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How to Make the Rebel-500 Fast? Anybody Know?

58K views 33 replies 20 participants last post by  andy352299 
#1 · (Edited by Moderator)
Hello, I have now had my Rebel 500 for 3-4 months. I have put on all available mods, but still don't like the seat height. So I'm probably going to get the scrambler kit to raise the seat.

I like Honda, and I have a CRF250, and it's twice as fast as this Rebel-500. On the CRF I have the TNT ECU which means no limit, and I can configure the EFI. I have done all available mods and it is JOY to Ride.

With the Rebel, there seems to be no after-market performance mods. Why is this? I have asked lots of people and they just say "I don't know, and I don't know anybody that does"

For the ECU there seems to be an outfit ECU-SHOP in Thailand that sells an ECU, but expensive and you must go through dealer-network, and I like to install it myself. In the USA there is the Dyno (5+-year-old tech, no upgrade of hw for years ), and that's about it, but there's next to nothing online about actual performance and experience from others.

In my life whenever I bought a new bike, and that's from dirt bikes to Harleys, I always change everything, remove all factory stuff, and make them "FAST". But for this Rebel-500 it seems that they have 'closed' this bike for this.

In Thailand, there are tons of stuff for the CBx bikes and 150s, but nothing for performance for the rebel.

...

Besides all the cosmetic stuff the first thing I did to the rebel-500 was put on a good exhaust, which made it sound better but had no performance gain.

The rebel has been on the market for 3+ years, but there is nothing on Youtube except making them pretty,

I guess I bought the Rebel-500 because it was a cheap 500cc base frame bike, I paid less than $6k new, and most of the other bikes of this engine size are twice as expensive, I was thinking this was the base, and I would just put on mod's to make it fast, like in the USA you can buy a head-kit (Chinese) for a Harley 883 to take it to a 1700cc, for about $250 USD. Lots of stuff, or even valve kits, for the CRF there are tons of things you can buy to make them fast.

For the Rebel 500, there is nothing.

For me driving the R500 is like driving a bus, and my legs hurt from that position, I upgraded the seat and it still didn't help, I'm not sure how much height the scrambler seat buys.

Most people say the R500 is a 'girls bike' as it can fit a 5' woman rather well, meaning she can touch the ground. I'm not tall, only about 5'11'', yet when I sit on the Rebel I find my knees up above my waist. This is a terrible position for long riding.

...

I'm rather surprised that on the entire surface of the planet earth there is NO after-market stuff for making the Rebel's FAST, maybe in time but from talking with shops, they don't even sound interested, what's up? Does anybody know?

Maybe there's some 'secret' GOV deal? Or maybe Honda has closed this motorcycle and locked it like a 'locked cell phone'. Who knows?

I'm an engineer so in time I'll find the schematics, China sells ECU chips for about $1, and they are all the same, every ECU on the planet uses the same chip set, after that it's just glue to stabilize, and tune the chip.

Top-End kits? Valve Kits, EFI mod kits, performance mods for getting more fuel?

I don't care if I burn up the engine, that's part of the fun of retooling the engine and making it better.
 
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#2 ·
Smaller rear sprocket. Larger front sprocket. Problem solved. :grin2: The Rebel doesn't need all that torque anyway.


Honestly though, I think there are so few mods because if there's anyone looking for a 900+ cc bike, they could easily just go buy one for only $1-2k more than the Rebel is. You have the Yamaha Bolt, Kawasaki Vulcan, Triumph Street Twin/Bonneville, Suzuki Boulevard, etc. all around the $7-8k range (at least where I live). It's just not worth it to spend thousands of dollars on mods to go on a pretty generic and cheaply made Rebel when you can already buy a brand new motorcycle with the cc's you want for not that much more money. Most of the pieces on the Rebel are not great quality and are plastic. It's a budget bike. And it's a model that has only been around for 3 years. The old Rebels and Harleys have been around for a long time and therefore have people willing to make parts as there's been a longer demand for said parts. The 300/500 Rebel's are likely too new for any company to want to waste their time creating mods for it when there likely isn't much demand for it right now. Not to mention, people usually are not trying to soup-up their cruisers. The CBR has lots of mods because people wanted to play "sport bike" with a tiny engine. They have to do something to keep up with those willing to spend their money on a true sport bike which costs a bundle.
 
