Topic: Another timing issue 1971 CB750

[itsahonda4]

Replaced both sets of points and when redoing the timing Im finding that Im out of adjustment on the left side (1/4) points before the points start to open at the mark......
So I pulled out three different advancer plates and checked all of them and they are all the same......
When fitted, , with the points set at 12 thou, I cant get my points to open at the mark, but they are opening late (or retarded).
Bike runs great, but I know timing is retarded...
IVe never seen this before and dont remember if it was retarded last summer, but it must have been......
Comments?

[BomberMann650]

post pics

[pablo63]

I recently purchased a brand new genuine honda points plate with points and condensers , I have found that setting the points @14 thou it's impossible to get the timing set correctly using the static timing method ,what I have done is set the timing mark on the rotor for the 1-4 cylinder with the index line , then connect a static timing light , then adjust the point gap so the light just comes on ,this indicates the points are just opening , you will find that the point gap is about 22 thou once @ the widest opening , not the reccommended 12-16 thou , I double checked with a strobe light and found the timing was spot on , the bike works fine , pulls good ,starts easily ,so will be running it like that .

[itsahonda4]

Thats what I suspected...the points plate is definitely later so ill do the timing with my light and make it work......
Thanks, eh

[Nic]

Back in the day there was never a drama setting points and timing, today things are different.
The points plate whether new tec or old will usually be a bit sloppy in the 3 engine case bosses. So you set the points gaps then check timing, it's when you rotate the plate to adjust timing that because of the slop you will, well I do at least, find the points gap/s have changed dramatically. You can do it one of two ways:
#1-- loosen the 3 rotation screws and find the correct size feeler gauge and jam it in between the points plate and the lower case boss, tighten the screws and adjust your points gap. If and when you need to rotate the plate to adjust timing, take the feelers out n rotate the plate BUT MAKE SURE you put them back before tightening the 3 screws. This will ensure the points gap doesn't change.
#2-- If you don't use the feeler gauge method for whatever reason then after you have rotated the plate to adjust timing and done up the 3 screws you'll need to check the point gap and adjust accordingly. This can take 2 or 3 times to get it right. I have had to do this with  brand new tec plates, it can do one's head in but if you realize it's the slop in the fit of the plate to the case bosses then it makes sense.
 Set the points to 14 thou.

[pablo63]

next time I go to adjust the points will definitely give that a try as setting the points @ 14 thou and getting the timing marks on 1-4 cylinder all lined up I could not get the static timing light to light and that's with turning the backing plate  all the way in both directions , the plate is fairly snug in the case but there is a slight amount of slop , so could be the problem '