The ongoing saga of the Benelli m50  By  beerkeg (Read 1,465 times)

One of the mechanics said it revved great on the stand but died under load. Seemed odd to me at the time but I was not there when he tried it. At one point they thought it was done, I went to pick her up and found it would not go past 25. My first thought was the auto choke but have no foundation for that. They checked and said it was pulling 35 ohms across the choke when the bike was off, and were going to replace the choke. Don't think they stayed with that idea though. I was told that the cdi was retarding the timing at 42 mph and it would drop back to 25 and then rev to 42 again. I don't believe it will even rev to 45 anymore. I never got much past 20 when I tested her. They say there are 9 connections to the cdi due to the alarm and remote start. I'm confused as to why it will not go past 25 now when it originally got close to 30 as a 49cc. I have no idea why they would have changed anything electrically to install the performance parts. Perhaps these guys have all been wrong in their diagnosis of the problem? Beyond my level of expertise for sure. They were trying to by pass the alarm and remote start to use a different cdi but could not do so. I will try to get a better grip on what she sound like on the stand versus under load when I get her home. They said they were delivering it which to me hinted that she may not even be running. It was running fine when I took her in, just limited to just under 30 mph and no restrictions in the variator or exhaust that I could see. Just under 30 top speed is dangerous around here as cars will run you right off the road trying to pass on either side. I'm still a bit doubtful about the cdi story too but these are well known and well regarded mechanics so far as I know.

What size jet and is that performance filter an open element filter?
Also did you do anything to the CVT like change the roller weights?
I don't think its your cdi.

If you up grade your engine, you also need to up grade your CVT.
Roller weights, clutch springs.
cdi's cut RPM's not MPH.to protect the engine from over reving.
Rider weight also adds load.

Thank you Gentlemen! I have come to the conclusion that a different shop is the only solution for me. Since I am physically unable to do this kind of work anymore. No matter how much I want to, my body just cannot. I agree that it is very likely not the cdi since nothing electrical was changed and it's now more anemic than it was as a 50cc with the same cdi. There is no restriction in the variator, that was the first thing checked. Other riders get 45 mph out of this same model right out of the box so I doubt the variator needs to be changed. I did consider a variator with a slightly larger outside diameter which would increase the rpm to the clutch. I also considered that perhaps there is a way to change the gearing to use the additional punch from the larger bore. I'm pretty sure they would not have the piston in wrong as it's stamped right on top which side is to exhaust and they have 5 mechanics with experience. I just have to feel rather than think that it's likely a fuel issue. I have a list of 20 questions for them when I pick the bike up which I hope to do today. I suspect that I will get vague or nonsense answers but I hope to ferret out what they have done to it so we can begin to undo it. We know that the cdi controls timing and can certainly restrict engine speed which is the starting point for gearing or variator set up. Changing the weights would only affect how quickly she engages and changing clutch springs would affect how long it took to shift to higher speed. I don't think either of those is the issue here. She is not getting out of the 20's mph range. The last time I rode it I had the feeling it was bogging down due to being too rich and I thought possibly it was the auto choke or fuel enrichment valve as they call it. If that was not warmed to temp it would be trying to run too rich and choking off. One time she quit running on me before anything was done and I thought it might be electrical and that possibly I had switched the kill switch to off instead of hitting the turn signal switch, (same action, different hand) The bike sat for a few minutes and restarted. All else failing I will take her up to the summer cottage as a leisure rider around the lake where speed is not a factor. How ever it turns out, I'll post here and let you guys know the outcome. Thank you for all the great input. I agree with the consensus of opinion that they just don't know scooters. As they say on tv....stay tuned for the next exciting adventure!