Old Bike - Hard Starting

[khabich]

Hey,

Just bought an old dirt bike(1976 Suzuki), first time rider.

Trying to figure out what's wrong with my bike. Here's the scoop:

Takes like 15 kicks before I get any juices flowing from the motor. From there it takes like 15 more before it starts. This is all done with the choke fully open. When it finally does start it sounds real weak. Turning the choke down kills the engine.

I looked at a few sites and some say my pilot is too lean. What does that mean? Is there any images anyone has that might help me find the adjustment on my bike?

Any suggestions, comments or cheapshots are welcome.

Thanks, Kevin

 

[Ol'89r]

Sounds like you need to clean the carb out. If it has been sitting for a while the pilot jet is probably clogged. Also check the compression and crank seals. May need rings and seals.

 

[whenfoxforks-ruled]

Worn engine, dirty carb or filter, and the fuel will not flow correctly. Check the plug when you are trying to start it, wet or dry?

 

[1987_cagiva_125]

my bike is the same way, and i cleaned my carb, now it wants to start but has some trouble, found out that my compression it low, so im trying to find rings cause that seems like the main problem.

 

[rmc_olderthandirt]

Is this a two stroke or a four stroke?

When you say "choke down", is that the normal position or the cold start position?

If it will only start with the choke on then I would say that you are not getting enough fuel to the cylinder. The most likely reason is that the carburetor has one of the jets clogged. Taking the carburetor off, taking it all the way apart and cleaning everything really well would be a good place to start.

If it isn't the carburetor then it could be because air is getting in through some other path other than through the carburetor. This could be from a major leak between the carburetor and engine. On a two stroke it could also be bad seals in the crankcase.

If it is a two stroke then another possibility is that the reeds are shot.

Rod

 

[khabich]

Thanks for the help thus far.

I found the idle knob and adjusted it to some help. (It starts in less kicks). Now I have no idea what my carb looks like, so thanks for those suggestions I will def ask a mechanic friend of mine to help me take that apart and clean it.

However, just now I was riding it and everything was going well, but then I heard like a metallic ticking while I was probly in 2nd or third gear. I slowed down to be safe and the bike died. Now it seemed real F'd up.

The kickstart seems to be stuck. Sometimes it doesnt even move when I go to kick it. Every other time it hardly turns the motor and makes a horrible grinding noise. NO IDEA what I did there. If there are any ideas (other than cleaning the carb, which I plan to do tomorrow) please share.

Again, thanks for all the help guys.
Kevin

 

[whenfoxforks-ruled]

2 ways to diagnose trouble, 1 take it apart at intervals and check it, 2 run it till it has catastrophic failure. Method 1 is cheaper in the long run, and in some cases healthier. So the issue was a worn motor. Complete engine rebuild kits are around 300 dollars. A manual is priceless. Cylinder repair is the only other possible bill, around a couple hundred. No wait, a 76 rm!!!!! Wow are you in trouble! NOBODY makes a piston for that bike. Tell me that it is not an rm?

 

[oldguy]

From your last post my guess would be you have now created much bigger problems then you had before. It sounds like you have seized the engine because you forced the situation and did not correct your origonal problem. As was said earlier it sounded like you were way to lean whether it was carb or air leak caused. You forced the bike to run and the result is that what was bad is probably now junk- time to do a complete teardown and be prepared to junk the whole thing unless you can find parts

 

[whenfoxforks-ruled]

I will ask my buddy if he wants to let go of a piston and ring set. His last one he received from some guy in JAPAN, courtesy of evilbay. I did not know they took lunch boxes to work, 33 years ago! Also, unless you are concerned about keeping that year jug, a 77 will fit and has parts available.

 

[khabich]

Hello friends (can I call you friends?)

I did a little messing around with this Bike yesterday. I took out the sparkplug and some other screw that let me see into the gears. When I tipped my bike on its side a whole bunch of oil spilled out and now the kick start is loose again.

With the sparkplug out, it seems to work fine. shoots up access gas and the sound is just as I remember.

With the sparkplug (a brand new one too) in the bike nearly reverts back to its old ways. kickstart now seems slightly jammed. it almost sounds clogged, definitely not even close to starting. When i take the new spark plug out, the bottom of the plug still looks brand new. When I connect it to the wire that connects to the top of the plug and touch the metal again metal on the bike and try to start it, i get no spark (I was able to get spark before).

