Moskito bogs

wschmechel · Post by **wschmechel** » Sun Apr 13, 2014 5:11 am

I am a proud Buddy 125 owner but recently picked up a 50cc MZ Moskito from a neighbor for a case of beer. When I got it it wasn't running and probably hadn't run for 2 years prior. It's a 2t which I have no experience with.

Anyway I brought it home drained the gas tank & existing oil and replaced the spark plug and the in-line fuel filter. I checked the vacuum lines and did get fuel flowing and got the engine started. It idles perfectly and responds well to acceleration when it is on its stand in that there isn't hesitation.

When I ride it it bogs down occasionally to the point where I fear it will shut off. It doesn't but if I play with the throttle it will sometimes get going again. It is worst when trying to go uphill. I've played with the idle and mixture settings on the carb but don't necessarily know what I am looking for. Any thoughts/suggestions on what this is? Maybe a clogged main jet?

OldGuy · Post by **OldGuy** » Sun Apr 13, 2014 6:02 am

That sounds like an incredible scooter score!

I think that a clogged main jet is possible, maybe likely. But, since it runs well enough to ride a little, I'd be tempted to add a good dose of Seafoam and run it. That may help to clear it out with time and some patience. If it doesn't help then a carb cleaning may be needed.

wschmechel · Post by **wschmechel** » Sun Apr 13, 2014 1:21 pm

I will give that a try. Is it possible to OD on Seafoam or should I dump a lot in and go from there?

OldGuy · Post by **OldGuy** » Sun Apr 13, 2014 2:34 pm

Yes, I think you could add too much and OD it; because you also need plenty of gas in there. I might add double the recommended amount of Seafoam, but not much more than that. Others may chime in with their suggestions and experience.

I assume the gas you added is good and fresh too.

wschmechel · Post by **wschmechel** » Sun Apr 13, 2014 4:25 pm

Pretty sure it was a mqin jet probem as the bogginess has been much improved with some seafoam and some wot riding.

But now annew issue seems to have presented itself. I don't think the Moskito is restricted but I can't seem to get it over 30 mph on a flat surface. It seems to have a transmission problem when I ride to a stopsign ane then punch it again. It sometimes will fire off the line with decent power but other times the engine will rev under load but it doesn't really move very well. Would that be a roller issue or something? It only has 4000 km on it so it would seem pretty early to have that kind of issue. But it was his daughter's college transportation so you never know. Judging by the plastic on the body it looks like it has had a pretty rough existance thus far.

TVB · Post by **TVB** » Sun Apr 13, 2014 6:50 pm

wschmechel wrote:I don't think the Moskito is restricted but I can't seem to get it over 30 mph on a flat surface.

I don't know if it's applicable to this bike, but the restrictions on the Buddy 50 have two components: one on the CVT the other on the exhaust. So maybe it's still partially restricted.

agrogod · Post by **agrogod** » Sun Apr 13, 2014 7:28 pm

Your under load hesitation could be a couple of things. As TVB stated you could still have a restriction some where on the exhaust side which is the most probable place to start. You need to do some research to find out about the restrictions used if any.
Continue to use Seafoam on a regular basis, varnishes from ethanol gas settling are probably your culprit here.
As for your acceleration problems your rollers may have developed flat spots which could cause the symptoms you have described. Replacing them with one or two grams lighter than OEM stock should give your acceleration a good boost. Again researching your new ride should help you determine what size OEM is.
Good luck with your endeavor's.

wschmechel · Post by **wschmechel** » Mon Apr 14, 2014 3:47 am

Thanks for your info guys. It seems the more I run it the better it seems to get. I will keep the seafoam treatment going for the rest of this season. I did notice that the air filter was bone dry as well. I will put some oil on it and see if that makes a difference too.

jrsjr · Post by **jrsjr** » Mon Apr 14, 2014 10:39 am

wschmechel wrote:But now annew issue seems to have presented itself. I don't think the Moskito is restricted but I can't seem to get it over 30 mph on a flat surface. It seems to have a transmission problem when I ride to a stopsign ane then punch it again. It sometimes will fire off the line with decent power but other times the engine will rev under load but it doesn't really move very well. Would that be a roller issue or something? It only has 4000 km on it so it would seem pretty early to have that kind of issue.

Here's a couple resources.

First, the Moskito uses a clone Minarelli motor. Here is a cool resource on derestricting Minarelli motors with lots of pix so you can compare it to your setup - http://www.adrenalin-pedstop.co.uk/Tuto ... rial7.aspx See if that looks like what you have. Do you still have that washer in your Variator? How about the exhaust restrictor?

Second, I agree with the others that it sounds like you may well have some easy-to-fix issues in your CVT. I bet your rollers are shot and you may need to go for new clutch shoes. None of this is a big deal. There are a lot of scooters with the Minarelli clone motors in them so you will be able to find parts. (Not body parts, you're going to have to repair what you have)

Third, here is the mother of all Moskito modification threads over on 49ccScoot.com - http://49ccscoot.proboards.com/thread/825 Don't let the first page about the silly LED mod throw you off because he later explores just about every possible mod and fix on the bike. It's an epic thread worth reading, especially since you are now a proud MZ Moskito owner.

Fourth, as Syd has noted elsewhere, the old Scootdawg (chinascoot) folks are migrating to a board called ItIsTheRide at http://itistheride.boards.net and they have a bunch of folks who know the 2T Minarelli clone motors who can steer you to parts sources, etc.

Hope this helps. Good Luck. Please report back what you learn. Thanks!

wschmechel · Post by **wschmechel** » Mon Apr 14, 2014 4:07 pm

Awesome resources, JR. Thanks!

