Houston we have a Problem....Help

[JhallettEX]

Well I got it all put back together and I went to fire it up and she won't. It starts to turn over and then makes a loud backfireing noise. When I put my hand over the silencer, as it POPS it blows lots of air out and then sucks in alot. Is this normal. Could I be 180 out. When I put it back together the index lines were lined up, I was at TDC, and the lobes were down. I am not sure about anything else. What about the comp. and the exhaust strokes could I have been on one of them. Please help me out, first time doing this by my self. Thanks.

[knighttime]

like its not gettin very much gas :confused:

[VegasEx'r]

The sparkplug fires every time the piston is at TDC, so you don't have the strokes reversed. It sounds like you put everything back together right. I had a hard time getting my engine to fire when I put mine back together (although it never backfired). What I finally did to get it started was remove the airboot & spray some ether into the carb. then I fired it with the air filter off. It fired up almost instantly. I let it run for a minute then put the boot back on.

[JhallettEX]

OK, i have taken it apart again, I lined up the "t" on the side cover on the compr. stroke, I take off the cover and everything seems ok inside of the engine. The index marks are lined up on the sprocket, and the lobes are down. Now when I started rotating the flywheel and lined up TDC again it was 180 out, the lobes where up and the top index mark was down but the two side ones where lined up, does this mean I am 180? Thanks for the help, I have stopped for the night and I am going to the bar. I expect some good info when I get home. Thanks again

[beerock]

If the lobes were down and you were at top dead center that means you are 180 out, because with the piston at tdc the valves should be closed not open.

I am assuming when you speak of the lobes your talking about the cam lobes.

You sort of made it ery difficult to decifer exactly what was going on.
I hope the valves dont open so much that you smacked the valves with the piston.

I could be totally wrong, but it does sound like your exhaust valves are opening when the piston comes up and the intake valve is opening when the piston goes down

it should be

intake valve opens
piston goes down and sucks in gas
intake valve closes
piston goes up and compresses gas
power stroke- piston goes down
exhaust valve opens
piston comes back up and pushes exhaust out

thats why the exhaust is doing that.
because it id doing this process 180 out.

I dont know if its good to run it now, I would pull the head off and inspect the piston and valves.

you may have stretched the chain too.

I could be wrong though.

If you are getting spark on tdc (when the flywheel lines up to tdc)
then dounds like the cam is 180 out.

im not sure though cuz I couldnt understand your description to well.

[beerock]

heres a pic this compares a 4 stroke to a rotary

yr lobes should face down at tdc. make sure you lining up the right mark at the fly wheel because there are several on it. one tooth of could make yu back fire on it so also make sure those lines on the cam sprocket are lying flush with the cylinder head.. good luck..mine fired right up so i dunno what else it could be

[Leo]

you can't put the camshaft in 180 out, because it doesn't matter...

as long as all the camshaft marks line up every other time you reach the T mark, your cam timing is fine...

1 turn of the camshaft = 2 turns of the crankshaft...

make sure your turning the crankshaft counter-clockwise (as viewed from the side w/ the timing marks) or you'll wind up with a very loose exhaust valve (it'll still run, but it will be very noisy :)).. now that you know everything is lined up properly, re-check the valve lash..

find the T mark, if you can't see all 3 cam timing marks turn the crank one full turn back to the T mark again..

Two of the cam marks should be even with the cylinder head, and the center mark should be straight up (straight up in relation to the cylinder, not the ground).. If that looks good then cam timing is OK. It can be tricky to get the cam timined properly, patience pays off here..

So, double check the cam timing and valve lash, let us know and we can take it from there :)

Leo

[dhines]

Did you add a new cam when you had it apart? If so did you remember to adjust the valves? They will not be adjusted correctly if you have put in a new cam.

[JhallettEX]

Well then I don't see the problem. I put it all back together the right way. The timing is fine, they are all lined up.

Should I just spray some ether into the carb? What would happen say if I was 180 out and did this? Would there be any damage caused?

What exactly happend to someone is 180 out?

Thanks guys. I have to go to work now but will be statin on it again at 4:00.

