Lack of power under load

[Lionel]

After replacing Delorto's with the weber the Bike rev's free and crisp but is lacking power when riding. the Delorto's had similar lack of power but didn't start or rev well. after talking to a couple of bike mechanics they convinced me it was running too rich on the Delorto's and I wanted to put it back to original so I fitted the Weber. the engine sound good with no rattles. the both cylinders both have 120+PSI which I believe is normal. both front and rear sprockets are standard (according to google search).
Any suggestion would be appreciated.
Regards Lionel

[paso750]

120 PSI? I'd expect to see 130-160.
When was the last time the belts were replaced and the valve clearance checked? Do the markings of the belt pulleys align with those on the engine?

[Lionel]

120 PSI? I'd expect to see 130-160.
When was the last time the belts were replaced and the valve clearance checked? Do the markings of the belt pulleys align with those on the engine?

I should of added 120psi cold and dry. But will check again
belts haven't been changed since I received it. plan to replace, want to get it running correct.
Will check all your above suggestions and let U know
I don't get time in the shed very often so may take a while.

[Mc tool]

a P750 lacking power .................um , yeah , sounds about right . Id wanna look into that 120psi comp tho , Ideally youd want at least 140psi . It could be just as you say cold and dry

[Lionel]

120 PSI? I'd expect to see 130-160.
When was the last time the belts were replaced and the valve clearance checked? Do the markings of the belt pulleys align with those on the engine?

Finally got around to doing the compression test again with worm engine came up too 155psi both pots
also found spark gap at 8 and rectified
timing is spot on
still yet to test the bike

[Lionel]

finally got out on bike still lack of low down and climbing power.
starting to think its still running too rich font cylinder is fowling plug