Final Drive Gear ratios

[John]

Hey Y'all. Me again. A question...Are ALL final drives geared alike or are there any differences between standard and special models? What about the middle drives? How about the 750-850 triples? I'm looking to lower my engine rpm's at freeway speed. At 60 mph I'm turning about 4300rpm, and I'd like to lower the engine speed, and get better fuel milage. I only get 33 mpg with a windshield on, and 36mpg without it. I know the acceleration will suffer maginally, but with all the grunt the motor churns out, don't think that will be a problem. Besides, I don't ride it that hard anyway. Gotta make it last...Twilite special has over 89k miles and I want to see it hit 100k.

[TopCatGr58]

Hey there John,

Well, according to my owner's manual for the 81 H/SH series, the only differences in the drive trains are the sizes of the rear tires, Special =16", Standard=17", so using a standard wheel would get you some reduced RPM, but from what I've read/heard, it can be a bit of a pain to try to swap wheels.

And, with almost 90K miles, and still getting over 33mpg, that's really pretty "Standard"-pardon the pun! I didn't get any better than that with my 81SH when it was new, and now with a big bore kit, it's still in that same range.

I've heard about others getting 40+mpg, but there are many other factors that could be contributing to yours. Air filter, good carb synch, tire type-sticky or hard compound, brake drag, clutch wear, Your weight, valve and ring condition, exhaust pipes, carb jet size......etc.!

Good Luck! T.C.

[dragxs11]

Howdy John,
I've done the wheel swap on my special. I ran into some issues with the brake disc and caliper due to the disc position being different between the two wheels. Nothing major, I had to make a spacer, and cut one down. I've asked around about the gearing too. Everyone, so far, has told me "You can cruise at 90 all day long, what do you want?" As for now, the low gearing is something we just have to tolerate. Wheel and tire sizes are the only things you can do about it.
Matt

[Snow]

Originally posted by dragxs11
[B Wheel and tire sizes are the only things you can do about it.
Matt [/B]

Almost - a person can also convert to chain drive and play with sprocket size...but why would you give up our shaft drives for that?

[pgg]

I sent merriam cycles an email querying them on their absurd claim of 160mph on standard gearing. Received a load of garbage about DOUBLING port sizes, then was told to send $40 and buy their book. Asked them if they had ever seen or done gear ratio alterations, but never got a response back.

[fusionking]

"DOUBLE"

Does anyone here know what that book is about? Maybe we ought to be reading it. The guy and all his employees lives are and have been for many years centered around the XS-XJ 1100 Yamahas. Maybe if we were to go to him as a group we could persuade him into a group rate on certain items, sort of a win-win situation. I really doubt that if he or his friends read this forum that e-mails such as that will help out. (IMHO) I was actually thinking that having a sort of a day trip/shop tour during the off season could be really cool. Course he might not like it. We only represent 1200+ members and their families and other xsfriends that ride but don't compute. I know the mid-west is week in this group for some reason but is one idea. BTW double does sound awfull big but if it is true I would love to check them out "firsthand". Sounds like a lot of welding and grinding to me.

[pgg]

Sounds like a load of bollocks to me. Doubling the port size would be a useless exersize without MAJOR carburetor and top end alterations to utilise the extra flow. Some of these outfits wouldn't know the truth if it rode up and bit them on the you know what. Next time someone has their carbs off, take a look at the inlet ports - I'd love to know how those ports can be doubled in size. I'd also love to see a photo of the mother of all port jobs - but I ain't holding my breath.

[dragxs11]

Yeah, I'd have to say that Bob is a wierd dude. I have some respect for him being that he puts so much effort into these old bikes, but he's definitly on his own page. I thought that book of his was all about his life story and so on. Not really interested in that. I''ve done some business with him. It's been okay. Considering the situation I see why his prices are a little high, but the service I've gotten has been worth it. The local guys here don't have a clue about my xs11, so I guess Bob has propably saved me some grief. When I've called them, they know exactly what part I'm talking about and I've gotten exactly what I've needed, when people here are still trying to find a part #. Bottom line is, Merriam Cycle is great for some things, but maybe not all.
Matt

[beechfront]

"This book's 20 chapters tell the story of numerous and exciting cross-country rides by the author, as well as what it takes to build, modify, ride and maintain the XS Eleven. The owner of seven "tricked-out operational XS Elevens, "Jones speaks directly to motorcycle owners and collectors in colorful, technical, page-turning language. If you're not already a riding enthusiast, this book will inspire you - and if you are, it will validate your passion!"

[Renegade]

Originally posted by pgg
I sent merriam cycles an email querying them on their absurd claim of 160mph on standard gearing. Received a load of garbage about DOUBLING port sizes, then was told to send $40 and buy their book. Asked them if they had ever seen or done gear ratio alterations, but never got a response back.

It isn't all that absurd (their spped claim). I ran a spreadsheet that calculates the speed in each gear at 500rpm intervals, and 11,000rpm is about 155mph. Performing the required engine mods to allow an increase in the maximum rpm is all that one has to do.

Renegade

[pgg]

Absurd

Required engine mods for top gear pulling power at 10000 plus revs - 1. Lightened crankshaft. 2. Modified conrods. 3. Complete rebuild and alteration of all valve train components. 4. Custom built pistons. 5. Extreme high lift high duration camshafts. 6. Stage 3 port job (race specs). 7. Bored out standard carbs or a set of flatslides. Numerous smaller modifications. Result- one unpracticle pig of a streetbike - only any use on a dragstrip. Spreadsheets and reality are a million miles apart.

[Robert Haller]

Re: "DOUBLE"

Originally posted by fusionking
Does anyone here know what that book is about? Maybe we ought to be reading it. The guy and all his employees lives are and have been for many years centered around the XS-XJ 1100 Yamahas. Maybe if we were to go to him as a group we could persuade him into a group rate on certain items, sort of a win-win situation.

I'd be interested to see the book, but $40 is a little steep for me. It is nice to see a shop devoted to XS-XJ 1100s.

[Renegade]

Re: Absurd

Originally posted by pgg
Required engine mods for top gear pulling power at 10000 plus revs - 1. Lightened crankshaft. 2. Modified conrods. 3. Complete rebuild and alteration of all valve train components. 4. Custom built pistons. 5. Extreme high lift high duration camshafts. 6. Stage 3 port job (race specs). 7. Bored out standard carbs or a set of flatslides. Numerous smaller modifications. Result- one unpracticle pig of a streetbike - only any use on a dragstrip. Spreadsheets and reality are a million miles apart.

I never said that it would be practical, only that it was possible.

[pgg]

Hey Renegade - for merriam cycles to claim turbo-like performance from a LIGHTLY tweaked motor is plain bull**** in my not so humble opinion. Jeez - I've got to give up sucking lemons! Time for a ride to chill out!

[Renegade]

Originally posted by pgg
Hey Renegade - for merriam cycles to claim turbo-like performance from a LIGHTLY tweaked motor is plain bull**** in my not so humble opinion. Jeez - I've got to give up sucking lemons! Time for a ride to chill out!

I can understand where you are coming from. What is being overlooked here is that everyone has a different opinion of what a lightly tweaked street engine really is. For instance, a few years ago I built what I considered to be a mild street Sportster. Stroked and bored, cams, ported heads...what I considered to be mild. The shop that ordered some of the parts said that their drag bike wasn't a wild as my street engine.

It is all in the eye of the beholder.