Ns power.

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bloodnut
Posts: 334
Joined: Sat Jul 03, 2004 1:58 am
Location: New Zealand

Post by bloodnut »

Interesting Ian, did the 500 produce more torque down low?

Are they both running single ring pistons?

What radiators are you running, hows the temp?

And finally have you fiddled with the ignition yet?

cheers
Jared
if all else fails - gas it

ian wright
Posts: 155
Joined: Sun Oct 02, 2005 8:16 pm
Location: huddersfield

NS Power

Post by ian wright »

Hi Jared,
The 500 made around 3BHP more between 4 & 6000rpm, but everywhere else the 444 was better.

Using 2- Ring Pistons on both bikes.

Running Temp was around 75/80 Using standard re- con radiator

Ignition is standard.

I'm doing a race meeting this weekend on quite a short track, hopefully 70BHP will be enough here for setting the bike up. However think i'll need around 80BHP to do anything on the longer circuits. If you have any idea's on where the Horses are hiding please let me know!

steve d
Posts: 66
Joined: Sun Feb 27, 2005 12:46 pm

Post by steve d »

Hi Ian
Are you able to post up power and torque curves from your dyno runs?
It would be interesting to compare the shape of the curves etc between the 440 and 500 and mine.

I don't think this engine was originally designed as a 500, it may be that it works more efficiently with air flow through the transfers etc as a 400 or 440.

Certainly, if you invert a cylinder and look at the size of the transfer entries they look quite small compared to a later 2-stroke this may play a part I guess.

You've mentioned piston cutaways, the 500 kit I used has a full length skirt on the intake ( and with no intake holes) so intake open duration is less than the stock piston on the 400 and/or the 440 pistons you were using.

I'm not quite sure how relevant this is as you still have in any case the 2 ports either side of the intake which are not opened or closed by the piston.

I've just got back some carbs which have been bored out 2mm over stock, I'll be trying these to see if it makes a difference as bigger carbs seem to have helped on your 440,

Steve

ian wright
Posts: 155
Joined: Sun Oct 02, 2005 8:16 pm
Location: huddersfield

NS Power

Post by ian wright »

Hi Steve, I've tried to post curves on the site before, but my computer wont have it. I could photocopy them at work and fax them to somebody.
I was also on the phone with Terry Shepherd the other day and he agreed that modding the rear piston skirt would feed more fuel in and probably increase power.
Are the carbs you are boring out standard or NSR250?

bloodnut
Posts: 334
Joined: Sat Jul 03, 2004 1:58 am
Location: New Zealand

Post by bloodnut »

Hey All,

I have thought a bit about it . When you develop an engine you continually move from 1 restriction to the next restriction as you tackle the next most restricted part. This means there has to be some order to your development, ie you cant make your pipes to suit one engine displacement and then change it and expect them to still work, so you have to have a complete picture of the finished engine in your head and then work forward with that in mind, - or just progress through things in a natural order and dont go over board anywhere.

So my guess so far would be you need to;

1- Reed cage size, can't be made big enough but you need to maximise what you have, what model reed cage are you using? is there a larger one that will fit with a bit of grinding?

2 - Your ports will need a large amount of hoovering to make near 40hp per barrel (crank) but it could be done.

3 - Piston - this is the single most important component in your engine, next time you need pistons change to a single ring wiseco pro-lite, these are gp level pistons that are very reliable, alright you will have to change the ring every eight hours of racing - who cares great fun.

4 - Design your chambers to this set-up( the fattest part of your pipes diameter is determined by the diameter of the outlet/exhaust port (this is one of the advantages of going to the CR125 barrel as the exhaust outlet is 15% larger than the ns one could ever be), as well as matching your engine set-up ignition etc. Wobbly will do this for you if you like?

5 - Ignition - what can I say ? and the flywheel is heavy and huge, adapting a modern ignition would do wonders. We are developing a set-up that I would be happy to share with you.

6 - Carbs - have you bored them out and fitted a jet kit etc?

Also you can put a Kkevlar/alloy barnett clutch which will help the engines spin up much quicker, remember this is were they are getting all the horsepower in modern engines - less reciprocating mass, if you lose the heavy flywheel off one end of the crank and half the weight of the clutch on the other, put in light, low friction pistons on the ends of that crank you are going to reduce the strain on everything while making an awesome improvement in horsepower right through the range.

Good luck

Jared
if all else fails - gas it

steve d
Posts: 66
Joined: Sun Feb 27, 2005 12:46 pm

Post by steve d »

Hi,
Just ridden the 500 for the first time after jumping off a 250 last week.
Reminded how well these motors pull in the low/mid.

Had a good look at Ian wrights dyno sheets last week also.
Considering slightly different set ups ( his with bigger carbs/reeds etc)
- the curves are similar- mine making more in mid range , his slightly
better at 9-9500.

I guess pipes are the dominant factor ( ignition curve also - but not easy
to alter).

As we both use the same pipe kits , i wonder how the jolly moto pipes
fare?

The only 500 i know with these is Wavydavy. how about it Dave?- would
you be able / interested in running yours on a ( un? :) ) dyno ?.

