Anyone use #300 main jets on a MK3?

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Never heard of this carb mod being needed on a Norton. IMO, as others have noted, it's some other issue, not a need to drill/mill float bowls.
 
I pulled the sprag it was not exploded like I thought it would be, but it must have flipped backward, I knocked the dog bone rollers around a little and it now works. It was a used one and the cage slots seem worn which could cause the rollers to flip. My overload was too tight, I tightened it up years ago with no issues until recently. Adjusted the overload with a modified splined washer per suggestion here, (thanks whoever ). Still gotta figure out why the thing is backfiring.


Anyone use #300 main jets on a MK3?
Anyone use #300 main jets on a MK3?
Anyone use #300 main jets on a MK3?
Anyone use #300 main jets on a MK3?
 
I might have found an electrical smoking gun( a tiny one) that caused intermittent funny running. The Lucas Rita white pick up wire was rubbing on the ignition rotor and it finally wore through the insulation, causing the ignition to ground out sometimes when the rotor peaks rotated by. Sloppy workmanship on my part.:(

Anyone use #300 main jets on a MK3?
Anyone use #300 main jets on a MK3?
 
The rotor also looks a bit chewed up, like it’s perhaps been hitting the pick up ?
 
jimbo said:
I might have found an electrical smoking gun( a tiny one) that caused intermittent funny running. The Lucas Rita white pick up wire was rubbing on the ignition rotor and it finally wore through the insulation, causing the ignition to ground out sometimes when the rotor peaks rotated by. Sloppy workmanship on my part.:(
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Bad on the wacky wire routing .
Remember the RITA red fiber stack can ease and get loose causing skipping from bad contactt. I have diagnosed this several times on bikes. The double nutting on top of the stud may need to be tightened a bit to run well again.
 
jimbo said:
I might have found an electrical smoking gun( a tiny one) that caused intermittent funny running. The Lucas Rita white pick up wire was rubbing on the ignition rotor and it finally wore through the insulation, causing the ignition to ground out sometimes when the rotor peaks rotated by. Sloppy workmanship on my part.:(
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On my old Rita, I would loop the wires over the top of the pillar screw to prevent that. There was enough room with my cover for them to fit.
 
I use 260's on the MK3, FA head and large cam. This has been dyno'd and there is plenty of adjustment to make it run richer, which was surprising.
 
Jim Schmidt suggested to me that I should be running large mains on my 850 (10.5:1 with PW3 cam + flowed head). I was running 270, then 280 when I had my little incident.
I'll probably start with 300 and work on from there, possibly with a FA meter.

They cost about £120, which is rather cheaper than another set of Jim's lovely creations.....
 
SteveBorland said:
Jim Schmidt suggested to me that I should be running large mains on my 850 (10.5:1 with PW3 cam + flowed head). I was running 270, then 280 when I had my little incident.
I'll probably start with 300 and work on from there, possibly with a FA meter.

They cost about £120, which is rather cheaper than another set of Jim's lovely creations.....
Click to expand...
I pulled the 300's , I could send them to you?
 
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