90 CR250 won't start

[joh9356]

:bang:

I will be ecstatic if any can help me with this one. Here goes:

1990 CR250R
Keihin PJ38 (already rebuilt)
main: 170
slow: 55
air screw 1-1/2 turns
needle: 1370
float: 16mm

it is getting plenty of fuel

engine compression is good.

spark plug: NGK BR8EIX

stock reeds look OK

PVL ignition system has been bench tested by Penton imports and show OK. timing is set to 2mm BTDC

FMF Gold pipe with repacked silencer

fuel: 32:1 93 octane with synthetic

The problem:

When I kick it over with the plug out, it only sparks 60% of the strokes (Penton says this is normal for slow revolutions on their PVL system).

I cannot get it to start at all. Every time I kick it over, it sounds like the first kick wants to start, then any after that, nothing. I pull the plug after the first kick and the plug is soaked. There is no fuel down in the crankcase, I have checked that. Timing has been changed from 15mm - 0mm BTDC, no difference.


HELP!!!!!

 

[joh9356]

As asked by another member, I did change my plug from a BR8EG (tried two new ones) to a BR8EIX which is in there now, still same problem.

 

[rmracer]

Maybe your coils on your stator went bad? This is what happened on my bike and it just stopped and wouldn't start no matter what I tried

 

[joh9356]

No, good thought, but they have been tested to be good.

I also checked the grounds and they seemed ok. I have heard of ignitions that run fine on the test bench but on the bike another story......

Stator - norm: 162.45-179.55 ohms---- mine: 167.8 ohms
Coil - norm: 4.8k ohms-5.1k ohms---- mine: 5.0k ohms

 

[Bullwinkle58]

How about the plug wire?

 

[joh9356]

Actually, I was just sitting here looking at that very thing. I pulled off the boot and the clip that clips on to the plug end has a sharp point on the end of it where it presses into the wire. Must be a custom wire thing from PVL. I went ahead and cut the end off of the wire about 1/4 inch or so and repunctured the wire with the clip. Checked the resistance again and it seems ok, I will try to fire it up again tonight and we'll see.

 

[joh9356]

OK,

It didn't work either.

I went ahead and ordered a CDI module from my bike shop for it even though it was "OK".

When it arrives I will post an update.

 

[joh9356]

While I am waiting for my CDI box, I have another question. Does anyone know what the original carb was on this bike?
I have a PJ 38mm, but is that the original series?

I spoke to Keihin USA and they told me since this carb was probably the original (they couldn't be for sure), and needed to be replaced. Reason: Keihin, being an excellent carb, has a problem. The jet needle seats in the carb housing itself, not a brass threaded seat like in Mikuni's and others. While this is not a problem right off, it will slowly wear out the seat of the carb housing causing mixture problems. The only way to fix this is by replacing the carburetor, which I find myself needing to do at this point.

Now, back to my earlier question, the reason I need to know the original carb, is because I want to get a PWK series and I am undecided as to which I need. Being a 250cc, I want to go with the PWK 38, but the PWK 35 may be closer to the original. Can anyone please tell me which would suit me better? If you want the specs, they're at the first part of this thread.

The PWK 38 is closer in dimensions to my existing PJ38, but my PJ38 is also a tight fit to the intake boots, causing me to think it had replaced the PJ 34/36 by someone earlier.

Any help would be appreciated.

Jim

 

[joh9356]

I hate to be pushy, but does anyone have an opinion? I am planning on ordering the PWK tomorrow.

Should I get the 35 or the 38?

 

[Nevada Sixx]

i assume you cleaned your carb, did you also take apart the choke and clean it? I would have ordered the stator instead of the cdi (you can get get the with the plate and wireharness for easiest installation), I dont think anyone on this planet can really "test" the ignition on a dirt bike, its almost always the stator. also, check the wires at your kill switch to make sure they are not grounding against your handle bar. Its all about fire, fuel, and air when it comes to cranking a bike that has good compression.
you said you had a wet plug,,maybe your floats or inlet needle in your carb are not working right and giving to much fuel. I have a feeling its gonna turn out to be your stator though. I spent 300 bux on my cdi and coil only to find out my stator was bad (and it was a fresh one, and bike had a little spark). flywheel still magnatized?

 

[joh9356]

Hey Nevada, thanks for the reply.


To answer your questions,

I checked the stators resistance and it shows good... now, in your experience, does this really reflect a good stator? I have been told that it could still be bad. Is this true? And if so, does the strong spark reflect that?

Next,

Yes, I completely rebuilt the carb, a few times. Me being the one building it could be a factor, but Eric told me my settings were all correct in an email a while back. That's when I called Keihin USA and they told me a bout the jet needle problem I posted earlier. I think the carb is 15 years old, and they simply responded, "replace it".

