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Looking for 28 tooth rear sprocket

11K views 50 replies 12 participants last post by  Geodude1613 
#1 ·
Been running the 30T sprocket for a year now. Bike tends to top out a little too soon.

Currently its a 520 chain with the JTR279-30T and that's the smallest they make.

Anyone know/have a 28T they are not using or where to get one? I already have a call into RebelGears but if I don't need to go full custom that would be great. Am fully aware of the sacrifices it makes to low end grunt but ok with that. Just have the bike/rider on a diet. New 3D chain is on the way. Time for new sprockets.
 

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#2 ·
You will not get any more speed out of a 28 tooth sprocket, in fact you will lose top speed and performance into wind or up hills. I assume you already have a 15 tooth countershaft sprocket. 28 tooth would also be a bad choice with a 14 tooth sprocket since the same links would always ride on the same sprocket teeth.
 
#43 ·
My daughter just bought her first bike, a 08 rebel 250 < 8000 miles. She is 105 LB and 5' 2", somehow I do not see her on a bigger bike for a while. She is not into speed but would like to be able to take some longers rides. I am not familiar with stock top speed but have been told riding long distances at high RPM is not fun. Would a larger drive sprocket or smaller rear cog cut the RPMs without limiting the top end? I think 14/33 is stock and I have seen a chainset going to 15/30. Would 15/30 make enough difference? Is there a better combination? Should she just ride this bike as is for a year or so limiting her miles per day and then get a bigger bike?
I do not have any experience with a bike like this. When I was 13, I bought a Honda 55 (5 HP). From that, I would think the 250 should have the power to cruse in a taller gear than stock. When I pedal my bike, I like to run a lower cadence (RPM) and a tall gear but to go faster I downshift and peddle faster. I would think some of that would transfer to the Honda.
Running at max RPM does not seem to be a good way to go.
Any input?
 
#3 ·
My bike is very far from a Rebel, (Grom with a CBR250r transplant) it uses the JTR279 sprocket though... Right now I hit 80's pretty easily... Am very familiar with the potential loss of top end when changing to that small a rear sprocket, but have plans for more power to drive it harder and already it's a 6 speed. Looks like time to just get a custom sprocket made. I may wind up regretting it, but it may also be just what the doctor ordered. Thanks!
 
#5 ·
My bike is very far from a Rebel, (Grom with a CBR250r transplant)
Since this is a Rebel board, you might point this out before asking what is a fairly common question on here.
I'd be nervous about a Grom with more power. Those little wheels combined with a short wheelbase would be scary at anything more than scooter speeds I think.
 
#6 ·
I agree, one would think a first post at a Rebel board would involve a bike that was a Rebel, not something that has absolutely 0% worth of Rebel in the mix.

After all, the latter is what the Honda Rebel 300 And 500 Forum is for. :D
 
#7 ·
Man all the H8rs.... We are all riders aren't we? Yeah I have a different bike, still a Honda, still a small bore bike, we have several in our Group here in Austin. Duckster, my Grom will kick some butt. And steering dampener, carbon wheels, etc.. its much more stable at 80mph+ than you'd think. Thanks FliteControl for the eBay link, last time I searched there had no luck (likely because it was limiting to US sites or something like that), have one coming. I was asking about a specific part which is on a Rebel but if you guys want to be that condescending, above it all, throwing stones then....
 
#8 · (Edited)
Been running the 30T sprocket for a year now. Bike tends to top out a little too soon.

Currently its a 520 chain with the JTR279-30T and that's the smallest they make.

Anyone know/have a 28T they are not using or where to get one? I already have a call into RebelGears but if I don't need to go full custom that would be great.
Man all the H8rs.... We are all riders aren't we? Yeah I have a different bike, still a Honda, still a small bore bike, we have several in our Group here in Austin. Duckster, my Grom will kick some butt. And steering dampener, carbon wheels, etc.. its much more stable at 80mph+ than you'd think. Thanks FliteControl for the eBay link, last time I searched there had no luck (likely because it was limiting to US sites or something like that), have one coming. I was asking about a specific part which is on a Rebel but if you guys want to be that condescending, above it all, throwing stones then....
Okay, I'm being condescending...tell me where I can get a 50T rear sprocket for the bike I'm currently working on. But first you have to guess what kind of bike I am referring to, because as a hater I'll do the same thing you did and not divulge that fact right away. Then you can take a wild shot at exactly what it is I am trying to accomplish along with what results may occur with a 50T cog on the mystery bike.

