Won't start everything checks out fine, HELP!

Desert Rat · Apr 27, 2015

Greetings
I have an old grubee 48cc with many miles, Been sitting for a year.
I have been getting it ready to run again, Here's a list of what I've done!
Repacked rear wheel bearings replaced pedal assy. and bearings.
(had to be done with over 13,000 miles)

Replaced carb and put on new fuel tank. (tank Flowing well, carb just came off
working bike) Replaced CDI (pulled spark plug grounded it, getting spark)

With spark plug out piston turns freely, with it in really hard to turn over
by pushing bike.(good compression)
When I'm pedaling it and let off clutch it chugs chugs chugs
but won't start.

No air leaks that I can find.

Could old gas residue be it the crank case causing problems?

crassius · Apr 27, 2015

I see what looks like a white wire going to the CDI this could cause a problem.

Seems like the clutch arm is way in under carb, could clutch be slipping a bit?

When moving carb to this bike, was throttle cable checked to see if slide goes all the way down?

Desert Rat · Apr 27, 2015

crassius said:
I see what looks like a white wire going to the CDI this could cause a problem.

Seems like the clutch arm is way in under carb, could clutch be slipping a bit?

When moving carb to this bike, was throttle cable checked to see if slide goes all the way down?

The white wire is just bundled rather than cut it's not connected to anything

No clutch slippage that's just where the arm is (works just fine always has)

yes on carb, just changed it in case jets were fouled in old one

Was running fine till I drained the tank and let it sit for a year
thanks for the input

bluegoatwoods · Apr 28, 2015

Good to see you, Desert Rat. Where've ya been?

I'm not coming up with anything to suggest for your no-start situation. But I'll think about it and see if any brainstorms happen.

Mike B · Apr 28, 2015

If you've got spark and you've got gas and there is good cylinder compression, I suspect the seals. Especially since you were a bad boy and didn't run the motor for a year.

xseler · Apr 28, 2015

Since it's been sitting a while, you might check inside the muffler to see if any critters have built a nest. I don't know about Arizona, but we've got lots of mud daubers that will build their mud nests inside of about anything.

Best of luck to 'ya!!

bluegoatwoods · Apr 28, 2015

Oh, man.........imagine opening up your muffler and finding mud daubers or hornets.

Just last summer hornets built a nest in one of my walls. I didn't notice until they became really numerous. I didn't notice, in fact, until I hear what sounded like dripping water in my wall. A wall with no plumbing in it. I guess it was just the sound of their activity. Whatever nest activity they engage in, it seems to sound like a drip.

I was semi-horrified, when investigating, to see just how many of them there were. And attacking them, over the course of a couple of evenings, was kind of frightening, too. I got rid of them without a single sting. But a lot of them got into my house, fleeing the insecticides I was using.

It all worked out. But it wasn't very much fun.

Desert Rat · Apr 28, 2015

bluegoatwoods said:
Good to see you, Desert Rat. Where've ya been?

I'm not coming up with anything to suggest for your no-start situation. But I'll think about it and see if any brainstorms happen.

Thanks for noticing
It's been a heck of a year, Dad died, I found out I have stomach cancer
Which I'm beating so far, much to the dismay of the doctors ( I refused their treatments and went with my own at this point I am in remission)
and then my new bike is acting up so now I am having to rebuild the old one
My newer bike is a crank seal problem, It's dumping oil into the clutchpads

Question: if the crankseal is bad wouldn't it be sucking in air and lowering
the compression?

Desert Rat · Apr 28, 2015

And for the rest I am looking at every suggestion
I set it up so I could screw the muffler out and it and check it out, seems to be fine

GoreWound · Apr 28, 2015

if you can get it to sortof run when pedalling walk it to the top of a big hill, and force the engine to rotate untill it warms up. as you mentioned it could be residue in the engine, forcing it to get warm like that (there may be a better way to force it to warm up) will get fresh gas-mix into it and hopefully flush out the old oil residue.

when you checked inside the muffler did you also check the flexible tube? those things sometimes can flake apart on the inside, though I imagine if you tried to start it with a rubber flake in there it wouldn't be in there long.

Desert Rat · Apr 28, 2015

GoreWound said:
if you can get it to sortof run when pedalling walk it to the top of a big hill, and force the engine to rotate untill it warms up. as you mentioned it could be residue in the engine, forcing it to get warm like that (there may be a better way to force it to warm up) will get fresh gas-mix into it and hopefully flush out the old oil residue.

when you checked inside the muffler did you also check the flexible tube? those things sometimes can flake apart on the inside, though I imagine if you tried to start it with a rubber flake in there it wouldn't be in there long.

