Bad to Worse.

[iquitmyscene]

Hello! So I'm writing to you today about my Zongshen Sierra 200. I'm at a complete loss as to what to do about it. First off, the bike does not start at all. I have been working on it for months and months. November was the last time I rode it on the road. I drove it to the store around the corner (without problem), was in and out in less than five minutes, and then was ready to go home. It was a warm day and I knew the engine was still hot, so I figured that I would not have any problems. Long story short, after trying to start it for at least an hour and a half, I had to get the truck and tow the motorcycle home.

Since that day, I have checked all fluids, (minus brake fluid, I haven't gotten to that yet) changed the spark plug numerous times (always have spark), checked/cleaned/replaced all filters, used fresh gas, sprayed starting fluid into the airbox, checked compression (120 & 150), cleaned carb, etc, etc, etc. I'm at a total loss. So, I bit the bullet and decided to take it to a mechanic.

Before bringing it to the mechanic, he assured me over the phone that he was fairly knowledgeable about Zongshens, and his company actually sells QLinks on their showroom floor. Its been a week now, and after speaking to him today, he said he has no idea what is wrong with the bike. It still does not start at all, but has spark, compression checked out, etc etc. He thinks that the problem is all centered around the carb, which has been taken apart and cleaned, also put back following factory specs, but nothing seems to work. I even told him that I would just purchase a new carb from Zongshen and try that, since he doesn't have one I can switch it out with.

I'm really hoping that either someone else has run into this problem, or has some advice that I can tell my mechanic. We are both at a complete loss and have no idea where to go from here. Thanks for your time!

[Wild_Alaskan]

sounds like a similar situation to the guy with a bad exciter coil

[Weldangrind]

I agree on the exciter. That said, your compression readings sound a little low. Have you adjusted the valves?

[Fonfe]

Is your plug wet after trying to start continuously?
If its not then its a fuel problem.
I cleaned my carb as the bike wouldn't start, all the jets looked fine and I swore they were clear.
Had an air leak from the head to carb joining rubber....sorted that out then bike would only run with the choke on.
Took carb apart again and found pilot jet to be blocked.

I'd get the bike back and start from scratch.....forget about everything you've done so far as you may find something you've already checked you missed a small flaw somewhere. -done it several times myself and I've been working on cars for years!
I'm a range rover mechanic so bear with me on the bike engine thinking but internal combustion engine is the same regardless. + sure spud will correct me on anything I may have a bit off.
You need 4 Things for a 4 stroke engine to run:

Fuel -
CORRECT air fuel ratio
In that system you can include your fuel tank, fuel petcock (i think it's called that...it's the fuel "tap") the carb and the lines and filter.
Also factored into that is your air supply through your carb, and the joining rubbers and vacuume hoses and air filter.

Compression
The cylinder must have good compression that is sealed via the piston rings, head gasket, and the inlet and exhaust valves shutting and seating correctly at the correct time.

Ignition
Spark must be active at the correct time, and a good strong blue. Non blue just isn't good enough when its a single cylinder....

Exhaust
There must be a clear path for the exhaust gas to exit ie not blocked.

So to start I would strip the carb, clean it, check your jets are totally clear (you can see daylight through it) check all the o rings and seals are in good condition and haven't been "pinched" or shrunk and check the diaphragm for pin prick holes.
Next check the fuel line is a good flow when not hooked upto the carb. If not take the filter out and see if the flow improves.

Then refit the carb to the joiners ensuring you can not see any of the carbs round body and it is fully inside the hoses. (Mine was short so had to make a spacer to fix my air leak, see my thread if yours is short)

Unbolt the exhaust and leave it hanging - this will ensure if your exhaust is blocked the bike will still start regardless.

Recheck your compression -see that the pressure holds for a decent amount of time.

Check your valve clearances - follow spuds thread on it

check your spark is bright blue, and that its at the correct time. -you will need to use a timing light. Check the resistance of the lead and that the plug is correctly gapped. Whatever you do DON'T clean it with a wire brush.

If all of that checks out there is no reason why it should not run. If it were electrical you wouldn't have spark at the right time or it would be a weak spark or shorting before it reaches the electrode. If you have good air fuel mixture your carb is ok and you have no air leaks.
If valves aren't seating correctly, rings are shot or your got a crack in the cylinder head or piston your wouldn't have good compression that holds.

Hope that helps....if not or I'm totally off the mark just tell me to get stuffed I won't be offended! 8)

[zingshoen]

fonfe, good onya, that s comprehensive. i ve been chasing my own tail on various projects until i found a solution which often tends to be easy - once i get my head around it.

the one point i d like to add: as far as the zongs go, a spare cdi is good to have, as these cdi are known to have a tendency to fail sooner or later.

i would also make sure all the connections are tight and the on off switch is in good nick. could also be failure of sidestand cutoff switch?

[Weldangrind]

I agree with Fonfe and Zingshoen, but I'll add that Spud says the flywheel key is very robust, meaning that timing is the least likely culprit.

