Installed a new sprocket and now she wont start...

[theycallmebob]

As the title states, I installed a new 36t sprocket and now the bike wont start. After I installed it last night I took it for a ride and it started just fine, but the engine had been warmed. I realized there was some up/down movement in the sprocket so I stopped riding it after a couple miles and parked her for the night.

Last night we had a freeze warning and the temperature dropped down to 29F, mind you im in Florida. The bike was parked outside, if that has any effect. Woke up, hoped on to drive it 1.5 miles to work and couldn't get her to crank over, it was about 50F at that time. Pedaled to work (forgot how much that sucks) and got her home now.

I have no experience troubleshooting these two stroke motors. However, this is what I plan on doing to figure it out....

1. Readjust sprocket so it loses the movement.
2. Readjust chain tension.
3. Readjust Clutch tension
4. See if it fires up.
5. Assuming this doesnt work, check for spark by removing spark plug, supporting bike and pedaling in place.
6. If it has spark address the carb.
7. Dont know!

Do any of you in colder climates have to do anything to protect the bike, or use some starter spray in the cold?

If I have flooded the engine what do I do with the carb, just take it off and shake it out?

Any tips you have to share with regard to troubleshooting are appreciated. Thanks, like I said very new to troubleshooting on these 2 strokes.

PS - I used to start the bike @ about 8-10 MPH with the 44t sprocket, I tried starting @ 15-16 MPH with the 36t.

 

[Bikeguy Joe]

1. Readjust sprocket so it loses the movement. Do that, but that's not it.
2. Readjust chain tension. Not too tight, 3/4" of freeplay, but that's not it either.
3. Readjust Clutch tension. Does it turn the engine over? If it does, don't mess with it.
4. See if it fires up. It may, it could have been a small chunk of ice in the fuel system.
5. Assuming this doesnt work, check for spark by removing spark plug, supporting bike and pedaling in place. Good start, but I'm betting that'sa not it.
6. If it has spark address the carb. I'd do that first.


Do any of you in colder climates have to do anything to protect the bike, or use some starter spray in the cold? Starting fluid is not overly healthy for two strokes, I'd use a LITTLE HEET or other fuel line de-icer.

If I have flooded the engine what do I do with the carb, just take it off and shake it out? Shut off the fuel, hold the throttle wide open and pedal your arse off, if it's flooded it will clear out and fire up then quit.

Any tips you have to share with regard to troubleshooting are appreciated. Thanks, like I said very new to troubleshooting on these 2 strokes. I think you have it covered.

PS - I used to start the bike @ about 8-10 MPH with the 44t sprocket, I tried starting @ 15-16 MPH with the 36t. You can actually pedal slower with the 36T....maybe you did flood it. Also, when it's colder out, use the tickler and give it a little more choke, it's kind of hard to flood a two stroke when it's cold out.

Keep us posted as to your progress or lack thereof.

 

[theycallmebob]

Well I did everything in the order I said it, and everything checked out. I wasn't able to get rid of all the movement in the sprocket, but it has significantly less now. Went to Lowes and bought some better hardware for the tensioner bracket as I stripped the OEM crap.

Put on my warm weather night gear, laced up the boots, even brought a water bottle because I was sure I'd be peddling for awhile to get all the gas outta the carb which I had flooded it with.

Pop the clutch and BAM, shes alive again. First try! Took her around the block to let her warm up again.

Not sure what was fixed what but Im just glad it's running again.

Thanks for the help.

Also, why would I be able to start the engine at a lower speed than before with the new sprocket? Doesn't it allow the me to cruise at the same speed before but at lower RPMs, thus if I was barely able to start the engine before at 8mph wouldn't it be harder to turn over at the same speed?

 

[misteright1_99]

The smaller the rear sprocket the more revolutions the front sprocket turns at the same speed when peddling. You will be able to motor at the same speed with less engine rpm's with the smaller sprocket, but might have to peddle from a stop to get moving.

 

[Bikeguy Joe]

4. See if it fires up. It may, it could have been a small chunk of ice in the fuel system.

 

[Bikeguy Joe]

I'll bet you a dollar.

 

[theycallmebob]

Ha. Well its freezing (literally) here again tonight so we'll see if I have the same problem in the morning.

