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Post by epitome on Oct 11, 2021 18:03:45 GMT -5
Hey guys!
I finally got my scooter started today. Very exciting after my first rebuild (1339QMB 80cc BBK), but it was really tough to get going. We had to pull the air box and use some starter spray. Even then it took quite a while. It won't start using the electric start. It will try, slowly, but no start. The one time I started it (earlier today) was using the kick start. It was also connected to my battery charger at the time (in case that matters). Once started, it was running too high. The rear tire was spinning like crazy and something on the bottom of the engine started to smoke a little. So I turned it off and disconnected the charger to see if I could start it with the electric start this time. No go, again. My smart charger said my new battery was at 80%. Prior to that, I checked spark, and only got spark when using the kick. So...
Is there a difference between the kick start and the electric start as far as electrical parts go? Does this point towards part of the starter system being faulty? Or do I need a battery with more CCA to accommodate my new BBK?
Thanks!
Steve
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Post by scooter7878 on Oct 11, 2021 19:15:04 GMT -5
A few more info needed. One did u up jet the carburetor to accommodate the bbk. 2nd with any bbk the best thing to do bc it strain's the starter is upgrade the negitive and positive cables. I use automotive battery cables for this I buy pre set cable with the eyelet ends already on I first run a negative from battery to the frame usually right behind the battery in the stock location than from that location on frame to a starter bolt to ground engine. Than run automotive cable with eyelet from battery POS to starter solenoid and from solonoid to starter making sure every connection is tight and clean if needed sand metal where connections are to clean. Do not ground to paint sand paint off frame if needed. I also don't use standard scooter batteries I use lawn and garden equipment battery there bigger and do not fit without modify but I had nothing but trouble with scooter batteries and have had the same lawn equipment battery for over a 1 1/2 year. I have a high compression piston and stroker crank and my starter does not struggle at all. As for the running high idle u will need to install bigger jets in the carburetor or u will be running lean and possibly blow something up. I would go up one size idle jet and probably 5 numbers up on the main jet to start with. Ur idle jet should be between 30 to 35 and ur main should be around 85 to 95 to rich can't blow anything too lean/ small jet can cause overheating or burn something up
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Post by scooter7878 on Oct 11, 2021 19:22:07 GMT -5
Once u up jet to get a base setting on carb then the mixture screw till it bottoms out but not tight just till it touches. Than back out 2 1/2 turns. Now back idle adjustment screw out till it doesn't touch lever. Than turn in till it touches once it just makes contact turn one more full turn. That will get u close to where u need to be. Things will need to be adjusted as u start the jetting process. When u start it hold throttle u want to hold about 2500 rpm right away and let it run at 2500 for like 3 min unless something really sounds wrong. It should start clearing up after a min or two. It may smoke a bit as things get hot it's burning whatever oil and grease off. After running a few min at 2500 see if it will idle by itself. If it's still idle high turn the idle screw out a little at a time see if it comes down. If it stalls turn screw in a half turn and re start. Play with idle screw till u can get it to idle on its own
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Post by epitome on Oct 11, 2021 19:34:21 GMT -5
Yes, I already put a 96 main jet in the carb, and just this morning before starting I turned the idle screw 1 1/4 turns. However, I haven't changed the idle jet. I'll take a look at getting new cables as well, thanks for the suggestion. The battery is brand new, so I'm hoping I don't have to replace it already. I've found a couple of semi-relevant YT videos since posting, and they've given me more to consider as well. I'm not 100% positive my ground is sufficient, so I'll check that as well, and I have some electrical troubleshooting steps to try. And thanks for the tuning help too, that'll come in really handy I'm sure. Even just getting it started today was a big morale boost, but now the problems need sorting.  |
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Post by scooter7878 on Oct 11, 2021 20:13:04 GMT -5
The cables are important the bigger battery isn't a must but u will always have cranking trouble without doing the cables. I make 210 compression so I need the bigger battery mine won't even turn over without it. Look up some stuff in ring break in it's very important to get best performance I prefer what they call a hard break in it's a long explanation but I don't believe in soft or easy break in if u read up u can make ur own choice and opinion but I know for sure the hard break in I do works I have 13,000 miles on my build and don't use a drop of oil in between changes and still make 210 psi compression.
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Post by GrumpyUnk on Oct 12, 2021 10:25:54 GMT -5
Given the carb settings worked previously, they should not cause the engine to fail to start.
What size battery did you get, the same as original?
Have you tried jumpering past the starter relay, big connector to big connector, or directly battery + to the starter connection post on the starter(BIG SPARK IF YOU TRY)? That would take all the relay & controls out of the problem set.
Did you re-install the engine ground wire from the rocker arm cover to the chassis? You need that ground or one equally as well connected(large wire).
