I think they are called "common back" belts.....
I am runing a new "b belt" pulley on the gen head and running the belts on the flywheel face.
I questioned this method but I see several done in this fashion with success.
I played with it a little yesterday and after a belt adjustment and playing with 2 springs on the
gov I get about a 2.5 hz loss between 0 load and 5kw. I would like to get it closer and will play
with it more in the future.
I adjusted the valves on the engine per Butch's method and it does seem to run a little better ?
In answer to the other question : The picture is from the coolong side....intake and exhaust are stock.
Gary
My apologies - I hadn't taken from the photos that the B-belts ran on top of the big drive pulley - I had assumed there were grooves machined (hence my comment on groove and belt profile compatability
There will be other with direct experience of this method - and they will be better-informed than I am
However - just from an engineering POV I would guess the drive contact area provided by a flat-on-the-surface approach would be maybe 1/3 of that provided by belts running in suitable grooves?
Also, since the grooves have tapered walls and the belts have tapered sides, when the "load comes on" the belts will pull into the grooves - if you watch videos of loads being applied in hundred-horsepower applications and the like you will see a surprising slackening of the belts on the non-drive side (enough for them almost to "flap" sometimes) - and, obviously, this is single-digit HP application here, but I suspect the principle will be similar?
It may be there is a limit to the response you can get from what might be a fairly casual belt set-up if you have inherited it?
That "chirp" and the difference in response between one belt and two are clues - and to me they suggest you're not getting power because you're not getting drive? Maybe?
A transmission company person would be able to advise . . .
If it was a factory application I was responsible for I would be looking at:
Belt condition
Belt tension (try it tighter than you think is good, and see what happens, maybe?) Also, there will be deflection charts online to allow you to gauge correct tension for given belt types between given centres
Belt match across the two of them
Consider using "belt grip" aerosol to have a play and learn something?
Maybe have a good look at the faces of the grooves in the driven pulley for wear or grooving? "Drive" depends on the ability of the belt and groove surfaces to match nicely
Just some thoughts . . .,
Cheers