Could it be Ignition timing or worn crank seal?


blic

Member
Jan 11, 2000
33
0
Hi

I need your help to solve my problem with my bike.
I´ve had the problem for a long time but it seems to get worser.
I´m fouling plugs and the bike is spooging a lot, the rear fender is black. The bike isn´t running to good.

I´ve checked a lot of things, and I´m going to check two more things. The ignition timing and if there´s any leak in the crankseal to the gearbox, if it´s sucking gearbox oil.

What is the symtoms of a bike that has “bad timing”. Fouling plugs or what?
And what is the symtoms of a leaking crank seal?

I have no tools for checking ignition timing and no tool for checking cylinder compression. So how do I know if the crank seal is worn out?
And how can I check if the ignintion timing is set incorrectly, there is no mark stamped on the stator. I can turn the stator clockwise or unclockwise, how will that affect the timing?

Thanks for the help!
 

Studboy

Thinks he can ride
Dec 2, 2001
1,818
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Your problem sounds more like a crank seal to me than an ignition timing problem. Have you checked your crankcase oil level frequently? Is or was your bike jetted correctly before this happened? Bad timing usually doesn't foul spark plugs, timing that is too advanced will create pinging and detonation. I do not know how the ignition advance (stator plate) works on your bike, sorry! But it seems to me to be something else besides timing.
 

David Trustrum

~SPONSOR~
Jan 25, 2001
1,396
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Well it could be a myriad of things, I’m assuming you are talking about the Husky. First off try the basics. Clean the carb, the airfilter (replace?), change the sparkplug (again) change the sparkplug cover. Clean the ign connectors.

Hit pick: Repack the muffler that may be blocked.

Sounds like your bike probably needs a bit of a recon. If it hasn’t been pulled apart for a long time a compression tester won’t tell you much as the head could be heavily carboned. You need a leak down tester to test the crank seal. Does it use gearbox oil? Also possible the ignition is breaking down. Does it stutter at high revs? Timing will not have changed so unlikely to be the problem.
 

blic

Member
Jan 11, 2000
33
0
This is what I have done:
New silencer, new pipe, new top end + gaskets, reed gaskets, new plugs, air filter cleaned, carb cleaned. And maybe more that I don´t remember right now.

David: What do you mean with sparkplug cover?

And yes I´m talking about my Husky.
 

cr250

Member
Oct 28, 1999
51
0
I just went through this problem with my yz 125...It did the same thing ...I knew it was properly jetted and the fuel mix was correct but it ran bad and fouled plugs a lot. Turned out to be my crank seal...although this is the last thing I would check, it definently was the cause of my bikes' problem. It's fixed now and running great.. Some of the other riders in DRN helped me out with that one, thanks guys!!!
Vanessa
 

blic

Member
Jan 11, 2000
33
0
I can tell you that this problem started after I smashed my pipe pretty badly, just after some minutes it started to ran bad down low and it hasn´t changed since that. Even after I have put on a new pipe and everything else I´ve told you.

And, how do I know that it really is the crank seal? I don´t want to change it if that´s not the problem...

Can I change the crank seal on my own? Or do I need special tool to fit the seal or balance the crank shaft, (I´ve heard something about that).
 

RM_guy

Moderator
Damn Yankees
LIFETIME SPONSOR
Nov 21, 2000
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North East USA
The only way to know if it is the seal is to do a pressure leak down test. You local shop should be able to help you. Or you could just change the seal. It really does sound like a bad seal.

On some bikes you can change the seal with out splitting the cases with out any special tools. I’m not familiar with the Husky. Check in the KTM/Euro forum.
 

