Ill admit the 2-stroke world is new to me so im stumbling through this. Recently purchased a '69 Benelli 125 (piston port engine with magneto ignition) in great condition. It had been sitting for decades in a New Mexico shed and was in great condition.
I gave the bike a once over; cleaned the fuel filters, changed the gear oil, put a new gaped plug in, etc. With fresh gas in it cranked right up and idled perfectly. Flip the throttle and it revs through the range well. The problem comes when you go to ride it and put it under load. It bogs and just has no power. You can keep it running and get it up to speed only by feathering the clutch.
Heres what ive done to narrow the problem so far:
-Taken carb apart and cleaned thoroughly (was clean to begin with, no varnish or trash). Reassembled with idle air screw in same position.
-Cleaned air screen (and tried without screen at all as well)
-Removed exhaust and decarbonized using both the caustic soda and wire whip methods. (it now weighs ~0.2lb lighter )
-Installed new exhaust gasket
-Tightened all case bolts
-Removed head to inspect piston and cylinder for damage and reinstalled with new gasket
-Replaced seals in both petcocks and installed new fuel lines.
After all that it runs exactly the same. Before I go too far I wanted to get some input on best plan of action. I can not get a good enough run to do a plug chop, but it appears dark upon removal. This all leads me to think its running rich at mid throttle and I should adjust the jet needle. Thoughts?
The carb is a Dellorto ME if that helps.
I gave the bike a once over; cleaned the fuel filters, changed the gear oil, put a new gaped plug in, etc. With fresh gas in it cranked right up and idled perfectly. Flip the throttle and it revs through the range well. The problem comes when you go to ride it and put it under load. It bogs and just has no power. You can keep it running and get it up to speed only by feathering the clutch.
Heres what ive done to narrow the problem so far:
-Taken carb apart and cleaned thoroughly (was clean to begin with, no varnish or trash). Reassembled with idle air screw in same position.
-Cleaned air screen (and tried without screen at all as well)
-Removed exhaust and decarbonized using both the caustic soda and wire whip methods. (it now weighs ~0.2lb lighter )
-Installed new exhaust gasket
-Tightened all case bolts
-Removed head to inspect piston and cylinder for damage and reinstalled with new gasket
-Replaced seals in both petcocks and installed new fuel lines.
After all that it runs exactly the same. Before I go too far I wanted to get some input on best plan of action. I can not get a good enough run to do a plug chop, but it appears dark upon removal. This all leads me to think its running rich at mid throttle and I should adjust the jet needle. Thoughts?
The carb is a Dellorto ME if that helps.