Thanks

[PsychoDave]

CRANK THE ENGINE WITH THE PLUG WIRE REMOVED (OR WITH IT ON STOP) TO MAKE SURE YOU ARE NOT HITTING A VALVE( I THINK YOU ARE FINE THOUGH!!!)...ETC. BE CAREFUL WITH EITHER...TOO MUCH AND YOU CAN BLOW A HEAD GASKET. IT SOUNDS LIKE A FUEL ISSUE. ONE QUESTION...DID YOU HAVE THE CAM FLANGE REMOVED AND PUT ONTO A NEW CAM? OR DID THE NEW CAM COME WITH A SPROCKET FLANGE, BECAUSE IF IT IS PRESSED ON WRONG IT COULD THROW OFF YOUR TIMING......GOOD LUCK

180 shouldn't be a problem. make sure you had all the slack outta the chain when putting it on the cam sprocket

[Rastus]

Seems like the valves aren't adjusted right.
That would make the POPing sounds, and the air being sucked back in.
Sounds like the Intake valves are too much closed, and the exhaust are too wide opened.

[MIKE400EX]

jhallett, as LEO said, if all the the flywheel indicators line up and the lines on the cam are parallel with the valve cover/head surface, you're not off 180 degrees.
The cam flange only goes on one way because of the one wide indexing tooth.
Do you have a (Sparks) advance key for the flywheel/ignition? If you do, you'll have to line the flywheel mark up at about 6 deg. after(clockwise) "T" (so you'll be at true TDC) and then "line up" the cam lines. BTW, 6 deg. is about a quarter of an inch at the outside of the flywheel.
Don't use ether - it's He!! on the bearings! Squirt a little fresh gas down it's throat, then find out why that FCR isn't doing the same when you crack the throttle.
If you turn the motor over without the plug and/or wire attached, make sure there is a plug in the boot and it is grounded to the engine. Otherwise you can very easily blow the coil or CDI unit. Good Luck!

[RED121572]

Heres my two cts...

Wow man, something isnt put together right. Double check your shop manual over and over.

This might be a bit off base for a good suggestion, but check to ensure your cam chain is on its gear inside the crankcase. The only reason I say that is that the cam chain on mine fell off....and I had to remove the clutch cover to work it back on.


When I rebuilt mine, My valves were anything but close to where they should be. but my machine did fire and idle fine, although the valves sounded like a slot machine hitting a jack pot.

Good luck hoss, hope it all works well. Hey, let us know your two cts on the performance increase. Over last winter, I did a 406. Next winter, I may do a 416.

[JhallettEX]

Ok, What is wrong, I have done everything, except check for 180 out. What exactly would be going wrong if it were 180 out? Also why in the HE!! is it sucking in so much air from the silencer, sh** it almost sucks my friggin hand up in there when I cover the end up? Please advise. I am going to start taken it apart again to see if it is 180 out now. THanks

[400exJOE]

A little list of stupid mistakes that I have encountered:
1) Make sure you have gas and that it is ON. Put it on RES. just for the he!! of it too.
2) Pump the throttle before you start it to get some gas in the carb.
3) MAKE SURE YOU PUT OIL IN THE QUAD! When I went to fire up my 440 for the first time, I almost forgot to add any.:eek:
4) Make sure your cam chain tensioner is retorqued.
5) If you did any modifications with the rebuild, did you re-jet for them?

Anymore info you got will help us out. JOE

[phatswinn]

ok, just a trick i picked up but try it any wayz, fill a sprayer (like a windex sprayer) up and put it on the jet mode (when it sprays a long stream instead of a mist), take the boot off the carb, and hit the starter and spray gass in the carb when its turning over, this problem happened with my stepdads scrambler 400 and it started after like 1 min. of doin this and i think it is because the line has air in it or something, but it worked. it may not for you but i say give it a try, and make sure u spray in the carb where the needle and jet is.

[beerock]

wow dude frmt eh answers you been gettin I wish you could describe what it in line with timing marks and what s out of line, instead of saying what you did and what t was like after in the samepost cuz im coonfused and im sure if you explained it in detail and correct wording then I could help you.

cuz soemthing is not lined up right..

