what have you done in the hope of increasing the powers

Greetings from Finland

I thought I'd put here a little of what has been done to my beloved motorcycle over the years, especially in terms of power increase.
the first two pictures show the difference between the old configuration between the Delkevic and the original exhaust.
other mods are the same.

-PAIR valve mod, Flapper mod, and airbox mod
-O2 sensors bypassed
-Power Commander V
-Air filter Pipecross
-Iridium plugs
-LeoVince Slip-on.

Dynorun 2023 in the picture
shows the changes made during the last year. Other mods are the same except the original headers catalysator cut off.
-cylinder heads are lowered by 0.4mm
-intake camshafts 8gen.
-Air funnels all long.

In a week there will be another attempt on the dyno. Changes to the old one.
-intake and exhaust camshafts have been increased by 0.8mm more lift
-adjustable camshaft sprockets
-exhaust camshafts 6gen the camshafts are 4 degrees later
-intake camshafts -8gen the camshafts are in their original position
-V-tec system deactivated
-airbox modded (own design)
-Modded Delkevic 4-1 headers to 4-2-1 headers (1 Cyl-4 Cyl. pipes same Collector and equal length.
2cyl-3 Cyl. pipes same Collector and equal length. ) 2/3 cyl. pipes are 10cm longer than pipes 1/4 cyl.
I don't own a tig welding machine, so the exhaust pipe seams are welded with a mig and stick machine and it looks like that 🙂

I haven't been able to do a test drive yet, because the arrival of summer is late and it's too cold outside to go for a ride.

My english is bad so i have used google translator

[image: hp originel headers vs delkevic.jpg]

[image: torgue originel headers vs delkevic.jpg]

[image: dynorun summer 2023 .jpg]

[image: unfinished exhaust pipe.jpeg]

[image: finished exhaust pipe.jpeg]

[image: 20240413_184349.jpg]

[image: 20240413_184437.jpg]

[image: 20240413_184506.jpg]

[image: airbox top.jpg]

[image: airbox under.jpg]

[image: vtec parts 1.jpg]

[image: vtec parts 2.jpg]

[image: 20240204_182338.jpg]

[image: 20240204_182703.jpg]

[image: 20240204_182709.jpg]

[image: +0.8mm lift camshaft and standard camshaft.jpg]

Well, I did a small test drive of about 5 kilometers, everything works at least for now. 

I didn't want to go far when the air is like a 4 degrees warm and it's raining a little.
 At the end, I gassed up a little in the yard to the delight of the neighbors.

You really did quite a bit there. How do you like the defeating of the V-TEC? I kind of did the same, but I did it with putting a 5 Gen engine into my 6 Gen frame, with the added benefit of gear driven cams, I like to hear the gear whine 🙂. You'll definitely have to update us once you get to test ride it.

Amazing, Interesting and clever work you've done. Engine sounds very healthy in the video. Just like Duc2V4, interested in knowing more about disabling VTEC. Does the Power Comander V allow remapping/fueling for continuous 4 valve ops? And what about at the 6800rpm zone which would normally be the 4 valve transition rpm, can you modify that zone?

I was thinking how different it sounds to my 5th gens. 

1 hour ago, bmart

I was thinking how different it sounds to my 5th gens. 

Yep, nice quiet cams! Oops, did I say something wrong?? :fing02:

52 minutes ago, Grum

Yep, nice quiet cams! Oops, did I say something wrong?? :fing02:

Moderator! Ban this heathen!

That sounds like the sound of spring 😁

Someone (sorry their name escapes me)or on VFRworld, did a high tune up on a 6th gen motor circa 2009 ish. Similar to this but more so, got 120hp IIRC. Replaced Vtec valves with non-Vtec ones, skimmed the head for higher compression, retimed the valves. Plus intake & exhaust changes. 