georgieboy

Member
Jan 2, 2001
416
0
Blic, check yr powervalve also, maybe you hit and bent the hts system of the powervalve.
Disconnect the cover of the hts and rev the bike. See if it works properly. You can also disconnect the pipe and have a look tru the exhaust into the cilinder and move the hts by hand to see if it closes all the way. In closed situation you shld be able to put a .6mm feeler between piston and valves. Too much opening, say 1.0 mm, gives bad low-end. I assume you don't have a huskie manual of yr bike. Checking the timing. When your piston is at 2.8 mm btdc, (put a caliper or kind measuring defice tru sparkplughole) and check that the marking (1)on the stator plate(the baseplate behind the flywheel) corresponds with the slot end on the rotor(flywheel or magneto). They show a picture of this in the manual. The slot end is actually one of six holes made in the rotor you can see tru. So they use one of these holes as being a timing mark.
Is yr bike running bad at any throttle opening, or only at low throttle?
I mean when you give it full throttle, is it cleaning out and running nice, then it is probably not a crankseal gone bad.
let me know, ok. bibi
 

blic

Member
Jan 11, 2000
33
0
georgieboy:
I have completely disassemled the powervalve, cleaned it and checked that it´s moving when I rev the bike. But the problem is still there.
You mentioned something that I should check the gap between pistons and valves... I don´t really know what you are meaning by that, but I know I haven´t checked any gap there.

The bike runs bad when I hit the throttle wide open at low rpms. And it runs bad at low rpms.
On high rpms it runs good and revs good when you come off that bog in the low-end.
I can say that it starts to run good when the power valve opens.

Trustrum:
Do you mean that the wire isn´t connected to the plug cap?

Hope you understand me...

And thanks!!
 

cr250

Member
Oct 28, 1999
51
0
Ok I knew my crank seal was bad by taking the cylinder off and checking for tranny oil...also I took the ride side cover off and checked my crank bearings by checking the free play in my crank...these tests only take a sec...if thats your prob...go get seals and bearings...but check your jetting and everything else first...also do you have a fuel filter??? You might be getting dirt in the carb...take it off, clean it, clean power valves, check packing, check air filter, All this stuff takes a couple minutes but it should be done anyway to check up on stuff...Replacing the seals is not bad...you may need a shop for the rod bearing though...Good luck
Vanessa
 

georgieboy

Member
Jan 2, 2001
416
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Blic, the powervalve has to close as close as possible to the piston as the manufacturer find safe. So between the piston, moving up and down in the cilinder, and the powervalve there shld be a gap, which you can measure.
No gap means the piston-rings are hitting the powervalve. You definately don't want that to happen. But and other extreme is the gap is too large, so the powervalve don't seal enough at the lower revs.
I find a leaking seal hard to believe as you mentioned the engine runs fine at top revs. So, when there are no birds dropping out of the sky by yr exhaust smoke, i feel safe to say you don't have a sealing problem at yr "wet-side".
I also think you don't have a timing problem than, for the same reason.
I think you have a pilot-jet clogged or maybe some leaking slide. Focus on the carb side. Have you fiddled with yr choke, to see whether the bad running is due to lean or rich conditions?
 

David Trustrum

~SPONSOR~
Jan 25, 2001
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From your new info I’d agree with the chap above. Pull the carb & it’s float bowl. Remove the small jet down the hole next to the larger main jet. Blow through it to clean it (never poke anything into it) & if you don’t have a compressor use a piece of tube to blow through all the holes to ensure they are clear.
 

jmics19067

LIFETIME SPONSOR
Jan 22, 2002
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a rather easy way to check the crank seal is to drain the tranny oil and let it drip for say half an hour bike setting level or atleast as level as you can get it twice in a row measure the poper amount to fill it up go riding for a day dont bury the bike in water or anything or flip upside down bring it back get the bike settin the same way you did put your measuring cup under drain and let it drip for the same amount of time it will not be an exact science due to some oil clinging to everything inside but if it is a signifacant loss you know your problem also you said you replaced the top end did you could you have inspected the reeds or possibilty of damaging them? you smashed your pipe? did you buy the same pipe and silencer ? do you need to rejet for it if it is different?
 

blic

Member
Jan 11, 2000
33
0
I have cleaned the carb recently, after that it ran better than before, it took a longer time to foul a plug. So maybe I keep getting dirt in the carb.

I´m going to work on the bike this weekend I hope.
I will fit a fuel filter on it, clean the carb again, measuring the gap between the piston and valve, get a new plug and check the gearbox oil level.
And hopefully ride it for a while, until it starts to run bad, then check oil level.

I don´t have a compressor, and I know that I have poked things in to the pilot jet before (like thin needlepins), to try to clean it. Could that have damaged the pilot jet? shall I replace it?

