How to Make the Rebel-500 Fast? Anybody Know? - Honda Rebel 300 & 500 Forum
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post #1 of 24 (permalink) Old 03-21-2019, 09:32 PM Thread Starter
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How to Make the Rebel-500 Fast? Anybody Know?

Hello, I have now had my rebel 500 for 3-4 months, I have put on all available mod's, 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 its 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 mod's 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 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 this Rebel-500 it seems that they have 'closed' this bike for this?

In Thailand there is ton's of stuff for the CBx bikes and 150's, 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, that 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. Lot's of stuff, or even valve kits, for the CRF there are ton's 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 buy's;

Most people say the R500 is a 'girls bike' as it can fit 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 waste, 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 shop's, they don't even sound interested, what's up? 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, 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.
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post #2 of 24 (permalink) Old 03-21-2019, 11:52 PM
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Smaller rear sprocket. Larger front sprocket. Problem solved. 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.
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post #3 of 24 (permalink) Old 03-22-2019, 06:38 AM
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Seems the much rumoured, unrevealed, Rebel 1000 might suit you better.
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Just do it! (I did: 2017 Rebel 500; 2014 MT-07)
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post #4 of 24 (permalink) Old 03-22-2019, 01:30 PM
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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!
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post #5 of 24 (permalink) Old 04-04-2019, 02:53 AM
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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.
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post #6 of 24 (permalink) Old 04-04-2019, 06:52 AM
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Originally Posted by rebel401 View Post
in the USA you can buy a head-kit (chinese) for a harley 883 to take it to a 1700cc, for about $250 USD
are you sure about this? can you give me link?

Keith from Maine USA - Rebel R1
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post #7 of 24 (permalink) Old 04-04-2019, 01:47 PM
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NOT being harsh, just stating reality.

Without trying much I can find a faster bike than a 500 Rebel.
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post #8 of 24 (permalink) Old 04-04-2019, 04:47 PM
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Originally Posted by jdock View Post
NOT being harsh, just stating reality.

Without trying much I can find a faster bike than a 500 Rebel.
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?
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post #9 of 24 (permalink) Old 04-04-2019, 08:42 PM
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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.

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post #10 of 24 (permalink) Old 04-05-2019, 12:47 AM
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Originally Posted by DaveRS23 View Post
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.
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.
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