Removing the V-Tec valve is quite simple.  
The machine itself fits the pins into the valve locking hole. 
they can be of such a size that the spring goes to the bottom
 (the valve now catches the pin and cannot move through the v-tec valve) 
and the other end of the pin is stuck on the inner edge of the valve cup so it cannot move. 
after that, just to the dyno to adjust the fuel mixture. 
I turned the holes suitable for the adjustment pieces in the upper end of the v-tec, 
because when I machined all the cams of the camshafts for more lift, otherwise the v-tec valves would have too big clearances.
Power commander fuel maps can be adjusted as long as there is a dyno bench and a competent guy doing it.

[image: vtec valve mod.png]

Well, the first dyno didn't go very well, horsepower dropped by 7hp and torque by 5nm over the entire rev range.
We stated that we need to set the timing of the exhaust cams to the original numbers and try again.
On Sunday, I adjusted the exhaust camshafts to the original numbers and did some test drives, 
the 3rd cylinder plug broke during the first test and the 2nd cylinder plug broke during the second test. 
The third test went very well, although the air was so cold that I didn't feel like going far for a ride when it was 2 degrees Celsius warm. 
I ordered new plugs and the dyno will be back in a week. 
I just started to wonder if the old plugs had any effect on the first dyno pull when the result was so bad.
So I can't say anything specific about the test drive yet, I need to get more miles under it.

Today I visited the dyno and now the camshafts are in their original settings. 
I don't really like the result.
Next I have to go and try the dyno with the original exhaust pipe, so that if that homemade exhaust pipe doesn't work correctly.
The engine starts well when cold, but not so well when warm.
I was wondering if there is too much compression or what could be the cause.

“to much compression” ??

I just bought a 7th gen lol

16 hours ago, Timuli

The engine starts well when cold, but not so well when warm.

That is usually a sign of valve clearances being tight. What were the clearances? Did you increase the lift by grinding the base circle of the cam or by welding and then regrinding the lobe?

It is interesting to see that having 4 valves operating in the lower part of the rev range doesn't increase the power. It seems that in the lower part of the rev range the engine can ingest enough air through a single intake valve to operate at full power. Same for the exhaust.

Edit; having all 4 long velocity stacks will make a slight increase in the 8-9k rpm, but a slight decrease in 9-10k rpm power. I've tested it in my thread on variable velocity stacks. If you want maximum power use all short stacks.

19 hours ago, Timuli

Today I visited the dyno and now the camshafts are in their original settings. 
I don't really like the result.
Next I have to go and try the dyno with the original exhaust pipe, so that if that homemade exhaust pipe doesn't work correctly.
The engine starts well when cold, but not so well when warm.
I was wondering if there is too much compression or what could be the cause.

[image: dynorun summer 2024.1.jpg]

20240520_155840.mp4

Anyone else have a Dyno in their living room? I guess the front door was open to let the exhaust out😁 (look at the video).

PS: there was a reason Honda decided on 2 valve ops in the lower rev range

10 hours ago, gropula

That is usually a sign of valve clearances being tight. What were the clearances? Did you increase the lift by grinding the base circle of the cam or by welding and then regrinding the lobe?

It is interesting to see that having 4 valves operating in the lower part of the rev range doesn't increase the power. It seems that in the lower part of the rev range the engine can ingest enough air through a single intake valve to operate at full power. Same for the exhaust.

Edit; having all 4 long velocity stacks will make a slight increase in the 8-9k rpm, but a slight decrease in 9-10k rpm power. I've tested it in my thread on variable velocity stacks. If you want maximum power use all short stacks.

Cam shafts are machined by grinding.
When starting when it's really warm, it feels like the starter can't turn the machine properly. 
I'll have to check the valve clearances after the next Dyno because I guess the standard exhaust works even worse,
but I want to test it before I start disassembling the moped again. 
Along with adjusting the valves, you also have to measure the camshaft intake and exhaust timings with a dial gauge to see 
if they are at all within the values given by the factory.

I'm not really looking for maximum power, but maybe I'd like more torque. 
I still have one cam shaft from which I machined by grinding only the 8 valves that work normally all the time
 and I left the original ones that come with 6800rpm

Now it was time to test the differences between the original and self-made exhaust pipes.

Homemade seems to work a little better.

The redline is the original exhaust

Next, we'll get to work getting the degrees on the camshafts right.

