250-500cc 250 starting problems

Ive checked the carb all seems ok, replaced a jet that was damaged. compression is around 120psi has a new piston and rebore so not yet bedded in. there is a good spark.
but all I am getting is a slight rumble, not a bang!

seems like it may be over fuelling as exhaust joint is wet.

any ideas?
my old AJS stormer (2 stroke) wouldn't start if crankcase had fuel under the crank, but then it had a drain plug for this purpose. am I looking at the same thing??

assume nothing on the spark plug and replace
hat to say it but when it's flooded it was usually a starting error or bad plug
if you positively need it started,,, i don't recommend it but starting fluid does work

120psi sounds really low. almost all swede 250 bikes are around 175-180 psi kicking full throttle till needle quits climbing, when fresh. the last swedes (87-88) are over 210. something is wrong there if you only get 120 psi. i ve noticed when they get down to 160 or so they want a leaner main jet due to blowby.i have never noticed an increase in compression from "bedding in", no more than a few psi anyway. i always check my compression after a top end, its always within 5 psi.
where is your timing set at?
do you have bad crank seals causing the compression loss? have you done a leakdown test? or even a bad center case gasket? sometimes there is rot down there also.
what are you running fr your jetting specs? float level?
check for blockage in exhaust, nesting, etc.
it does sound like you are flooded, it may be needed to tip bike to empty exhaust, they can really fill up. if it is flooded, it will never start like that. i would be more concerned with why its only showing 120 psi however.

thanks for the replies, I need to get a new plug but the local Husky/Berg dealer dosnt stock them they say its a special order.
the bike had just had a top end done on it, it came with a gasket set so possibly leaking elsewhere. will look at a leak down this weekend.
Ive tried without exhaust , should be stock jetting if I remember.
probably why previous owner sold it then...

NGK say B9 EGV250 for a CR but my old catalogue says B95 EGV for WR250 1992. the B95 is what it had in it, is there a great difference between the two??

a B9ES will work fine
EGV
E is extended reach means 3/4" vs 1/2"
GV is gold-paladium center electrode, special V-type for racing

as in a lot of hoopla, i replaced my $16us EGV with a $3us ES from a parts store

would you like extra whipped cream on that?? it's extra

right, here we go again!!
put new B9EGV plug in and a new cap still not made any easier to start.
have made a phone call and apparently it is now a 297, barrel and piston.
retested compression and its 170 with carb off and 150 with reed block out and exhaust off.
I may have fitted new crank bearings to it last year for previous owner, but that's all I did. he rebuilt it and apparently on last ride before or first ride after (he wont communicate now) , it top end seized. don't know if he fitted new seals. I would have thought it would have started and run even at 150psi!!
still looking for answers?/thanks

not exactly following here
is this your bike or someone else's bike?
did you buy it back?
was it running and now its not?
when you post a question for mechanical advice where we can't see what you are working on or know the circumstances it helps to put up a little more info
so iy seems the bike was yours and you sold it, did you buy it back and now it won't start, was he a friend?

YEP HE LOST ME AND WHAT ARE WE TRYING TO START ?92 WR250

Did you set the float height?
Is the float needle sealing correctly?
I don't understand so many different compression readings.......

It's time to pull it apart and have a look see....Something else may be wrong.....

Is your spark good Bright Blue in color?

Paw Paw

sorry for the confusion...you take a bike in and don't get the full story.

1/ Ive had many Huskys, my youngest son bought this 1992 WR250, our first 2 stroke Husky!!
2/ he couldn't get it to start, now he has asked me if I want to buy it off him.
3/ cant find details from frame number.
4/ ive checked carb and had to replace main jet as old one broken.
5/ I have pictures on my business pc of Husky crankcases I fitted new main bearings to over a year ago..
6/ asked son tonight , seems they may be the cases I fitted bearings to. some when it had a top end seize. don't know if before or after it was rebuilt. not getting any answers from seller now.
6/ now appears to have a 297cc top end. not started since rebuild. and only a few new gaskets used, don't know if crank seals were replaced..
7/ had a B95EGV spark plug which seems correct for this model, there is a spark not brilliant but have got a plug cap that shows a good spark.
changing plug and cap still has the same strength spark.
8/ tried moving timing best I can get is a light bang wont run or put more than 1 bang at a time. timing at 0.8mm before tdc.
9/ compression was 175 psi with carb removed and 150 with reed block and exhaust
removed.
10/ wont start with easy start/ aerosol starter fluid.
looks like Im going to have to tear it down, or try a leakdown test first

Ok
lets recap
your son bought a 92 250
you checked the basics, compression, spark and fuel
where it gets gray
you worked on it a year ago?
why?
now it has a 300 kit?
you played with the timing, do you have a service manual or just guessing?

so you said the exhaust pipe had fuel in it, seems like there is either a carb or ignition issue
FYI they really never had a bright spark
if you have tried to start it over and over it is probably full of fuel and oil now
you might need to flush it or dare i say use starting fluid to clear it out

pull the exhaust and dump, clear the crank case..

if timing is correct and you have a nice blue spark and there are no air leaks:

with carb on engine- drain bowl, shut off fuel at tap-
1- yank plug
2- yank pipe, kick- anything coming out exhaust port/plug hole?

if so, cases are flooded.

dump carb bowl, invert bike and let it all drain out ports and spark plug hole and [air dry] for a day or two. also, wash pipe with acetone to clean out, hang and let air dry til VERY dry.

disable kill switch on bar, install a new plug, turn fuel on til bowl fills, then turn fuel off. install a [dry] (to eliminate possibility of over-oiled element) air filter. choke and kick with pipe off. bet it fires up.

if not and plug is wet, it's still flooded. repeat 1 and 2.
toss plug for new one and start over.


if it does lite, coax it to life gently, dont WFO to clean out, you can hydro-lock it. it may take several plugs to get it going. it wont hurt the engine to run it for just a few seconds with the pipe off.

never EVER use compressed air to un-flood a motor, or, use ether start fluid in a 2-stroke. or you will be doing crank seals again.

edit- sorry 'justin', was typing this as you posted...didnt mean to usurp ya.