Yes I did and everything seems fine maybe I can use a heat gun to gently heat up the crank case?

Mike B · Apr 28, 2015

Desert Rat said:
My newer bike is a crank seal problem, It's dumping oil into the clutchpads

Question: if the crankseal is bad wouldn't it be sucking in air and lowering
the compression?

Nope, crankcase compression has nothing to do with cylinder compression. Another reason 2 strokes suck! The crankcase has to hold vacuum to suck in the fuel and it has to hold pressure to blow it into the cylinder.

If the case leaks, you're screwed.

crassius · Apr 28, 2015

just had another steel intake that didn't let the carb go on all the way until I cleaned up some lipping on the end - maybe you have an air leak in there (try sticking a piece of safety wire between the 4 slots in the carb mount

oylavabeer · May 4, 2015

I just obtained a old motor and there is holes in the casting next to the crankcase seal

crassius · May 5, 2015

I saw one once that had the mounting hole for the stator drilled all the way thru the case, but as long as the mounting screw was present & tight, it didn't matter.

I your holes go all the way thru, I'd throw some jb-weld onto them.

Desert Rat · May 9, 2015

Update
Says this scratching head!!!!

Crank seals good

crankcase gaskets good

NO air leaks checked entire case with bottle of water dish soap combo
that includes carb

Replaced CDI and magneto getting really good spark now
Interior of magneto case bone dry with corrosion present
not bad but enough for concern

muffler clear and taken off

NO GO WON'T CATCH

As far as clutch is concerned when clutch lever is pulled in can push it easily
when it's out it will not move, tires slide on floor and can't rotate
piston at all.

and yet I can't get it to start

Next I raised piston to top of stroke so I could use a tube and put strait gas
into case from carb side and am letting it sit overnight, tommorow I will put some
carb cleaner in base same way and with spark plug in ride it with cdi unhooked
blowing out the old crud I hope, I just don't know what else to do! It should be
running

Side note I think I found out what the white wire was originally for

This is a grubee I bought back in 04 and I hooked it up as manual said
and the white wire went to one leg of the kill switch and the other was
grounded with screw in frame. An idea of how old this is, on the new ones
I've seen where the wires come out of case there is a rubber plug that the
wires go thru, on mine it's a threaded nylon nut that screws into case.

keep in mind everything was original until recently, this was the first time I've
had to crack open the mag case ever! with now over 13,000 miles on it
when I set it aside, I would have to say pretty dependable motor!
in it's life so far, the after the fact work has been 1 ring replacement
and 3 carbs NT's

I JUST DON'T KNOW WHAT ELSE TO DO
THANKS FOR YOUR INPUT
RON

crassius · May 9, 2015

could be your timing is bad, if you have a timing light & 12volt batt available look here: http://motorbicycling.com/showthread.php?t=56351&highlight=timing+mark

Desert Rat · May 9, 2015

crassius said:
could be your timing is bad, if you have a timing light & 12volt batt available look here: http://motorbicycling.com/showthread.php?t=56351&highlight=timing+mark

Thanks and if I have to resort to tearing into it I will check that
but I don't see it the bike was running fine I drained the tank and let it sit 1 to 1 1/2 years I don't see how the timing could have changed?

crassius · May 9, 2015

about the only reason we see timing changes is because some internal part of the CDI fails - this can give good spark, but at wrong time

I've seen that often enough that I built that test rig shown in the referenced thread.

Edd · May 10, 2015

This might sound stupid, but it happened to me once. Had the same problem you're having: Good spark, good compression, wouldn't start. I cleaned out the carb, and did every kind of adjustment I could on the needle and float, no dice. Finally, during one of my start attempts, I cracked the throttle open halfway. It roared to life. Turns out, the idle was set so low, it didn't even try to start -_-...

You've probably already tried this though, and everything else suggested hasn't worked. What a curious little problem. The only thing to fix that I could think of, and someone already touched on it, is if there was old fuel left in it, it might have hardened into varnish-like goop. Might be plugging something; is your fuel system clean?

Won't start everything checks out fine, HELP!

New Member

Attachments

Well-Known Member

New Member

Active Member

New Member

Well-Known Member

Active Member

New Member

New Member

New Member

New Member

New Member

Well-Known Member

New Member

Well-Known Member

New Member

Well-Known Member

New Member

Well-Known Member

New Member