[400exJOE]

make sure the mark next to the T is lined up with the slot. Then look at you cam sprocket and make sure that is pointing up and all the marks are in line. Make sure the tensioner is in place. And the "pointed" ends of the cam should be facing upward.

[RED121572]

Ok ok, Ive thought about this...lol

The silencer is sucking air. Which means the exhaust valves have to be open when the piston is on the down stroke....which means the cam timing is still off.

Wish I was there to help ya out bud. Have a few more beers and start again. :D

[JhallettEX]

OK........Beerock from your first post you said I was 180 out, so I took the cam off the sprocket and rotated it 180. Put it all back together, now when I am TDC comp. stroke my lobes are up and all the index lines are matched up.

I took into consideration that I may be out of gas so I turn it on Res. also I took the air boot off the carb so I could cover the carb with my hand, to act as a choke, after a few times cranking on it it blew a lot of blew smoke out of the carb and along with some gas I believe. After this light smoke kept coming out for a 10-15 sec. and began again when I cranked on it again.

I know beerock I am not explaining my self that good, I am not that good with motors and this is my first time doing this by myself.

[Leo]

There is no way the camshaft can be 180 degree's off...

The plug fires every time the piston goes up, so it doesn't matter, not even a little bit.. As long as every other time the "T" mark lines up, the camshaft lines up (one mark staright up, two marks even with the cylinder head) then your good to go..

Some silly things to check, make sure your going by the "T" mark, not the "F" mark, or any of the other stampings on the flywheel..

If the cam timing checks out OK, and the valve lash adjustment is close, time to head back to the basics...

spark / compression / fuel..

does the bike sound like it has decent compression while cranking over (not spinning really fast)..

do you have good spark from the plug?

when you crack the drain screw on the bottom of the carb does gas come out..?

Leo

[JhallettEX]

Wait, you know what I just thaught of, the spring that goes on the compressor or I gues it is called the plunger under the cam was missing when I put it back together, could this be the probelm?

Leo.....

Every other turn the marks line up.
Feels like it has good comp.
Gas does drain out when I take the bottom out of the carb
Yes, I have spark from the plug

After doing my last work, changing the 180 out like beerock said, since my lobes were down when I was at TDC, Know my lobes are UP at TDC. on the comp stroke. Does this matter.?

I have called around to shops around here and noone can get me in tomorrow to check it out. I have a ride coming up Friday night, hope I can figure it out Iif not THANKS for all the help guys.

[Evan]

Since you got it torn aprt, do this. Take the head off and turn it untill the piston is at the top, then go from there. Make sure the marks are right on the cam sprocket. Its better if you have it on TDC and then stick the sprocket in and move it around till the two side indicator marks are level in the right spot then take the cam and attach it to the sprocket with the lobes down. I know what your going thorugh cuz I just rebuilt mine today. But mine started on about the 3rd lick. Thats when you know its been put together right.

[Evan]

Ah ha that its. Mine was missing too, I just took one out of a ball point clicker pen and used it. Works fine.

[Leo]

Originally posted by JhallettEX

Wait, you know what I just thaught of, the spring that goes on the compressor or I gues it is called the plunger under the cam was missing when I put it back together, could this be the probelm?

I'm not sure, but I would say probably yes.. The spring / pluger are used to hold the decompressor assembly in position, but in all honestly I'm not exactly sure how it all relates.. or what effect it would have.. at the very least I'd be worried about the spring finding it's way out and into some place where it shouldn't be.. I'd also be very nervous about exactly where the pluger wound up... ?!?! (hopefully not inside the motor) I'll have to run downstairs and look at my stock camshaft and see if I can get it through my head how it works exactly..

Every other turn the marks line up.

this is a good thing..

Feels like it has good comp.

also a good thing..


Gas does drain out when I take the bottom out of the carb
Yes, I have spark from the plug

even more good news..


