Up-gearing from Stock 34 (rear) to 32 - NICE !!!

Wharfcreek

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Have been wanting to try the gear change from the Stock 34 tooth rear sprocket to a 32 tooth.....and see if it made any kind of significant difference. After all, it's only 2 teeth, so could it really make any kind of 'notable' change?........... OH YEA!!! REALLY NICE!

Needless to say, when changing rear sprocket, one needs to assess the overall condition of both chain and front sprocket as well. In order to be simply as safe as possible with this, I decided to spend the $20 or so on a new front sprocket as well as purchased a new chain. Also well worth the time and effort! My old 'stock' gears were getting worn to the point where I could start to 'feel' the mesh quality suffering. I'd changed chains previously, and while I think everything was still within acceptable 'wear' standards, I put keeping these items in tip-top shape at the top of my maintenance list. So, with the entire package costing only about $80, and with only about 2 hours of wrench time involved....this is a simple and satisfying project....with GREAT results!!

So, as this is more about the change in the ratio than the process of doing the work, suffice it to say that this job creates a good opportunity to 'clean up' the crud that accumulates under that front cover. Once done, and with new sprockets in place, it was time for a test ride! I've spent some significant time in 'tuning' lately, and I've got my 'stock' engine running pretty well. It easily hits red line, and after a 70 mph run on the open highway earlier today, I decided this 'ratio' change was absolutely necessary. And, having ordered and received this stuff in the past few weeks, I decided tonight was the time to 'git 'er done'!! So....with job complete, it was time to go make my A-B comparison in running down the same stretch of highway at the same 70 mph!

I can honestly say that I did NOT take RPM readings....either earlier this afternoon, or on my test drive this evening. But, I didn't even get out of the neighborhood before I was already 'diggin' on the gear change. I have a 30 mph road that departs my 'hood. That's usually a 3rd to 4th gear run. Well, with the new gears, the 30 mph run was smooth and comfy without shifting beyond 2nd. So, out the hood I turn, and on to my 40 mph highway...normally run by most at about 45 and even 50. Well, the acceleration up to about 50 was delightful.....and strolling down the road at 50 in 5th gear was effortless....and perhaps more importantly, the reduction in vibration was REALLY significant!

So my 45 mph highway dumps in to an interstate highway with a 65 mph speed limit, that again is commonly run at about 70 by most travelers. So, on the highway I went.....again accelerating through all 5 gears and noting with extreme pleasure the fact that the torque of the engine was easily providing an increase in the acceleration rate the bike had previously. AND.....the reduction in vibration was just SO NICE!!

In all fairness, I have to give some credit in the 'smooth' factor to simply having a new chain and sprocket set. If I had the original 'stock' gear ratio but also with a new gear-chain combination, I think it too would have provided somewhat of the same pleasing reduction in vibration. However, as I rode down the highway, I quite clearly noted the reduction in engine RPM.....the 'buzz' at highway speed was gone, and the ride was really MUCH more pleasurable!! Or course, getting run off the road by an SUV put a damper on my mood...... but when gassing up about 30 minutes later a woman at another pump had actually seen this event and asked me how I survived. Funny, but sad! These 'close calls' happen all too often..... DON'T TEXT AND DRIVE!!!

Anyway.....let me conclude by saying that while this gear change may not be for everyone, I found it REALLY nice! I do think that having an engine running at peak performance may be a critical aspect to making this work. And, if your clutch slips with 'stock' gears, it's going to get worse with this!! But, if your engine and clutch are strong....then I think this worth a try. I'll be anxious to see if anyone 'posts' to this thread with their impressions.....good or bad. I hope more 'pro' than 'con', but either way, it's a relatively 'cheap' way to make a notable change in how your bike runs!!

Good luck............and happy and safe motoring!!

Tom D.
 
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Byookanun, I imagine you're right! However, I have a fear about gearing that much higher! I don't know if you're aware of the symptoms that boat engines suffer when they run too large a propeller, but it's not at all uncommon for them to burn valves....particularly the exhaust valve. This 'over-pitch' is essentially the same problem that would evolve in a vehicle when 'over-geared'. While running through the lower ratios, it would not necessarily become an issue. But, with a lot of highway driving, it could. I believe that somewhere there's a sweet spot in gearing. Generally I look at where the factory set the 'stock' ratios, then if the engine has been enhanced, some gearing up may be appropriate. But, 'power' is a HUGE factor in doing this.....and if you've done nothing to increase the HP and torque, then gearing up could potentially do some damage. In my case, my 'stock' engine has been enhanced by removing the 34mm carbs and replacing them with 38s. I also have a 2-into-1 exhaust. Both of those will add some performance that I think support my gear change. But, if you're still running 'stock' and went that high, you may want to consider backing down that ratio just a bit. And, admittedly, I'm taking some cues with that from some of the recommendations I see from others. If you're all around town and solo, then you may be fine. But, going from the 17 to th 18 is nearly the same as my going from the 34 to the 32. But then dropping from the 34 to a 31 along with it.... whew!....that's pretty steep IMHO .... particularly if you're still 'stock'. In any event, I appreciate your comments! Nice to know that someone at least read the post!! Thanks man..... Good luck, and be safe! Tom D.
 
