Final Drive Transplant _ Kudos 2 Chop!

[pggg]

Well I've done probably 15-20,000 kilometres with various taller gearing ratios, and no probs with gears 2,3,4 & 5, you gotta keep a more vigilante eye open on the speedo to avoid speeding tickets especially in tailwinds, but if the bike's doing 5500 revs @ 100mph the motor's often straining harder than at stock 6500 revs - and actually often uses MORE petrol at those high speeds

[ExcessiveBiker]

750 final transplant

pggg,
This is the same answer I read from you before. I don't care how you feel about higher gear ratios, however misguided, I am only concerned with the mechanical aspects of this specific transplant. If you are not running this combo, you have no information I need. Xcessives will continue to do this mod no matter what you say. let it go.
ExcessiveBiker

p.s. anyone with some miles on this mod, please respond, thanks

[MAXIMAN]

I have about 500 miles so far.

Chop...the originator of the mod has in XS of 1000 miles with no problems yet.

But as soon as the weather breaks I'll be taking Zilla on a long haul...2000+ miles. At that time I'll report back. Before this year ends I'll have 10 to 15,000 miles on this mod. That will really tell us how solid it is.

John has done it too so maybe he'll chime in.

[xschop]

miles

I've got just over 1100 very hard miles (half-city/half-hiway). I have raced my friend with a 2002 1200cc sportster and he can now stay with me light to light. Before the swap,he could not.But the hiway is another story he can't believe how fast I pull away from him. I sip the gas in 5th at 70mph and when I need to pass, drop to 4th and let the G's kick in. Now he want's to lower his rear pulley ratio....

[Dennyz]

Me too!

I picked up one for my '79 Special. I should have it installed by riding season. The Special needs all the help it can get with respect to fuel range.

I am also looking forward to the lower RPM around town. The stock exhaust has a real nice rumble when the motor is under a bit of a load (slow speed). Nice for cruising.

[John]

I have got about 1000 miles since I swapped over also. My real world milage improved to 34 MPG. That's 4.5-5 MPG better than before. I can get over 110 miles to a tank now. So far I am totally happy with it. Ya know, I wish we had some of those roads that PGGG has, here in Texas. I may have been tempted to keep the original FD. If I ever feel the need to swap it back, it's only about an hour's work.

[ExcessiveBiker]

Final Drive Transplant _ Kudos 2 Chop!

Thanks for the info update. I'm going to change out mine when I find the time--can't wait. It just feels strange, revving that high at normal road speeds, always looking for that next gear.
later,
ExcessiveBiker

[MAXIMAN]

John

That's been my experience so far. About 5-6 mpg across the board. My "real world" mileage is now firmly in the 36 range.

I also kept my original FD. I doubt I'll ever use it again but I want to keep it until I have at least 10,000 miles on this mod.

[pggg]

Re: 750 final transplant

Originally posted by ExcessiveBiker
pggg,
This is the same answer I read from you before. I don't care how you feel about higher gear ratios, however misguided, I am only concerned with the mechanical aspects of this specific transplant. If you are not running this combo, you have no information I need. Xcessives will continue to do this mod no matter what you say. let it go.
ExcessiveBiker

p.s. anyone with some miles on this mod, please respond, thanks

Hey Mr high&mighty, I couldn't give a frick if 'Ecessives' were riggin' their elevens with rockets and flying them to the fricken moon!! If you're 'concerned with mechanical aspects' - do the frickken mod and find out for yourself then!!

[TopCatGr58]

Please let cooler minds prevail!

Hey Excessivebiker and PGGG,

Pissing contests will not be tolerated here! This website and these FORUMS are for FRIENDLY discussions about technical aspects of our bikes. If you want to get into a pissing contest, take it PRIVATE! Everyone is entitled to their opinions.

I think this mod is a great way for folks that want to reduce their running rpms and increase their gas mileage. Our suspensions and frames have difficulty in maintaining stability when reaching top speeds in top gear, and most folks don't ever venture into those speeds. So, the ability for the engine to be able to push to red line in top gear is essentially mute.

Higher final gearing WILL put more stress on the tranny dogs and slots in the lower gears, but whether it will cause the 2nd and 1st gear failure to occur sooner is mostly a matter of choice. Most likely if an 11 is ridden long enough, 1st or 2nd will eventually fail, so folks keeping their bikes for a lifetime will be doing this repair anyways. But having the ability to use less rpm and save fuel is probably a bigger incentive than worrying about "WHEN" their gears will fail.

I personally like to run in the higher revs, I like the speed and response I get when revving at 6+K rpm, and I like to ride the twisties, and so I won't be doing this final drive mod. But as others who live out in the wide open territories have stated, it's more preferable to be able to run in lower rpms at a certain cruising speed than negotiating the tight twisties at 10 mph!

SO...in conclusion, let's keep things POLITE, offer opinions, experiences, etc., but if you disagree, just state it as a matter of fact, DO NOT TELL SOMEONE THEY ARE STUPID, etc, otherwise YOU may find yourself without a VOICE here.

Thankyou!

[pggg]

Pull your head in TC, YOU should know by now I'm not into that pissing contest s**t. WHO did I call stupid? Get your facts right Mr and don't threaten people. And it ain't MY problem if various types get snaky and snotty about trivial garbage!!

Forget the revs@mph thing for now, they're just figures on paper, all in the mind, if your rev counter was unknowingly reading low, you wouldn't even think about changing anything.. better still - bend the speedo needle clockwise a wee bit.

