Hello all. building an adventure sportster 2005 1200r and having Brock Smith at side effects build me a custom adventure off road car. Will be going to a chain drive conversion and was wondering on the sprocket size. want to be able to putt around on gravel roads. with wife in the hack. top speed of 110 kph or 70 mph would be ok for me on the highway. was thinking 23 on the front and 55 on the rear. Would that work.
Not too many Sportster guys here. Maybe Swampfox knows, or knows where to point you. If your conversion is anything like most chain drive bikes, it's fairly easy and cheap to try different combos until you find the one you like.
883's run lower primary gearing than the 1200's. That then leaves more options for your final gearing. First and second gear ratios for off road/gravel should be your primary focus ... no pun intended. The tractor I ran ( FLHT ) was converted to chain to get away from the PITA of having to drop the whole primary/clutch/swingarm in the event of a belt failure. The sporty doesn't suffer from this problem as a belt change is far simpler at the side of the road.
diver, I have no personal experience with the chain drive conversion, but the general consensus for 1200 Sportster tugs is to gear down to the 883 gearing - which employ a smaller OEM front pulley. So figuring the stock 883 gearing and crossing that over to the chain conversion is a good starting point. But from my Sportster experience and considering your application, I would suggest going a little lower: -- my 2002 XL883R is geared down another 4% with a 1 tooth smaller aftermarket front pulley, which still permits 70mph, although I rarely travel more than 62mph with my little rigid mount tug. If I recall correctly, I run ~3200rpm's at 62mph. Please keep us informed.
I have not done the chain drive conversion however we have done a Sportster dual sport rig based around our Enduro sidecar, as the person we built it for was never going to go off road and just wanted the look of going off road we did not worry about it. I wanted to let you know that the Big Foot sidecar club has one or two events in your area every year. Jay G DMC sidecars www.dmcsidecars.com 866-638-1793
I do not know about the newer Sportsters but according to may factory manual for 1991,92 models the primary drive ratio was the same for all Sportsters. 35:56 for a 1.60:1 ratio. There were 2 different transmission pulleys 27 on the 883 and 29 on the 1200. All belt drive bikes used the same 61 tooth rear wheel pulley. The chain drive as used on the 883's used a 21 tooth front sprocket and a 48 tooth rear sprocket. As for changing the belt on the side of road, not a bad job with a few hand tools and small jack to hold the weight off the rear wheel. Done it twice so far!
Not all sportster's are born equal. http://883sportster.webs.com/products.htm On a sportster , yes. A big twin such as my FLHT ... not so much. ALL the primary comes off , inner , outer , clutch , chain , compensator sprocket ... plus you need to drop the swingarm to get the belt around the pivot. And you had better be carrying the special tools Big twins also ran different primary ratios depending on if they were carbed or injected. Carb' like mine came with taller gearing in the primary from the factory. All international models compared to US domestic models came with taller final gearing. .
Hey thanks jay. Im the guy here in Kamloops that has your enduro hack on my KLR 650 luv the thing to pieces. will be talking soon for triple trees for the Harley. talked to pete at zipper performance and has set me up with a 530 oring chain. 24 counter sprocket and a 60 rear, will start there and change as needed
Stock 883 final gearing is around 2.28/1, the 23/55 would give you 2.39/1 and might be just about right for what you're wanting to do. I have a 21/48(2.28/1) on my Sporty chop hack and it's a little faster than what I want on my ADV Sporty hack, when I finish the ADV Sporty hack I will probably go with a 20/48 for 2.4/1 ratio or a 20/49 for a 2.45/1 depending on how it feels. I know the newer rubber mount bikes need larger sprockets to clear parts of the frame and mounts compared to the older solid mounts motored bikes like I have. Make sure you have clearance, the 55 in the rear should be fine.
From the referenced site: The 883 has a very flat torque curve. Usable torque starts about 2200 rpm! You can take full advantage of this curve (which is Harley engine design) by 5th gear cruising in the 2800-3100 rpm range, this is where the fuel economy range lies! So, pick the speed you want to cruise at (see chart in "Documents" section) and pick the pulley that matches your desired cruise speed. That's exactly what I have discovered, 2800-3100 rpm's push me along at 55-60ish MPH and result in the best overall fuel economy on the '02 XL883R rig. Any faster and fuel economy suffers dramatically.
Hey drbike. Bike is at side effects as I write this, talked to Brock the other day and his Dad came out of retirement to do this build, pipe is being bent and welders are buzzing, am dying to go see how it is coming along but don,t want to be a PIA. will gets some pictures up soon, ETA is the end of this month
This dude is UBER talented ! Bike is so bitchin pictures don't do it justice! http://www.advrider.com/forums/showthread.php?t=667638
I can attest to that, have done it twice on my 1992 Sportster:eek1 As long as you have a good set of tools in the sidecar and a jack takes maybe an hour could do faster but hot parts are hard on fingers About the worst part of the job is getting the clevis pin out of the brake linkage. I'm tempted to replace the stock one with the knurling with a smooth one that just slips out.
Convert it to chain and be done with it. I punched a belt in Montana years ago, It wasn't enough to have to change so I ran it home, since then I have converted all of ours and several for our friends. It's a pretty easy job, gives you piece of mind on the road and lots of gearing options. Here's a good how to on it, I use 530 chain instead of the 520 but thats personal thing. http://www.chopcult.com/forum/showthread.php?t=15790
Well after putting 100,000 on a chain drive Sportster I like the cleaner rear wheel of the belt drive one. And I don't mind riding all day in the rain on a trip like I did when running a chain.