Performance Mods For Rc36

I want to install a jet kit and a slip-on to boost the HP of my 97 VFR. Are there any particular ones that work best? Also, are there any other bolt-on engine mods that will increase power?

Hello King,

If you get satisfaction from tinkering (like I do). go for it. But don't expect too much more HP. I see you have 3 so by all means, play!

If your aim is quicker acceleration or top speed, playing with the sprockets can help.

Advantage of an aftermarket muffler can be weight savings, the oem weighs 6.1 kilo, my Akrapovic 1.6......

If you do find the Holy Grail, do post up here please.

You can get a significant amount of extra oomph with a TTS big bore kit (837cc), but that involves a full engine rebuild, plus the cost of the new pistons, rings and head gaskets. I had TTS do my 3rd gen ten years ago, and it's still working well, but I can't say it's a necessary mod. Many other more modern bikes put out the same HP with no expensive modifications at all...

Ciao,

I would add a K&N or other high flow air filter before jetting. Once the weather warms up in Maine I am putting my bike on a dyno to check horsepower and AFR. I am running a stock filter with a TBR header, left exit exhaust. It was jetted according to the previous owner.

Great responses. Sprockets and a filter are an easy way to add some power. 100-105 rear wheel HP is my goal. And I would like to get my hands on that TBR left side header. Been surfing the web for one but no luck.

They are hard to find. Depending on how long I keep my 750 I may have a replica made out of stainless with a couple changes.

What modifications would you make to the TBR header?

Changing from slip joints with springs to a v-band clamp and moving where the joints are for the rear headers.

When I dyno'd my VFR, with the Aftermarket TBR Pipe (stock header) and stock airfilter and Carbs the AFR's were good. I imagine a better air filter still wouldn't warrant jetting.

One sure fire way to increase performance on a 750 is to keep it in the garage and buy a 1200 instead :D

But seriously though, so many people have tried to squeeze more out of this motor, Honda got it just right....it's great for what it is, plenty of go in my opinion. Best bet would be to shed weight. Swap the led subframe with aluminium, get a carbon fibre tank (they can be had) etc...you'll get it down to under 190kg and will be increasing the seat of pants dyno HP by 15-20bhp due to power to weight being so vastly improved.

Look into swapping the 34mm 4th gen carbs, to the 36mm 3rd gen carbs before you start messing with the jets on the factory carbs. I would imagine that this would trade a little lowend torque for some added top end hp.

CandyRedRC46

Look into swapping the 34mm 4th gen carbs, to the 36mm 3rd gen carbs before you start messing with the jets on the factory carbs. I would imagine that this would trade a little lowend torque for some added top end hp.

nope!

bigger doesn't always mean better. you think honda didnt already try this ??

besides the carb angle is different. that a hell of a a lot of playing !!

new carb intake boots

custom plenum to fit the airbox...

all that work when you just change the jets for and needles for 100 or so bucks.

Honda did already try 36mm carbs, from 1990-1993...

They were not trying to build a performance mod bike, they were transitioning from the 1986-89 sports bike to the 1990+ touring bike.

I am sure that when they went to 34mm carbs in 1994-1997, they did it for more lowend throttle response at the expense of top end hp.

Then Honda went back up to 36mm throttle bodies for the 1998+ VFR800's.

Why would you need to do custom anything? Just find 3rd gen parts or a 3rd gen bike...

slowbird

When I dyno'd my VFR, with the Aftermarket TBR Pipe (stock header) and stock airfilter and Carbs the AFR's were good. I imagine a better air filter still wouldn't warrant jetting.

From my experience and what I have gathered from talking to a few other people an air filter tends to be the reason to rejet a bike over a basic slip on muffler. I don't recall if it had a muffler or not but my father has a cbr1100xx K&N kicking around because it made the bike run like crap and the jetting/sync costs were more than he was going to pay for the gain.

Free dyno run a lillte while back

OEM air filter

no rejet

Akarapovic with db killer in

vertical axis HP

horizontal axis speed in kmh

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clickerdiclick

http://vid113.photobucket.com/albums/n206/Dutchy_748/HPIM2493.mp4

Dutchy

Free dyno run a lillte while back

What gear? Atmospheric data? I just want something to compare to as I haven't seen many dyno sheets for the 750.

coupedupsubie

slowbird

When I dyno'd my VFR, with the Aftermarket TBR Pipe (stock header) and stock airfilter and Carbs the AFR's were good. I imagine a better air filter still wouldn't warrant jetting.

From my experience and what I have gathered from talking to a few other people an air filter tends to be the reason to rejet a bike over a basic slip on muffler. I don't recall if it had a muffler or not but my father has a cbr1100xx K&N kicking around because it made the bike run like crap and the jetting/sync costs were more than he was going to pay for the gain.

