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Discussion Starter · #1 · (Edited)
Just thought I would put some info out there about the dynojet stage 1.

Warning,, please make sure you have serviced your bike before you start tuning, this will have a big impact on how your bike reacts and how you can best decide on which direction to take at each stage.

I have a motad front pipes, and a micron straight though end can, K&N filter.

The kit comes with 4 main jets in 4 different sizes, 116, 118,120 and 122.
The kit states that you have the needle on the 4th clip from the top, and 2 and a half turn out on the pilot screw..

After a total of 5 runs ive got it dialled in.

The 122 mains were to big, after 9,000 rpm it was like hitting a rev limiter, which told me that the main jet's were to big, so back in off with the carbs, put 120 mains jets in,, this time 2nd gear full throttle from 6,000 to red line just kept excellerating right into red, so this means I have the right main jet in.

Next I notised in 2nd gear full throttle, there was a lag/hole in the accelerating between 3-6,000 rpm, so I took the carb tops off, and dropped the needle by 1 space, by hiring the clip on the needle to position 3.
This got rid of the lag/flat spot as at this rpm it was causing the engine to run a fraction to rich, so by lowering the needle it leaned the mixture slightly.

Next I turned the pilot air/mixture screws to 2 and a quarter turns (EDIT, 2 and a half) out from fully turned in, this is your start up tick over circuit, when you do a throttle blip test, if the needle dips below tick over upon return, then it is running a bit rich, how ever if the needle hangs on its way down to tick over, then it is running lean..

I found that 2 and a quarter turns out (EDIT, 2 and a half) was the best possible result, and then balanced the cabs together with my morgan carbtune.
Then I went out again and did a few more WOT runs,

The results were excellent front wheel in the air in 1st 2nd, nice pull all the way to red line in every gear, no flat spots or back fires, and the cruising speed was very smooth, no surging or hunting.

So to sum up:-

Cbr900rrv 1997 uk

Dynojet stage 1

120 main jets
3rd clip position on needle jet down from the top
2 and a quarter turns out on pilot air screw. (EDIT 2 and a half)

I must point out that every body's bike and set up mite very slightly, and you may still have to do a bit of tuning to get your blade how you want it, but I thought I would put my info out there incase it helps some one in a jam.

Also, it helps to get a carb O'ring rebuild kit for each carb, as the old seals will be toast by now.

And if you can spare the money get your self a set of carb gauges to balance them all together when your done.

This post is for any one who may have ventured into doing there own dynojet install and mite just need a few words to help them on there way.

Every body rides there bikes differently, and these days with the amount of cameras on the road the vast majority of road riding, for the UK at least, is done at about the speed limit and you are never going to ride your bike flat out all the time.

The reason I fitted the kit was to update the engine and to make sure I should be getting more longevity out of my engine with it running right, if you don't agree with any of the above then so be it, every one is entitled to there own view of things.
ride safe and live long.
 

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Great info, thanks for posting your personal findings:thumb:

I'm sure this will help more than a few people down the road.
 

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You will likely notice that you still have a small stutter or a lull of power as you start to open the throttle just off idle especially when you whack it open. That is caused by the K&N filter. Those things actually hurt the overall horsepower delivery of the 96-99 900RR engines more than they help. In fact that is actually true with most K&N filters, but I have done dozens of 900RR's specifically and the K&N filters have never worked in favor of the bike.

I wrote an article about this for the RC51 years back, but a lot of the info I discuss rings true across the board
ROGUE RC51 Airfilter questions page


All that being said I miss my 97 model the most... I loved that bike. Sold it to a young man that killed himself on it about 2 weeks later

 

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Hi Bikerian
Can you tell me what the standard main jet size is in a 1997 rrv model please ? I don't have a workshop manual.
I have recently bought a 1997 rrv that has a non standard stubby end can, a standard air box and filter and someone has fitted 122 main jets, I assume from a dynojet kit ?
I want to put the carbs back to standard so any info would be most helpful.
Cheers
Andy
 

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Discussion Starter · #7 ·
Main jet size is 115 as standard, while you have carbs off, take the carb tops off, and if it is dyno jetted there will be groves in the needles to set the clip on for the dyno jet stuff.

remember that you will also have to change the mixture back as well, which is 3 turns out from fully and lightly screwed in, but count how many turns it is out already as you screw them in.

the last owner on mine put 118 mains in and turned the screw 3 1/4 turns out, this was done a while ago as the poor mans attempt at tuning, it ran rich and when you were past 5000 revs I was getting a weird rumbling feeling, so off they came, on went a new k&n air filter and a motad 4 in to 1 and i put the micron can back on, its a straight though no baffle and the dyno jet kit, runs great now.

Take your time doing it, and get your self a manual as soon as pos, every one should have one.
 

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You will likely notice that you still have a small stutter or a lull of power as you start to open the throttle just off idle especially when you whack it open. That is caused by the K&N filter. Those things actually hurt the overall horsepower delivery of the 96-99 900RR engines more than they help. In fact that is actually true with most K&N filters, but I have done dozens of 900RR's specifically and the K&N filters have never worked in favor of the bike.

I wrote an article about this for the RC51 years back, but a lot of the info I discuss rings true across the board
ROGUE RC51 Airfilter questions page

Interesting stuff sir! A little disconcerting....but interesting.... How would you tune a 94 blade to give real world drive ability?

It seems to me that it is not top end that makes motorcycles (or cars) feel fast for most of us, it is low down useable power that can be rolled on from standstill or a rolling start.... Without dead spots...
 