#25 ·
He didn't ask about a different bike. He obviously likes the look and feel of this specific rebel and wants to know how to make it faster. Im also with you, I have different bikes that are much faster however modding the rebel 500 would seem fun. It's a great all around bike.
 
#4 ·
WHY does everyone want as fast as possible???

If you wanted to go fast - super sport bike.
If you wanted a higher seat- which is opposite of most - Sport bike.

THIS bike is a cruiser, doesn't go super fast and the seat is low BECAUSE its a cruiser.

WHY would you buy new then destroy the whole bike??

Go get a 1000 Ninja. That seems to be what your after!
 
#5 ·
I would not be that harsh as others - making a bike faster never hurts. Some like to alter for aesthetics or appearance, others prefer performance or farkles. I personally don't care about looks, but I usually upgrade brakes, suspensio and performance on my bikes before touching anything else.

As for getting more go from the bike. I'll strictly speak about the 471cc twin version, never touched the single so far. I have worked on many of the new twin engines tho and have quite some experience getting them fast. The most powerful I've seen so far is around 67hp currently and also has much more torque everywhere in the power band than the stock engine. Generally speaking the two major bottlenecks in the twin engine are the cams and the head. Changing anything else alone brings very modest results if any.
So the rebel engine is derived from the CBR500-CB500F-CB500X trio by altering intake cam timing, airbox and fueling to provide torque at lower RPMs and sacrificing top end power. Not much change here tho, but a definitive change in character. While low end grunt is helping relaxed cruising acceleration and top speed is limited by engine power (hp or kW). So if anyone wants to go faster the changes (except the airbox as it is limited by the bike's frame geometry) can be modified back to CB standard (installing a stock CB cam set and matching ecu, or reflashing the rebel ecu with cbr tables).
Next step would be upgrading to 2019 CB cams and programming. The new CB series have higher lift intake cams timed similarly to the rebel 500, so they give a significant boost at lower RPMs, but due the higher lift does not compromise top end power. The difficulty is that the new bikes have a new type of ecu, so one definitely needs to get a custom ECU flash to not get lean running conditions at higher RPMs.
There are aftermarket cams which can be bolt on, giving even bigger gains everywhere in the RPM range so they are not sacrificing anything in the engines character.
Of course supporting changes like higher flowing air filter and decat headers help a bit too - but those alone does not bring much to the table.
So far all of this is just bolt-on with a difficulty level of a valve adjustment type of an installation procedure, and can bring up to something around 55-56hp with aftermarket cams and supporting mods.
Going further there are other options like ported heads, higher compression pistons etc - which eventually lead to the 66-67hp but those are a bit more complex and expensive too so might not wort for evryone to invest in those.
The rebel might be different, but the light weight cb500x proved to be such a unique bike in it's category that I felt ot worths for me to upgrade the engine of mine. Since I've made a few packages for others too (complete ready to bolt on ported, polished heads with reground higher lift cams installed and shimmed with the matching ecu flash fikes) and helped fellow racers to build their CBRs too to be competitive in their category. Rhis is not an ad, just saying that it can be made without sacrificing character or anything of the engine (well, fuel economy can be hurt if the added power is being used, but horses should be fed after all). If anyone interested I'm happy to help building yours too.
 
