odd behavior (ron, ree, mbartell?)

Jake Van Order /

I have a 1986 sachs carrier I.

When I start the moped up it has excellent acceleration but right around 25 mph, the engine starts to shake. This continues until its max speed of 30 mph is obtained. The bike will act like this until I shut if off, walk away for a moment and then start it back up. After that, the bike will have less acceleration but won't shake and gets a top speed of 34-35 mph. Any ideas why this would happen?


Re: odd behavior (ron, ree, mbartell?)

So, it's the engine, not the chain alignment. One "out there" possibility- it could be a 2-speed motor, that isn't shifting well. Check your tranny fluid and freshen it.

That's about the only way I can explain your 2 speed ranges tho. I haven't messed with a 2 speed sachs motor, so I'm not sure what makes it shift. Have you tried letting off the throttle and getting back on it when it shakes?

Trans Fluid Temperature ?

Reeperette /

Whatever you're using in your transmission might respond different when it's cold than when it's warmed up a bit.

I only thought of this cause the fluid-type differential on my trike does that when cold too, so it's a thought.


Re: Trans Fluid Temperature ?

Have you drained and re-filled the tranny fluid, using type F fluid?

Just use the hole on the side, the one on the top shouldn't come out (belive me- you don't want it to)

Re: Trans Fluid Temperature ?


I replaced the trans fluid with some new type f today and that didn't make a difference.


Your theory could make sense except that it would gradually get better if this were the case. It's not like that at all. I run the moped for 10 minutes and then stop it. When I restart the moped it runs fine.

It's just totally odd behavior that mystifies me to the extreme.


odd behavior (ron, ree, mbartell?)

I thought this thread was about them. I was going to mention they've always been a bit odd. So, whatever behavior you were mentioning was actually 'normal'



Re: Trans Fluid Temperature ?

Do you think the carb could be that sensitive to temperature changes?

I kind of doubt it. The thing that makes me wonder is your good low end pick up when "cold", and better top end when "warm".

Really weird.

Re: Trans Fluid Temperature ?

would carb problems make the engine shake like it does? I have been four-stroking lately with this warm, humid weather but it passes. I was going to do a plug-chop to find out if my mix is right, but I thought the shaking and four-stroking would be unrelated.


Re: odd behavior (ron, ree, mbartell?)

Hey- watch it "gizmo boy"


When are you going to put a TV on it?

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