Please help, bike was fine and now runs like crap?

[crip123321]

Hi everyone,


Just wanted to say that this forum is great. This is my first post so here goes:

I purchased a kdx200 1997 model last week. When i test drove the bike, it ran fine, no bogging, very zippy and sounded and idled great.

I have not had the chance to take it on the trails. I was simply riding it in my street as i couldn't resist. However, it ran out of fuel, so i switched it to the RESERVE and it started fine. When i took it for a quick joy ride it was bogging out spluttering and jumping around. I decided it could be a fuel problem so i filled it up with a 32:1 ratio. The bike then started smoking a lot more. I took it for a ride and the same thing was happening. So i took the carby apart and tried to see if there was any dirt etc as i dont think it was cleaned in a while- the guy i bought it off hadnt ridden it for 18 months. He said that it had a problem of fouling plugs. I havnt checked the plug, but i dont think it could have fouled as it was still starting first or second kick?

I then took the carby apart again and it still is spluttering. I have emptied the fuel again and will refill with 40:1 as i have read many on here suggest. The other thing i have noticed is that it is leaking oil slowly (a few drips every couple of hours where the pipe joins the head). I'm quite sure this was not doing this when i bought it. I havn't taken out or adjusted the jets or anything. Does anyone know how i can actually get them out to clean them because when i tried to unscrew them, they wouldnt move? I just want to get it running back stock like it was when i bought it before i go messing around with jetting etc. i dont see how it could be running so well a week ago then all of a sudden stop and start spluttering between 1/8 and half throttle? Could the fuel mixture be the problem, too much oil in the ratio? I have only ever ridden four strokes and this is my first two stroke so i dont know heaps about them. I just really wish i knew how to get it running like it was so that i can take her on the trails and have a bit of fun...

Sorry for the long post, i just dont know what else i can do besides taking it for a service but i have no cash right now which means i cant ride her anytime soon :(

Thanks in advance to anyone who may be able to help.

[scheckaet]

1 drain tank and refill with fresh gas with watever ratio you like. sometimes mixing different brand of oil makes the bike run like **** and foul plug.
2 get that carb apart, clean the jets real good, tell us what they are. Us vise grip if you can to get them out. you may need to replace them with some stainless alen screw like RBD sells.
3 read jetting guide in jet and needle section.
4 go ride

[crip123321]

Thanks for the speedy reply scheckaet,

ok so i pulled apart the carby again and cleaned it, including the jets. The pilot (or long jet that needs to be taken out with a screwdriver) is a K45 size. The main jet (the one that needs to be taken out with spanner) is K165 size.

I cleaned everything and i am thinking the carby is no longer the problem? There seems to be more oil dripping from where the pipe joins the head of the engine...it looks as though it is loose and is not on tight enough....are there supposed to be any bolts that hold it in place or just springs? if i try to move the pipe, i can see it wobbling at the join to to the head...could it be that there is a leak and air is getting in which is making it ride badly? I took it for a ride and it was still spluttering and jerking around. I cant see any bolts or nuts that are holding the pipe to the engine head, just a couple of springs that obviously arent doing their job right...any suggestions???

Thanks

[Julien D]

The pipe joint is fine, although you may want to relace the o-rings there.

Your carb is jetted very rich. Check the jetting sticky as mentioned above, and start jetting.

[scheckaet]

45 - 165 seems indeed very rich.
You will get spooge coming out of the head pipe if it doesn't seal right, replace the orings, some put a bit of high temp silicone to make it seal better, let it set and re-install the pipe.

[gsa102]

Try a fresh plug anyway, they are meant to be disposable. I try to always keep a spare, it's the first thing I change when a bike acts up. Cheap and easy. They will keep fouling periodically until you get it jetted right.

[KarlP]

It was running to your satisfaction with the current jetting.
It hit reserve and has been acting up ever since.

Those pilot jets can be hard to clean. I'd pull the carb one more time and take another look.