#34 ·
I would not be that harsh as others - making a bike faster never hurts. Some like to alter for aesthetics or appearance, others prefer performance or farkles. I personally don't care about looks, but I usually upgrade brakes, suspensio and performance on my bikes before touching anything else. As for getting more go from the bike. I'll strictly speak about the 471cc twin version, never touched the single so far. I have worked on many of the new twin engines tho and have quite some experience getting them fast. The most powerful I've seen so far is around 67hp currently and also has much more torque everywhere in the power band than the stock engine. Generally speaking the two major bottlenecks in the twin engine are the cams and the head. Changing anything else alone brings very modest results if any. So the rebel engine is derived from the CBR500-CB500F-CB500X trio by altering intake cam timing, airbox and fueling to provide torque at lower RPMs and sacrificing top end power. Not much change here tho, but a definitive change in character. While low end grunt is helping relaxed cruising acceleration and top speed is limited by engine power (hp or kW). So if anyone wants to go faster the changes (except the airbox as it is limited by the bike's frame geometry) can be modified back to CB standard (installing a stock CB cam set and matching ecu, or reflashing the rebel ecu with cbr tables). Next step would be upgrading to 2019 CB cams and programming. The new CB series have higher lift intake cams timed similarly to the rebel 500, so they give a significant boost at lower RPMs, but due the higher lift does not compromise top end power. The difficulty is that the new bikes have a new type of ecu, so one definitely needs to get a custom ECU flash to not get lean running conditions at higher RPMs. There are aftermarket cams which can be bolt on, giving even bigger gains everywhere in the RPM range so they are not sacrificing anything in the engines character. Of course supporting changes like higher flowing air filter and decat headers help a bit too - but those alone does not bring much to the table. So far all of this is just bolt-on with a difficulty level of a valve adjustment type of an installation procedure, and can bring up to something around 55-56hp with aftermarket cams and supporting mods. Going further there are other options like ported heads, higher compression pistons etc - which eventually lead to the 66-67hp but those are a bit more complex and expensive too so might not wort for evryone to invest in those. The rebel might be different, but the light weight cb500x proved to be such a unique bike in it's category that I felt ot worths for me to upgrade the engine of mine. Since I've made a few packages for others too (complete ready to bolt on ported, polished heads with reground higher lift cams installed and shimmed with the matching ecu flash fikes) and helped fellow racers to build their CBRs too to be competitive in their category. Rhis is not an ad, just saying that it can be made without sacrificing character or anything of the engine (well, fuel economy can be hurt if the added power is being used, but horses should be fed after all). If anyone interested I'm happy to help building yours too.
Thanks for this post, Your the first person who has answered this question with proper knowledge as opposed to just buy a bigger cc bike. My wife is 4ft 11 inches, size wise this is perfect, she doesn't want a taller sports bike (she's actually got one as well but prefers the lower seat) she could just do with a bit more power
 
#8 ·
As far as I see the OP didn't ask if there are faster bikes than the Rebel, but how to make it faster. I always love smart guys who just drop their unquestionable wisdom on the fool and thinking their and only their opinion is valid - but very seldomly add real value to a discussion.
There could be million and one reasons why someone would like to make his or her bike modified in any way. Yes, there will always be a faster bike to any bike currently in production, same way as there is a more appealing, lower, taller, less weight, more cylinder, larger capacity, better fitting a pillion and luggage etc. And what? Should we all only ride stock bikes and if something is missing from it we should always change? The Rebel was specificly designed to be a customisable bike. Why should we only change appearance, and why not engine?
 
#9 ·
Hey Oyabun, I like the idea of 10 more horses from the cams and ECU. And I especially like the idea of keeping the low end power at par or even improving along with the increase in upper RPM power. Do you have a 'recipe' for this? And who does the ECU flash? What else needs to go with the cam and flash ? Any additional details that you would care to share would really be appreciated.


Thanks!
 