Some air filters are designed as a drop in replacement and some are designed as a performance filter that may require fueling changes. A perfect example of this is the vfr800s, the kn and bmc are drop in filters that flow no more than the factory filter, while the pipercross was designed as an actual performance filter.

It was a free run at a dealer event.

1,5 meter below sea level

Partly cloudy

in a gear

I have no idea really, sorry :-)

No doubt there can be gains to be had, "better" is the enemy of "good" after all.

For for me she is good enough.......

Instead of more power, my advise (free) is to invest in better suspension and fuel to burn and ride her.

I agree with Dutchy above, sort your suspension first, then upgrade your brake components. The stock suspension and brakes aren't bad, but can be easily overwhelmed if not properly serviced, and more hp/torque is added.

time for cbr front end

Well, I've purchased a Viper race s/o, a Factory stage 1 jet kit and a Piper Cross air filter. The problem is that I really don't want to molest any of my three RC36's because they are all completely stock and in showroom condition. Spent hundreds of hours and $$$ to get them in that condition. At the same time, I want to experiment with some performance mods. I'm conflicted.

Factory pro used to do an ignition advance mod,I think it just involved sending them your flywheel and they modified it to 5 deg advance. I sent them an email and they don't seem to have any info on it other than they used to do it and don't any longer but it's something else to look into.

Brakes, suspension, geometry improvements, better tyres & reduced weight will give performance advantages. Exhausts and if headers are changed - jet kits too, will give more smiles.

Awe man, have I been down this road big time. like most have said Honda did good with this one. Going bigger carbs as noted doesn't work, been there, not worth it. Now jet kits are cool and all but there's a trick to em, been there as well, they need to be matched to the exhaust flow capacity and that is where it gets tricky, there's really nothing out there, there was, but that 20 years ago GL finding it. you could build one all the while dyno testing this and that. there also some sacrificing going on with mid torque and top end HP it's a bamboozling act at best. I did a lot of experimenting thinking sure there's an easy solution, there ain't, unless you want to open up the engine. My best happy medium was dialed in at 99hp with stock carbs K-N no piper cross then as I knew, Stain tune slip on. Believe it or not, just fine tuning the needles is all that's needed, and a lot of patience and a dyno, yes it's that touchy bottom line get air in and out as fast and efficient as possible. if you want fast acceleration, change the gear ratios, if you also want a well balanced machine that handles well there huge gains here, make sure you up grade the suspension, it's a great bike, it's just that Honda did pretty good with this one right out of the gate.

A long time ago when there were Dyno jet kits for these bikes (About 20 years ago), I put a slip-on onto it and took it to Rino Dyno in London, to have a chap called Nick tune it on a Dyno. I think it made maybe 3-5 hp more than before, if that.

It's still got the same jet kit fitted but a different high-level slip-on exhaust now. Backfires a tiny bit on the over-run every now and then, which isn't down to anything else than carbs. I've tried to tune out by enrichening the pilot jet settings but couldn't so I just live with it. It's so little I don't care any more.
If Tyga makes the left exit exhaust for a high level silencer we'll have to see if there's any way to get jets to improve it again, as I guess there will be demand for such kits from the supplier that offers such a kit.. Time will tell.

Alhazred

Factory pro used to do an ignition advance mod,I think it just involved sending them your flywheel and they modified it to 5 deg advance. I sent them an email and they don't seem to have any info on it other than they used to do it and don't any longer but it's something else to look into.

Did you talk to Marc? He (the owner) talked me out of an ignition advancer for my RC36...that was about 15 years ago. It wasn't the flywheel they modified, but the "Pulse Rotor". It doesn't show up on the RC36 microfiche for some reason, but you can see the RC46 pulse rotor in the parts diagrams for that bike. Basically, Marc's view was that it was not especially useful on a VFR engine, unlike on other engines, such as the inline-4 CBRs.

Ciao,

We used an offset woodfuff key to advance ignition timing years ago. Wonder if that still works? But I have good news! Shelving the performance parts for now. Picked up a new 2014 VFR800F for US$7,500.00 and no dealer fees. That's a steal. Honda is liquidating the bikes through their dealers. The RC36's are safe for now!!!!

I am not really a fan of the fixed 5 degree advance over stock, as it may make a big gain in mid range, but it could be at the expense of top end or low end.

I know that on my 2007, I can adjust the ignition map instead of just a fixed number and what my bike likes is a few degrees of advance starting at 2500 and quickly ramping up to about five degrees from 4000-7000 rpms.

Then slowly ramping down to zero advance by 9000 and actually pulling 2 degrees of retard from 11000 to redline.

Also I would not want to be idling and running 5 degrees of advance at light throttle as this would make the bike run very hot in traffic.

This is why I zero'd my ignition map up to about 30% throttle, before any advance is added over the factory ignition map.