This post is real long winded, I still don't know much vocab. Any suggestions, comments or hazing will be appreciated.

Thanks,
Kevin

 

[whenfoxforks-ruled]

Take the plug out and turn the bike upside down. Wrap a cloth or something around the plug cap, to avoid any chance of a spark. Slowly push the kickstarter and see if fuel starts dumping out. If it does, it is in the pipe also. That would be a stuck float or a float valve that needs replacing.

 

[rmc_olderthandirt]

Hello friends (can I call you friends?)

Yes, that is appropriate! :-)

I took out the sparkplug and some other screw that let me see into the gears.

the part about seeing the gears confuses me. How big was this screw? Many bikes have a small screw on the clutch cover case that oil will flow out of when the level is appropriate but I would not expect you to be able to see anything through this tiny hole.

When I tipped my bike on its side a whole bunch of oil spilled out and now the kick start is loose again.

Where did the oil spill out of, the small screw hole?
I suspect that the oil spill was not related, if you remove the screw and tip the bike oil should come out.

With the sparkplug out, it seems to work fine. shoots up access gas and the sound is just as I remember.

You shouldn't have "excess" gas.

With the sparkplug (a brand new one too) in the bike nearly reverts back to its old ways. kickstart now seems slightly jammed.

After you earlier post I had assumed that the engine seized. After this post I am suspecting that the carburetor is flowing so much gas that it has actually hydrolocked the engine.

Although it shouldn't happen and won't if all the vent tubes are routed properly and not plugged it is possible for a carburetor to allow raw gas to flow into the engine. I have seen people get concerned about the gas flowing out a vent tube and either plug it or route it up higher, which fixes a "symptom" but causes a much worse problem.

If the float valve fails to shut the flow of gas off the gas will flow somewhere. If it can't flow out the overflow/vent lines then it will flow into the engine. Note: I am assuming this is a two stroke. If you end up getting enough raw gas into the bottom end it can flow into the cylinder. A tiny amount raises the compression, a bit more and the cylinder is "hydrolocked" because there isn't room for the piston to come up.

Removing the spark plug will remove the hydrolock and allow the engine to turn over. If the bottom end is full of gas then I would expect to see it spray out the sparkplug hole when you kick it over. Put the plug back and in a few kicks it could hydrolock again.

If this is the case then the first thing you need to do is figure out what is going on with the carburetor. There are at least two problems: A stuck float and a clogged or improperly routed vent line. Fix these two problems first.

Now you have to deal with all the gas in the bottom end. You are taking the carburetor off anyway so go ahead and remove the reeds. Inspect them as it is possible that the bottom end hydrolocked as well and blew the reeds out.

Like whenfoxforksruled said, turn the bike upside down to get the gas to run out of the bottom end. Take the tank off, have the carb and reed plate off, spark plug out. Put the transmission into gear and spin the rear wheel to turn the engine over. After the gas has finished spraying/running out let the bike sit this way for an hour or so.

A word of caution: If this theory is correct you are going to dump a fair amount of gas out. Do this outside, well away from the water heater and other forms of flame!

Rod

 

[dewme5]

Finding a good manual should be your first priority.

Understanding the mechanical basics is going to be a great help as well. Starting with something as old as you have chosen, can be quite a problem as well. Your resources are going to be harder to come up with. Manuals, parts, knowledge. The specifics are important.

There are a few good books out there that will help even if you can't find your manual. I just picked up "motocross & off-road performance handbook" by Eric Gorr (controversial author that some people don't like), but there are a lot of good pictures that will help you diagnose problems. good reeds, bad reeds. Good plugs, and different bad plugs, to help diagnose your problem. What seals cause what problems and tuning your carb. etc. etc. for $25, it's money well spent., and will save you at least that much money.

Carbs are really simple devices, but they must be set right. When you pull off the float bowl (should be the bottom most portion of the carb) there will be 1 or 2 large objects called floats in there. The floats should be really light, and be completely empty (when you shake it, there should be nothing) These floats determine the amount of fuel to be let into the carb. Without that being right, it is possible that the fuel from your fuel tank will flow straight into your engine. If everything will run right before you park it for a period of time, and then it hydro locks the next time you try to start it. that's your problem.