MOPED ARMY

Are you absolutely sure you set your timing correctly? Exactly how did you determine your current timing?

Also, what's the history of the engine? Has it been rebuilt with fresh seals and a roller crank?

A video of the bike idling, running and riding would be helpful to diagnose your issues. Could be as simple as having your jetting off. I don't use VM or mikuni carbs in general so I cant help much there.

Also, just to be sure, make sure your brakes aren't dragging. (edited)

Yeah the Kstar kit basically sucks unless you could base space it up 3 mm and deck/take down cylinder 3 mm,

The Mikuni carburetor, most people do not know how to tune it in, even experts on a piston port moped kit, I once made $200 to tune one in in and once I put a 14 mm bing in its place and put the side cover on and I gave it up only charged 65 bucks and from a friend of mine gave me $100 because the bike blasted, after eight years still runs today, with stock crank stock ingation stock everything,

I’ve been dealing with Mikuni‘s on Japanese Enduro bikes for 44 years on enduros and someon mopeds,

Most on kitted mopeds are only 3/4 tuned in so I don’t recommend any of them on a puch except for the 24tm flat side on a 74 cc or polini reed kit puch or tomos reed kit,

Get a Cheap 70cc dmp pp kit (at dos cycles) on a 14 mm bing 72 jet,222 atomizer with a metal mesh filter, 17x40 gears tune stock clutch with thick springs and go 48 to near 50 mph with great takeoff at 14 to 14.5° timing with stock magneto,

These people with the high rpm pipes, hpi ignitions all the stuff don’t mean nothing unless you’re on a race track,

I used Moped’s for every day use for 43 years because my vans and cars MPG‘s suck balls,

As long as the streets are dry and it’s above freezing (it could be below freezing but as long as the streets are dry)

The Atlanta boys and Dos cycles are the greatest places to buy stuff for every day use and are great for NOS stuff you name it,

I wouldn’t mind living in that area but my weather blows their weather away as far as rain p/wet roads is concerned, my precipitation, I’m three times the average is lower than the rest of my state so for 43 years I was able to use a moped or small displacement motorcycle instead of a car or bus many times throughout the year,

doesn't that pipe die at like 8k?

your gearing puts you at like 8k in the high 30s

so maybe get a higher revving pipe?

@wes I put a lot of time & money into the rebuild, so I am pissed it's not running like a proper 2 stroke. I'm pretty close to trying to sell it and just get a Zuma or something, it's been quite the trial and error.

@overpriced, I still have my bing 15, so there's potential I could try that again. Although I like the mikuni because it seems to be more reliable with my idle + starting it. As for the top end, I'm pretty close to just buying the airsal kit. My goal with this moped is to have a great daily driver, that is reliable and hits the Powerband/top speed like a two stroke should. Wish you were in Boston I'd pay you to come take a look at this. I've tried almost everything

That's interesting, I might try to order some lower jets then.

I still think the spacing/deck height is messing with my full performance potential. My roommate bolted his airsal on and tuned it and it's golden. I've been trying a lot of different things with my treats kit, but running out of ideas.

I'm going to check the timing, and try to get some lower jets to try. Anyone else ever have a similar issue?

And I've heard this pipe maxes at 8k rpm, but my roommate has the same pipe and the Powerband is ridiculous & the top speed was faster at 14x45 than mine at 17x45

What kinda 250 is that? I think you're lean or it's a four stroke

For sure you need to upjet, 117 is far too low. Most people don’t actually know how to tune a carb and mikuni carbs are perfect for those people as they will run ok way out of tune. Less than 2 sizes on the main will make the difference between tuned and not tuned at wot. Also double check your Compression and set your points gap to .45mm.

After that $250 you could of just bought a reed kit.

Okay Check timing

Check squish

Chek compression

Is this some kind of rival? Did you maybe ask your friend for help? If your looking for our help to smoke your buddy and trying to keep it a secret, I would Ask your friend for help instead.

Does he have a ma account lol

Update: you live in Massachusetts? Great! (edited)

Yup I definitely know you lol

Small fucking world!

Terbo- it's a 2 stroke twin cyl twin carb VM20's 1966 Suzuki T10. Im comparing same carb to a stock setup for a VM20, 70 main and 125cc jug vs his 115 main and 70cc jug.

Dont know if Mikuni changed their jet configurations an numbering since then. Could be. (edited)

Im running a 170 main and a 17.5 idle jet on my wifes E50, Treats 70cc with a Vm20, Estoril pipe and 13x45 gears....that thing gets up and goes, Its a swinger 1 and it didnt come with a speedo, but im going to add one and see where shes at. Id say high 30's and thats not wide open.

Its the treats kit for the peeps, I ran the gaskets included, everything bolted right on, no problem at all.

That's the exact kit I bought. I bought a new head because I thought the one in that kit (o-ring head) didn't have the right squish, but I could be wrong. Maybe I'll throw the old hi hi comp head back on.

So you're running the single base gasket, the hi comp head with head gasket, and then vm20 with 170 jet? I also love that you can change the jets so easily on the vm20, which was a major reason I bought it.

Might have to take the cylinder off again and remove some gaskets, and then up my main jet. It seems like itll be way too rich but who knows!

Just curious, what needle clip setting are you on? I'm on the leanest, as the richer settings made it hard to start me engine and it ran extremely rich

Why do you keep insisting that you are running rich when it sounds like you are experiencing lean bog and need to upjet?

UPJET THAT SUMBITCH!

Lean bog, from my experience, feels like a surging almost, as if it's got enough fuel and then it doesn't. Rich bog, from my experience, is when it sounds like the engine is almost being choke, and when I give it full throttle while around 50-75%, it runs worse than if I very slowly ease up.

For the head, you sure I don't need the oring? I feel like it will have an air leak. I'm also going to put the smaller sprocket in, but from my experience, a properly running 2 stroke with a pipe and decently tuned carb would still hit some sort of powerband. Maybe I'm wrong? I don't feel like different gearing will magically bring out the powerband, but hey, worth a try.