#10 ·
Hey Oyabun, I like the idea of 10 more horses from the cams and ECU. And I especially like the idea of keeping the low end power at par or even improving along with the increase in upper RPM power. Do you have a 'recipe' for this? And who does the ECU flash? What else needs to go with the cam and flash ? Any additional details that you would care to share would really be appreciated.
Thanks!
Other than the cam you'll need a service manual, quite bit of time if you do it firts, a lot of elbow grease, a few valve shims, a garage and tools. If you do your own maintenance and have done a valve check already it won't be a too difficult excercise.
On the CB the best supporting act goes to an MWR filter which allows to open a larger hole on the airbox. Interestingly it is not really the oem filtering element what is a restriction, but the snorkel and airbox entry - and it is not possible to enlarge those while still using the oem filtering. We found that a modified engine made 3 more hp on the dyno with the airbox lid removed compared to the oem setup. Apparently noone wants it's engine to breath unfiltered air on the street, but this area needs to be addressed.
I haven't specifically checked the Rebel air filtering solution, but google for "MWR air filter cbr500r" and you'll see how it is implemented for a start.
A better flowing exhaust will be also needed. Again, it is less about the silencer, but the oem cat and exhaust runners are the restriction. On the cb removing the cat from the oem exhaust brings quite a bit of torque already. Many of us uses the ixil cat less stainless exhaust headers as they are cost effective, come without a cat and have larger diameter downpipes than oem. Interesting that the +19 bikes also come with fatter exhaust headers and a larger, better flowing cat out of the factory.
The cams have no adjustable cam gears, so there's no easy way of timing them off from their factory settings. If someone wants to play tho a freezer and a hydraulic press always helps.

Regarding the ecu flash, first you'll need a flashing cable. You either buy one from Lonelec, or you can build your own fairly easy. Once you get that, or want to build your own cable - send me a PM and I'll help you to move forward.
I haven't seen the fuel and ignition tables out of a Rebel yet, assume that they are different from a CB as the Rebel airbox has different length intake velocity stacks for the two cylinders- this cam be serving three purposes. To have a bit more character of the engine, to widen the torque curve by tuning the harmonic frequency of the two cylinders to different frequencies - which also sacrifices some peak power, and to overcome an intake inefficiency what is caused by the 180° firing order of the engine. I don't think it would be a restriction, just means that a CB flash potentially could not be used directly to a Rebel engine.
Sorry for my typos, using a phone for forum posts.
 
#11 · (Edited)
Maybe there's some 'secret' GOV deal? Or maybe Honda has closed this motorcycle and locked it like a 'locked cell phone'? Who knows

I'm an engineer so in time I'll find the schematics, China sells ECU chips for about $1, there all the same, every ECU on the planet uses the same chip-set, after that its just glue to stabilize and tune the chip.

Top-End kits? Valve Kit's, EFI mod kits, performance mod's for getting more fuel?

I don't care if I burn up the engine, that's part of the fun of retooling the engine and making it better.
I've never read this part of your original post - but now I gotta laugh hard.

No I don't think it would be a secret govt deal, it's rather that peeps look down on the rebel as a low cost entry level bike and rather change the bike, than upgrade for the same money. Neither it is around since stone age as a pushrod harley to have a whole industry built around customising it.

You don't specify what kind of an engineer you are, but if you think that all ecu chips are the same, and one can buy one for 1$ and all the rest is needed is some glue - you are certainly not an electronic engineer with automotive background.
To get you started, the Rebel ecu is based on an NXP SPC5602 chip which has ppc architecture. ?
 
#13 · (Edited)
Thought i'll add a few pictures here just for fun.

The first is a stock used head. Showing the bowls behind the valve seats, both on the intake and exhaust side. Look how the seats are not blended with the bowls due to machining tolerances. Watch the exhaust port how carbon builds up due to turbulence where the seat steps down to the bowl.

Next is after the head porting and polishing is done. Intake left rough, exhaust ports and combustion chamber is polished to avoid carbon buildup as possible. Seats are not yet recut, and head is not decked yet.

Third is the finished product, head decked for increased compression; valve seats recut; valves installed, lapped and shimmed to proper tolerances with the reground cams - all ready to install.

These with the intake mods, exhaust and an ecu flash bring roughly 58-60hp with more power everywhere in the power band.
 

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#15 ·
You're awesome! I will be contacting you after I'm back from deployment. I love this little bike and Have no problem giving it the love it deserves. Having one a bit tuned up will be unique and a bit of a sleeper. Not a crazy sleeper but a sleeper none the less and a fun one at that.
 
