PDA

View Full Version : 503 Jetting



JCotton
4-Apr-13, 05:27 PM
Anybody got any suggestions for initial jetting on a 2 x Bing carb fan cooled 503 without gearbox so that I do not blow any engines up this year? Currently running manufactures recommended 158's

Ewan Black
4-Apr-13, 10:19 PM
158 should be fine with fan cooling- 170 is usual for free air cooled.

Nick Drew
5-Apr-13, 07:50 AM
Yep, standard 158's all good

Nick

JCotton
8-Apr-13, 04:40 PM
Thanks for that, in one way it is re assuring. But it riases another question if the jetting was OK why did a rear piston melt in less than half a lap at Claydon.

sweetm2369
8-Apr-13, 07:32 PM
Could be that an air leak leaned off the rear cylinder!
Check carb manifold for splits and crank seals and gaskets.
Hope that helps!
Derek

willa494
9-Apr-13, 05:52 PM
Hi
I would think it would need more running in , 503 need a lot of running in

JCotton
15-Apr-13, 06:33 AM
Thanks I hope to get some hours on it this weekend.

Nick Drew
16-Apr-13, 07:39 AM
Google 503 run in, and you should find the Rotax run in procedure.

Nick

JCotton
16-Apr-13, 07:18 PM
Thanks will do as in ultralight news

JCotton
23-Apr-13, 05:25 PM
Run in fine. I do not have a EGT guage so bought an Infrared Thermometer to monitor exhaust temperature only 19 at Maplin or from 12 on ebay. it works a treat.

Nick Drew
25-Apr-13, 07:40 AM
Cool,

Maybe a bit tricky to use as your driving ;)

Nick

pest619
30-Apr-13, 06:12 PM
Im new to this 503 thing... Has anyone tried the halfords own synthetic 2-stroke in a 503 or otherwise? (couldnt get any other)

garagewayne
1-May-13, 05:53 AM
Im new to this 503 thing... Has anyone tried the halfords own synthetic 2-stroke in a 503 or otherwise? (couldnt get any other)

Any oil is better than no oil, however I would go for a good branded name, Rock Oil, Castrol etc