Power mad: GS850G to 1100G engine swap

[talkinboutshaft]

Hello Everyone,
I am a returning GS owner, had my '81 850 for about 10 years now, and I've been contemplating an engine swap to an '82 1100 (8 valve to 8 valve). There is really nothing wrong with the 850, other than the base gasket leaks, and I want more horsepower, a crime in itself. I have surfed the archives, and know I need to exchange the driveshaft and ign box as well. The posts I read were 2 years old. Is there more I should know? Does anyone care to chime in on the misdeed I am contemplating? Thanks in advance for the advice.
-Jeb

 

[Steve]

I don't have both years in front of me, but I think there might have been some changes in the mounts, too.

Oh, almost forgot, ...

.

 

[SqDancerLynn1]

81GS850 I think you should still have the mechanical ign advance, so just swap to the 1100g motor. You may already have the larger driveshaft bolt pattern. The rear motor mount may need to be modified, get the mounts from the 1100 if you can. You should swap the carbs too. 850 uses 32mm carbs the 1100g should have 34mm carbs

 

[Nessism]

Sound like a fun project Jeb. What part of So Calif. is home?

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. talkinboutshaft,

Yes, please keep us informed. Let me say "Welcome back!" and point you toward some information that I've collected. You might find some of it handy.

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

 

[jimfj]

please take notes and pictures if you do this. There are plenty of others that will want to see your work and gain expirience from this.

I have had the 82 850 and I have the 82 1100G (8v). I believe the exhaust is different as well.

You will like the extra horses. You might not enjoy the extra vibration. The 1100cc motor vibrates a little more at 3-3500 rpm but the extra horsepower/torque makes up for it in my opinion.

 

[doctorgonzo]

please take notes and pictures if you do this. There are plenty of others that will want to see your work and gain expirience from this.

I have had the 82 850 and I have the 82 1100G (8v). I believe the exhaust is different as well.

You will like the extra horses. You might not enjoy the extra vibration. The 1100cc motor vibrates a little more at 3-3500 rpm but the extra horsepower/torque makes up for it in my opinion.

I toook a 1000G to an 1100G by boring the 1000G block and installing stock 74mm 1100G pistons along with an 1100G head, and even that was a big difference in power.

 

[elevatorman71]

i myself have an 82 gs 1100 that used to be an 850 and i had absolutely no problems swapping out the engines. i pulled out the 850 with no problems and when putting in the 1100 i had to remove the valve cover gasket to make room for the clearance issues and after i got it in replaced the cover. put it in and everything swapped out perfectly plug n play!

 

[talkinboutshaft]

thanks!

thanks!

Thanks, guys! Very helpful and insightful ideas. I will take pictures of the deed as it is done. Btw- I hail from Placentia, CA (in the OC!), so if you're up for a ride, let me know!
Jeb