The whole fixed timing advance is going to be a compromise. Give some here and take some there.

JZH

Alhazred

Factory pro used to do an ignition advance mod,I think it just involved sending them your flywheel and they modified it to 5 deg advance. I sent them an email and they don't seem to have any info on it other than they used to do it and don't any longer but it's something else to look into.

Did you talk to Marc? He (the owner) talked me out of an ignition advancer for my RC36...that was about 15 years ago. It wasn't the flywheel they modified, but the "Pulse Rotor". It doesn't show up on the RC36 microfiche for some reason, but you can see the RC46 pulse rotor in the parts diagrams for that bike. Basically, Marc's view was that it was not especially useful on a VFR engine, unlike on other engines, such as the inline-4 CBRs.

Ciao,

Yes we exchanged a few emails about it,when I asked him about any benefits he only answered that it was a long time ago and that it would cost a few hundred to do now.

I just stuffed 2 sausage rolls in my face so the -if any- performance gains from the Akrapovic have been nullified by extra rider weight..... :goofy:

Just shaved 24 lbs off the curb weight of my VFR. It only has one gallon a fuel in the tank. :beer:

TheStig

Brakes, suspension, geometry improvements, better tyres & reduced weight will give performance advantages. Exhausts and if headers are changed - jet kits too, will give more smiles.

Miguel! How's your VFR doing, all finished? Would love an update....

The easiest way to increase the hp in the 750s is to take the radiator cap off and place it in a 1000. :goofy:

I don't think the TBR left side system showed any significant gains in HP for anyone that used them on the RC36s. Anyway, they also don't look that great on the bike as they hang too low because TBR had to design them to clear the bottom of the swingarm and rear right peg. You're better off getting the Staintune high right slip-on. Sure, it also does not increase the HP on the bike, but it certainly looks a lot better than the TBR left exit systen, IMO.......and will most likely cost a lot less if you can find one.....

coupedupsubie, 2/21/2016 at 2:01 PM

They are hard to find. Depending on how long I keep my 750 I may have a replica made out of stainless with a couple changes.

I know this post is a few months old, but, if you do decide to have a replica made, I'd like to have one made for my 94 VFR. I too have not had any luck in finding a left-exit [in-stock] or the dimensions/bend angles so that I could have one fabricated.

1 hour ago, MIT

I know this post is a few months old, but, if you do decide to have a replica made, I'd like to have one made for my 94 VFR. I too have not had any luck in finding a left-exit [in-stock] or the dimensions/bend angles so that I could have one fabricated.

As far as getting a header made, any shop that does exhaust manifold fabrication should be able to make one pretty easily off of pictures if they have the bike. My reason for doing a semi-replica would be to reduce initial fabrication time. Once jigs are made it takes a lot less time to make each header.

20 hours ago, coupedupsubie

As far as getting a header made, any shop that does exhaust manifold fabrication should be able to make one pretty easily off of pictures if they have the bike. My reason for doing a semi-replica would be to reduce initial fabrication time. Once jigs are made it takes a lot less time to make each header.

I haven't really exhausted my local resources but I have been told by a bike shop owner or two that none of the local muffler shops would be able to make anything that would look nice. They also noted that the local muffler shops primarily do automotive mufflers which don't have to be pretty since they are underneath the vehicle. Finally, they also stated that to their knowledge none of the local muffler shops has the equipment to do mandrel bends.

4 hours ago, MIT

I haven't really exhausted my local resources but I have been told by a bike shop owner or two that none of the local muffler shops would be able to make anything that would look nice. They also noted that the local muffler shops primarily do automotive mufflers which don't have to be pretty since they are underneath the vehicle. Finally, they also stated that to their knowledge none of the local muffler shops has the equipment to do mandrel bends.

You need to basically find a "speed shop" for header fabrication. Depending on the amount of business they do they will have a mandrel bender. The shop I would use has made custom turbo kits for a few cars.

13 hours ago, coupedupsubie

You need to basically find a "speed shop" for header fabrication. Depending on the amount of business they do they will have a mandrel bender. The shop I would use has made custom turbo kits for a few cars.

@coupedupsubie

Thanks for the information. I will check around to see if I can find such a shop.

Hi, 
I have a left exit tyga

maxton rear shock

Andriane front internals

8 spoke

front brake upgrade.

this allows existing tunes to be used to the max

14 minutes ago, Iain2

Hi, 
I have a left exit tyga

maxton rear shock

Andriane front internals

8 spoke

front brake upgrade.

this allows existing tunes to be used to the max

only 8 years late!

35 minutes ago, Iain2

only 8 years late!

Sadly, that's not even a forum record...

Left exit Tyga?  On a VFR750?  Interesting.

Ciao,

JZH

6 minutes ago, JZH

Left exit Tyga?  On a VFR750?  Interesting.

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