I was skeptical because it was nearly 50 when I tried starting it.

On a side note I hit 34.9MPH and can cruise at 30 very comfortably now. Not bad for 25$ shipped.

 

[seca40]

The smaller the rear sprocket the more revolutions the front sprocket turns at the same speed when peddling.

I think you got this backwards. It sounds like you have it straight in your head though. I hate to be a butt insky but I'd hate for someone else to get confused by this.

 

[Bikeguy Joe]

Ha. Well its freezing (literally) here again tonight so we'll see if I have the same problem in the morning.

I was skeptical because it was nearly 50 when I tried starting it.

On a side note I hit 34.9MPH and can cruise at 30 very comfortably now. Not bad for 25$ shipped.

You may or may not, depending if the gasoline has water in it, and whether it freezes and blocks the fuel flow. Ice floats, so it could block or not block the flow. It also takes quite awhile to thaw in gasoline that was at 29 degrees.

 

[misteright1_99]

Seca you are correct. The LARGER the rear sprocket the more turns per revolution the front sprocket. Thanks for clearing that up.

 

[Bikeguy Joe]

...or you could have a magic buggaboo floating near your gofaster inside the muffler bearing.

 

[2door]

Well I did everything in the order I said it, and everything checked out. I wasn't able to get rid of all the movement in the sprocket, but it has significantly less now. Went to Lowes and bought some better hardware for the tensioner bracket as I stripped the OEM crap.

Put on my warm weather night gear, laced up the boots, even brought a water bottle because I was sure I'd be peddling for awhile to get all the gas outta the carb which I had flooded it with.

Pop the clutch and BAM, shes alive again. First try! Took her around the block to let her warm up again.

Not sure what was fixed what but Im just glad it's running again.

Thanks for the help.

Also, why would I be able to start the engine at a lower speed than before with the new sprocket? Doesn't it allow the me to cruise at the same speed before but at lower RPMs, thus if I was barely able to start the engine before at 8mph wouldn't it be harder to turn over at the same speed?

My bike (and me) are cold natured. We don't like it. I've found that just a little spritz of quick starting fluid, (ether) into the aircleaner with the throttle open before trying to start the engine does wonders. When it's below 40 outside my engine is slow to start and I've tried every throttle/choke/tickler setting possible. The quick start fluid will fire it off before I get to the end of my driveway and then it keeps running with about 1/2 choke for about a block or until the engine warms a little. The only problem you might have is finding quick start in Florida
Tom

 

[Bikeguy Joe]

No but water in gas will freeze and make little pellets of ice.

 

[theycallmebob]

Yea just tried starting it up on my way home from work.

Its 37 now and it wont turn over again, just too cold I guess. This weather wont last long, so Ill just ride my pedal bike.

 

[Bikeguy Joe]

You aren't choking it enough. Cold weather alone will not keep an engine from starting.

Just my humble-O.

 

[Dave31]

When I went on my Mt. Lemmon ride it was around 33*, I did not even use the choke for it to fire up. Just used the primer a few times and she fired right up...I agree with BGJ, I think something else is going on.

 

[MB-Monkey]

cold weather has a way of zapping electricity down to nothing if you still have the stock spark cable and boot on the engine i would get a good 7mm or 8mm plug wire and boot the cold could be shrinking the wire and not making a good spark at the CDI.

Just an alternative look at the issue.

 

[theycallmebob]

Went and got some starter fluid, didnt help. When I took off the air filter case the filter itself was already wet with gas. Also, the bike has been leaking what appears to be gas from the exhaust pipe while it's sitting.

Pulled the spark plug and it looks like this, was also a little wet. Swapped in another spark plug and that didnt help.

Its an NGK sparkplug, got it new a month ago with an upgraded spark plug wire and boot.

Dont know where to go from here.

 

[Dave31]

Your float level may need to be adjusted, or it could have some junk in there and is not keeping the proper level of fuel in the carb bowl. Sounds like the reason it will not fire is that you are getting too much fuel.

 

[theycallmebob]

Is the float the cylindrical piece of metal inside the card that slides up and down depending on the amount of throttle?

When I had the air filter off I could see a 1-2mm gap between the bottom of that piece of metal and the port itself.

I'll snap a pic later, I need to run to work.