Need help with mid to high range misfire!

[McQuade]

Hi all, I have an 85 200m I purchased with a donor bike. The donar ran great but no brakes or plastic. The other bike would start but not run past idle, and was leaking oil so I replaced the engine, coil, battery and carb from the running doner bike. I'm STILL having the same issue. Starts first pull with no choke idles perfect. Touch the gas slow and it will begin to climb rpm then about mid range it sputters and zero power. Won't move the bike. Hit it fast and it stalls. I've cleaned the carb to immaculate shape, new fuel and lines. Plugs good. The only thing that I didn't swap from the other frame was the little black box that has a connector with five or six wires. Could this be it? It has a different harness is why I havnt as the donor was an 84 and the plugs are different. Any help?

[cap]

That black box is the CDI.
Did you replace the whole carb or did you leave the slide attached the throttle cable and screw it onto the new carb? That slide is where the needle valve sits in the bottom and it may be too lean. Move the clip down on the end of the needle to raise it up a notch.

[McQuade]

I tried both cables/slides. The CDI box is literally the only thing I've not swapped.

[cap]

Possible, might be able to swap plugs so as to use the doner bike cdi

[McQuade]

That was my last resort, only because I wasn't sure if splicing would alter resistance through the wires. I will try that. I guess I was only curious if a CDI could cause this. I'm a cert. diesel tech, not familiar with capacitor discharge systems. My camaro has one but it's integrated, and never had to replace it. Thanks CAP. I appreciate it.

[McQuade]

Okay so I replaced the cdi. No difference. I put it in gear and it won't move nothing. It isn't running well but it revs high enough it should at least catch a little... I'm at a complete loss on this one. Any help would be appreciated

[atc007]

If you are absolutely sure your carb IS spotless . It will be spark. Ohm out your stator . There are manuals on here and the internet, free. You can pop the recoil and flywheel off and clean the stator,flywheel for piece of mind. Also your advancer under the CDI cover ob your cam is likely rusty/dirty/possibly broken springs/not advancing. This should have her purring. Complete flush and service, Adjust your valves and timing chain ,and she'll be like new.

[cap]

You said it ran good on the donor bike? Do you have good fuel flow from the tank? Tank cap vent open?
It sure sound like the main jet is plugged up, you should be able to blow or spray through both jets from one end to the other and the small ports around the end should be clear.

[atc007]

Good eye cap. I agree. Man,, I have found myself simply skipping through posts lately and only picking up half of what is there. Not cool! But if it was the tank,it should run like a champ for a minute,then starve.

[McQuade]

Tank flow is great. I've cleaned the jets four times today. Still nothing. Idles perfect. Mid to high is "bubbly" and inconsistent. But you can rev it up to half and it will run great, it points to the needle valve, but I'm seeing nothing wrong. It ran on the other frame perfectly that same day

[McQuade]

Would a bad ground do this?

[cap]

Bad ground will cause a weak spark, wire brush the coil mounts to clean it up.
More things to check,
airflow- pull the air cleaner and run it up, bees nest in the air tube maybe.
Is the thumb on/off switch jiggling around.
Spark advance springs under the CDI cap.

[McQuade]

Checked, and cleaned. No difference. I can see the springs move out and they are free moving. It runs with the choke fully on. Not well, but it does quieter.. Hmm

[DohcBikes]

Valve adjustment, check it cold at tdcc.

Now that I see you changed the whole engine, i'm leaning away from this suggestion, still worth a look.

So many times i wish i could teleport. If I were standing there i could fix it LOL...

[danbur55]

Bad ground will cause a weak spark, wire brush the coil mounts to clean it up.
More things to check,
airflow- pull the air cleaner and run it up, bees nest in the air tube maybe.
Is the thumb on/off switch jiggling around.
Spark advance springs under the CDI cap.
Lift the airbox lid had same thing on 82 200e was dirt dauber nest at top of backbone

[McQuade]

Filter is gone. No difference. Plug is getting fouled up now. Didn't before in other bike. I've taken both Intake and exhaust off thinking there was an instruction. Cleaned the grounds up. Checked fuel flow. Cdi advance is functioning. The ONLY thing I havnt swapped is the voltage regulator. But I'm not seeing how that would do it. Thanks everyone for the input

[cap]

I'm leaning towards pulling the carb, again. I've had to pull one apart 6x in one day until I found the obstruction.

