850 to 1100 ???

[Hacked850]

I have a 82 850G that has a sidecar attached to it.We are on a 10 day trip around BC and although I love the 850 ( I have had 4 of them ) when loaded down with 2 people and gear we are around 1100 lbs and any head wind or hill will slow us down to 40mph or less.I have heard that a 1100 engine is a bolt in to my frame but will I still be able to use the 850 shaft and wheel??,how about carbs are they different on the 1100??.Also will my stock exhaust fit and work with the 1100 engine??.Is there any benefit ( power wise ) on going to a 4 into 1 system??.
ANY help with this would be great..

PS..What is the HP/torque difference between the 2 engines??.

Alan..

[7981GS]

A 1000G engine will bolt right up.
Not certain about the 1100G engine though.

With the 70 mm versus 69 mm bore difference from the 850 to the 1000, not a bunch of HP increase.
But, with the much increased stroke, lots of more torque!

Eric

[tkent02]

Going to the 1100 gives a huge torque increase, and if you switch the gear ratios much lower RPM at a given speed. I get 45 or so mpg with my 1100, no sidecar though. A 4-1 will only give additional power at the highest RPM ranges, which an 1100 does not need any help with in cruising usage, even at high elevations carrying heavy loads at high speeds. Likely it will lose low end grunt and fuel mileage with the 4-1. With the stock exhaust and intake it gets a huge power increase at about 6,000 - 7,000, just like the 850 only bigger.

I think the exhaust is the same on the 850 and 1100, not sure. The bike's frames are the same, so everything fits. I think you will need the driveshafts, final drive and rear end from the 1100. The wheels are the same.

A lot of folks have done this swap.

[Hacked850]

With the sidecar I get around 30mpg with NO passenger or load.With it fully loaded I get around 27mpg until I start pulling LONG hills in 3-4 gear then it go's down to around 20mpg.I rarely run high rpms so torque is what I need.This will be a winter project so I have time to find a good engine and maybe freshen it up on the bench,how about carbs??.

[tkent02]

I think they both use BS32, so only the jetting would need to be changed. Not 100% sure about the 850.

[Dogma]

I have had opportunity to compare the 1000G and 850 exhaust. The flow area in the header pipes is less in the 850, roughly in proportion to the difference in displacement. The exhaust from one will hang on the other, but there are differences in the bolt hole spacing at the header clamps.

That said, I'm not sure of differences between displacements in the '82 and up models' exhaust. I would expect the 1100 to have larger tubing. I can tell you that a 1000G exhaust has a different hanger at the back (pre-'82) and will require some fabrication to work with your '82 frame.

The 1100 uses 34mm carbs vs 32 for the 850. I'm not sure if the airbox is different.

If I was you, I would look for an 1100G or GK parts bike, either untitled or smashed in the front, or both. Something with intact intake and exhaust, just to be sure I wouldn't have to fiddle with jetting to deal with a mismatch. If you can find just a motor with carbs, you could add pods and a 4-1 pipe with a Dynojet stage 3 jet kit to get a start on the re-jetting.

[Dogma]

I think they both use BS32, so only the jetting would need to be changed. Not 100% sure about the 850.

The 850s use BS32. The 1000G and 1100G use BS34. 1150E uses BS36, but that would be a rather more ambitious project.

[tkent02]

The 850s use BS32. The 1000G and 1100G use BS34. 1150E uses BS36, but that would be a rather more ambitious project.

Yes, all true, my mistake.

Getting a crunched parts bike would be the way to go.

[greg78gs750]

good looking rig by the way. interesting windshield?

I have a 82 850G that has a sidecar attached to it.We are on a 10 day trip around BC and although I love the 850 ( I have had 4 of them ) when loaded down with 2 people and gear we are around 1100 lbs and any head wind or hill will slow us down to 40mph or less.I have heard that a 1100 engine is a bolt in to my frame but will I still be able to use the 850 shaft and wheel??,how about carbs are they different on the 1100??.Also will my stock exhaust fit and work with the 1100 engine??.Is there any benefit ( power wise ) on going to a 4 into 1 system??.
ANY help with this would be great..

PS..What is the HP/torque difference between the 2 engines??.

Alan..

[mvalenti]

good looking rig by the way. interesting windshield?

Deer Deflector.....