R/S engine knocking

[mlcorson]

I've got a new Robin Subaru EHO35 engine on a BMP friction drive. The engine likely has about 30 miles on it. Under load and at slower speed, typically accelerating, I hear a knocking in the engine. At higher speeds and cruising the knocking is NOT present. Is this just because its new? Gas is only a month or so old. Do I need to treat the gas? Or is this normal or something I can expect until broken in? Performance is good, at least for new engine.
-Mike

 

[moped-dan]

I have the R/S engine too on a staton inc friction kit. I have a lot of knocking noises until I get going a decent speed (15 or so MPH). I think it maybe the clutch not engaging properly right away? Im not sure but youre not alone. Its not much of a problem in the country where I just cruise but its kind of a annoyance in the city because of the stop and go nature. Id love to solve this problem though it isnt a huge deal.

By the way, the noise. The best way I can explain mine is when I throttle up while going under 15 or so I hear a sort of resonating grinder sound, going up and down in pitch. Its not a very violent sound but its definitly noticeable and is louder than the engine itself. The engine runs fine during this as far as I can tell but when I hit that magic speed it goes away and it sounds much quieter and smoother. How does this compare to what youre hearing?

 

[srdavo]

here's a thought......
check your drive roller bearings.

when one of my bearings failed.... it would make noise during acceleration & low speeds.

 

[Zev0]

It's the clutch! The noise will go away with use. Mine did the same thing when new, but quiet as a church mouse now.

 

[mlcorson]

here's a thought......
check your drive roller bearings.

when one of my bearings failed.... it would make noise during acceleration & low speeds.

Maybe, but a long shot on a new drive system?

 

[moped-dan]

I thought bearings too.. but when riding with the engine off and drive roller engaged I hear none of the knocking noise. How long did the knocking last on your setup, Zev0

 

[Zev0]

How long? Oh geeze, not sure, probably a couple of months. Maybe 100-150 miles.

 

[5-7HEAVEN]

The sounds you are hearing are typically normal clutch/clutch bell noises when new, or replacing friction roller.

It happened to me also.

If it unsettles you, remove the engineand inspect the clutch, bell and clutch bellhousing for a broken clutch lever.

Sometimes you'll hear a ting-ting-ringing sound when the engine clutch is new, sometimes a scraping noise.

When in doubt, pull engine and check it out. It takes less than an hour.