Any Ideas???

[kx666]

My shop has been growing rapidly since it opend a year ago, i now have 2 other mechanics working for me and we have a suzuki that has us stumped.  I have talked to other mechanics from shops i have worked at in the past and some racer buddys and still nothing. 

I know it is not a Kawasaki but this is our last hope...

It is a 1988 LT250R.  It came into the shop in early December, had been sitting for years, no spark.  The carb was the worst i have seen in over 10 years! replaced all of the jets to stock cleaned every port on the carb installed all new gaskets. 

I noticed a crack in the piston skert so I did a top end.  when compeated the engine held 7psi for 10 min with no drop on a leak down test

cleaning electrical connections corrected spark problems, tested CDI and coil to be sure.

The bike ran like new and the customer picked up the bike. A month later he called me to tell me that it quit running. He was ridding it, shut off the engine and it wouldnt restart.


when he brought it back it again passed a leak down test and compression test. I have found that it does start and run with additional fuel applied to the carburator with a syringe.  The carb looks perfect.  Thinking that it could be a lean situation we replaced the crank seals. It now runs only on the chock and if fuel is appliyed down the carburator first. I had a Keehin PWK 36 off a 1999 yz125 laying around and intalled it "for the hell of it" and it ran ok.  but wont run on the Mikuni TM34ss.

Any Ideas???  Thanks!
~steve

[Hillclimb#42]

sounds like it must be running out of gas. like there is a blockage in the petcock or carb, or float hung up, but I know that is probably too simple. I did manage to get a float on wrong before. good luck.

[kaw rider]

check the blend passage

[kx666]

-Fuel has been replaced
-the float valve and seat have been replaced before the first time I ran it
-petcock flowes and after running the float bowl has fuel to the proper level
-all of the ports in the carb have been cleaned...

its seems like it is producing enough low pressure to draw the fuel.  I am half tempted to split the cases and look for a crack, but if there was a crack or leak the leak-down test would have exposed it.   

maybe somthing unretated like changing the wheel bearings will fix it  ... i've seen stranger things happen  maybe sell him an extra kx 500 motor i have

I greatly appreceate everyones input, 

[kaw rider]

You have a carb problem don't touch the motor. You have a pilot circuit problem.

[DoldGuy]

You have a carb problem don't touch the motor. You have a pilot circuit problem.

I agree with Kaw Rider, pull the pilot jet & squirt carb cleaner thru it's circuit & look into the bore while doing so to see if the cleaner has a strong stream coming out of it (it should be just in front of the slide on the floor of the bore) & wear eye protection (& keep your mouth CLOSED, don't ask me how I know  )

DoldGuy

[kaw rider]

Doug
Did you have cigar in your mouth at the same time.

[kx666]

You have a carb problem don't touch the motor. You have a pilot circuit problem.

I agree with Kaw Rider, pull the pilot jet & squirt carb cleaner thru it's circuit & look into the bore while doing so to see if the cleaner has a strong stream coming out of it (it should be just in front of the slide on the floor of the bore) & wear eye protection (& keep your mouth CLOSED, don't ask me how I know  )

DoldGuy

carb cleaner comes out in a strong streem, blowing low pressure air in the idle curcit with the float bowl attatch with fuel, fuel comes out the idle curcit.

[kaw rider]

does it stay running with the choke on.

[Purpletj]

I had a Keehin PWK 36 off a 1999 yz125 laying around and intalled it "for the hell of it" and it ran ok.  but wont run on the Mikuni TM34ss.

Any Ideas???  Thanks!
~steve

You said the answer in your first post.. It's the Carb. Check the needle and slide for proper adjustment. If this doesn't work. Clean everything again.

[Goat]

It's yellow burn it and get him a green one. Just a thought but how is the rubber intake manifold? If it's even slightly cracked and sucking air it will cause weird s**t to happen.

[agraebner]

Two bikes i currently Own I got dirt cheap with fresh rebuilds and a ton of work in them cause they sat over winter and their local mechanic cleaned the carb and they still wouldnt run.  Both were just like you problem and both were pretty simple.  EVerything looks clean when you take them apart from the earlier cleaning but in the passages there was the E10 mess that took me a while to get out soaked one in pro carb cleaner in the gallon bucket for 6 hrs.  The other one was on my 92 k500 it would start and run for a sec then die.  The K5 had a small piece of debris in one of the passages that would move around sometimes allowing it to work and others starve it for fuel.  Once Ive got them right i mix some SEA FOAM in my fuel and ive had no more problems with fuel or carbs.  this os going on 3rd year with no problems on most of my machines 5 yrs on my small outboard motors (3.5 -15 hp)

[kx666]

When the top end was done we replaced the intake boot because it was cracked. the reeds look great.  

I have probably gone through 8 or 9 cans of carb cleaner, have diped it 5 times

when pressurized air is forced through the venturi opening, fuel mixture comes out the ports like it should.  being that the pwk carb is jetted much more rich then the tm it would require less pressure to operate, it seems like the cranking pressure could be a cause.

everything everyone has sugested are logical steps to solve an issue such as this, for some reason on this quad it doesnt seem to correct the problem or provide any insight on the cause.  

Two bikes i currently Own I got dirt cheap with fresh rebuilds and a ton of work in them cause they sat over winter and their local mechanic cleaned the carb and they still wouldnt run.  Both were just like you problem and both were pretty simple.  EVerything looks clean when you take them apart from the earlier cleaning but in the passages there was the E10 mess that took me a while to get out soaked one in pro carb cleaner in the gallon bucket for 6 hrs.  The other one was on my 92 k500 it would start and run for a sec then die.  The K5 had a small piece of debris in one of the passages that would move around sometimes allowing it to work and others starve it for fuel.  Once Ive got them right i mix some SEA FOAM in my fuel and ive had no more problems with fuel or carbs.  this os going on 3rd year with no problems on most of my machines 5 yrs on my small outboard motors (3.5 -15 hp)

I had some sea foam in the last tank, i'll try putting som in this tank and clean and dip the carb one more time...

[tharden]

Ultra sonic cleaners do wonders with carbs.  I use one all of the time while I work on chainsaws.

[KXcam22]

Steve,
 Any chance the muffler is plugged?  I had a similar issue with my weedwacker, cleaned and rebuilt the carb a number of time, would only run with the choke on,  and it was a plugged muffler in the end. Cam.