Sometimes a cold engine will not want to start if the throttle is adjusted too wide open. You can back the hard stop off until the throttle is closed completely, and then open 1/2 turn, and attempt to start. If that is the problem, you should get 'pops/firing' as you increase the turns, slowly, trying after each adjustement. The alternative is to get it to start, and adjust the hard idle stop as best you can while it is running.
tom
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Post by epitome on Oct 12, 2021 11:58:54 GMT -5
Given the carb settings worked previously, they should not cause the engine to fail to start. Carb was rejetted and the scooter has never run since I got it. Previous owner blew the engine.What size battery did you get, the same as original? 12V 135CCA "GS-JSB GTX7A-BS Powersports Replacement Battery"Have you tried jumpering past the starter relay, big connector to big connector, or directly battery + to the starter connection post on the starter(BIG SPARK IF YOU TRY)? That would take all the relay & controls out of the problem set. Not yet, but I plan to this weekend.Did you re-install the engine ground wire from the rocker arm cover to the chassis? You need that ground or one equally as well connected(large wire). I will need to investigate that. I'm not very well-versed in the electrical components, so it's possible I don't have proper ground after the rebuild. Sometimes a cold engine will not want to start if the throttle is adjusted too wide open. You can back the hard stop off until the throttle is closed completely, and then open 1/2 turn, and attempt to start. If that is the problem, you should get 'pops/firing' as you increase the turns, slowly, trying after each adjustement. The alternative is to get it to start, and adjust the hard idle stop as best you can while it is running. Ok thanks, I'll keep that in mind as I troubleshoot further.tom |
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Post by james82nd on Oct 15, 2021 13:04:35 GMT -5
Hey guys! I finally got my scooter started today. Very exciting after my first rebuild (1339QMB 80cc BBK), but it was really tough to get going. We had to pull the air box and use some starter spray. Even then it took quite a while. It won't start using the electric start. It will try, slowly, but no start. The one time I started it (earlier today) was using the kick start. It was also connected to my battery charger at the time (in case that matters). Once started, it was running too high. The rear tire was spinning like crazy and something on the bottom of the engine started to smoke a little. So I turned it off and disconnected the charger to see if I could start it with the electric start this time. No go, again. My smart charger said my new battery was at 80%. Prior to that, I checked spark, and only got spark when using the kick. So... Is there a difference between the kick start and the electric start as far as electrical parts go? Does this point towards part of the starter system being faulty? Or do I need a battery with more CCA to accommodate my new BBK? Thanks! Steve |
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Post by james82nd on Oct 15, 2021 13:07:34 GMT -5
Usually Batteries on last 3 years on the scooter, but with a big bore kit either a higher gauge Positive wire going to the solenoid and starter would help. Others wise you might need to check e-bay for a high torque starter for a bout 70 dollars.
I rebuilt one one time with a big bore kit and the valve was to big for the piston and they where barely hitting.
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Post by james82nd on Oct 15, 2021 13:22:27 GMT -5
I have put over 10 kits on various 50cc's an 150cc's. what size kit did you have installed with the bore size and head valve size?
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Post by epitome on Oct 16, 2021 16:53:29 GMT -5
I have put over 10 kits on various 50cc's an 150cc's. what size kit did you have installed with the bore size and head valve size? It's an 80cc BBK (50cm bore). I don't know what size the valves are. The listing on Amazon doesn't give that measurement, and I didn't measure it before installation. Here's a link to the exact kit I bought:
www.amazon.ca/gp/product/B00SZZKU02/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 |
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Post by GrumpyUnk on Oct 17, 2021 7:19:04 GMT -5
They have been around a while, and likely have sold this same set for years. Given the history, I expect you are not having piston<>valve interference.
A starter, relay, battery and cables in good condition should be able to start the engine with no problem. Most of these have a larger than normal cable connecting the black tube of the chassis to one of the cam/rocker cover bolts. That cable provides the return path to the battery '-' terminal. The '-' terminal of the battery also should be connected to the chassis. Without those, not enough current would flow to operate the starter.
The red cable generally connects the "+" battery terminal to one post of the starter relay. The other post is connected to the lug on the starter. All connections should be clean, tight and free of paint.
You can check for battery voltage at these terminals, and should be with a volt or less of the battery voltage at the battery terminals. If that checks out, you can jumper across the two large starter relay terminals to provide power bypassing the relay. The internal contacts in the relay may be damaged or worn out, and not capable of passing enough current.
tom
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Post by epitome on Oct 17, 2021 22:10:58 GMT -5
Yeah, after reading all the posts here about proper grounding, I'm pretty sure that's my issue right now. I didn't have the chance to work on it this weekend, thanks to the "atmospheric river" we experienced, but I hope to soon. Thanks again!
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Post by steve1297 on Oct 18, 2021 21:41:03 GMT -5
Also, the reason it's sparking with the kick start, and not the electric, is because there's a safety switch on the side stand. Put it on the center stand to electric start
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Post by epitome on Oct 30, 2021 18:59:35 GMT -5
Ok, so there's some good progress. My buddy Chad came over, who knows alot more about electrical things and found that the resistance on the ground was about 5 ohms. He says that's way too high. He has fittings, so we're going to do up a proper ground cable. But even when we bypassed everything and went straight to the starter it wouldn't start electrically. So he thinks the starter is hooped. I'll search for the high torque starter that james82nd mentioned. But we got it started with the rebuilt kick-start many, many times today. We're having trouble getting the idle and air-fuel dialed in right. We started with the 96 main jet installed and Chad felt it was running too rich. The scooter would sometimes try to run away on us. If you cranked the throttle it would just stay running fast, even when the throttle was completely released. We swapped out for a 90 jet and things improved a bit, but we still have to fight it to keep it running right. The other thing we noticed is that using the rear brake would act like a choke? Is that right? It would run OK with that on, but sometimes when we released it, the scooter would bog down or even shut off. I checked the idle jet, and it's a 34. So I think that's fine, based on Scooter7878's info above. Any other suggestions on this one? Thanks again!
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