I did some research and it isn't restricted, so that's good news there. I took of the crankcase and the belt looks to be in good shape as well. The belt does seem to be a bit loose though. I'll have to continue to research and see how to tighten it properly (or maybe it already is).

I'll follow-up if and when I make strides!

wschmechel · Post by **wschmechel** » Wed Apr 16, 2014 3:37 pm

Alright, I got it going pretty well. I won't be setting any land-speed records, but I'm getting it up to 35 mph on a flat surface which is probably commendable for a 50cc toting my 230lbs around in the unseasonably cold Green Bay "spring".

I found this fantastic video that helped me check the transmission elements: http://itistheride.boards.net/thread/688. It's not a Buddy video, but it was a heck of a tutorial!

I think the issue was essentially a partially plugged main jet. I continued to run the engine and felt it getting better and better the longer I would run it. It snowed here recently, but I would start it every day and just let it run and rev it for a period of time. Again, it seemed like it would get stronger and stronger without any bogginess. I also changed out the gear oil and noticed a) it was dirty as heck for 4000 km, and b) it was WAY low compared to the recommended 300 ml. I don't know if that has much of an impact on the performance, but it seems like it's running like a top.

Being that this is my first 2t engine, it seems like it blows a lot of smoke out of the exhaust. In reading up on the 2t, it sounds like this is pretty normal, but it sticks on my clothes way more than I would have guessed!

In working on this bike, what strikes me is the quality difference between the Genuine and MZ brands. I look at my Buddy and it's well made, lines are smooth and everything fits perfectly. The Moskito is cheap, flimsy plastic and nothing quite fits perfectly. Sure some of it is the care it had before landing in my lap, but you can still tell an initial quality difference something fierce! Maybe now that I've got the Moskito running I'll have to sell it and get a 50cc Buddy...or sell them both and get the Hooligan!

jrsjr · Post by **jrsjr** » Wed Apr 16, 2014 3:52 pm

Nice write up. Thanks! There used to be a guy who sold strawberry-scented 2T oil on eBay, but I think that ship has sailed. Anyway, I love the idea of selling them both to get a Hooligan.

wschmechel · Post by **wschmechel** » Wed Apr 16, 2014 4:01 pm

Uh, I don't think I'd go for the strawberry. Lol.

I got this 50cc scoot for my wife to ride as she doesn't have her MC license, but I'm 99% sure she's not gonna be down with it if I'm on my Buddy. She likes the look of the Buddy, and although she's not driven it beyond the end of our street, I know she'd like that ride better. So, yeah, I'd love to sell 'em both and get the Hooligan...but I don't see that in my cards either.

jrsjr · Post by **jrsjr** » Wed Apr 16, 2014 4:44 pm

BTW, don't be too harsh on the MZ brand. That was a once-proud motorcycle mfg with a long and storied history. They just had the extremely bad luck to be on the wrong side of the iron curtain in East Germany after WWII. Back in the mid-80s when I lived in Europe, I badly wanted one of their MZ ETZ 250s. It was such a cheap, basic bike that I figured I could keep one running forever. During the 80s, they were the darlings of Brit despatch rider culture, buzzing all over London terrorizing cabbies and pedestrians, just like in the movie Quadrophenia, except that, by the 1980s, despatch riders were all about motorcycles. ETZ 250s always smoked and their OEM tires were worthless, but they were such completely elemental machines that I couldn't resist. Alas, I never would have been allowed to bring one back to the States, so it wasn't to be. Here's the MZ of my 80's fantasies...

wschmechel · Post by **wschmechel** » Wed Apr 23, 2014 6:47 pm

That's a nice looking bike! I like the minimalist type of bike they seemed to make in the 70's & 80's.

Just an update on the MZ, the engine seems to be running like a rockstar again! I've been switching off back & forth for my daily commutes between the Buddy and the Moskito. I'm not sure if it's the power difference between them, but I feel like the Moskito has no torque when I'm moving from a stop sign or up a hill. Is that a roller issue, or simply a 50cc engine doing it's thing?

I've also noticed that when "cruising" at 30+, the powerband seems to be best at say 1/4 throttle. I'll hit it to WOT, but there isn't any gain in power. I'll hear the engine whine a little more, but there's no difference in actual speed. Again, is that some sort of gearing/roller issue, or is that a 50cc engine?

jrsjr · Post by **jrsjr** » Wed Apr 23, 2014 7:43 pm

wschmechel wrote:I'm not sure if it's the power difference between them, but I feel like the Moskito has no torque when I'm moving from a stop sign or up a hill. Is that a roller issue, or simply a 50cc engine doing it's thing?

At the risk of bringing out my inner Sheldon Cooper, it has to do with the basic physics of how 2-stroke engines work. The valves in a 4-stroke motor do the job of sealing up the combustion chamber for a longer duration of the combustion stroke so that the combustion gasses can push the piston down longer, turn the crank, and make torque. The 2T motor has no such exhaust valve mechanism. Essentially, the 2T exhaust gasses start escaping as soon as the piston moves even a tiny bit past the the exhaust port opening and then there's nothing pushing the piston down any more. So, especially at lower RPMs, the 2T don't make as much torque. Does that make any sense at all? It's just the nature of the 2T design, which is offset by utter mechanical simplicity and high RPMs where 2T motors make horsepower, so it's a design trade-off. Thank you, Sheldon.

If you ever find a good article about the history of MZ, one of their engineers was the genius who figured out how to use standing waves in the exhaust to more efficiently scavenge the combustion leftovers out of the cylinder to make more horsepower. The story of this discovery is totally interwoven with the history of Cold-War politics, East-West defections, and Grand Prix motorcycle racing. It's a fascinating story if you're into it. Um, thanks again, Dr. Cooper...