Steve.

wavydavy
Posts: 374
Joined: Thu Dec 30, 2004 5:41 pm

Post by wavydavy »

Of course - I asked a while back if anyone knew of dyno near here I could use - am in Dept 46 in France. That's South West ish.....

Can travel within 50 or so miles.....

Dave

Racer
Posts: 227
Joined: Mon Jul 10, 2006 6:36 pm
Contact:

Re: NS Power

Post by Racer »

Hi Ian

Today I got two packages with the parts I bought from you on Ebay,. Thanx great. I see you have got incredible power gains, whit simle (and cheap) modifications. This is VERY interesting. Do you have Dyno charts available in your computer? If you have please send to: torhavn@tele2.no.Can you inform me on what main jet changes you did for each step? You have T-jointed all (high and low air correctors) what and were are they connected??

Thanx

Racer
ian wright wrote:Hi Mat,
Only dynoed bike with NSR carbs & standard airbox. I started off with a filter, rubber air horns & all the air corrector tubes blocked off =45BHP!
Remove Filter change jets= 55BHP
Remove air horns change jets =62BHP
Join all high & low air correctors together with T pieces=69BHP
Change jets = 72BHP

I did all this last year & have since discovered some aftermarket reed blocks that are worth another 5BHP! Modified YZ85.

Racer
Posts: 227
Joined: Mon Jul 10, 2006 6:36 pm
Contact:

NS400R airbox mods

Post by Racer »

Hi fellow blue smoke adicts

I have just serviced my all standard NS400R Rothmans. Went trough everything, checking brakes, head bearings, cooling system, carburettors, rubbers and reeds. The rubbers between carbs and reeds had startet to dry up and crack a bit. This was fixed with liquid rubber and rubberband, of that kind that melts up with the rubber surface when worked against each other. Its actually possible to make o-rings of this material. I guess this rubbers will stay some more years.
I tought it was time to modifie the airbox, to see if there was some gain.

My bike is all standard, with std jetting 122 mains. As many have experienced with this std setup, I experienced that the engine drops dead at 9800 rpm. I have had a feeling of that it was a bit rich over the hole rpm range, so I took the std foamfilter out, washed in hot soapwater. Dryed it and instead of soaking in engine oil and crush it, I put a light spray of K&N filteroil on the upperside before installing it again. Then i removed the two rubber inlets from the airbox lid. I then used the inner outled of this rubber as an template, and made two identical holes in each front of the lid. This did more than doubble up the std inlet area to the airbox. I do not use this rubber inlets anymore, just the four oval holes.

Then I took her out for a testride today, no other alterations was done.

I found that the sound of the engine at low rpm was crispier. It was more like the crackling sound of a RG500. from low rpm untill ca 6000 rpm you had a complete different intake howl, combined with the crispier exhaustnote. In my opinion, it also went better in the medium range of the rpm. From 6-7000 rpm the intake howl mostly disappeard and you only heard the exhaust, but crispier than before. It accelerated very good and it went untill 10 800 before it layed off. So this gave 1000 rpm on the top, and added power the hole way.

It confirms for me that When Honda designed this bike they tuned it in a rich mode, in the aim of reduced induction and exhaust levels. This is however at some cost in the power department. So Now I want to go further, and have to determine wich factor is to try next. Bigger carbs or bigger reed cages? Any suggestions anybody?


28.11.2006

Racer



Hey All,

I have thought a bit about it . When you develop an engine you continually move from 1 restriction to the next restriction as you tackle the next most restricted part. This means there has to be some order to your development, ie you cant make your pipes to suit one engine displacement and then change it and expect them to still work, so you have to have a complete picture of the finished engine in your head and then work forward with that in mind, - or just progress through things in a natural order and dont go over board anywhere.

So my guess so far would be you need to;

1- Reed cage size, can't be made big enough but you need to maximise what you have, what model reed cage are you using? is there a larger one that will fit with a bit of grinding?

2 - Your ports will need a large amount of hoovering to make near 40hp per barrel (crank) but it could be done.

3 - Piston - this is the single most important component in your engine, next time you need pistons change to a single ring wiseco pro-lite, these are gp level pistons that are very reliable, alright you will have to change the ring every eight hours of racing - who cares great fun.

4 - Design your chambers to this set-up( the fattest part of your pipes diameter is determined by the diameter of the outlet/exhaust port (this is one of the advantages of going to the CR125 barrel as the exhaust outlet is 15% larger than the ns one could ever be), as well as matching your engine set-up ignition etc. Wobbly will do this for you if you like?

5 - Ignition - what can I say ? and the flywheel is heavy and huge, adapting a modern ignition would do wonders. We are developing a set-up that I would be happy to share with you.

6 - Carbs - have you bored them out and fitted a jet kit etc?

Also you can put a Kkevlar/alloy barnett clutch which will help the engines spin up much quicker, remember this is were they are getting all the horsepower in modern engines - less reciprocating mass, if you lose the heavy flywheel off one end of the crank and half the weight of the clutch on the other, put in light, low friction pistons on the ends of that crank you are going to reduce the strain on everything while making an awesome improvement in horsepower right through the range.

