View Full Version : Dropping an EFI motor into a 1990 frame

07-18-2014, 4:25 PM
Got a line on a cheap EFI motor I would like to drop into my chop to make all my headaches go away, but aside from the huge change in the rear motor mount, how deep would I need to get into this frame to make it fit?

07-18-2014, 5:17 PM
Well shucks, if we knew what specific year and model motorcycle and what specific year and model engine were under discussion it would be easier to give a useful answer.

If the headaches were specified in your question they might also be usefully addressed, but even with the amount of leisure time I have as a retiree I ain't going to search out the background info.

It may be that EFI won't solve your difficulties and depending on how the swap is executed may induce new and entertaining problems.

Howsabout making the question post SELF-CONTAINED? Help the hive mind help you.

07-18-2014, 5:37 PM
Well my issues are with the motor I have, it's given me a nice run but the cases have been blown, repaired, and now I feel like they are too fatigued to warrant putting more time and money into the engine. Time to get another I think, sucks because I had this one fully rebuilt two years ago and was grossly overcharged to do so. Live and learn I guess. I just want to drop the most reliable engine I can in this roller without breaking the bank to do so.

07-18-2014, 5:53 PM
still no help huh?

07-18-2014, 6:47 PM
Route of least resistance is a low mileage matching takeout off a salvage/craigslist/Ebay.

However most complete low-mileage engines will be in the 'teens so the other way is buy a donor bike, swipe the engine out of it, then sell the titled roller after raping and pillaging both bikes so your rider has all the goodies.
Test ride, buy, swap engines in an afternoon, sell off what you don't need (titled rollers always attract lusting buyers) and press on.

Non-rubber mount Sporties have moved into the land of Jap bikes where it's cheap enough to consider engines disposable compared to the cost of a rebuild, and that's damn handy.

Even Evo big twins are sometimes cheap enough to buy for slaying.

Never marry what you can dismember and sell off.

07-18-2014, 9:01 PM
Right on. I have had to put a lot of love ($$$) into this one over the years, and I really beat on it so maybe it is just time to let the thing die. I parked it in front of Harley today and walked straight to the counter "Have any CV jets?" "Nope" "Ok thanks" walked out and found this.

I knew it was from my tranny, I had just changed my engine oil, it is still clear. Rode it home and found this


Countershaft needle bearing is missing. As you can see the case has been repaired right there, we replaced the bearing not too long ago with green locktite and looks like it gave up. Im lucky I made it home.

I suppose I can sell it for parts and sell the frame with the title. It sucks because this is my daily driver, but I have a 49 Pan motor I'm dying to build around, but I have to keep putting money into this thing so I can get to work. Debating selling the whole deal and trying to get the Pan going (its been freshly rebuilt) but every time I say that to someone they always say to keep the Evo, its more reliable. I guess now its decision time.

07-18-2014, 9:37 PM

Sportster, Big Twin, Buell, Honda, Briggs and Stratton ?

"EFI motor" doesn't tell us anything.

What frame ?

1990 doesn't tell us anything.


07-18-2014, 9:46 PM
Sorry, in my head it is all obvious. I'm talking about dropping a rubbermount sporty into my Paughco frame that currently holds a 1990 sportster. From what I can extrapolate, Sportster engines from 86-03 all mount the same, after which they went to rubbermount, and changed pretty much everything. Has anyone made this change before? My frame is stretched perfect or I would just start over with a new frame.

07-18-2014, 10:18 PM
Compare pics of the frames for the fabbing you'd need to do. Stretching isn't shit compared to that.

My frame is stretched perfect or I would just start over with a new frame.

So get another frame and copy your stretch or order it that way. You'll be done a lot quicker!

07-19-2014, 12:29 PM
so here's my two cents. unless you want to ride a stock bike, there is nothing about the sportsters made after '03 desirable in a chopper. There is no way to 'adapt' those solid mounts to a rubbermount motor. You would have to fab all new motor mounts. And then there is the efi shit show. I have an '09 (converted to carb- and loving it!), if I could go back and buy an '03/older I would in a heartbeat! The Moco's 'improvements' are a detriment if you want a chopper. Like I said, these are my opinions based on owning and trying to chop my '09 since brand new. Hope this helps.