I've ran 17/33 and 17/31 and now 18/31. The 18/31 is perfect in my opinion.
 
Byook, How do you ride? In my over-pitched boat analogy, the difference is that a boat is like being in 5th gear all the time.....and running up hill as well. You're basically 'on the power' in a boat consistently, and fighting the resistance of the water. So, that's why the damage can occur quite quickly in that application. In a motorcycle (or car), you have the benefit of the multi-ratio transmission. If you ride around town and spend very little time in 5th gear fighting winds at 60 or 70 mph, then that gearing may be fine for your kind or riding. It's just a pretty significant 'jump' from stock. Have you ever done plug checks at highway speeds to see how that engine is running with that gear ratio? Fortunately, with CV carbs, you're not 'as likely' to do damage from all this. Concentric or flat-slide carbs and you'll DEFINITELY want to check this further! If you can't get the bike up into higher RPM ranges in 5th gear and if the plugs are really white from leaning out up there.....then you're 'over-geared'. If you can still pull 7K and if you're NOT leaning out ....then you're fine! And, if you never ride the highway....then you probably needn't bother with any of this. Just offering this as consideration. Tom D.
 
This is not a boat. It's a motorcycle. Not the same man...

I ride mostly in town with an occasional hwy run when on a poker run. My bike is more of a bar hopper. So the way I have geared is the best of both worlds.
 
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If I ran an 18/31 I would have to slip the clutch to get started. Probably not the best for the clutch?
Some of the advice given on this site I just take to be truth. I don't have the education to figure it otherwise.
In this case I use Jayels advice of changing the rear to a 33/32 because the 17/34 allows the chain links to run/ride on the same teeth all the time. I am familiar enough with mechanical things to know changing the wear pattern will make the system last longer. I don't lose much of the bottom end torque so taking off isn't hard on the clutch.
The rpm's at speed isn't much lower (150/200?) but chain and sprocket wear may be less. Or last longer maybe?
So far I've been easier on the clutch and maybe have a longer lasting chain and sprockets.
So I next listened to Grizld1.
He says crank bearing design in these motors need a higher rpm to oil well.
So I don't putt. I try to pick a gear that at whatever speed will work the motor between
4000-6000 rpm.
The "buzz" doesn't bother me. I like the acceleration and engine braking reaction in that rpm range for the roads I ride.
If the gearing selection you have chosen is good to you, Ima ok wid tat.
 
Byookanun;

IMHO you're missing out on a lot of fun on your bike. 18/31 is gearing to run the expressways. With that gearing, your bike must be rather lethargic around town. If you ride mostly in town, you should use 17/36, for some real snappy acceleration...............beat everyone from red light to red light:)
 
Byook,

VERY nice build!! I trust that with that much investment, you probably have things the way you want them.....and in most cases, that the way it should be. As to bikes not being boats.......I agree, but to some extent; 'Engines are engines'! And, while we could debate that as well....the point I was making is that driving an 'over-geared' bike on the highway CAN produce the same problem as running an over-pitched boat on the water. The point being that the increased resistance of highway riding along with being in the higher gear creates a VERY similar set of circumstances to the engine. If everything is right, then no problems. But, if not, then bad things can happen. I'm NOT trying to preach to the choir, and given what I see of your bike, you probably know exactly what you're doing and I'll refrain from any more suggestions to you. That said, for any 'rookies' reading this, I think it's important that they understand that when in the lower gears, things work differently than in the higher gears at higher speeds. It's like: 'The clutch doesn't slip in 1st, 2nd, or 3rd gear, but does in 4th, and it really bad in 5th.' Why? Well, the 'gearing' that permits the engine to pull through the lower gears works in reverse in the upper gears. The resistance working against the engine is higher the further up the gear chain you go. So, that not only has an affect on the clutch/trans....but 'tuning' as well. And that's why over-geared bikes can burn up on the highways just like boats can on the water. Anyway...... your bike, your choices! Again, it's beautiful! I envy that kind of workmanship....and I LOVE the color choices. Very classy.....and very 'old school'! Mine is the opposite......not quite a 'rat' bike......more of a 'brat bike'. But, that's partially because that's the way it came to me. Over time I hope to change it's image some......and go for more of a 'classic' look with maybe a glint towards the 'cafe' style. It's getting there! Later, TSD
 
Bro...this is my first rodeo. I've been riding bikes of all types for many years and just about every one was geared under or over from stock. I couldn't be happier with the way my XS is currently geared. Works well for me and the riding I do.
 
