z50 flat spot

[misfit]

ive got this z50, 1971 model, and its got a big flat spot just off idle. it only happens when its warmed up. when you open the throttle after you back off to slow down its there. if i have the engine idling and open the throttle a little and hold it in that postion, the flat spot is there for a few seconds then the revs pick up. any ideas why it does this?

[Stan S]

ive got this z50, 1971 model, and its got a big flat spot just off idle. it only happens when its warmed up. when you open the throttle after you back off to slow down its there. if i have the engine idling and open the throttle a little and hold it in that postion, the flat spot is there for a few seconds then the revs pick up. any ideas why it does this?

Firstly put a new plug in it, C6HS if I remember correctly. Then check the points, clean and set at 14 thou then alter gap to set the timing either static or with a timing light. Check valve clearance of inlet at 2 thou and exhaust at 3 thou. If you still have a problem strip and clean carby including all jets. Now as I don't know the condition of the engine, electrics, carburetor jetting or air filter set up, all these things I have suggested are the basic common problems found with any early Honda mini's.

Regards Stan

[misfit]

ok thanks. ive checked it over a few times but cant seem to fix the problem. it wont run with a brand new plug that i bought which is the right type and heat range, put will run with the old plug that was in the bike when i go it. so i am thinking that its a strange electrical problem

[frostype400]

I have had similar problem when I had my z50 put an inline fuel filter in obviously it is a steel tank model, then clean you carb right out.

try put a new $5 killswitch on it funny probs can be caused by kill switches sometimes.

[caps 999]

blocked pilot jet