I'll even give you a hint, which is far more than we got from your opening post: it's NOT a Rebel.
 
#9 · (Edited)
There's no hate involved.. We naturally assume posters are talking about Rebels when asking for advice unless stated otherwise. My observation/prediction on the effect of your sprocket would obviously be different if I had known you were talking about a modified Grom.
I have ridden Groms in our training fleet and am not a big fan. My take on it is that it's a toy motorcycle with little wheels and short wheelbase that can do the parking lot maneuvers ridiculously easily. In this sense it's a bit of a cheater bike as a trainer for big motorcycles. The small wheels, short wheelbase and high C of G actually make it dangerous under emergency braking conditions when ridden by a normal sized man. The rear end gets light in a hurry when you try to stop quickly. All the Groms in our fleet had to have the clutches replaced immediately because they were all dragging and could not be adjusted. We are still having trouble with them.
If I wanted to cruise in the 80 MPH Plus speed band, I would not want to be doing it on something as twitchy as a Grom. YMMV.
 
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#14 · (Edited)
There's no hate involved..
Oh no, there's DEFINITELY hate involved. The ridicule and hate that certain members dump all over people with tastes other than their own is very obvious. Blacked out bike, anyone? The condescending attitude towards anyone posting about any Rebel that is not the obsolete model makes me angry. Yes, this forum is dedicated to the air cooled model, and it sure would have helped if the poster included the bike in their post, but rudeness isn't the answer. There is great info and knowledge here, but the attitude makes it tough to digest.
 
#10 ·
Exactly.

Coming in here and asking about a 28T rear cog --- which by itself pretty much renders a Rebel nigh useless and gets worse with a larger front cog --- and you get the textbook Rebel answers.

Since you're new here, we'll forgive you for not knowing how the membership in general also refers to the 300 & 500 models that the other board I listed is dedicated to are also "Not Rebels" because, well...like your bike, they have absolutely 0% worth of shared parts and design with the Rebel this board is dedicated to. ;)
 
#12 ·
I just saw on one of the Rebel facebook pages that folks are asking about 27T rear cogs for their bikes.

Sheesh...
 
#15 · (Edited)
Outspoken does not equate to hate. You really need to go read the "2017 Rebel" thread in its entirety and you'll see no hate, just opinions (and rather valid ones at that). Even yours truly --- head of the anti-YABOB brigade --- made numerous remarks how I would like the new models if they had any semblance of color and/or chrome. Instead all the new model lovers picked apart the opinion end of those posts as hate.

As far as my opening post in this thread, well I've also made the "what's in the water with some of these new members" point several times over recently too. This is just another example of that observation.

Besides, show me one thing the new models have in common with the originals beyond having two wheels and I'll retract the "Not-Rebel" sarcasm. They're CB/CBR300 & 500 variants, not Rebels...so Not-Rebel is very appropriate.
 
#16 ·
I'm quite careful not to dump on people for having different tastes than mine. In fact there are many threads that I do not comment on because "if you can't say something nice....etc". However, I have no hesitation to offer an objective opinion about something I am qualified to speak on, and where its important to clarify facts for those who may not know them.

Nobody was rude to this guy,,, If anything, he was a little rude to us for not being able to read his mind and know that he was talking about a modified Grom, rather than a Rebel 250.
I've owned or ridden just about all kinds of motorcycles over a very long time (including Groms), and I would counsel anyone against souping up a Grom with a bigger engine and taller gearing to get more speed. The Grom is a little short pit bike with small wheels that in stock form is already fast enough for the suspension, frame geometry and wheels it has. I have seen normal sized student riders lift the back wheel under moderately hard braking on these things and IMO they are not safe to ride at higher speeds on the street where the need for sudden hard braking is always a possibility,
There are plenty of stock bikes out there that are capable of off the charts performance right out of the box, so if you want to go fast there are plenty of bikes to choose from. The 150-200 MPH bikes out there at least come equipped with frames, suspension, tires and brakes to go with the hyper performance engines and give the rider a chance to survive. Taking a toy bike like a Grom and stuffing a bigger engine in it is a dangerous thing to do because the running gear of the bike is not up to handling the power increase safely and the bike will be badly compromised with such a modification.
 