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Fortunately I have a clean set of what seem to be standard carbs from a low milage 1996 RRT. They have 115 mains, 40s pilots, the correct 13.7mm float heights, correctly sealing float needle valves, mixture screws now set to 3 turns out (they were at 2 and 3/4 turns out initially) and all jets and passages seem to be clear so im gonna fit them and balance them and hopefully the bike will then run as the manufacturer intended, even with the stupidly loud stubby end can.
Cheers folks
 

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Just thought I would put some info out there about the dynojet stage 1.

Warning,, please make sure you have serviced your bike before you start tuning, this will have a big impact on how your bike reacts and how you can best decide on which direction to take at each stage.

I have a motad front pipes, and a micron straight though end can, K&N filter.

The kit comes with 4 main jets in 4 different sizes, 116, 118,120 and 122.
The kit states that you have the needle on the 4th clip from the top, and 2 and a half turn out on the pilot screw..

After a total of 5 runs ive got it dialled in.

The 122 mains were to big, after 9,000 rpm it was like hitting a rev limiter, which told me that the main jet's were to big, so back in off with the carbs, put 120 mains jets in,, this time 2nd gear full throttle from 6,000 to red line just kept excellerating right into red, so this means I have the right main jet in.

Next I notised in 2nd gear full throttle, there was a lag/hole in the accelerating between 3-6,000 rpm, so I took the carb tops off, and dropped the needle by 1 space, by hiring the clip on the needle to position 3.
This got rid of the lag/flat spot as at this rpm it was causing the engine to run a fraction to rich, so by lowering the needle it leaned the mixture slightly.

Next I turned the pilot air/mixture screws to 2 and a quarter turns (EDIT, 2 and a half) out from fully turned in, this is your start up tick over circuit, when you do a throttle blip test, if the needle dips below tick over upon return, then it is running a bit rich, how ever if the needle hangs on its way down to tick over, then it is running lean..

I found that 2 and a quarter turns out (EDIT, 2 and a half) was the best possible result, and then balanced the cabs together with my morgan carbtune.
Then I went out again and did a few more WOT runs,

The results were excellent front wheel in the air in 1st 2nd, nice pull all the way to red line in every gear, no flat spots or back fires, and the cruising speed was very smooth, no surging or hunting.

So to sum up:-

Cbr900rrv 1997 uk

Dynojet stage 1

120 main jets
3rd clip position on needle jet down from the top
2 and a quarter turns out on pilot air screw. (EDIT 2 and a half)

I must point out that every body's bike and set up mite very slightly, and you may still have to do a bit of tuning to get your blade how you want it, but I thought I would put my info out there incase it helps some one in a jam.

Also, it helps to get a carb O'ring rebuild kit for each carb, as the old seals will be toast by now.

And if you can spare the money get your self a set of carb gauges to balance them all together when your done.

This post is for any one who may have ventured into doing there own dynojet install and mite just need a few words to help them on there way.

Every body rides there bikes differently, and these days with the amount of cameras on the road the vast majority of road riding, for the UK at least, is done at about the speed limit and you are never going to ride your bike flat out all the time.

The reason I fitted the kit was to update the engine and to make sure I should be getting more longevity out of my engine with it running right, if you don't agree with any of the above then so be it, every one is entitled to there own view of things.
ride safe and live long.
I disagree that your #122 mains were too big. My experience with my 919RRV proved that mine, when it experienced the same "rev limitter" experience after 9k rpm was the result of an extremely lean mixture. When my bike did this, I was able to identify this by blocking one of the stock intake runners with duct tape and during a test ride afterwards, I found the bike pulled much stronger above 9k rpm....so it was then that I knew a lean condition was the cause....after that I kept increasing main jet all the way to #130 where it began really improving, and at #135 it was even stronger. I left the mains at #135. See my thread titled 2 Years trying to get tuning right 97 CBR900RRV . Regards!
 

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Great right up :) I do love the advice and knowledge on here (y)

I was toying with the idea of a dyno jet kit but decided to go the full hog and do the Factory pro MOD.

  • Modify the airbox as pictured (CBR 900RR-V Build/ride Thread)
  • Add 140 main jets
  • add 3 washers to each needle
  • Drill out the two smaller holes (slides)
  • Cut all four springs (2/3 rings)
  • Add Pod Filter
So far it rides amazing, no over fuelling hard to say if it's any quicker as I went -1/+2 at the same time :)
 

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Great right up :) I do love the advice and knowledge on here (y)

I was toying with the idea of a dyno jet kit but decided to go the full hog and do the Factory pro MOD.

  • Modify the airbox as pictured (CBR 900RR-V Build/ride Thread)
  • Add 140 main jets
  • add 3 washers to each needle
  • Drill out the two smaller holes (slides)
  • Cut all four springs (2/3 rings)
  • Add Pod Filter
So far it rides amazing, no over fuelling hard to say if it's any quicker as I went -1/+2 at the same time :)
Awesome. I never looked into any kits or specific mods. After confirming I was lean by blocking half the air coming into the airbox and getting more horsepower/performance I just ordered a bunch of mains from #100-#140 and bought a few M3 washers. After 20 removals/installs of the carbs and trying every combination possible I ended up right around the same place you are with #135 mains, a total of 3 M3 washers under the stock needles, a #42 pilot and the fuel screw at 1.5-1.75 turns open. Now it pulls hard, and pulls the front wheel up at 1/2 throttle in 1st gear and also pulls much harder throughout the entire rpm range.
 
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