new guy with a question

[ratherberacin]

hi guys, new here today and have a question.
84 200m bought three as a package deal and all were not running.

got the first one together and idled ok but wont rev past about 1500rpm. the rpm doesnt break up/pop or anything just wont rev. choke on/off doesnt matter.
fresh plug, NEW carb. did the top end gaskets today and still runs the same (lower gasket was blown) internally its in good shape with low miles judging by cyl and piston wear.
valve lash feels ok .
checked for a intake leak with carb cleaner and it didnt rev up.
swapped plugs and no change.


idles great, purrs in fact.

thinking now perhaps a coil/cdi problem? havent looked at anything electrical related yet.

what about the muffler/ header pipes, do they typically pack up inside?

if anyone could give me some pointers on where to look it would be appreciated.

[harryredtrike]

i would look in the direction of the carb.what (new)carb did you put on?is the throttle moving the throttle slide in the carb?yes exhaust can clog,i would look towards the tail though.air filter yes or no new or old?

[tri again]

some folks have mentioned that mice love t o build nests in the airbox and even the mufflers.

we have mud bees in oregon and they WILL plug darn near anything from 1/8" vacuum lines to 3 in sewer drains.

Can you see if the throttle cable pulls the piston almost all the way up?

I can't imagine that the timing would act like that especially with a purrrfect idle but the more I learn, the less i get surprised.

I think a coil breaking down would be more of a sputter or usually more related to the coil heating up after a while.

[ratherberacin]

thanks guys.
muffler removed it runs the same.
air cleaner removed runs the same as well.
full travel on the throttle slide

fuel flow is good out of the tank

carb is a stock ebay replacement. looks just like the original. bike ran the same with the original carb as well. this one just idles smoother.

[harryredtrike]

im still with the carb,something isnt right.pull the carb off and physically look to see the slide is moving up when the throttle is twisted.

[swampthang]

does your airbox draw air through the frame? I'd check that for blockage. I had one that had muddobber nest in the frame and I wouldnt let it rev out either.

[tri again]

thinking if the valves were loose enough to not open, you'd hear it rattle and knock from a mile away.

wonder what we're missing?

oh _____, I had a spark advance NOT do whatever it does one time, and can't remember what it was now.

I think it got stuck advanced and wouldn't idle correctly?

some of the spark advance may come from the cdi black box and some may come from the pulse gen under the aluminum cover that says 'cdi' on it.

There are springs in there and some red rust dust

but that could sure do something annoying if stuck in either direction, or not move.

or I could very easily have my model years wrong.

[bobotech]

When you say it won't rev past 1800 rpms, do you mean that you can gently push the throttle to the point where it hits max current rpm and then keep pushing the thottle like you are trying to floor it, and it doesn't sputter or anything?

Have you tried pulling the throttle cable up manaully on the carb itself while its running? You can do that and it should bring the throttle slide to the top. I wonder if its something as simple as a misadjusted throttle cable?

[ratherberacin]

hi guys, thanks for the replies.

tonight i did some checking

throttle goes full travel. so everything is ok there.
air box checked the air inlet tube and i wasnt sure if it was clear so i removed the inlet rubber off the intake box and no difference. air cleaner is new. ran without the cleaner and box and results were the same
checked coil wire boot end (plug end) and it was fine but cut it back and redid it anyways.
replaced O ring on intake rubber.

checked timing. on tdc the cdi rotor pointer was 90* out (6 o'clock) removed the rotor and moved it to where it "should" be (magnet end at 12'oclock) and would not fire. put it back it, ran like before.

i did notice a bit of fuel on the intake boot pre-carb side. fuel is shooting out the intake. air cleaner smells like gas.

what it seems to do it run ok up to about 1500 or s and thats it. just labors tring to rev higher. sounds sick while trying to rev.

plug is chocolate brown

tomorrow i am going to pull the cdi to confirm i am timed ok. thinking i may swap the cdi with a known working one i have here.

any other ideas?
again thanks for the help, i am used to mopar muscle cars so these things are out of my league.

[Thorpe]

i would look in the direction of the carb.what (new)carb did you put on??

Couldnt agree more with Harry!
Carb out of the box is not likely going to come tuned and ready to run.... We need more details.