I too have many years of this. I recently spent some time with a company called Zippers....who specializes in Harley Davidson Performance Engines. I got quite an education from them.......but again, it's all relative. I did spend quite a bit of time in Dyno tuning....which is also quite revealing. I've done the performance boat thing as well.........which is where my analogy comes from. But, in the end, it's all about what the individual wants. Like the J.G.Wentworth ad: It's your money....... So, what ever works for you! Street-light shotgun gearing like the 17[36, or 'highway gearing' like the 18/31. As long as the engine is 'tuned' for it, things should be OK. If not, well........you see some of 'your money' going into repairs or just diminished value of your now broken motorcycle. WC
 
Speaking of 1st gear, the XS1 and XS1B had a taller 1st, by about 11%. 31/14 gears versus the later (XS2-on) 32/13.

To get close this same 1st gear feel on the later bikes, you'd need to resprocket from the stock 17/34 combo to a 17/31 or 18/32 combo.

My other XS1B is sprocketed 18/34. To get its 1st gear feel on a later bike would require a 17/29 or 18/31 combo.

It would hit 60 mph in first. But, that's too tall. Always wanted to drop that down, so have been collecting later tranny parts for that...
 
I had heard about the trans gear ratio changes in the earlier XS productions. Mine is an '80.....so pretty run-of-the-mill. I heard that when ratio changes are really close, an advantage can be had by using the larger sprocket on the front....just so the extra size can help reduce chain wear by providing some additional 'wrap'. Honestly, this is so subjective......and so 'purpose' driven! I do 'general' riding, with as much time on the highway as I spend around town. I also do 2-up riding, so I didn't really have a problem with the stock gearing. But, I DID feel the vibrations......and I actually had a bit of fuel economy as another goal. So, dropping from the 34 to the 32 made just enough of a change that I did experience some smoother acceleration and a nice ride at 65 to 70 MPH. I doubt I'd go any higher.....to a 31 or below. And, with yet another XS in the trailer, I may try going the other way on that one....and drop a 36 in it with the 17 and see how it performs. But again, I think engine condition, tuning, clutch condition, all that needs to be considered in any of these changes. FWIW. TSD
 
17/36??? you are out of your mind...

You're not the first person to ask me that question.:)

Obviously you have never tried using a 17/36 on an XS650. These bikes will accelerate like a scalded cat with that gearing.

Your workmanship and paint on the bike is first class. I see you have taken off several stock parts to cut down the weight of the bike. Wasn't that done to improve the performance of the bike? Maybe not?

Perhaps your bike was created to be just a "show" bike. If that was your intension, then you have done really well.

So its an in-town, low speed bike, with expressway gearing. :shrug:
 
You're not the first person to ask me that question.:)

Obviously you have never tried using a 17/36 on an XS650. These bikes will accelerate like a scalded cat with that gearing.

Your workmanship and paint on the bike is first class. I see you have taken off several stock parts to cut down the weight of the bike. Wasn't that done to improve the performance of the bike? Maybe not?

Perhaps your bike was created to be just a "show" bike. If that was your intension, then you have done really well.

So its an in-town, low speed bike, with expressway gearing. :shrug:



The stock parts that were removed was done so because they would have looked like crap on the bike.

If you would have read my previous posts you would see that I said.... "I ride mostly in town with an occasional hwy run when on a poker run." But with the way the gearing is setup now I would not be scared to ride it anywhere long distance.

Stock gearing on these bikes sucks in 5th gear. Way too low. Absolutely horrible on the hwy with stock gearing and in town for that matter too. I played with the gearing with multiple combinations until I came to where I am now which is amazing. My goal was to make the bike better in 5th gear without having to tare apart the engine/tranny and replace the 5th gear. And the bike is still fine in 1st, 2nd, 3rd and 4th...
 
I've ran 17/33 and 17/31 and now 18/31. The 18/31 is perfect in my opinion.

Hi Byookanum,
I don't like 18T front sprockets because using one lets the chain gnaw little notches in the shifter shaft and that bothers me.
And hey, a 17/30 will get you nearly the same ratio (1.765/1 vs 1.722/1) as an 18/31
and if you can find a 29T rear, 17/29 will get you 1.706/1.
Whatever, so long as you can be gentle on the clutch while pulling away and realize that what you now have is a 4-speed tranny with overdrive, you'll be fine.
FWIW, my Heritage came stock with 17/36 which, along with the 17/38 I'm currently using, is perfect for sidecar use but NFG on the highway.
 
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