Soul Searcher

Looking for other Riders who have installed a tachometer on their Rebel. If possible use this format.

Year : 1999
Sprocket Set : 14/33
Make : Tiny Tach
Speed : Rpm's - In 5th Gear
50 : 5,000
55 : 5,500
60 : 6,000
65 : 6,500
70 : 7,000
75 : 7,500

Would like to collect enough data and combine it in a chart for different Sprocket sets combination.

Any and all Help would be most appreciated.

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Ghost_Rider

Soul Searcher,

Add mine to your chart.

Year : 2000
Sprocket Set : 14/30
Make : Tiny Tach
Speed : Rpm's - In 5th Gear
50 : 4,600
55 : 5,100
60 : 5,600
65 : 6,100
70 : 6,600
75 : 7,100

Hopes this Helps.

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Soul Searcher

A big Thank You, to cagie. How to solve the image that is in my mind, so somebody else can see the image.

My first step in the process. Being that the word processor on the Forum, only recognizes one blank space. Each character that is displayed, are in different widths.

So no old MS-DOS drawing characters. MS-DOS is a text based language and display. Each of the 255 characters, are displayed in the same size character box.

What you are viewing now is what is called a GUI (Graphical Users Interface) Display. Each character is scaled to a different display width.

How do I over come, the text to GUI exchange. Rather simple, if you apply a little logic. An example to show the difference.

The first chart was typed in Notepad, with font changed to Terminal, and size changed to 12. It was copied and pasted into the word process on this Forum.

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The Quest goes on. I've collected enough data to compile a simple chart.

I think most Rebel Riders will appreciate this information.

The following information was collected from my own personal 1999 Rebel. For reference ONLY.

Sprocket's 14/33 14/30 15/30 14/27

Trans Gear 5th 5th 5th 4th 5th

Speed MPH Engine RPM's

50 5000 4600 4200 4800 4200

55 5500 5100 4700 5300 4500

60 6000 5600 5200 5800 4900

65 6500 6100 5700 6300 5300

70 7000 6600 6200 6800 5700

75 7500 7100 6700 7200 6300

Over 10,000 Test miles on 14/27 Sprocket Set.
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The Next Chart will show the same chart, but in a different format.

Same document, printed on an HP 300 series printer, using same format as the above Chart. Then scan the document. Loaded and resized in a image editor application. Hosted at photobucket.com.

. . . . . . . . . . Now for your viewing pleasure. . . . . . . . . .

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Now, I have found a process, that I can use, to show others, what I'm trying to describe. An interchange from an old MS-DOS user, to the new GUI.

Now I can use paper, ruler, square, marking instrument and draw, the old fashion way. With out having to learn, a complex new application.

Who says an old DOS user, can't learn from new technology. Which Chart is the easiest to read and understand ?

My Thanks Again to cagie.

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Guba

That's a nice reference chart soul searcher. I for one, appreciate your efforts to inform us of the various sprocket combinations and engine RPMs. But so far you've left out one of the more popular 15/33 set ups. Any particular reason why?

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Some days beer tastes good...other days beer tastes better!

'07 Rebel 250 26,000 miles

rebelCAFE

thats what i was going to say. i have the 15/33 also. hey SS, where did you get a 27t rear sprocket from? what was the part number? i wouldnt mind trying the 14/27 myself.

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have a REBEL of a day!

Leaf

Running the math, it looks to me like it should come out like this in 5th gear:

mph - 14/33 - 14/31 - 15/33 - 14/30 - 15/30 - 14/27
50 - 5425 5096 5064 4932 4603 4439
55 - 5968 5606 5570 5425 5064 4883
60 - 6510 6116 6076 5918 5524 5327
65 - 7053 6625 6583 6412 5984 5771
70 - 7595 7135 7089 6905 6445 6214
75 - 8138 7645 7595 7398 6905 6658

Note the discrepancy against the collected data. I think this may be because the Rebel's speedo runs about 5mph too slow at 60mph.

14/33 seems passable to me on these windy mountainous West Virginia roads, though at 55mph wound out climbing a hill in 4th, I fear of overtaxing my engine (that'd be 7079 rpm, and the rebel probably redlines at what, 7500 or so?).

With a 14/31 ratio, I'd be pulling 6650 rpm in 4th at 55 mph, which seems a lot healthier to me, and is probably better centered in the rebel's powerband? What -is- the rebel's peak power RPM, anyway?

