run/stop/run/stop problem By eagleridermb (Read 537 times)

[eagleridermb]

Just thought I'd pick other's heads for an answer and see what you come up with.

History- Benelli 2 stroke 1E40QMB bike with Hoca 70cc kit came in spitting and popping, wouldn't run well at all. "Little plastic cup" was not staying filled, so suspected (and changed) fuel pump. Still spitting and popping, exhaust pipe glowing cherry red (too lean). Drilled out main jet to size 90, now exhaust is cool, no more spitting and popping. Runs smoothly, but at top end, engine cycles on/off, on/off, on/off, like it's losing ignition. Checked CDI module by parts substitution with a known good module, same problem. Customer states coil was changed previously, so I'm not sure it could be a problem. The ignition module is DC, so I'm thinking it draws power from the battery circuit. Battery is new and is charging correctly, so I don't suspect the battery or stator/charging circuit. I'm about to change the trigger coil. It acts almost like the turn signal flasher is controlling the ignition, but the length of time power is lost is somewhat/slightly random, not really a specific time period. If anyone has any idea, please post it. I'm going to change the trigger and if it fixes the bike, I'll repost so others may benefit from my experience. Thanks, Eagle Rider MB

[Alleyoop]

Also check to make sure the plug sticks out into the chamber, some heads were made little thicker and the plug electrode doesn't stick out into the head and at high rpms it grounds out.
They will run good up until top end.
Alleyoop

[eagleridermb]

Changing the ignition trigger didn't fix it. I see that someone has replaced the ignition coil- with the wrong one. Although I doubt that would cause any issues, I'm going to see if I can locate an OEM Benelli ignition coil for it. It mounts wierd so I can't use just any coil. The one in it now was mounted with a wire tie. It doesn't use a conventional 2 stroke coil that uses the frame for ground. I'll check the spark plug and see if it protrudes- but this is a HOCA 70cc kit, so should have a "normal" thickness head. Will keep everyone posted...

[Alleyoop]

What does being a HOCA kit have anything to do with it!! I ordered 12 gram HOCA rollers the package said 12grams I weighed them and they were all 11.6-11.8 grams. I complained and sent them back for a full refund including shipping, I then ordered Dr. Pulley weights and all were 12grams.
Alleyoop

[eagleridermb]

Picky, picky.... Being a Hoca should mean (with reasonable expectations) that the aftermarket head should be approximately the same thickness as a "standard" head. If roller weights I ordered were only .2 to .4 grams off, especially at that heavy weight, I wouldn't have worried much and used them anyhow. What type of scooter did you install them in? For a 50cc scooter, those would be pretty heavy! (Most of the stuff my customers bring me to work on are 50cc) Not to mention most suppliers charge about 1/3 more for Dr. Pulley rollers... and my customers are so cheap their pennies have fingernail dents where they won't let them go!

[rob63]

How long does the loss of power last , is it momentary or a few seconds or longer ? As it only happens at top end, I`m just wondering if this is a simple misfire due to plug or coil breaking down, split in the ht lead, or even a dodgy plug cap which is shorting out.

[Alleyoop]

Not picky picky 1/2 gram or more off is quite a bit when tuning your CVT. It may not amount to much on a 50 but on bigger scoots it makes a big difference. The weights were for my BADASS TRIKE you see in my SIG. If they were 11.9 or so I would not have sent them back BUT NOT ONE was NEAR 12grams. It appears some of these dealers are snatching up HOCA's REJECTS knowing that 99% of the buyers will not weigh them. Not to many folks have a small scale that weighs things in grams or will invest in one just for that purpose you can pick one up for under $10.00 dolores.
Alleyoop

[eagleridermb]

OK, as it turns out- this Beamer III has a DC-operated CDI. The CDI module I have on hand doesn't specify if it's a DC or AC unit. The wiring on the bike is:
White/Blue to ignition coil
Orange to +12VDC
Black to Ground
Blue/yellow to trigger

Not sure where I'm going next, but hopefully, this will help someone else out.

Eagle Rider MB

[eagleridermb]

Didn't work. The "generic" CDI module (I believe) must be an AC unit, and the scooter is definitely a DC arrangement. +12VDC on the scooter's orange wire. Blew fuses and would not work. Next time I have an AC-operated 2-stroke with a bad CDI module, I'll try it again.

[Alleyoop]

Check this out apparently the CDIs for the BEAMER are special:
Scroll down to the Beamer CDI.
Alleyoop
www.scrappydogscooters.com/50cc_2stroke_Performance.html

[eagleridermb]

Main problem (DUH!) was cheap customer didn't want to pay for a Beamer CDI module (admittedly, they aren't cheap), but he found one that was mis-ordered at another dealership. They cut him a deal on it, I installed it, so all is now working. And a heads-up, scrappydog can't get any more aftermarket Eton CDI modules... they were one of the first places I contacted. They're out and have no source at the moment. Thanks! Eagle Rider MB