Engine possesed by demon

[warriorpoet]

Hey guys,
so i went to start my bike today and none of the electronics turned on. I figured the battery was dead so i push started the bike to recharge the battery.(super fun to do since Florida is still 90 degrees in january....not) I got her fired up but the throttle was very unresponsive. Any time i would give her gas the engine would sputter with the occasional backfire, but speed would not increase. Anytime i completely let go of the throttle she would settle at about 10 mph but would not drop any slower. By the time i got back to the driveway the engine was smoking white where the exhaust meets the engine. I shut her down and the battery had not charged at all(i rode her in second gear for about 10 minutes.) Battery is 8 months old and she was working fine last week. One last detail is when I would give her any gas it sounded like something was banging around in the engine, very not good. Anyone have any idea what this could be? thanks

[Fawlty]

I would suspect the battery. Have it load tested. You should be able to get it tested for free.

[chandlerbingfl]

I had almost the same issue. Easiest thing to do is first get the battery tested. That turned out to be the problem I had as I had 2 bad cells. My symptoms were that my bike would start but die when I tried giving throttle. Once I replaced the battery, problem was gone.

Now if it's not the battery it would lead me to the charging system itself, not putting out enough juice to fire the bike properly. At idle maybe so but once the rpms increase it's possible the charging system can't keep up with the demand to fire.

Hope this helps,
chandlerbingfl

Originally Posted by warriorpoet

Hey guys,
so i went to start my bike today and none of the electronics turned on. I figured the battery was dead so i push started the bike to recharge the battery.(super fun to do since Florida is still 90 degrees in january....not) I got her fired up but the throttle was very unresponsive. Any time i would give her gas the engine would sputter with the occasional backfire, but speed would not increase. Anytime i completely let go of the throttle she would settle at about 10 mph but would not drop any slower. By the time i got back to the driveway the engine was smoking white where the exhaust meets the engine. I shut her down and the battery had not charged at all(i rode her in second gear for about 10 minutes.) Battery is 8 months old and she was working fine last week. One last detail is when I would give her any gas it sounded like something was banging around in the engine, very not good. Anyone have any idea what this could be? thanks

[Water Warrior 2]

Originally Posted by chandlerbingfl

I had almost the same issue. Easiest thing to do is first get the battery tested. That turned out to be the problem I had as I had 2 bad cells. My symptoms were that my bike would start but die when I tried giving throttle. Once I replaced the battery, problem was gone.

Now if it's not the battery it would lead me to the charging system itself, not putting out enough juice to fire the bike properly. At idle maybe so but once the rpms increase it's possible the charging system can't keep up with the demand to fire.

Hope this helps,
chandlerbingfl

Before running out to buy a new battery I would suggest checking the battery post for tightness. It doesn't take much for a battery to go dead if the post are not snugged up good. A good fix to keep the posts tight is to use star washers on the little bolts. Get a battery tender and leave it over night to charge. Then let the battery sit for an hour before measuring the voltage with a meter. Both charger and meter are cheaper than a new battery and you will always have them for years to come.
Never charge with more than a 2 amp charger, that will do a fair bit of damage to these little batteries.

This way you rule out the battery or determine it is the culprit. Keep us up to date with your progress. Best of luck.

[chandlerbingfl]

Thank you for your reply but I have previously done what you explained. The new battery made no difference as you can see in my update to my original post:

Broken bolt, hard starting...

I believe the culprit is lack of enough compression and not the battery (the old or the new)...

chandlerbingfl

Originally Posted by Water Warrior 2

Before running out to buy a new battery I would suggest checking the battery post for tightness. It doesn't take much for a battery to go dead if the post are not snugged up good. A good fix to keep the posts tight is to use star washers on the little bolts. Get a battery tender and leave it over night to charge. Then let the battery sit for an hour before measuring the voltage with a meter. Both charger and meter are cheaper than a new battery and you will always have them for years to come.
Never charge with more than a 2 amp charger, that will do a fair bit of damage to these little batteries.

This way you rule out the battery or determine it is the culprit. Keep us up to date with your progress. Best of luck.

[Water Warrior 2]

Oops, forgot about that. The broken bolt would allow the cylinder to suck ait on the intake stroke and lean out the fuel mixture which would keep the revs higher and run hot. Don't ride or you mght have a melt down. Not a good thing.

[chandlerbingfl]

And I totally agree with your statement. Like I said though the bike runs like there is nothing wrong other than a lack of top speed which I attribute to age...

Am I correct in saying that when I push start and release the clutch in 1st that the compression must be higher? As opposed to just using the starter...

Thanks again,
chandlerbingfl

Originally Posted by Water Warrior 2

Oops, forgot about that. The broken bolt would allow the cylinder to suck ait on the intake stroke and lean out the fuel mixture which would keep the revs higher and run hot. Don't ride or you mght have a melt down. Not a good thing.

[Water Warrior 2]

Two factors likely come into play. First, the ignition system has all the battery power to itself for a stronger spark. Secondly, when you push start, the engine reaches a higher rpm than the starter will turn it. This is just my opinion but it makes sense to my old brain cells.
With the engine running in this very lean hot condition may cause all sorts of things like burnt/broken valves, a holed piston and the piston rings will also be damaged. You might even wind up seizing the engine. Sounds like a perfect recipe for a major repair or replacement.
Would you rather repair the broken bolt or do a major repair?
If the bike is your only transport then beg, borrow or steal something temporarily till you get the bike fixed...............................just kidding about the steal part.

[chandlerbingfl]

Great points... not sure about the bike running lean/hot, but at the end of the day I would like to get this repaired. I'd like to have a decent bike to use to trade up or for something different if nothing else. I really like the bike though, works for me for local transportation and I still get that feeling of riding on 2s.

I do my own oil/filter and spark plug and chain maintenance. The mechanic I generally use for valve adjustments, etc quoted me a repair cost of $700-$800. I'm thinking with that cost it probably wouldn't be worth it.

Any opinion on whether this can be done by a "shade tree mechanic"? I'm thinking if I could do at least a majority of the work I could probably save a lot of the labor cost. My mech charges $65/hr...

Any opinions or thoughts much appreciated,
chandlerbingfl

Originally Posted by Water Warrior 2

Two factors likely come into play. First, the ignition system has all the battery power to itself for a stronger spark. Secondly, when you push start, the engine reaches a higher rpm than the starter will turn it. This is just my opinion but it makes sense to my old brain cells.
With the engine running in this very lean hot condition may cause all sorts of things like burnt/broken valves, a holed piston and the piston rings will also be damaged. You might even wind up seizing the engine. Sounds like a perfect recipe for a major repair or replacement.
Would you rather repair the broken bolt or do a major repair?
If the bike is your only transport then beg, borrow or steal something temporarily till you get the bike fixed...............................just kidding about the steal part.