ESE's works engine tuner

[katinas]

Here is pic of partial solution for the TM cylinder.
Cold water is squirted back over the transfer tops, with only small holes under the Exhaust duct cooling that with flow direct from the case below.

On TM 125 MX 2010 engines they use all flow over exhaust ( like on RGV 250 ). Later they used cylinders with all flow under exhaust .

Very interesting, when cooling intake and outlet is on opposite sides how to spread the flow, how much through cylinder and how much through head.

[yatasaki]

Setting the ratio litlle longer and using the tow of a faster rider might be a good strategy too but I think this depends on the speed you are racing at. In my case top speed is little over 80 kph.

In my story I'm more garelli rider
For that reason I was calculating all possible final ratios ,36 of them, then pick sprocket which would be universal for the rear wheel as it is much harder to change. My question is, (and partly answered by Frits some years ago on this thread) to choose between acceleration from corners AND acceleration to max speed and where max speed point should be .
In some cases you need crucial intermediate gear (let's say between 3rd and 4th) and to adjust that you have to change your final ratio in expense not using final gear 5th or 6th at all.
In your case Pavel I would go for huge 100cc kart overrev

[husaberg]

Attachment 340617
The cylinder on the left is not from an RS125 NX4 but from an early-model NF4 that was still strongly based on the CR125 MX-engine, with a hose feed from the pump to the side of the cylinder.
Later NF4 cylinders got their water from below, under the exhaust, through internal channels cast in the crankcases, as did all subsequent Honda racers,
including of course the RS125 NX4.

I'm still trying to get used to you guys talking about Honda NSR street models. I don't think we ever got any NSR street bikes over here. To me, NSR is the designation for a 250cc or 500cc Honda works racer (there never was an NSR125, only A-kits for a few selected riders and B-kits for riders with more money than talent).
The Honda production racers were called RS.
The cooling channel through the exhaust bridge was exclusively reserved for the late-model NSR cylinders.

You are correct i just went through and had a look 87,88,89,90, all as per you description the opposite to the CR125 ftrom what it was based on. As detailed from Katinas a few posts ago.
I missed that in my attempt to make sense of it.
Maybe as i said Honda just used the shortest hose to save money and they thought the RS feed was just better
it seems the side feed bung was just a left over from using the same castings. so it would seem late NF$ they made the change to the crankcases but not the Cylinder design. likely again to save money.

When i am talking re road NSR125 they are generally JC22 or JC20, i can't say if they had them in Holland but they did in Europe they also had the CRM125 which had the same engine.
i think They actually made the NSR125's in Italy. for Europe
https://en.wikipedia.org/wiki/Honda_NSR125
looking at this the Netherlands is one of the few countries in Europe who never got the NSR125
https://www.cmsnl.com/honda-nsr125_model1222/

Road NSR MC16,18,21 mc28 (pro arm) these were sold in Europe mostly i think as Grey Imports, no idea who got official imports
These were available with F3 kits for racing and quite a few came factory with Dry a clutch SP models etc etc.
Here is all the models quick details http://www.tso.us.com/parts-book/hon...x/model-id.asp
https://en.wikipedia.org/wiki/Honda_NSR250R

NZ never got the NSR125 and 150 other than as Grey imports
But we gotthe NSR250 extensively as official and used imports

The first model RS250 Production racer shared design with the NSR250 MC road bikes and many parts gearbox inc swap over.
Later RS250's and NSR250 Racers are different and have the chain on the other side

the NSR road bikes are all Crankcase reed designs and have a RC valve std
I think pretty much any NSR road bike will accept a RS cylinder of some sort, or the late PV Cr125 cylinder

Katinas has a NS250 which i think was MC14 which is more like a 2 cylinder NS400.
They had the in fashion Atac Valve over square bore and stroke.
NS250 and NS400 are cylinder reed designs but Honda cylinder reed Cr125 Cylinders bolt on.
NZ and Aussie were keen on the 250 as we had 250cc learner laws here. plus 250 proddy racing was very popular
Mick Doohan raised to prominence was on a proddy 250 two years later he was on NSR500
Matt from Tyger can correct the stuff i got wrong

[F5 Dave]

Think he'd start with his company name

[husaberg]

Think he'd start with his company name

http://tyga-performance.com/index.ph...qilg4v9m51fb87
I would agree if he spelt it English in the first place.

Awe shucks I had nearly all the letters though . I was at least 45% right.
I am not so sure i even spelt Matt right either now.
Just so we are clear TYGA TYGA TYGA is the company Name.
Purveyors of fine looking Bodywork and Exhausts and many other parts for Exotic sports bikes. Such as the NSR NC and CBR's plus RGV etc etc etc.
Although i also called Katinas a Japanese Sword. or a gay looking Suzuki twice in that post.

[katinas]

Yes Husa, CR 125 cylinders from 1983 to 1986 bolt on NS 250/400 case. NS 250 coded MC 11 and NS 400 NC 19.
I have all CR 125 reed cylinders from 1980 to 1986 and they differs every year. From 1985 they stick to 54mm stroke, but trans and ex windows height on 85 86 cylinders left the same like on previous 50,6mm stroke types. just cylinder was higher.
1980 1981 cylinder had huge transfers port and windows, maybe left from air cooled 1979 cylinder.
But very interesting to see how they changed cooling around EX port on these cylinders. Every year more and more cooling around EX and on 1986 cylinder they let water flow little under EX. In 1987 Honda stick to case reed engine on CR 125.