The cylinder to pipe joint will leak at bit of spooge if it does not fit well. I don't think that is your problem. If you take the pipe off and put some new o-rings on and a bead of hi-temp RTV on top of the o-rings it should seal up O.K. You can probably get the o-rings at a hardware/auto parts store for cheap.

If you have enough cash for jets that would be best. I'm thinking they are only $3-4 each.

By the way, in my experience, no good ever comes of taking a trail bike up and down the street, revving the piss out of it. IF that is what you were doing......

[scheckaet]

take a look at the filter inside the tank, I'd bet the one on reserve is fubar and you sucked some crap when you switch to reserve. AS Karlp suggested might be your issue...

[Ol_Man_B]

I've gone to adding an external inline filter. It is easy and cheap and keeps whatever crud upstream out of my carby. I've gotten the filters at Advance Auto for a couple of bucks.

[scheckaet]

Now might be a good time to inspect the inlet filter inside the tank to make sure it's not clogged up with crud ...

[crip123321]

wow thanks for the above guys!

just replaced the spark plug to the BR8ES (stock plug)- still no difference.

I will order the new jets (42 and 152) to make it less rich. However it should still run like it was a week ago but it doesnt. Im really thinking it could be the expansion chamber to the head which is loose as i can see it wobbling around? could this gap which pressure escapes through be causing it all? instead of buying the new gaskets and orings, i might just use RTV gasket glue to seal it up???

Who here thinks this will fix it? i pulled both jets out and could see through the other side which means they are not clogged up so what do you guys think is the problem? starts first kick, its just when i go to ride it it still sounds bad?

[scheckaet]

bad ground, weak stator?
I doubt the pipe is the issue.

[crip123321]

okay so i just went and ordered the new jets and gasket and o ring set...

the bike mechanic also said the same as you scheckaet, he thinks its not the pipe thats the problem, may be electrical or something...i just dont see how it could be running so well then just change...i will give it another extensive clean out when i put the new jets in and see how it goes as it has to be the carby....im hoping its the carby as anything to do with electrics or big service to find the problem will cost $$$, this has really put a dampner on my purchase :(

could it be anything to do with the throttle cable or needle....im just put of ideas...

[scheckaet]

did you clean or do anything to the bike after you got it?
maybe an air leak in the intake appeared?
crack in the boot?
losing any coolant, or tranny oil? maybe bad crank seal?

[crip123321]

no didnt clean or fiddle with anything...just took the flywheel side of the engine cover off (opposite side to where clutch and oil side is) and its clean as a whistle, no oil signs of leaking or anything, does this mean that the crank seal is okay? or do i have to take the other side off as well? will oil spill out if i do?

[crip123321]

ps the oil looks grey or murky through the peephole, but it reads exactly as full when the bike is upright...?

[scheckaet]

being a new bike to you I'd flush that oil (god knows how long it's been there).
If it looks milky, it might indicate water contaminant (like a leaky head gasket or if the bike was submarined....)
Not saying that's the reason your bike is acting up though, just sayin.

[crip123321]

yeah it does look a tad milky grey....thanks for the help il empty it and refill it!

im thinking it has to be the carby as it started acting up as soon as i switched it to reserve...i will wait for my new jets to arrive and then clean again...could it be that my float is not set right? each time i open the carby up it seems as though there is not much fuel there in the bowl....that or my throttle cable....

[scheckaet]

are you saying it ONLY happens when you switch to reserve?
If you suspect the float height to be out of whack follow the manual instructions, if you don't have one, well get one. (top right of the page for H serie)

[crip123321]

Sorry no im saying it only happened once is switched it to reserve. Before that it was fine (it ran out of fuel so i put it to reserve so that i could ride longer lol). Yeah i have a manual, i will look at it and try and set the float height. If it is a crank seal, will it cause this much of a difference straight away or is itmore gradual? Thanks so much mate, im just hoping it is all to do with the jetting or carby issues
And nothing major