Converting a G to an E

[Barnfresh]

I have found a '78E engine to put into my '80G and have some questions. The link below shows the pickup coils and advance for both engines. The '78 is corroded bad and I would like to put the '80 ignition on the '78 engine and use the '80 ignition box. The '80 looks like the bolts need to be drilled out to get the pickup assembly off? Is this some kind of emissions foolishness? How about the carbs - my '80 carbs should work just fine on the '78 engine, right? <fingers crossed>.

As always - Thanks for help.

http://www.facebook.com/media/set/?s...1&l=c1e3d98133

[petejw]

The '80 looks like the bolts need to be drilled out to get the pickup assembly off? Is this some kind of emissions foolishness? How about the carbs - my '80 carbs should work just fine on the '78 engine, right?

hi Barnfresh,
yep thats pretty much it, just drill those bolts
out and replace, the carbs will also work without any problems'.

[crazy steve]

Just which ignition parts are you planning on swapping? The E model shares the TCI (box) with the '78-80 bikes, so that's no problem, but there are differences in both the mechanical and vacuum advance units. The E had a bit more aggressive curve, and along with it's hotter cams and more initial timing, that's what made those motors the strongest of the line. You can swap the pickup coils, but that's the only parts that are the same...

I'll also note that the early carbs are a bit better in terms of performance, with the later carbs being set up more for emissions. Either will work though....

[petejw]

the vac and mech adv might not be exactly the same
between models but u can certainly swap them out as
a unit, there might be a very slight difference in performance,
but if i was stuck for parts i wouldnt worry about swapping
them over.

[Barnfresh]

I did not consider that the vacuum and mechanical advance is matched to the cams... Thanks Steve..
I may try just changing the coils & vac servo and cleaning up the rest as best I can... lots of corrosion. It looks like the engine was on it's side in water The carbs on the left are solid white power inside, while the right are just varnish.
Thanks for advice guys!

[petejw]

I did not consider that the vacuum and mechanical advance is matched to the cams... Thanks Steve..
!

there not, the cams are the same thru out the models
except for the 81, they had different cams.

[petejw]

i couldnt edit in time,
disregard my last post, the 80g did have
different cams to the 78/79 models,
the ignition parts could still be interchangable tho.

[3Phase]

The 1980 and 1981 XS1100 and the 1982 XJ1100 all use the same valves and camshafts.

Bolting a 1980 mechanical advance onto a 1978/1979 engine will work but it won't work correctly if you see what I mean. "Any port in a storm!" and all of that until you can find some good 1978 parts.

All of the XS1100 or XJ1100 carburetors and ignition systems will physically fit onto any other year/model engine but you need to know what you're doing or you'll get frustrated and eventually sell the bike to some other poor^W lucky star.

[crazy steve]

You have to be careful when swapping the ignition parts on the motors around; every year is a bit different. As a general rule (unless you want to spend some time 'custom' tuning), you need to keep 'matching' parts together. Here's some info on the mechanical/vacuum advance units... http://www.xs11.com/forum/showthread.php?t=34277

Note that each mechanical advance has a 'paired' vacuum advance unit; they really should be kept together. The '78-79 motors don't seem to run very 'happily' with the '80 ignition curve from some reports of owners who tried this, and also note that the '78 bikes ran the 1/4 mile nearly .4 second quicker compared to the '79 model, with the only big difference being being the ignition curves. You can swap the timing plate/pickup coils between the 78 through '80 bikes, but the advance units should be kept together...

[Barnfresh]

Thank you for that link Steve... That explains things very well - and it has pictures! I can see now that I already have enough gremlins from Mr. Murphy without introducing my own... I will keep it all '78 ignition even if it requires ebay... and I'll be able to sleep .4 seconds longer in the morning before riding to work!

[yamahansolo]

Early F's are the same timing as a 78e. Sheesh people ... both my 79s were made in 78 and they both have rge ignition from the e.