[ratherberacin]

bought 2 carbs new and the 2nd one is running awesome on the 2nd bikel so were going to swap it today and see.
i am hesitant about the carb because the old carb did exactly the same thing. but worth the try for sure to know everything is ok.

if that doesnt work i think i will take a video and post it here for you guys to hear it.

[ratherberacin]

ok carb swapped. runs the same. this 2 new carb works awesome on the big red so its not a fuel problem.
intake seals are both new and no rips in the intake tube. air box inlet tubes are clean and it has a new aircleaner

one thing i find weird is when it doesnt want to rev the air box to carb rubber has fuel on it.

so back to ignition or?

long shot how about a broken intake valve spring?

[MTS]

Sounds to me Like a Combination of a Bad intake valve Or spring, Havent seen a Spring break, But did have one Wear through the Spring seat and into the head and Stretch right out on a 110 recently, Caused Alot of similar problems..

[tri again]

man I used to have your patience. congrats on the approach.

I really think there is a spark advance plate behind the pulse generator that's supposed to rotate.

it has springs and is usually covered in red dust, unless I have my model years mixed up.


if it does exist and is stuck, it is behind the cover that says 'cdi' up by the cams on the head.
and can hang your ignition timing .

We ALL want to know what it is so please don't ride off when it runs and forget to tell us, ok?

good luck, I think you're doing great .

I guess a timing light would be the fastest way to rule out the advance curve effect in the cdi box too but i think you said the cdi swap did nothing...hmmmmmm.

[tri again]

would the main carb needle move if you push up on it?

like it's able to slide up into the piston ?

I'v seen those needles come loose when their hold down clip slips over.

[ratherberacin]

it does have the plate. i know the pulse generator is spinning when its running but not sure if the plate advances. will have a look tomorrow after work

[85_BIG_RED_250]

i am an A.S.E certified electrical technician. i had a car the other day that was doing the same thing. the coil was cutting out at a certain rpm, im pretty sure there was a fault in the primary winding..? my guess would be to turn to electrical...but it is also possible that the crab is starving at a climbing rpm? just figured that i would try to help

[ratherberacin]

update

tore into it again today. pulled the tappet cover and checked for a broken spring. both are good. rockers arms are in good shape. redid the lash.
rechecked TDC and it was lined up.
checked the advance plate and it advances and returns fine. removed it and lightly lubed it
checked coil wire, wire is fine. plug boot shows alot of resistance. swapped it out. will swap out the coil tomorrow.


runs much better but still starving/missing at higher rev's. (maybe 2500rpm now) to me it seems almost that its running out of fuel. what size is the factory fuel line? maybe the one thats on it is too small? (shot in the dark)

going to take a video and post it here tomorrow. maybe that will help.

[ratherberacin]

ok now with video.

i am just guessing now. nothing seems to change. havent done a compression check, maybe thi smotor is just wore out. will check it tomorrow.

any ideas?

link to youtube.
http://www.youtube.com/watch?v=cXks0ofQehw

[harryredtrike]

is the plug still brown as before or getting darker?im starting to think intake valve.have you checked the setting?clearance.might be hanging up and staying open enough to push fuel backwards into the airbox.time for compression check

[ratherberacin]

plug is a little darker but tip is clean (white)

feels like very little exhaust is coming out of the pipe. no restrictions that i can see.

[MTS]

is this all based on Running it in Neutral ...? and running the crap outa it cold??? or riding it..? Sounds like Something is slapping or a bad Exhaust gasket too...Heck almost sounds like a loose plug...One cant tell..Unless your in-front of it.

[cbx1170]

RICH RICH RICH
1 ck compression runs decent so i think this is OK
2 ck ignition dynamically with auto style timing light down thru timing hole "F" for idle and 2 "I I" marks for full advance prob good here also i bet. Oh yea adjust your cam chain also!! and fix your exhaust leak(s)
3 clean main jet emulsion tube area good-its under the main jet. then ck float level when bowl off turn carb sideways keep float pin to top let floats hang as needle sets light NOT compress the float needle spring make sure seam lines on black floats are parallel to gasket surface. Always BLOW out needle and seat first before cking this and run CLEAN FILTERED fuel.

