Ignition timing question

[Craizeehair]

Apologies for the basic questions that I’m posting.

Today was to be the day that I checked the points and set the ignition timing, for the first time. I hadn’t banked on the timing being so much of a pain!

The points are pretty much cooked and I will be ordering new ones but I cleaned them up for now, set the gaps and cracked on with the timing. This is where the fun started.

I could set the timing on 1-4 to light the bulb bang on the F mark.

If I then set the plate with one screw to check it, everything was fine, as soon as I tightened all three screws it would throw it out. This went on for about an hour, what I found was that if I tightened the top right screw on the plate at any point it went out of whack. If I tightened one of the other screws, or both of them, it was fine. As soon as the top right screw was tightened it advanced it.

Is there a knack that I don’t know about. Could the plate be dodgey, or any other issue that could cause this? I didn’t expect it to be such a pain.

[Oddjob]

Possible the plate is bent, take it off and check it.

It's common when non original points are fitted to find timing 2-3 difficult, with TEC points it's a doddle but not stuff like Daichi.

Original points are very expensive and can be hard to find.

[Craizeehair]

Possible the plate is bent, take it off and check it.

It's common when non original points are fitted to find timing 2-3 difficult, with TEC points it's a doddle but not stuff like Daichi.

Original points are very expensive and can be hard to find.

Thanks, I did wonder if the plate might be the problem.

I am going to order new points anyway and I’m sure the condensers are after market so had contemplated changing them for originals whilst I’m at it. DS sells the original plate with points and condensers already fitted, cheaper than buying the points and condensers separately, not cheap but I may go that way for peace of mind?

[Bryanj]

If you want genuine points and condensers the only sensible way is the complete plate, comes with nice new white covered wiring as well

[Martin6]

You are tightening up 1 & 4, to lock them in, before moving to 2 & 3?

[Bryanj]

The other thing to check is that the shaft is running true, they can easily be bent a fraction if you turn the engine over with the big nut on the advancer

[Craizeehair]

You are tightening up 1 & 4, to lock them in, before moving to 2 & 3?

Yes, when I tighten the top right screw on the plate for 1-4, that’s what knocks it out of alignment.

[Craizeehair]

The other thing to check is that the shaft is running true, they can easily be bent a fraction if you turn the engine over with the big nut on the advancer

Sounds more serious than a new plate! What’s the best way to check that?

[Martin6]

You are tightening up 1 & 4, to lock them in, before moving to 2 & 3?

Yes, when I tighten the top right screw on the plate for 1-4, that’s what knocks it out of alignment.

Ah, got it. 👍

[Oddjob]

Possible the plate is bent, take it off and check it.

It's common when non original points are fitted to find timing 2-3 difficult, with TEC points it's a doddle but not stuff like Daichi.

Original points are very expensive and can be hard to find.

Thanks, I did wonder if the plate might be the problem.

I am going to order new points anyway and I’m sure the condensers are after market so had contemplated changing them for originals whilst I’m at it. DS sells the original plate with points and condensers already fitted, cheaper than buying the points and condensers separately, not cheap but I may go that way for peace of mind?

I'm not 100% sure that what DS are selling are the original points and condensers. Check first before buying. The originals are clearly marked TEC.

[Trigger]

The original 70's points plate for a 750 was Hitachi and was marked by the Hitachi logo and had ND points and condensers 

[Bryanj]

To check the shaft remove points plate, which means undoing the 6mm thread nut, remove the advancer unit and spin the engine, bad ones are visibly bent but you may have to fit a wire pointer to see slightly bent, or a dti if you have one.
The shaft screws into the crank with an O ring to seal oil

[Oddjob]

The original 70's points plate for a 750 was Hitachi and was marked by the Hitachi logo and had ND points and condensers

As you can no longer find that part number, 30200-300-005, and even IF you could DS would be charging a fortune for it as it would be labelled "Sandcast" and we all know that doubles the price of it. So for all intents and purposes it's the TEC version that he requires, unfortunately DS has a nasty habit of not updating his pics, so he shows what they should look like and then sends something else. The replacement plate is made by Daichi and when you search for the part number of the plate 30200-300-154 that's what you normally get offered. Unless you know, you're liable to buy it thinking it's genuine. Then you find out it isn't, as it's a bitch to get timed up.

Forewarned is forearmed as they say.

[Craizeehair]

Thanks chaps, I got a bit too previous last night and jumped straight on DS and ordered before the above comments. I will wait and see what turns up. They can always go back if they’re not right.

On the off chance, does anyone know where I would be able to get the TEC version if needed?

[Oddjob]

Let's just hope they are still selling the TEC version. It's not impossible to find the right one, it's just a matter of looking. TBH, just finding the backplate shouldn't be hard, should be loads of those around. DS still has genuine TEC points but £30 each is a joke. So, worse case scenario, you find a second hand backplate and swap your existing points et over to them and see if that works. I'd also check there is nothing on the casing where the plate sits, like a blob of paint for instance.