In addition, 14/31 would preserve the even/odd combo thus wearing the chain and sprockets more evenly, provide higher 4th gear top speed while (hopefully) still not lugging the engine on a 9% grade, and better gas mileage while cruising in 5th. I think if I ever get around to trying some regearing, 14/31 is what I'll try, though I've never heard of such a thing, which leads me to believe that there is not a 31 tooth sprocket available for this thing.

Then again, maybe it doesn't really hurt it to run it like a blender with the current gearing, lol. It loses mpg for sure though.

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Leaf

Hmm, on second glance.... Gearing Commander lists the rebel's peak power RPM at 8250. Neat site that, btw: http://www.gearingcommander.com/

So I punched in some different gearings and got the following graphs, if y'all are interested:

14/33:


14/31:


15/33:


14/30:


15/30:


14/27:


In summary, it looks like 14/33 puts 55 mph hill climbing right in the best place. I guess I'll leave my gearing alone and not be afraid to rev it a little higher, lol. 14/31 would probably put it too early in the powerband...

However, if I lived somewhere flat, I think I'd probably drop to 14/31 or 15/33 to get a few more mpg.

I think I am firmly in the Jerry camp of Stock Gearing now, though. ;P

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Soul Searcher

When I first started the gearing change. I was not Internet proficient. The local shops was of little to no Help. At that time, only a 30t sprocket was avaiable from the local shops. I was looking for a drastic change in rpm drop. At a later time, when I learned a 15t was avaiable. I used it to change the final drive ratio to a lower number (15/30). The 15/33 combination, was not enough of a ratio change, that I was looking for. But in the near future, I'm going to change to a 15/33 ratio, so I can finish the chart.

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Soul Searcher

I found what is now called, the sprocket gold mine. Rebel Gears. A family orentied business. Call and had a very nice conversation about sprockets. They told me, that they could produce any rear sprocket I wanted for the Rebel. I first ask for a 28t. No problem was the answer. Then I ask for a 27t. I don't know if that one will have enough clearance for the chain, was the reply. She also said if the 27t didn't fit, they were not liable. I had measured the rear hub before hand. I knew it would fit, with plenty of chain clearance. So I ordered a 28t and 27t rear sprocket. Aluminum alloy of course, not steel. Three days later, the sprockets were at my front door.

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Soul Searcher

When complying the data, you have a tolerance factor. This compensates for the various difference in the same make and model. I rounded off the rpm's to the nearest 100 rpms. So the reference rpms at any given speed could vary by 100 rpms either way. After finally purchasing a GPS, for our trip to Arkansas. My Speedometer is 4 mph fast, from 50 to 80 mph.

Some specs for Rebel engine.
Power: 17.00 HP (12.4 kW)) @ 8250 RPM
Torque: 18.00 Nm (1.8 kgf-m or 13.3 ft-lb's) @ 5500 RPM

I don't think you will over Tach the Rebel's engine. Just keep in mind, the red ticks on the Speedometer face. OEM recommend max shift points, for stock gearing.

With the advancement in metal technology. The tolerance in the manufacture of a chain, is so small, I don’t think the odd/even tooth combination is valid today. Look at the timing chain and gears in an automobile engine. They have always been even/even. Ratio of 2:1.

Changing gearing on the Rebel is what you decide. What works for one, won't necessarily work for others.

I'll cover more about my gearing test results in "My Quest. Searching For My Ultimate Touring Rebel." Thread.

Call Rebel Gears. They will be more than happy, to provide you with any tooth sprocket you desire.

How I test my Rebel. With stock gearing. I find a stretch of flat level pavement. Operated the Rebel in 5th gear at 15 mph. Then slowly add throttle, till I reach 55 mph or greater. The Rebel's engine, if operating properly will perform flawless. No misfire or jerking. Just a smooth steady pull till I reach what ever speed I want.

Lugging the engine, is mention quite often on this Forum. How I define Lugging. If the engine will maintain, a set speed in the gear you have selected, your not lugging the engine. Now if the speed starts to drop and the engine can't produce enough power to maintain that speed, you lugging the engine. Like anything else, there is always exceptions. If I'm traveling on the highway at the speed limit, say 60 mph. I have a slight incline in the road ahead. The distance to the top is far enough away, that my speed is going to drop by 5 mph, with full throttle applied. With no traffic behind me, I maintain my reduced speed, till I top the rise. There is a time limit involved. If it takes longer than a minute, to reach the top. I downshift, accelerate and keep to the speed limit. By using these two technique, I don't worry about lugging the engine.

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