I still can't for the life of me understand why anyone would want to deliberately LOSE PERFORMANCE on their motorbike??? Long roads(don't worry John, there's still plenty of long boring roads down here too) short roads, twisty roads, straight roads, whatever, STOCK 5 speed gearing gives BETTER POWER/PERFORMANCE at ALL speeds in ALL gears!! GET THIS! Raising the gearing SLOWS the bike. Why not just de-tune the motor?? Smaller carbs anyone?? That should improve mpg. What about a rev-limiter set at, say, 5000 revs? Jamming fibreglass up ya mufflers should give the same effect. I've been talking 'Real World' the whole time... If you wanna hamstring your 1100cc machine with a sluggish, dodgy 1st gear ratio, then by all means do it! Good luck! When you're finished, just give the 'new improved' machine a good hard fistfull of power on take-off... then kindly tell me what happens. Must sign off now, gotta find my flak jacket..

[MAXIMAN]

OOPS…we pissed off the PO-LEECE!
Thanks for moderating TC...seriously dude.

I would like to say this about the validity of the modification:

I talked to my engine builder Bobby Pugh at length concerning this issue before I ever did it. Bobby has been racing legends cars for over 12 years and places nationally every year. Last year he scored highest in the world standings.

He is also a Legends dealer and one of only three that can legal work on a sealed engine form the 600 series racing association. In the past 12 years he has built in XS of 1000 FJ1200 motors.

As you all know the XS11 was the predecessor to this fine engine. The strenght of the FJ tranny and gears is almost identical …if you’ve ever rebuilt an FJ transmission. The bulk of the gears is almost identical. And the FJ had a similar problem with premature second gear failure.

Mr. Pugh assured me that this mod would not hurt this tranny anymore than it would normally suffer from the stock final drive ratio. His reasoning was quite sound. The FJ1200 in these cars is making 115 to 120 hp at the rear wheel. Also the car weighs 1200 lbs! and thus creates far more stress than a 500 lb FJ1200. The transmissions of the FJ and XS are essentially equal in design strength. Add to this the fact that these cars are gear anywhere from 3.40 to as tall as 2.7 depending on the type track (road racing versus oval or dirt).

These engines suffer no more transmission failure than the ones that are essentially geared at the same ratio from the factory. As a matter of fact he said once they’ve rebuilt the transmissions and re-spaced/shimmed the gears…and gone to back cut gears they have far fewer failures.

He also is a huge advocate of Bel Ray lubricants. He said in the racing circuit they have tried every oil under the sun. They could tell no real difference in engine wear but regarding the transmission they was a significant difference. The Bel-Ray semi synthetic has given their team for fewer transmission problems than any other oil they’ve used over the past 12 years.

Bel-Ray is not one of their sponsors. He found this out on his own and simply decided to go with it instead of using other oils that would sponsor him.

In short he is convinced that this FD mod will cause no premature failure of the transmission. This comes from a guy that makes his living racing Yamaha air cooled inline fours of 80’s vintage…a guy that has likely rebuilt more Yamaha air cooled I-4’s in his career than any ten of us have collectively.

I’m putting my stock in Pugh. He rebuilt Zilla’s motor for more power and mid-range grunt (as per my spec) and it worked…beautifully I might add. I have no reason to doubt his judgement concerning this modification. And I’ve “Put my money where my mouth is…” to the tune of several thousand dollars.

Over the next several months and coming years we shall all certainly see. The stock transmission on my Maxim failed at 28,000 miles total. So if I get that much or more I’ll be pleased. However considering how long these racing engines are holding up…I feel quite certain I’ll get far and away more mileage than that out of this new tranny.

[MAXIMAN]

PS:

For those of you wondering....my stock transmission failed several hundred miles before I did the FD mod.

[Pat Kelly]

Originally posted by pggg
I still can't for the life of me understand why anyone would want to deliberately LOSE PERFORMANCE on their motorbike??? ..

Harley owners

[TopCatGr58]

All things in Moderation

Originally posted by pggg
Pull your head in TC, YOU should know by now I'm not into that pissing contest s**t. WHO did I call stupid? Get your facts right Mr and don't threaten people. And it ain't MY problem if various types get snaky and snotty about trivial garbage!!

Patrick,
I only mentioned you two guys in the beginning because it appeared tempers were flaring, the rest of my comments were really directed to ALL MEMBERS(especially the newbies) as a reminder!

I don't care how you feel about higher gear ratios, however misguided,

was interpreted by me as a slam on "your" intelligence.

Hey Mr high&mighty, I couldn't give a frick if 'Ecessives' were riggin' their elevens with rockets and flying them to the fricken moon!! If you're 'concerned with mechanical aspects' - do the frickken mod and find out for yourself then!!

And I guess I misinterpreted the TONE of this, so you weren't pissed off then?

And I wasn't threatening anyone, just stating the possible consequences of unacceptable behavior, again to ALL members, not specifically directed just to you! Your contributions to the site have been appreciated, and I, for one would hate to see you leave for any reason.

I don't consider the performance of my XS11 as trivial, just as I'm sure you don't either, otherwise "we" wouldn't be here. I'm still planning on doing "YOUR" chain drive conversion sometime, and I hope to be able to bug you about it IF I run into problems, etc.!?

Max, I gotta earn my keep around here somehow!
T.C.