[McQuade]

Where would it be obstructed? I can clearly see through the main jet. Would the mixture screw have anything to do with this? These are fairly straight forward carbs, I've dealt with quadrajets before. I just don't see where it could be faulty

[atc007]

If it runs better w choke. your carb is not right.These are stubborn little buggers,,not really. But if you're new to them they are. High compressed air. Paying close attention to the air ports that go up in to combine the main and pilot jets. If you have a pale of carb soak,strip it and dip it. if not ,good ol compressed air.

[McQuade]

I stripped and dipped. I'll let it set over night. The port that goes from below the choke plate to the emulsion tube seemed a little plugged. Perhaps this was contibuting. I'll keep you posted, I'll assemble in the AM. Thanks again for your advice

[McQuade]

No dice: I took the air box core off and it seems to be popping and very loud in the intake! Any thoughts?

[cap]

You might check the timing to rule it out, never know who or what has been done to these old bikes.

Not hard to check it.
Pull the CDI cover, pulse rotor and pulse base off so you can see the cam sprocket.
Line up the flywheel "T" mark in the inspection hole, (you have to peer in towards the inner motor to see the marks.)
The "O" mark on the cam sprocket should now be lined up on the mark on the valve cover @ 12:00, very important now to see the dowel pin on the cam shaft at the 11:00 position because this is what index's the pulse rotor. Now install the pulse base/generator and the pulse rotor. The lines should line up just before the generator/rotor pickup. Move the crank to "F" and the generator/rotor lines should line up, if not adjust the generator slightly.

see page 73 in the manual
http://www.oscarmayer.net/atc/manuals/

[McQuade]

So there is both a "t" and "f" on the flywheel? Does this base go in only one way? I'm timid if this all because it ran fine in my other bike

[cap]

There is a "T" : and "F" : Use the line not the actual letter.
The base is held in with a couple screws and you can't mess it up, just pulls out, remove the rotor first of course.
We have gone over the simple and obvious stuff and it still don't run right so if everything else checks out you need to start from step one.

[McQuade]

Okay cap. Here's the DL. When my coil is perfectly in line with the pickup. The line on the flywheel is on the T"" this be the problem? How do I rectify this?

[cap]

Line up the F mark and You should be able to loosen the generator pickup part and rotate it to line up with the pulse rotor.

[McQuade]

Okay. Slid it as far counter clockwise as it would go. I could see where it slipped. Started it and ran a little better... Still poor tho lol. Took entire cam cover off and the "o" doesn't exactly match the indent on the valve cover close but not perfect. Is this also a problem?

[cap]

That should be okay, some don't line up exact.
Do you have another carb to try?

[McQuade]

Nothing made a difference. I'm at a total loss why this power plant and acc. Worked on one bike and 45 mins later doesn't on this bike.

[cap]

Yea don't let it kick your you know!
There is a little o-ring in the bottom of the idle air screw port. If its missing or plugging up the port it will run like crap.

[danbur55]

if worked on other trike seems wiring on this one may have a loose connection or hidden break some where may have been pinched at one time sounds like most everything else has been swapped or tried stay at it and youll find it we're pulling for ya:)

[McQuade]

That's my gut feeling here too. It has to be harness or frame related. This bike had the harness torn apart because someone lost the key and hot wires it past the ignition, so the lights and everything thing else was disconnected. It was a mess but I thought I had sorted it out. I put a toggle instead of the ignition and got the power bavk to everything but perhaps I've missed something. Thanks all for the help. I'm going to spend a while stripping all the harness and making sure it's good. Would a bad wire make it spit through the carb and carbon up the plug?

[danbur55]

Sony swear to it but my 85 lt230 broke aground wire at a solder joint in the harness and didn't go past half throttle without spitting

[cap]

Just pull the tank and seat and the whole harness can be swapped from the other bike.

[McQuade]

Can do lads. I'll try this all out. Thanks again. But as a side note, in the other bike I was able to pull start it first pull and it didn't bog at all. No choke. I know my camaro has to sit there for ten mins or it will flood like you wouldn't beleive. Would this indicate a pre-existing rich condition?

[McQuade]

Okay guys I'm back. Swapped the harness to no avail. BUT I did notice something infuriating. I'd only bought this a few days before this thread so I didn't know... The middle gasket on the jug, (head gasket?) is bubbling oil and a bit of smoke out. Would this do it? Is this destined for the scap pile? Haha

[danbur55]

I would think its possible. Losing compression as well as suckin air in

[McQuade]

Okay. So the parts are all in and the engines done, ready for assembly. Pretty simplistic but I want to make sure I do this right. There are two I rings that go on the stud spacers. Do they go "jug, spacer, or ing, then head gasket? It seems as though that's how it came apart. There was only one installed* and it seems when I do it this way the head gasket may not seat properly? The manual is so vague it's literally no help.