Georgieboy: Do you own a Husky 125 -96 too? it sounds like you know much of it. (If that´s the case: What´s your jetting like?)
And what is a leaking slide? the carb slide is leaking or what? where could that leak?

I have checked my reeds and they are fine.
And, do I really have to replace my head gaskets if I remove the top?

Thanks for all the help guys!:D
 

David Trustrum

~SPONSOR~
Jan 25, 2001
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The pilot jet is very small so any damage to it will affect the jetting somewhat. Yes I would replace it. You may find a size smaller or larger pilot jet may help to experiment with. Drain/replace the gas as well.
 

jmics19067

LIFETIME SPONSOR
Jan 22, 2002
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Originally posted by blic
I have cleaned the carb recently, after that it ran better than before, it took a longer time to foul a plug. So maybe I keep getting dirt in the carb.

I´m going to work on the bike this weekend I hope.
I will fit a fuel filter on it, clean the carb again, measuring the gap between the piston and valve, get a new plug and check the gearbox oil level.
And hopefully ride it for a while, until it starts to run bad, then check oil level.

I don´t have a compressor, and I know that I have poked things in to the pilot jet before (like thin needlepins), to try to clean it. Could that have damaged the pilot jet? shall I replace it?

Georgieboy: Do you own a Husky 125 -96 too? it sounds like you know much of it. (If that´s the case: What´s your jetting like?)
And what is a leaking slide? the carb slide is leaking or what? where could that leak?

I have checked my reeds and they are fine.
And, do I really have to replace my head gaskets if I remove the top?

Thanks for all the help guys!:D

how dirty was the carb? and does it keep getting dirty each time you ride? pay close attention to that please one of the most important things to fix a recurring problem is too look and study and understand what you have done and how it has affected what you need

if you are going ot put a fitert inline for the fuel drain the tank look at the fuel remocve the petcock and check the screen no use putting a filter in it if it is only going ot clog up in my eyes a filter is insurance not a fix to me

poking something harder than brass thru the jet could ver y possibly destroy the jet even a scratch will change it flow characteristics
 

blic

Member
Jan 11, 2000
33
0
Georgieboy:
I have taken off the top of the cylinder, but how do I check the gap between piston and valve?
In what position should the piston be?
Or should I measure tru the exhaust?

I know it´s hard to explain but maybe you could make a simple sketch of it.

Thanks!
 

georgieboy

Member
Jan 2, 2001
416
0
Blic, don't focus to much on the powervavles as i think it is not the problem.
But, to check the gap just get the piston-skirt opposite the powervalve and see what the gap is. You can take feelers, and just slide in between the valve and piston-skirt. O sorry, from the top you can only put the feeler in when you have the piston-top alongside it. You can not reach the piston-skirt.
When you have done that go back to the carb.
By the way what did you hit?
Have you already fiddled with the air-screw?
good luck george
 

blic

Member
Jan 11, 2000
33
0
Okey
I don´t really know what you mean about measuring the gap, piston-skirt=the piston side (under the piston ring)?.
I suppose I need short feelers? that I can get in through the exhaust. And what to do if the gap there is to big. Is it possible to adjust?
What do you mean with piston-top alongside? (sorry, my english isn´t that good)

I hit the pipe in a sharp rock at the front of the pipe ( a little to the left).
It doesn´t get any better by adjusting the a/s.
 

georgieboy

Member
Jan 2, 2001
416
0
yes Blic, piston-skirt is under the rings. It is where you measure a piston for its size. You can check via the top(when you removed the head) or you can measure tru the exhaust opening. Let us say that the gap is too narrow. The powervalves will hit the piston. Okee so far. You don't have to measure that, cause you can hear it. Just rotate the crank and listen. Okee, but the powervalve is not hitting the piston, so you want to know what the distance between the piston and powervalve is. Standard is 0.5 mm. Bent a feeler and put it between the powervalve and piston. Do not care about the piston-top or the piston-skirt(that is the lower part of the piston, which is it widest part) When the gap is too wide you will lose low-end. You can alter the gap by adjusting the powervavle-screws.
 


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