Then you will prob find the off idle richness (1/8 to 2/3) is due to worn JET NEEDLE and NEEDLE JET. Have to replace both. You will prob see wear on top of needle just below clip grooves 1/8 ~ 1/4 inch. BUY AS A SET from HONDA. prob part # 16012-958-681 I have replaced dozens of these.
Ride and have fun.
PS you CAN file the angled air cutaway LARGER on side of slide to do a real real cheap fix BUT eventually you'll get tired of bad running and buy a slide and jet needle/needle jet set. been there.

[mike1979]

I see the back of your front fender looks like it is black, do you have a bad exhaust leak at the head?

[ratherberacin]

thanks guys.
pipe was leaking at the head and new gasket was put on, so thats old smoke. pipe leaks where it meets the muffler. an exhaust leak isnt going to cause running like crap. so was going ot sort out the other issues first

motor was warm in the video, not revving the snot out of it cold.

t-chain is tight.

carb works awesome on a different bike. so not a carb issue but will check.

lash is .003 cold both intake and exhast

i will use my timing light on it and make sure thats all good too. will check cranking compression too.

changed the coil out from the other working bike. maybe swap the cdi as well?

frustrating for sure

[84atc200]

My 1984 200s ran like that, found out my cam was toast.I wish you luck with getting it running correctly.

[ratherberacin]

My 1984 200s ran like that, found out my cam was toast.I wish you luck with getting it running correctly.

that thought crossed my mind. i did look at the cam and it looked ok but never measured it. what did yours do? wipe a lobe off?

[84atc200]

Here are some pics of mine looked like,after i took it out.

[cbx1170]

exhaust leaks at pipe to muffler and holes in muffler (yes they wont run right with rust holes everywhere in muff I chased a bunch of these and muff always fixes this) cause higher RPM misfires and poppin on decel. Your video sounds like ign misfire or rich. Also ck suppressor cap resistance should be approx ~ 5K ohms. then compression ignition carburetion ALWAYS. Compression Ignition Carburetion. otherwise you go in circles. Again Comp Ign Carb. Got it. I did this for ~25 years 1975-2000. It always works. Chow.

[123-shaneomac]

i have a 200m doing something similar and ive checked everything to do with fuel and air so its got to be in the electricals somewhere.

[85_BIG_RED_250]

also, do what i call a tug test. tug on the wiring harness at various locations. the rev @ 2500 or so may be the exact proportion to vibrate the most? sounds weird i know, although it vibrates more when w.o.t.

[ratherberacin]

ok update...again.

cranking compression after its run approx 4minutes. 85psi. pretty low i would think.

timing is hard to do with my timing light as oil is spraying up while i do it. i need to mark tdc and try again

what i did do though is not the best plan but just as a test i ran it without the exhaust, straight out of the head (not for long) i found it revved just fine. no issues at all. so................exhaust system?????

[ratherberacin]

took 2 weeks but the dodge mechanic figured it out. not carb, not timing, not electrical. not fuel, not plug

WINNER!!!!!!!!!!!!!! runs great. like a new bike.

[harryredtrike]

took 2 weeks but the dodge mechanic figured it out. not carb, not timing, not electrical. not fuel, not plug

WINNER!!!!!!!!!!!!!! runs great. like a new bike.

what??????what was the problem

[bobotech]

What was the issue!!??

[muthey]

the issue was his header pipe was plugged, what I was thinking, when he had checked everything else, makes sense. with the push back of air through the carb, fuel not going through the intake at high rev, and flowing backwards, the only other cause for fuel in the air cleaner is a bad float needle or intake valve. congrats on your trike being alive again

[harryredtrike]

i told him to check that two weeks ago,first response to his post.

[cbx1170]

After relistening to vid I thought that leak sounded wierd. Definitely obvious now.

[ratherberacin]

yep, header pipe. pulled the muffler weeks ago and it ran the same. never thought it could be the header pipe.

when we pulled the header pipe off and it revved fine. funny part is i dont see any restrictions in it. ran a wire down the inside and nothing blocking it. took the garden hose to it after it was off and it flowed water just fine.

so........ its a mystery charlie brown


works now though. this is my gf's sons bike. the smile on his face after it was fixed was worth the weeks of screwing around. lol first place it went was in the mud.

thanks for all the help guys