The kill switch is fine, I checked that too (bypassed it, tested continuity, etc)

Anyway, I decided to get the CDI box first, because believe it or not, hold on to your hat, it is only 43 bucks, yes, I said 43 bucks, it is the analog, not digital CDI. My stator is 148. From what all the techs tell me, it is likely the CDI box causing it, but I certainly am open to suggestions, but decided to get the cheaper part first,which is usually the stator for most other bikes' ignition systems.

Flywheel is magnetized fine.

Nevada, thanks for the input, do you have a suggestion on which is the best carb for a 90 250? PWK35 or 38?

 

[Nevada Sixx]

Hi,, you have been working hard on your bike, you must be a serious rider....

Is this bike new to you? did you just now buy it? or have you been riding it a
while?
I"d get the pwk35 if it will fit so maybe you will have more bottom end power.

your plug can still have spark, and your volt meter can show resistance, and the stator still be bad, mine was. I had spark about every other try, so i assumed it was my cdi since i had replaced my stator about a year before,, i think i shorted out my stator by spraying wd40 around in there thinking it would get water out of my ignition. daa...
But that was a killer killer deal on your cdi, mine was 175, so you still got plenty of money left if you decide to replace the stator,, and like i said, buy the stator coils,plate, and harness all in one so you wont have to sauder anything.

I assume your gas is fresh and your tank is full... i wonder if a big wasp nest has built up in pipe/silencer over the spring? or maybe your new pipe has some of that popcorn plastic filler stopping it up. kinds sounds like something is stopping up the air flow, maybe a rag in your air boot? or maybe your powervalve is stuck.
you said your plug was wet,,could it be antifreeze leaking onto it instead of gas?
let us know what it was if you find out...

 

[joh9356]

Your right, I do need to give a history on this thing. I have only had it a year. I paid $0.00 for it. A friend gave it to me.

I rode it around for a while, and I work right next door to where I live and we have a flood plane with two 8' ramps to level that are kind of fun, so it is a good place to practice. I don't race pro, just goof off out there, so I don't kill anyone but myself. :coocoo: It ran half-fair, but it sounded like it missed, sputtered and popped a lot, until you cracked it wide-open, then it was ok.

Anyway, I completely stripped down the bike to the last screw. I replaced all bearings in the shock and swingarm, wheels looked ok. I repainted the steel frame, cleaned all parts and reassembled. The silencer was repacked, all broken parts in the engine and frame were replaced, pipe looked fine and flows good. Powervalve is another story. I haven't stripped it apart yet. If I can get the spark working properly, that will be my next step.

Definitely not antifreeze, fuel is new, 32:1 synthetic on 93 pump gas, hey, it's a 90 anyway :cool:

Appreciate the response, so you think I should go with the PWK35? I decided to wait until I could get some advice on it, and so since noone else is going to advise, I'll take your word for it and that's the one i'll get, thank you.

To give you a background, I have been building and rebuilding engines for 17 years, nary a one has been a motocycle. Plenty of lawnmowers, plenty of dodgers(Was a Dodge tech for two years). So I know the mechanics of engines very well, but you know, two-strokes are a different beast all together. I understand the theory just fine, just haven't been around them a long enough time to gain experience to troubleshoot their driveability problems.

Thanks, man.

I will continue to post updates as I get them, my shop opens up in an hour and I'm gonna call and see whe my CDI box is comin' in!

Later,

 

[Uchytil]

I brushed over your thread briefly, looks like you have the primary and secondary electrical covered. You said the compression was good. If the exhaust is not plugged, the intake is unobstucted, and the carb is clean, you may want to look at the internals. You can pull the expansion chamber and check the PV. I would pressure test the crankcase. If you have a leak at any one of these areas, i.e. crank seals, jug base gasket, or reed gasket you will probably never get this thing to fire up. Are you sure about the reeds? I had a CR once that had a small crack in a reed and it would not fire for anything, new reeds and 1st kick. The good thing about 2 strokes is that they are pretty easy to diagnose especially if the basic pri/sec elec circuits are fine. Good luck, maybe it's the CDI ( I've seen a few go south).

 

[joh9356]

:ugg: Why do I have this sneaky suspicion you might just about be right?

I certainly hope not. I am going to try the CDI box and carb first, then my next step is as you have said, it'd be time to get the gasket and seal set.

BTW, the reed valve seems to be ok, but you tell me: It is the stock system, and the petals themselves are perfect, no cracks, no fraying, nothing. However.... yep, however, there is about a .01mm gap between the housing and the bottom reed. I was told by a tech that that should be no problem, it wasn't enough of a gap to cause a problem. I mean you could blow a small amount of air from your mouth on it and close it. If you think this could be a problem anyway, I'll go ahead and make a phone call to boyesen.