Now the camshafts were adjusted to hopefully working values. 
I can say that adjusting the witch's cam shafts is not an easy task for a first-timer, but it's also done now. 
Hopefully I can get to the dyno this week.

At the same time, I measured the cylinder pressures

1cyl 200psi

2cyl 190ps

3cyl 180 psi

4cyl 190 psi

Original camshaft values

lobe center intake 97.5
max lift 8mm

lobe center exhaust 102.5
max lift 8mm

modified camshaft values

intake 96 
exhaust 98 

new setup

intake 99
max lift 8.95mm

exhaust 103
max lift 8.8mm

[image: 20240601_134734.jpg]

[image: 20240531_204439.jpg]

Again a new dyno pull was done and adjusting the lobe center of the camshafts did not affect anything.  
I have to call the camshaft maker tomorrow and ask if he can tell me what steps the cams should be set to.

And then just go to the garage again to attack the bike, that's how the Finnish summer goes :)

gropula, 5/21/2024 at 3:37 AM

That is usually a sign of valve clearances being tight. What were the clearances? Did you increase the lift by grinding the base circle of the cam or by welding and then regrinding the lobe?

It is interesting to see that having 4 valves operating in the lower part of the rev range doesn't increase the power. It seems that in the lower part of the rev range the engine can ingest enough air through a single intake valve to operate at full power. Same for the exhaust.

Edit; having all 4 long velocity stacks will make a slight increase in the 8-9k rpm, but a slight decrease in 9-10k rpm power. I've tested it in my thread on variable velocity stacks. If you want maximum power use all short stacks.

If two valve operation cost power at low rpm, that would mean that the VTEC mechanism was included solely to increase the perception of performance when VTEC hit (by way of an artificial power suppression below the crossover). Such a gimmick would be stupid on any bike (as I think the perceptible vtec transition hurts rideability at the limit), but I could see it existing as a marketing gimmick on a super sport (which are already rubbish at low rpm, and shouldn't be anywhere near the crossover point when being ridden fast anyway). On a sport tourer that needs to be enjoyable at lower rpm? Unforgivable. I actually regard VTEC to be a low rpm feature more than a high rpm one (at least our "vtec" operating on number of valves, as opposed to the automotive version which switches between different profiles). If you remove vtec from our bike, the only place performance changes at all is below the crossover. 

The reason (as I vaguely understand it) that the two valves perform better at low rpm relative to four valves is that is maintains intake charge velocity into the cylinder. This is apparently good for a more homogenous air fuel mixture in the cylinder as well as complete evacuation of exhaust gasses from the prior cycle. So, more gas/air into the chamber, and a more complete burn thereof. So not just a boon to power but efficiency as well.

18 hours ago, IanSummers

If two valve operation cost power at low rpm, that would mean that the VTEC mechanism was included solely to increase the perception of performance when VTEC hit (by way of an artificial power suppression below the crossover). Such a gimmick would be stupid on any bike (as I think the perceptible vtec transition hurts rideability at the limit), but I could see it existing as a marketing gimmick on a super sport (which are already rubbish at low rpm, and shouldn't be anywhere near the crossover point when being ridden fast anyway). On a sport tourer that needs to be enjoyable at lower rpm? Unforgivable. I actually regard VTEC to be a low rpm feature more than a high rpm one (at least our "vtec" operating on number of valves, as opposed to the automotive version which switches between different profiles). If you remove vtec from our bike, the only place performance changes at all is below the crossover. 

The reason (as I vaguely understand it) that the two valves perform better at low rpm relative to four valves is that is maintains intake charge velocity into the cylinder. This is apparently good for a more homogenous air fuel mixture in the cylinder as well as complete evacuation of exhaust gasses from the prior cycle. So, more gas/air into the chamber, and a more complete burn thereof. So not just a boon to power but efficiency as well.