[iquitmyscene]

Hello and thank you to everyone for your suggestions so far. I will pass this info on to my mechanic. To respond to some:

Fonfe,
The sparkplug is not wet after trying to start. The motorcycle technically runs for about 1-2 seconds, but then it immediately dies. I pretty much isolated the problem to be the fuel delivery. I personally cleaned the carb myself, and the mechanic claims to have taken it apart and put back together at least two times. They do not use the gas tank when testing the motorcycle, they have a line that "bottle feeds" it gas.

As for spark, I know that it has a strong spark, and we even tested it in the shop when I dropped it off. Originally we thought it was the coil pickup due to a weak spark, but I had brought an extra spark plug and once we threw that it, it was fine.

As for the air leak, that could be a possibility. I will pass this information on.

I did do the valve clearances to Spud's specs.

zingshoen,
Originally I was just going to order a new carb, but I do plan on placing an order for a new CDI just to check. I'd buy multiple ones, but I don't want to waste money if the bike doesn't start again.

Thank you again for everyone's help. Keep the ideas coming!!! I will keep you posted on any new information I receive as well :)

[Fonfe]

Take the carb off, and the head to carb joining hose.
Place a bag round the hose and tape it so its a tight seal.
Hook the carb up to the fuel line and draw the bag outwards so its sucks in air through the carb. Check the bag contents and see if there's fuel vapour in there.

You may not understand what I mean.....but ask a stoner how to make what's called a "lung bong" same principals. Or google it.
That will show you that the carb is indeed delivering fuel out of both the main and pilot jet.
I'd still take both jets out and check you can see the daylight through em to be 200%. Mine were fine I swore then found later on pilot to be blocked.

[SpudRider]

It sounds like a carburetor/fuel problem to me. The plug should be wet with good fuel delivery, yet it isn't. Also, the bike would not run for two seconds if the CDI unit were bad. ;) CDI failures are intermittent for quite some time before the unit fails completely, and you haven't reported such failures before the current problem.

I would inspect the fuel system starting at the fuel petcock, and working my way through the entire carburetor. If you have ordered a new carburetor, that is well. ;)

The hose between the carburetor and engine is very robust, and unlikely to cause problems, unless the carb is not fully seated into it. If necessary, unhook the hose from the airbox to the carburetor, or allow it to be loose, rather than have a loose hose on the engine side of the carburetor. ;)

Also, it's very easy to install the carburetor diaphragm incorrectly. ;) Make sure the top of the diaphragm is properly located inside the groove on top of the carburetor for the entire perimeter of the diaphragm. ;)

Spud :)

[katoranger]

Sounds like its the carb. They tried a separate fuel line and tank so that should have eliminated the fuel delivery to the carb.

[SpudRider]

Sounds like its the carb. They tried a separate fuel line and tank so that should have eliminated the fuel delivery to the carb.
I agree; that's what the mechanic said he did, and I believe him. However, it's very easy to verify good fuel flow from the gas tank. ;) If all is well with the fuel flow, it will be very easy to confirm it. ;)

If spark, air, and compression are truly working well, the problem must be with fuel delivery. Therefore, I think getting a new carburetor from Zongshen America is the fastest way to resolve the problem.

The Zong has a good carburetor. This carb is virtually identical to the carburetor used in all late-model, Yamaha TW200 motorcycles. Spare parts for this carburetor are readily available from Yamaha. Carburetor problems with the Zong should be relatively easy to diagnose and fix. ;)

Spud :)

[iquitmyscene]

Ok so I finally got in all supplies the other day. I have a new carb, new CDI, and I also ordered the hose from Yamaha from the airbox to the carb. Since the shop is closed Sundays, Monday morning I will be dropping everything off. Wish me luck! Really hope this solves my problem :?

[SpudRider]

Please do keep us updated. :)

Spud :)

[iquitmyscene]

Ok so just got off the phone with the shop. Still bad news. Brand new carb, excellent spark (new CDI) took apart flywheel, everything is fine. Compression is fine. Timing is fine. Valves are fine. He is completely stumped.

He thinks it could possibly be the rings, but he honestly has no idea.

Spark plug is dry, and even when bottle feeding the motorcycle, there is still no gas going into carb. When kicking, it just keeps turning and turning. I thought it may be the vacuum, but he stated that he does not see any place where a vacuum could be?

Any suggestions?

[Corvairkid]

use a fine mist spray bottle to spray fuel in to the carb like a primer see if it coughs and tries to run keep the carb un-hooked from the fuel and full throttle

[Wild_Alaskan]

Ok so just got off the phone with the shop. Still bad news. Brand new carb, excellent spark (new CDI) took apart flywheel, everything is fine. Compression is fine. Timing is fine. Valves are fine. He is completely stumped.

He thinks it could possibly be the rings, but he honestly has no idea.

Spark plug is dry, and even when bottle feeding the motorcycle, there is still no gas going into carb. When kicking, it just keeps turning and turning. I thought it may be the vacuum, but he stated that he does not see any place where a vacuum could be?