Jim

I had also replaced the dry seal for the crank on the ignition side as they are known faulty, still no change.

Oh yeah, my CDI box's ETA is Wed. the 30th.

 

[mobrown]

Pj38

Original carb was the PJ38. I was on the phone with Sudco (think that's the name) to get info on my original carb (1991 CR250) and asked about yours too.

My CR has the same problem that yours has after sitting through the winter. What has always worked for me is to lean the bike over on it's side (before I try to start it) to get old gas in carb out, take out the plug and kick it to get all fuel out of the cylinder, put in brand new plug and then kick it. Here's the thing though... for some reason these bikes only want to start if you kick it from TDC. I have gotten really good at doing it and I can get it to start after sitting for a long time.

The trick is to get it started one time and after that it never has any problem starting. I keep the choke all the way on and when it does kick over only give it a very very small amount of throttle until it gets going. If you try too much throttle it will die and you have to do the whole process over again.

I'm not suggesting you haven't tried a lot of stuff because you seem to know a lot of what you are doing but I've had mine for 2 years and it has become an aquired art to get it started after sitting for months.

Thought maybe I could help... good luck. My '91 is really fast, my brother has a '97 RM and he can't touch mine!

 

[joh9356]

Hey man, thanks for the advice!

I'll give it a try, probably will wait until Wed. to do so, should have my CDI box in then. Never thought about kicking it from TDC, I'll give it a whirl. Also, thanks for asking about my year for the PJ38, I kinda figured it was the orig. but wanted to make sure.

I hate waiting on parts :bang:

 

[mobrown]

My pleasure

You never know what might help and everyone in these Forum are so very very helpful... you can save tons of time and money just by asking these folks. I'm quite sure with all of your knowledge that you've given a lot of help yourself!

Yea... you'd think they have to manufacture the parts from scratch as long as it takes to get them sometimes!

Mo

 

[Nevada Sixx]

di dyou say you have spark? anyway,, i wonder if your connection rod is still connected to the powervalve and didnt come loose.

 

[joh9356]

Spark is only hitting 60-70% of the strokes. Course this doesn't fare well seeing that it doesn't mean it is sparking at all under compression. I can only think it is. When it does spark, it is very strong.

You know, one way to make sure it gets running is to rebuild the entire engine. :think: I am not gonna rule that out, but hopefully not necessary.

Remember now, I do not have the original Honda ignition, it is an aftermarket PVL racing system.

 

[joh9356]

:( I am STILL waiting on my CDI box.................

 

[joh9356]

Okey-Dokey, my shop called and told me it came in.

I'll let you guys know if it works or not....I'm bettin not.

Optimism is not my strong suit.

 

[joh9356]

:pissed: :pissed:

Well..........

My entire engine is now disassembed. I probably don't have to tell you the CDI box didn't work, wasted 50 buck following a tech's advice.

Anyway, I pulled off the cylinder oh so easily. Guess why? SOME STUPID SHMO :pissed: removed ALL of the guide dowels and used a stinkin screwdriver to pry up the cylinder in THREE different places!!!!!!!

Some people should not be allowed to ride dirtbikes, at least those who try to fix it themselves without knowing how.

So anyway, After seeing that, I decided to see what else the moron did. I turned upsides down the case and fuel mix pours out.....


and so does coolant....


and so does tranny fluid.... :think: Hmmmmm.......

I wonder why my bike wouldn't start?

Jim

 

[Nevada Sixx]

if you got to get into all that rebuilding, it may be better if you just tried to a few hundred bux for your bike, and buy a newer one, if not a brand new one. you can spend thousands on updating an old bike, and you still have a old bike when your done,, either way,,it cost about 100 bux a month to pay off a new bike,, or 100 bux to keep an old bike maintained. that was my experiance with restoring an old bike...you can probably get a 04 yz or cr pretty cheap now. let us know how it all comes out....

 

[joh9356]

Well, I was stupid and rebuilt the entire bike, ground up, bearings, seals, repainted frame, etc. before I opened up the engine. Reason was, the engine actually ran, albeit not very well, but at least it ran, before the rebuilding started.

I ordered a gasket kit, seal kit( I am rebuilding it myself), and getting ready to order a wiseco piston kit for it, too. I have everything disassembled on the engine, cracked the case halves properly(not with a flat blade screwdriver like the idiot before me :coocoo: ), cleaned everything, checked everything, and am ready to reassemble.

Have already spent all the money I have to for the entire engine except for the piston, and will get that next paycheck.

But.... I have already decided to sell the bike when it is running good, I should get a fair amount for it, being completely rebuilt from the ground up. I'm thinking about asking 1500, is that good?

I'm planning on a 2005 KLX300R. Whadya think?