Good luck

Jared[/quote]

Racer
Posts: 227
Joined: Mon Jul 10, 2006 6:36 pm
Contact:

Re: Ns power.

Post by Racer »

Hi all

Long time since anybody contributed to this thread (myself included). Since my airbox, carbs and exhaust mods I have dynoed my std NS and it gives 59-60 RWHP (SAE corrected on a Dynojet 250). It is good for a std engine,with above mods, considered our dyno is not particulary forgiving either.

This summer i also bought Jollymoto pipes (ATACs had to come of, wich I regret on my roadbike, but.....) With no alterations it peaks at 66 RWHP, not bad for a std 387 cc. I believe some more power is available with fine tuning, thus I have 130 MJ that i believe is too big.

If anybody is interested I cold try to post the dyno chards.


Racer
ESW Rotax 250 tandem twin racer, VFR400R Racer, NS400CR Racer, NS400R street special/VFR400R racer hybrid, Kawasaki S2 350, Yamaha RD500LC. RGV250 VJ23. Bianchi Motor Sport P2 "Compe Cliente" minimoto

Mark
Posts: 1360
Joined: Thu Oct 25, 2001 1:01 am
Location: Up Norf

Re: Ns power.

Post by Mark »

Yep, get them posted up.

I'd be interested to see how much power you loose in the mid range without the ATAC units fitted.

Top end is all very well, but I'd prefer more rideablity
If it ain't broke, fix it 'til it is.

Racer
Posts: 227
Joined: Mon Jul 10, 2006 6:36 pm
Contact:

Re: Ns power.

Post by Racer »

Hi Mark

Check my earlyer posts regarding this. There is also a dynoprint attached. You loose aprox. 5 HP at 6000 rpm without ATACs. If you want more midrange I have also made up some ATAC expander kits (same as JHA in Japan produced earlyer). This kit will raise midrange with additional 5 HP. I have also posted a dynoprint of this (Note that this prints are taken on different dynos in different time and climate conditions. The last print (with ATAC expander)is from our own Dyno)).

If you are interested in a set, please PM me. You can also visit our website at http://www.nwracing.no and check the dynoprints and other testing results as well.


Racer
ESW Rotax 250 tandem twin racer, VFR400R Racer, NS400CR Racer, NS400R street special/VFR400R racer hybrid, Kawasaki S2 350, Yamaha RD500LC. RGV250 VJ23. Bianchi Motor Sport P2 "Compe Cliente" minimoto

Racer
Posts: 227
Joined: Mon Jul 10, 2006 6:36 pm
Contact:

Re: Ns power.

Post by Racer »

Hi all

Two weeks ago I took the Jollymotos of my roadbike. I put my ATACs and gutted std pipes back on the bike. Speaking frankly, it was a big relief to have the midrange back on my roadbike. Jollymotos gave 6-7 more HP on top, with a very generous overrun, the downside is approx. 10 HP down at 6-7 000 rpm. While at it I also jetted down from MJ 130 to MJ122 (29 mm drilled out carbs). I have tried to load up the dynoprints, but they are too big, can anybody help?
The Jollymotos is now mounted in my NS racer with tuned engine. Had my first testrun on my dyno this weekend and it was promising: When hitting on the pipe at 63 HP, the clutchslip was massive, so I believe there is a HP well into the 70s. I have now turned some 3 milimeter shims on my lathe, so I hope the clutch is stronger when testing next time.


Racer
ESW Rotax 250 tandem twin racer, VFR400R Racer, NS400CR Racer, NS400R street special/VFR400R racer hybrid, Kawasaki S2 350, Yamaha RD500LC. RGV250 VJ23. Bianchi Motor Sport P2 "Compe Cliente" minimoto

Racer
Posts: 227
Joined: Mon Jul 10, 2006 6:36 pm
Contact:

Re: Ns power.

Post by Racer »

Hi all

Just trying to post up my dynotest with gutted std pipes, compared to Jollymotos.
You do not have the required permissions to view the files attached to this post.
ESW Rotax 250 tandem twin racer, VFR400R Racer, NS400CR Racer, NS400R street special/VFR400R racer hybrid, Kawasaki S2 350, Yamaha RD500LC. RGV250 VJ23. Bianchi Motor Sport P2 "Compe Cliente" minimoto

Racer
Posts: 227
Joined: Mon Jul 10, 2006 6:36 pm
Contact:

Re: Ns power.

Post by Racer »

Hi all

:roll: Bit of a struggle uploading the dynoprint.............
Dynotest Jollymoto 163 kb.pdf
Dynotest Jollymoto 163 kb.pdf
Racer
Dynotest Jollymoto 163 kb.pdf
You do not have the required permissions to view the files attached to this post.
ESW Rotax 250 tandem twin racer, VFR400R Racer, NS400CR Racer, NS400R street special/VFR400R racer hybrid, Kawasaki S2 350, Yamaha RD500LC. RGV250 VJ23. Bianchi Motor Sport P2 "Compe Cliente" minimoto

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