As about NS engines, both 250/400 with 50.6mm stroke crank, but there is so much differences everywhere.
NS 250 crank same as first RS 250 ND5 1984 1986 racers, crank web dia. 86mm ( on NS 400 93mm), big end 22mm ( NS400 24mm ) and both with same conrod length 109mm. Carbs on 250 28mm, 400 26mm. Ignition CDI on 250 simply goes with huge retarded after 10500rpm, on 400 no restriction.
Cylinders ( bore 250 - 56mm, 400-57mm but 400 for South Africa version 56mm) looks same from outside, but castings in cooling zone differs ( cylinder wall thick on 250-7.5mm on 400-10.5mm. And primary gears are very wide on 400.
All indications on NS 400 shows that maybe Honda engineers started 3 cylinder street project with 500 cc in they minds. But maybe after some tests found too much warm from engine, and decide lower capacity, but this is just guess.

First street NSR 250 MC 16 cylinders had much narrower EX windows than later MC18 21 28, but biggest change on later mC21 28 was bigger and heavier crank with thicker stronger conrods ( mc16 18 96mm dia. big end 24mm, MC21 28 100mm dia big end 25 mm.) F3 crank for mc16 18 goes with stronger RS 250 NF conrods.
And one interesting thing on crankcases - the space between crank web and crankcase upper wall that left for mix flow on front cylinder, on MC21 28 much smaller than on MC 16 18. And not because of the bigger crank web, but castings lower. More flow between crank webs.

[F5 Dave]

Think they just decided that Japan was dominating market and with 400cc barrier that's what they'd sell most of. Suzuki did 400 and 500cc versions. Seemingly Yamaha though a 400cc, 500cc replica was just not a 500, but must have questioned their logic when the others made 400s.

[katinas]

Think they just decided that Japan was dominating market and with 400cc barrier that's what they'd sell most of. Suzuki did 400 and 500cc versions. Seemingly Yamaha though a 400cc, 500cc replica was just not a 500, but must have questioned their logic when the others made 400s.

So for 400cc NS engine had huge material reserve everywhere.

I want to ask you about your project pistons again. As cylinders on your engine is with Boyesen are you tried Wiseco pistons with holes or without.
Thanks.

[husaberg]

Think they just decided that Japan was dominating market and with 400cc barrier that's what they'd sell most of. Suzuki did 400 and 500cc versions. Seemingly Yamaha though a 400cc, 500cc replica was just not a 500, but must have questioned their logic when the others made 400s.

I think Katinas might be onto it with the cooking model rather than full monty 500.
The never released the Fireblade for 2 years as they were worried about lawsuits.
Another reason might be how much trouble the MVX250 gave and how much the NS500 and RS500 vibrated.
i am not really sure how the NS400 is balanced i don't think its like the MVX with the heavy piston and rod in the upper center.
either way Making it a 400 meant it never had to directly compete with the full 500's

[F5 Dave]

So for 400cc NS engine had huge material reserve everywhere.

I want to ask you about your project pistons again. As cylinders on your engine is with Boyesen are you tried Wiseco pistons with holes or without.
Thanks.

Sorry I have no idea what you are asking. My current project is a CPI kit 496 RZ, nothing experimental just kit bits.

[katinas]

Attachment 340617
Honda works racer (there never was an NSR125, only A-kits for a few selected riders and B-kits for riders with more money than talent).
The Honda production racers were called RS.

I have one cylinder from RS 125 that differs from others. Seller said that this cylinder was used in WGP race, but I didnt know anything more.
All ports looks best that I ever see, but one thing is very interesting. Looks like they added some material to normal production cylinder from C side for bigger B ports.
But I cant understand how they do that, additional casting form or welding on. Add photo

[katinas]

Sorry I have no idea what you are asking. My current project is a CPI kit 496 RZ, nothing experimental just kit bits.

Yes this is about CPI cylinder block pistons. Just interested are pistons inlet skirt with two windows like on most pistons with reed on cylinder configuration.

[F5 Dave]

Ahh. Yes as many holes as you can poke a stick at.

[wobbly]

Just a short note to Frits re the KZ class engines.
We have a blind on rails down each side of the main radiator , and with this in place the red warning light for 40*C comes on after about two racing laps so cooling on the grid isnt an issue.
Also if you rev a KZ on the stand there is a slight discernible vibration in the chassis ( pedals ) under 6000 rpm.
Above that level ( racing rpm ) there are no vibes to speak of at all.
At the 58 % balance factor most of these engines have - a balance shaft violates KISS for no reason ( or Occams Razor as I learnt just recently ).

[katinas]

Ahh. Yes as many holes as you can poke a stick at.

Thanks Dave,
As original Honda NS cylinder intake route is very similar to CPI, just Boyesen arranged downward more blocked from B, so I interested how piston looks like.