#18 ·
So by that logic, I could convert a Goldwing to a Rebel by changing out the badges? Is that what you are asserting?
 
#19 · (Edited)
Yep, just like slapping a big firebird sticker on the hood of a Grand Am doesn't make it a Trans Am.

See, here's how name badge evolution works:

Shadow:

Shadow:

Shadow:

Shadow:


Note how they all have a liquid cooled OHC 3 valves/cylinder single pin V2 w/53º between the jugs while retaining certain styling cues along the way over 30+ years. Same DNA, various model years.

Now compare that to this:

air cooled SOHC 2 valves/cylinder single pin AKA parallel twin


liquid cooled DOHC 4 valves/cylinder offset crankpin AKA inline twin


liquid cooled DOHC 4 valves/cylinder offset crankpin AKA inline twin


Would you equate the middle bike with the top bike's DNA or the bottom bike's DNA? Retraction denied.

 
#22 ·
I see your logic. When the Porsche 911 became water cooled, it stopped being a 911, right? When cb750 switched to dohc it became something else, right? No, it became a more modern version of the same vehicle. Progress does not change that Honda's entry level cruiser style model is the Rebel. You can stick to your guns, I'm fine with that.
 
#23 ·
A parallel twin and an inline twin are both twin cylinder engines with the cylinders arranged side by side or "in line" or "parallel", so there is no distinction between these 2 terms for a twin cylinder engine.
some parallel or inline twins have 360 degree crankshaft phasing (like the Rebel 250) that is that both crankpins are inline and the pistons go up and down together and the power strokes are 360 degrees of crankshaft revolution apart. These engines vibrate purely up and down.
Other parallel twins have the identical inline cylinder arrangement but 180 degree crankshafts so that the 2 pistons are always moving in the opposite directions. These engines will vibrate more in a rocking side to side motion since the pistons and rods are balanced in the vertical direction.

Another type of parallel twin crankshaft is the 270 degree type where the crankpins are offset by 270 degrees. this type is somewhat similar in operation to a single pin V twin with a mix of vertical and rocking vibrations and a more irregular idle sound.

The designaton "twin" is referring to the number of cylinders of the engine. the adjectives "parallel" and "inline" in this case mean the same thing, although inline is normally more applicable to a multicylinder engine where all the cylinders are in line with each other in the plane of the crankshaft.
In order for cylinders to be parallel to each other and connected to the same crankshaft, they must lie in the same plane as the crankshaft, Strictly speaking a square 4 (look it up Ariel, Suzuki Gamma) is a parallel 4 since all cylinders are parallel with each other but not in line since they have 2 crankshafts.
 
#25 ·
Sorry, I was unaware that the new Rebel had it's engine moved to the back, and I didn't think 500 cc was that much more than 450. I don't think either of us will be convinced. You definitely have more motorcycle knowledge than I do, and more experience too. I'm never gonna debate that. However, I will stick to my belief that the entry level Honda cruiser is and was the Rebel. I guess the "hate" comments were over the top too, but some remarks about a generation of Facebook using, low pants wearing, bike destroying people in other threads were certainly less than friendly. I will try to refrain from adding to this side track. I believe this was originally a thread about sprockets?
 
#27 · (Edited)
Sorry, I was unaware that the new Rebel had it's engine moved to the back, and I didn't think 500 cc was that much more than 450. I don't think either of us will be convinced.
Now you're just arguing for the sheer sake of being argumentative. If I have to explain it to you any further, you probably wouldn't understand.

(I can't believe I actually used that old saw)

Just for the sake of being argumentative though, the 450 shares a lot more DNA with the 250 than the 500 does with either model. That brings us right back to the point I've made numerous times in this thread now.

However, I will stick to my belief that the entry level Honda cruiser is and was the Rebel.
Well, yeah...it's not a belief, it's a fact. Both models just happen to be the smallest displacement cruiser in each respective line up so it stands to reason they're both the entry level model.

