1127 ignition issue

[E T]

My 7/11 slabby has been sitting under a cover since last September, I had it about finished and tank started leaking so got that repaired and haven't touched it since, put fuel in it the other day and it fired up straight away but not running right. 1&4 ok as exhaust getting hot 2&3 just warm took tank off and coil for 2&3 was hot so changed coil and tried again but no change so thinking pick ups might be faulty and hopefully not cdi.  So is there a way to test the pick ups ? The only spare pick ups I have are from a 85 750 and as the rotor is different I take it they wont work on 1127 motor.

[clivegto]

If it has the same amount of pickups it'll work if not swap the CDI as well.

[davecara]

85 750 pickup will work, just the right side one doesnt plug into anything. Use the 1127 rotor/trigger wheel. I'd err towards a coil if 2/3 is the issue though

[Dezza]

Pick-up testing procedure is in the manual, available for free as a pdf on webs. It takes about 2 min with a multimeter because all you need is access to the feed plug going from the sender into the CDI.

[E T]

On 8/3/2023 at 12:32 PM, davecara said:

85 750 pickup will work, just the right side one doesnt plug into anything. Use the 1127 rotor/trigger wheel. I'd err towards a coil if 2/3 is the issue though

I didn't know there was only one pick up on these motors , as only ever had early 750's and air cooled 1100. That's why after changing coil and no difference I thought maybe pick up. 

This afternoon I checked coils with meter. The manual says to set meter at x1Kohms but but the 3 different ones I have go from 200, 2k & so on so set it at 2k and both coils give same readings. Put new plugs in and fired it up starts no problem but tick over is not right sounds like running on 2 .

If I piss about and get it past 4500 revs it runs on 4 and will rev cleanly but header pipes on 2 & 3 no where near as hot as 1 &4   the coil for 2 & 3 is warm not hot but noticeably warmer than 1 & 4.  

Anybody any ideas what I should be looking for ?

[clivegto]

I'm having a similar problem with a b12 motor but it's not the electrics or the lump. I have a set of standard b12 carbs from a recent running bike and the lump sprung into life when these were fitted. Other set of carbs have been cleaned and serviced but refuse to play nicely 

[E T]

@clivegto It's the coil getting warm that makes me think its an ignition problem, and doesn't take long to start getting warm. Checked wiring and connections all look fine I'll take carbs off and check them over tomorrow 

[clivegto]

24 minutes ago, E T said:

@clivegto It's the coil getting warm that makes me think its an ignition problem, and doesn't take long to start getting warm. Checked wiring and connections all look fine I'll take carbs off and check them over tomorrow 

Yes I see that just something else to eliminate. Might not be that at all. Bit tricky some time to eliminate stuff.

[SMARTY]

Man,,hahah,, im reading all this and my damn moneypit have a similar problem, but mine is a Eblag parts pit..so not one think came from the same bike..

I was looking at the coil wiring over all the models as it is impossible to know what model my loom is from...maybe "K" i see i made a note..

 

But their is like 4 different ways to wire the coils from 1988 to 1992 uk and us models..

Makes me drink..

 

Edited August 26, 2023 by SMARTY