After doing my last work, changing the 180 out like beerock said, since my lobes were down when I was at TDC, Know my lobes are UP at TDC. on the comp stroke. Does this matter.?

when the lobes are up, they should be opening some valves, which would make it impossible to be on the compression stroke.. unless some valves where adjustd VERY loose.. If you don't have the valve cover on, the valves are closed all the time so every stroke is a compression stroke..

I'm at a loss here, basically you just tore it down to replace the headgasket right.. and it was running fine before that (except for the oil leak).. so you slapped a new headgasket in, and now it won't run? or does it just run very poorly?

Kind of late right now, and my brain isn't working to good.. Let me know if exactly what you did to the bike, and how it was running before and after, and I'll reply back in the AM after I've had some time to sleep on it..

Leo

[Leo]

just re-read it.. you have the plunger, but your missing the spring... see, it's to late for me to be thinking this hard :D

I'd get the spring / plunger back in there (assuming your running a cam that still has the decompressor assy) before I pulled out to much more of my hair if I was you :D

Leo

you need to re-check your timing.. i think you skiped a tooth or 2 lining it up cause there shouldn't be alot of vacum at the exhaust(you said it was sucking your hand in) as for cam lobes face tem down or when you go to tighten down the valve acover it will put preasure on the rockewrs nd you'll strip you valve cover bolts

[RED121572]

LOL LOL!!

What is it with that little plunger spring? I lost mine too AND I also used modified a spring from a ball point pen so it would work.

To be honest, I dont know what effects it would have on the motor not to have the plunger in there, but what I do know is the that the plunger will not function without the spring.

Keep on wrenchin there hoss, youll get it!!

[JhallettEX]

IT"S ALIVE.....

I dont know what I did, I took it a completely apaty again and put it back together and it fied the first try. I still have to adjust the valves etc. and I will be off the the sand pit for the weekend for drag races and TT"S. Thanks guys

[PsychoDave]

GLAD IT WORKED OUT.....!!!!

[JhallettEX]

Believe me, me too. Now if my ELKA's would get here I could leave.

[YLW400]

If I ever want a 440, 416 , or whatever. I am coming to one of you guys!!:devil

Originally posted by JhallettEX
IT"S ALIVE.....

JhallettEX IT"S ALIVE.....

Now thats great news to hear.

I have been going through the same exact problem and watching this post but sadly have not got it to fire yet. Funny I had tried to tear it down a few times and when I had checked back here you were doing the same thing, and I know how pissed you were when it all looked right and still didnt run. its a real bummer.

Well I am about to give in and bring it to the dealer or ??.

This is what has been done.

I have torn this thing apart 5 times now(this time) and all it does is crank like crazy, and could only get it to backfire 3 times. This is funny as it was running great proir but had low compression.
so after changing the rings and head and base gasket and still not getting the right compression I had narrowed it down to the valves (a friend had been helping and took some sandpaper to the valve faces, dumb) well after getting the new 3 angle valve job finished and installing the head and lining up everything perfectly and reinstalling everything I hit the starter and boom NOTHING.

I have tried everything listed here and more but still nothing. This has me totally at a loss as I have had this motor apart several times and have never had any problems with it starting.

I am beginning to thinki the machine shop has something screwed up. maybe they did the valve job wrong and the valves are not seating??? would this lower the compression enough to make it not run??

When looking for TDC it seemed to have compression (felt like about 40+ ft lbs to turn the fly wheel).



does the bike sound like it has decent compression while cranking over (not spinning really fast)..

NO ,, well it sounds ok but does spin fast, and the battery charger was hooked up so I was thinking it was from the extra juice.

the only other thing that was done is a new throttle cable, could there be a problem here??

Anyone have any ideas ??????????????????????????????????

Thanx

[JhallettEX]

I would check and make sure the spring is in with the plunger, if not get one in there.

[SANDTRAX361]

it seems that you have done everything right when i tore that area of my motor down and got it abck together i had trouble getting it to start fill it with oil and drag start it behind somthing it works everytime and if it doesnt work then somthing else is wrong. drag starting is the way to go after a rebuild of somesort.
later
grant