Swop over 84 engine to 86 engine

[trike05]

Hi I am changing my 84 gl1200 engine for a 86 engine, I have changed over to clutch etc. Now do i need to change anything else electrical for it work. hopefully someone has the knowhow,
Appreciate any help /advice you can give me
Regards phil.

[Earl43P]

The freight $$ would be high, but this guy has an entire 84 engine: viewtopic.php?f=9&t=40558

The reason I respond at all (having no experience with the 1200's) is that I believe your task will be daunting.
The 84 spark control/vacuum advance was on the aft engine top right of the rear cover, just like the older GL1100 models.
Your 86 engine has a mag pickup under the front engine timing covers and I know little to nothing about the compatibility between those systems of spark control.

Perhaps you could share the reason for this engine swap?

[trike05]

Hiya, thanks for the reply, the reason I am switching engines is that I have loads of trouble with it from day one, so I managed to get a 86 short block. when 84 threw a valve smashed the piston to bits that was the last straw. I thought it was a straight swop over but no. I am lost with the electrics side of the job

Boom

Boom

[Earl43P]

Ouch, that looks a bit like my 1100 when an intake valve snapped, took out the piston and split the cylinder wall.

Only other suggestion that I have is to compare the rear covers with the thought of transplanting the vacuum advance/mag pickup/cover from the 84 onto the block of the 86.

The "drive" for the 84 spark assembly may be transplant-able into the 86.

This is a THEORY on my part. I hope you can get some expert advice on this subject.

[trike05]

Hi & thanks it is a different pattern for the 86 back cover which is a ball ache and as I said the electrical part lm new to, which I find hard to get my head around, ney mind it will be something simple, thanks again

[Shadowjack]

You can't swap the ignition assembly from the back of the '84 to later models, nothing fits. You just need to change the ignition module, under the false tank.
The '84 pulsers should only be used with the '84 ignition module, since their resistance is different from the '85-up carburetor pulsers. Get a later module to replace the one from the '84, then make the wires from the front-mounted pulsers on the '86 engine reach the plug in the '84 harness at the rear. Since all the '85-up carb ignition modules are the same, they're a lot easier to find than the '84s.

[trike05]

Thanks, the only wires/coming from the front is the same as the one on the 84.I presume that it's for the gear indicator, so should there be others coming out of the front? I will post some pictures of what is there tomorrow. bit, dark at present. Appreciate your help thank you

[Shadowjack]

The lead from the gear indicator comes out of the front cover under the timing belts. The lead for the pulsers comes out through a slot in the block above the right belt cover. Sealed with a rubber grommet to the cover.

[trike05]

Hi, a mate of mine came round with with a manual for the 86 engine, boy I was completely wrong. I thought the p/g, Were behind the back timing plate. That's what has happened they have been removed, so I need pulse generator & ignition module, once I get them ready to go thanks your reply and information great help

[Shadowjack]

The pulsers for an '86 carb model are available in the US for about $80. 30300-ML8-680. Ignition modules are all over Ebay, but they don't go all that cheap.

[trike05]

It's not the price of the item, it postage to the UK & import tax that knocks the price way up. I will try the dismantles here and hopefully get what I need. Regards phil

[Shadowjack]

What I meant to imply is that if we can get the part in the States, they should be available from a Honda dealer worldwide. CMSNL has them for 105 Euros.

[trike05]

Sorry, I've got on to parts UK which will post to all breakers with my parts list for free, I know getting second hand /used is a risk but I have a tight budget and Christmas, so I need to go cheap, in the US parts in general seems to be cheaper than the UK

[brianinpa]

Thanks, the only wires/coming from the front is the same as the one on the 84.I presume that it's for the gear indicator, so should there be others coming out of the front? I will post some pictures of what is there tomorrow. bit, dark at present. Appreciate your help thank you

How many wires are coming from the gear indicator harness? If there are only three, your Aspencade gear indicator will not function correctly as the engine you have came from an Interstate which does not have the gear indicator other than neutral and OD.

[Earl43P]

That 84 gear indicator sensor wil swap over to the 86 engine cover if there are more wires on his original connector. But the transmission front cover has to come off to make that swap, which is a pain.

Should inspect the water pump impeller for play regardless. The 84 WP may be in better shape, who knows? Now would be the time to find out!

[trike05]

Hi, that's good information never thought of the
Water pump which is only a few months old,
Thanks, Phil