Any suggestions?

if there is no gas going in to the carb than the float needle is probably stuck, If there is gas going in to the carb but not reaching the cylinder than the idle may be set too low.

[Weldangrind]

Ok so just got off the phone with the shop. Still bad news. Brand new carb, excellent spark (new CDI) took apart flywheel, everything is fine. Compression is fine. Timing is fine. Valves are fine. He is completely stumped.

He thinks it could possibly be the rings, but he honestly has no idea.

Spark plug is dry, and even when bottle feeding the motorcycle, there is still no gas going into carb. When kicking, it just keeps turning and turning. I thought it may be the vacuum, but he stated that he does not see any place where a vacuum could be?

Any suggestions?

Is this guy a mechanic? At the risk of sounding judgemental, it sounds like he doesn't understand engines as well as he should. If compression is "fine", then the rings are in good order.

Please ask him, how does he know that the compression is fine? Did he measure it? Did he actually set the valves? Placing a thumb over the plug hole is by no means scientific.

The bottom line is that the engine isn't getting fuel, as you stated. Since you have a new carb (which could still be the problem, but I'd look check the valves and compression readings first), my guess is that insufficient vacuum is being created to draw air and fuel in. I'd bet my lunch money that at least one of the valves is too tight.

[SpudRider]

...The bottom line is that the engine isn't getting fuel, as you stated. Since you have a new carb (which could still be the problem, but I'd look check the valves and compression readings first), my guess is that insufficient vacuum is being created to draw air and fuel in. I'd bet my lunch money that at least one of the valves is too tight.
I agree. I suspect a tight intake valve. ;)

Spud :)

[iquitmyscene]

Hello! I have finally gotten the motorcycle back from the shop today. I have yet to check the compression again, as well as the intake & exhaust valves (I plan to do those ASAP).

Few things:

1.) Stupid me left the key in the "on" position, therefore the battery is dead. I have a float charger, but I am pretty sure that the battery needs to be charged in order to use it. Is there a way to "jump" the battery, or charge it without having to spend big bucks on a battery charger?

2.) Is it able to be done/ok to check valves and compression without the battery working at all? The electric start has NEVER worked, so I'm assuming checking it with the kickstart fine?

The shop claims to have checked the valves as recently as this week and he stated that they were "too loose," but he didn't mention what he set them to, so I'm going to double check them again. I also doubt that he checked the compression, since I told him I did a compression test before giving it to him (120 & 155) and he kept throwing those numbers out there. I did verify that he installed the new carb and air hose, as well as a new spark plug and spark plug cap. But honestly, I think that is all he did. I just want this motorcycle to work again, since its a great bike and a lot of fun.

My biggest fear is that its the top end, which many people I speak to have been saying that it is the problem all along. I hope that I'd be able to do that service myself, but there are not many knowledgeable people around to go to for assistance, and ones that are charge top dollar. But baby steps, my number one problem is fuel delivery, so I'm going to try and solve that first.

Thanks again in advance for everyone's help.

[JPG1911]

As far as charging the battery for cheap, free is pretty hard to beat :) Just take it to your local advance auto or auto zone, I have worked for both chains and they charge customers' batteries for free, plan on leaving it overnight. If the battery won't hold a charge, they'll tell you that too. If you don't have one of those 2 chain stores near you, I'm sure most any parts store would also do it for free or maybe $5.

Also, you may find something at the below link to be useful, I stumbled on this page last night, it is very well thought out and offers a lot of good common sense information and technical repair info. HTH

http://www.dansmc.com/mc_repaircourse.htm

[FastDoc]

Dan's website is one of the best resources for the do-it-yourself motorcycle mechanic on the web :-)

[SpudRider]

I agree! :tup: Brother Dan is very knowledgeable, and has an excellent website. :)

[SpudRider]

Hello! I have finally gotten the motorcycle back from the shop today. I have yet to check the compression again, as well as the intake & exhaust valves (I plan to do those ASAP)...

...Is it able to be done/ok to check valves and compression without the battery working at all? The electric start has NEVER worked, so I'm assuming checking it with the kickstart fine?...
You don't need to crank the engine to check the valve lash. ;) You might enjoy reading the following thread which details this procedure. :)

http://www.chinariders.net/showthread.php?t=4539

Indeed, you can kick the bike to check the compression. However, I would charge the battery before I resorted to using the kick starter. ;) You can also hook up jumper cables to the battery to power the electric starter. You might enjoy reading the following thread which details how to check compression. :)

http://www.chinariders.net/showthread.php?t=5298

[iquitmyscene]

Thank you so much for eveyone's suggestions! First thing this morning, I dropped my battery off at Auto Zone to charge (excellent suggestion, never knew they offered that free service). From there, I will run compression tests again. I have done testing before, but I will read over the directions to familiarize myself. I'm almost positive its the rings, but I will double check with the compression test!

Battery will be charging today and tomorow (24 hr trickle charge), so some time early next week, I will have new readings.