I guess the "hate" comments were over the top too, but some remarks about a generation of Facebook using, low pants wearing, bike destroying people in other threads were certainly less than friendly.
As someone else already pointed out, stick around long enough to see the trends and it makes a lot more sense. Kind of like that old saw I just sharpened above...if you haven't heard it in the "proper" context before you might find it offensive, but once you do you'll see the humor behind it. ;)

I will try to refrain from adding to this side track. I believe this was originally a thread about sprockets?
Sprockets, as it was later divulged, for bikes that aren't Rebels. So technically anything that is off tangent from that is still tangent. :D
 
#26 ·
Just for the helluvit, here's another comparo between the 250 & 300 models for those willing to digest the differences:

air cooled SOHC 2 valves/cylinder single pin twin


liquid cooled DOHC 4 valve single cylinder


liquid cooled DOHC 4 valve single cylinder


Yep, the middle one is still much closer to the bottom than the top.
 
#29 · (Edited)
Just to further illustrate the concept of the evolution of a model name over time, have a look at examples of the BMW R type GS over time from its origins in the '80s. (I have an '04 model of this line which I love). Consider this progression

1981 the R800GS. 800 CC air cooled boxer engine with pushrods and carbs. The adventure tourer, A new concept from BMW.



1991 Still air cooled and carbureted, but punched out to 1000 cc now and somewhat different bodywork and shaft drive setup. Bash plate and a little more offroady looking.



2001 R1150GS the air cooled Boxer engine punched out to 1150 cc and now fuel injected and fitted with an oil cooler. Front and rear suspension changed to proprietary BMW telelever and paralever spec.



2011 R1200GS Boxer engine punched out a little more to 1200 CC and making 110 HP. Changes to shaft drive and front suspension setup.



Finally the current version of the R1200GS, now liquid cooled and downdraft induction making 125 HP.



The family resemblance can be traced year by year all the way back to 1981. Every year little changes and sometimes larger changes were made to improve the bike from previous versions. Even though the current version is vastly different from the original, it is still a boxer-engined adventure tourer that retains a recognizable lineage down through 35 years of annual changes. Compare this to what Honda did with the Rebel. 1985-2016 - almost no change at all. 2017 Everything different but the name. So do you see what we mean?
 
#33 ·
Beyond the engine, I don't see any similarities between Rebel and the CB you posted. Both Rebels are tube framed. Both have seat heights lower than 28 inches. Both weigh less than 390 lbs. Both are cruisers aimed at the entry level rider. It seems obvious that the majority of the evidence is on my side. I feel that I have repeatedly proved my point. Unless you can find more proof to counter this, I am done.
 
#34 ·
Beyond the engine, I don't see any similarities between Rebel and the CB you posted.
Therein lies where it derives from, i.e. the DNA. You're starting to get my point. :thumb:

Both Rebels are tube framed. Both have seat heights lower than 28 inches. Both weigh less than 390 lbs. Both are cruisers aimed at the entry level rider. It seems obvious that the majority of the evidence is on my side. I feel that I have repeatedly proved my point. Unless you can find more proof to counter this, I am done.
Recap:

However, I will stick to my belief that the entry level Honda cruiser is and was the Rebel.
Well, yeah...it's not a belief, it's a fact. Both models just happen to be the smallest displacement cruiser in each respective line up so it stands to reason they're both the entry level model.
So there you go again, arguing for the sheer sake of being argumentative. For someone who was quick to point out debate tactics, you sure seem to ignore a lot of debate tactics...I have never stated that either model was not an entry level bike --- and as per the quotes above you can clearly see that not only are we in agreement on this angle, but it is simply a fact that can not be disputed. Yet you keep bringing that up as if it has something to do with the topic at hand. My point all along is the new model should be called something else because it derives from something else (i.e. both versions stem from entry level sport bikes).
 
#37 ·
OP posted only 3 times, all on page 1, nothing more recent than 3 months ago, looking for a sprocket for his GROM. 30+ off topic posts later .... just saying....
 
#38 ·
30+ off topic posts later .... just saying....
Like I said earlier: what's off topic about anything off topic in a thread that was only later divulged to be not Rebel related? Had he opened with Grom sprockets instead of expecting us to read his mind then yes, everything after the first page would be off topic.

Just saying...
 
#40 ·
Either that or move it to "Non-Rebel Related Bike Chat" which is technically where it belonged in the first place...re: the OP's posting in the Rebel Wrenching section with what turned out to be a non-Rebel related issue. :D
 
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