My guess is that VTEC,  the flapper, and the change to chain driven cams are mostly noise reduction measures. Yes, your reasoning about intake charge velocity and fuel mixing is good, and it probably does matter a little bit. In practice though, 5th gen and 6th gen get almost exactly the same fuel consumption. Despite the fact that 6th gen also has 12 hole injectors with better fuel atomisation and the chain produces less drag than gears. Only 8th gen that has much better ECU, slightly milder cams and higher compression gets noticably better fuel economy. For reference, the full throttle dyno chart of 8th gen has the flattest 14.7 AFR curve I've ever seen. It's not even a curve, it's a line. It's probably running stoich at any part throttle and RPM.

48 minutes ago, gropula

My guess is that VTEC,  the flapper, and the change to chain driven cams are mostly noise reduction measures. Yes, your reasoning about intake charge velocity and fuel mixing is good, and it probably does matter a little bit. In practice though, 5th gen and 6th gen get almost exactly the same fuel consumption. Despite the fact that 6th gen also has 12 hole injectors with better fuel atomisation and the chain produces less drag than gears. Only 8th gen that has much better ECU, slightly milder cams and higher compression gets noticably better fuel economy. For reference, the full throttle dyno chart of 8th gen has the flattest 14.7 AFR curve I've ever seen. It's not even a curve, it's a line. It's probably running stoich at any part throttle and RPM.

I'm surprised to hear it's 14.7 even at wide open throttle on a stock bike. Even in cruising conditions, I'd have thought it it would be low 14's. The curves I've seen on tuned dyno graphs show an afr curve between 13-13.5. This suggests Honda left power on the table just for the sake of efficiency even at wide open throttle? That would be surprising. 

[image: image.thumb.jpeg.2238c8d4cb8dcfb8189d6d058cec0ee0.jpeg]Taken from VFRdiscussion headers thread. 8th gen, blue is stock. Stoich, flat as a pancake. Red is headers, green headers with fuel mapping. I was baffled by it as well. Now that I think about it, it's possible that the o2 sensor wasn't even used, and this is just blank setting when no data is collected. Detonation could be an issue at full throttle.

Edit: ok, now when I think about it, it's certainly not accurate data, or no data. Installing headers improved the airflow, so it's expected for the stock map to be lean, as it is where most gains are made. My bad, misinterpreted the data. It's probably rich stock.

3 hours ago, gropula

[image: image.thumb.jpeg.2238c8d4cb8dcfb8189d6d058cec0ee0.jpeg]Taken from VFRdiscussion headers thread. 8th gen, blue is stock. Stoich, flat as a pancake. Red is headers, green headers with fuel mapping. I was baffled by it as well. Now that I think about it, it's possible that the o2 sensor wasn't even used, and this is just blank setting when no data is collected. Detonation could be an issue at full throttle.

Edit: ok, now when I think about it, it's certainly not accurate data, or no data. Installing headers improved the airflow, so it's expected for the stock map to be lean, as it is where most gains are made. My bad, misinterpreted the data. It's probably rich stock.

I like your conclusion, I think you've got it sussed out. Sorry to Timuli for the thread jacking, I'm looking forward to seeing how your build progresses. 

You won't suffer detonation with this configuration. Unlike carbs, the Fi will self adjust some based on certain engine parameters. So a change of filter or exhaust with normal header size dimensions will not affect the running. Bigger changes, to intake & exhaust will require additional fuel metering changes. The 5th gen has better ignition timing based on RC45's & won't tolerate hardly any extra advance. The 6th gen has a narrower included valve angle & a remapped ignition timing because of the Vtec valving & will tolerate more advance in the mid-range. 
 

I have my 5th gen up to 118rwhp & have run it as lean as 14.4:1 AFR. It works well at that AFR producing 50+ mpg, but I have a Rapid Bike Racing module with fuel & ignition mapping, plus an accelerator pump function based on a MyTuningBike (MTB) wideband O2 sensor. 
 

I have reworked intake, RAMair, longer duration cams & a TBR exhaust system. This exhaust provided the measurements for the VFRd headers & I have confirmed they match the Ladybird Ti HRC RC45 replica system. So its as good as its going to get. The 5/6gens suffer from a lack of static compression ratio, but this is deliberate to allow you to run on cheap pump gas. More compression would up the power numbers, but restrict you to higher octane fuel. 
 

Have fun 👍