#16 ·
Oyabun,
You mentioned: "Many of us uses the ixil cat less stainless exhaust headers as they are cost effective, come without a cat and have larger diameter downpipes than oem. Interesting that the +19 bikes also come with fatter exhaust headers and a larger, better flowing cat out of the factory.

Which header pipe are you using? I'm asking because it looks like the cbr500 and cmx500 use the same header but the mounting brackets are in different spots. Does the cbr500 header bolt right up or do you need to make a new braket?
 
#21 · (Edited)
Slightly Confused

Ok... so, you have Some (/maybe a lot of) experience with the CB500X etc.... Which use quite a few of the very same parts including Most of the engine itself as the Reb 500...

if you can reprogram or buy an aftermarket for the CB-X... Why not use the same aftermarket CDI(??) or reprogramed one for the CB-X and just use it on the Rebel?!? ... Same with the Cams!! If there is a CAM upgrade Kit for the CB-X, then the entire kit should be able to be used in the Rebel 500... (<IS> it the same exact engine!?!?) Well, The OEM CAMs use the same exact Part number, And so does the CAM Chain, the Cam Chain Tensioner, and the Crank Shaft... As I understand it, the Ignition units are only different in form.. but not (really?) in function or spec. therefore any upgrades should work out, just probably if only a bit of custom work and finagling. Then again; Just bringing a CDI from one of those Faster bikes (that use the same engine) Should be an upgrade in itself... Right?

.. .. So... what's the problem?
 
#22 ·
Well, Ok, Though I doubt this would be a problem, maybe a CAM upgrade kit would somehow not fit??? The Cylinder Heads are the same, but the Head Covers are slightly different. The parts book uses the same illustration, but the item may have some slight variation for structure, or external form or fitting? However, if any difficulty is met, The CBX head cover really should work on a Rebel.
 
#24 ·
Hello Greg
Lots of good thoughts. I can only add a few corrections and thoughts.
- The rebel engine is exactly the same internally as the cb series - except the intake cam, what is timed different and has different part number also. The exhaust cam is the same tho. So a cam developed for the CB platform would be usable in the rebel head.

- The unit you call CDI is in fact what is called PGM-EFI in Honda jargon but it is different in function too. A CDI takes care of ignition only. Our unit does fueling, ignition, immobiliser, self diagnostics, display driver etc - but these are not shared between the bikes. If any rebel owner would be willing to read a flash from his/her bike, I could potentially check if the ecu flash we have developed could be possibly ported to the rebel ecu.
- the cylinder head has a different part number, but it can happen due to a simple color difference too - I'm pretty sure the cbr head would fit.
 
#27 ·
Just joined this group as picking my new rebel s up in a couple of weeks. Noticed a few people posting along the lines of you want more power get a sports bike etc.
I have gone down the route of the rebel for the low seat height as, following a non bike related accident, I need get get my feet flat on the ground when stopped, I had tears (well almost) when I parted with both both my Kawaskis, Z1000sx and Versys 1000, both too high now.
Looked at the Vulcan but not a lover of the feet forward position.
Machine keeps up with traffic and does the speed limits, but would love a little bit extra poke for overtakes. Have added an aftermarket exhaust and a K&N filter will be added at first service.
Really looking forward to picking it up, loved my 2 and half hour test ride.
 
#29 ·
i find I have to be very choosy about opportunities to overtake. It is mainly a bike for relaxing and going with the flow - quite different from my MT-07. You will notice the difference compared to your Kwaks, I am afraid. But the Rebel is enjoyable to ride and it feels well engineered to me. I doubt there is much to be done about its performance which is all down low in the rev range (which I like).
 
#30 ·
Hey, Great Topic! I plan on Buying a Rebel 500. First thing I'm to do is Dyno it. Then from there start modding. Basics, Exhaust, Air intake, More aggressive programming in the ECM ect. It will be fun to see what I can do with bolt ons. After that I may open the engine up. Cleaning up any casting Flash (1999 Mustang Cobra issue) port matching ect. Anything to increase efficiency.
The Rebel is a great bike and its always fun to make anything you own work to its best potential.
 
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