehand? Coz i wouldnt know the first damn thing about tuning the fuckerz! Not that i wouldnt want to learn mind you --> And yeh it has been runnin a little hotter than usual, but coolant is full.. Where are these fuel tank drain vents? And yes, it ran really well for about 25mins before the dramas..
You wouldnt have the manual for VJ22M model would ya Lee? Wouldnt mind gettin mitts on a carb diagram and settings/specs etc..
O, and before i forget - YOUR MISSUS HAS A RS250! Thats fucken stylin mate, i cant even get my girl on the back of mine... Somethin about ..deathwish, no respect for anyone etc etc *mumblegrumble*...

ChildOf*RGV · 13-06-2008, 02:12 PM

Actually mate, its got a 94 motor - that would make it a vj22R correct? I wouldnt have the faintest if thats different from the 91 or not... Anyone?

rgvlee · 13-06-2008, 02:32 PM

Well the point where it chuggs does make a difference. When you took it for the last ride and it started chugging after 25 mins, did it only do it between 7-8k rpm or did it chugg no matter what rpm and gear?

The vj22s are known to suffer a bit of lag around 8 to 8.5 (and this happens to be where the powervalves open), but usually this is a result of aftermarket pipes on a stock SAPC.

The only thing that will change when pulling the carbs apart will be the floats if you take them off to inspect the needle jet. All the other jets are just a case of nip up and away you go. The jets will most likely be quite tight and are easy to damage so take care when doing it and use the right screwdrivers for the job. There are no air screws or anything, only idle adjustment and this is easy to adjust anyway.

They do not run well and can be hard to start when they are hotter, so how hot are we talking. I am assuming you've got a stock gauge, where abouts is it sitting when travelling down the highway? 9 o'clock? 7 o'clock? Coolant being full means nothing if you have air in the system, but this usually only happens when filling the system too fast after dropping the coolant. Was it a hot day? What plugs you running? It can be a lot of things. I don't believe this is the issue but it is interesting that the problem starts after 25 minutes.

The fuel tank drains, there are two. The one of the top of the tank and one on the filler. The one on the filler is the one I am referring too, compressed air down there will get any blockage out. The outlet for this drain is underneath the tank and is prone to corroding. When you get pressure build up in the tank from petrol + heat and this is blocked it has been known to cause fuel delivery problems.

Yes I do have a manual, it's just the pdf off the web. I will pm you the address.

Yes, Heidi has an rs250 and an rgv250. Diddles on the forum.

My thoughts:

If the bike noticably lags between 6 and 8.5, then I would be looking at the carbs and the jets

If the bike goes hard and starts stuttering at higher rpm for no reason when you are giving it herbs, i'd be looking at the floats.

Before doing too much do a grey wire test on the powervalves and make sure the powervalve controller is actually working. They do die and they can cause stutter when they aren't working properly.

If servicing the carbs doesn't do anything, clean out the fuel drain lines. See if anything comes out. Also inspect powervalves for proper alignment.

Being a 94 motor and an M model bike won't make much of a difference if it's a carb issue. I would guess it is still running M model carbs. The main difference I think is they run a smaller main air jet (don't quote me on that, can't remember if it is the later 22s that are different or the rs250 that is different).

Cheers

L

ChildOf*RGV · 13-06-2008, 04:54 PM

Ok, it had the original slight hiccup at 7-8000, but i just rode through it 'ignore it and it will go away' style. After 25mins the serious stuttering took over, and yes - any rpm, every gear. Now heat, well Im startin to wonder if the gauge even works - it seems to ALWAYS be sittin pretty much about a quarter to a third of the way round the dial - nowhere near looking concerning, yet the other day after an enthusiastic thrashing i could feel the heat off the motor and it was damn hot - hotter than usual... She didnt want to start after that either, had to bumpstart the ol girl. Plugs, plugs.. hmm too trashed to walk down the shed and look but i think B9RES, or ERS, sumpthin like that... Just standard, didnt know whether to run the platinums coz they werent listed in the bike shops' plug chart under rgv. Sorry to be an ignoramus but can u explain this 'grey wire test'? U talkin bout chuckin a multimeter on it just to see if its doin what it should?
Thanks heaps for grittin your teeth and answering my barrage of inquiries Lee - I appreciate it mate.

rgvlee · 13-06-2008, 05:04 PM

BR9ECM is the stock plug, although you can run the BR9ES as well with no ill effects.

The temp gauge should be just above the C, so about a 1/3 on the gauge so that sounds correct. They do lag a bit, only really a concern when the gauge gets to about half way whilst riding, then they are getting hot.

Grey wire test - there is an bullet plug near the battery on a grey wire. Turn the ignition on and short out this wire to the negative battery terminal. The powervalve servo will move the powervalves to 3/4 open. You will hear the motor and you want to hear a nice fluid motion, if it hesitates or is jerky you will need to look at the cables to make sure they are set up correctly and then if they are fine then the powervalve servo. You will know straight away, they sound very sick when they are on their way out.

ChildOf*RGV · 13-06-2008, 05:36 PM

Ok sweet, temp is good - plugs are correct - and the grey wire test could be performed by a monkey on crack. I think i should be able to manage!

Righto Lee looks like my weekend is filled.. Ill have a crack at dismantling those carbs, blow the fuel tank drains out, and give the powervalves a once-over...
Again thanks for your RGV wisdom mate, if you ever mission to Brisbane let me know and Ill show ya some sweet Brisbane City Council maintained racetracks - O, yeh, roads i mean. Cheers.