ESE's works engine tuner

[F5 Dave]

Well while we are talking about cooling I’ll throw in my radiator questions.

I’m readdressing my 500 (2 cyl RZ350 with 496 CPI barrel) & its temp issues. I’m not concerned with city riding, just backroads, open road & occasional trackday.

All the testing I’ve done around back suburb roads had temp around 55 deg so I was never worried. But once I got it a bit more legal I took it out on the open road & it was cruising at 100 on part throttle but 70 deg. Gosh, didn’t expect that. Up the Takas & under load it was maybe a bit hotter. Then roadworks & down to a crawl & she just rose to 99 where I got to the top & let her cool off. Down the hill was better of course.

So part throttle over heating. The Zeel ign doesn’t have TPS so I’m wondering if my 12.5:1 compression is contributing to the heat. I can take some out but don’t want to if I don’t need as its harder to put back. 1mm squish which is for a 250 (x2) roadbike pretty safe.

So back to the Rad. Space is very limited. A custom Rad would help but it would be a complex one to avoid wheel & funds aren’t likely to allow even a Chinese one. Currently with a ZX4 rad, so how to make best of what I’ve got?

Head feeds up to thermostat, which outputs to left top of rad which has a tank on either side. Outlet bottom right to pump.

So I can try running water wetter & un-flattening some of the fins that are bent closed (about 5-10%) seeing if that helps enough.

With this style of rad it seems you are lucky of the tank feeds from one side to the other using all the area. But I’ve never cut one apart.

It would seem an improvement to have the tank separated in half on the right & the inlet & outlet on the same side so the water flows Right to left, then down the tank & back left to right in the bottom half of the rad.

Looking at Wobs 400 set up I wonder if this is the case?


If I could find a thin rad I wonder if I could place this onto the front of the original & weld straps & cunningly tube them together (Ideally without looking to Frankeinbike).

Thoughts?

[wobbly]

Yep, thats exactly what its got = crossflow radiator, right hand tank split.
The other issue is the dumb water flow regime that came from the original RZ/Banshee.
Only way to help this is to machine inserts that allow some water next to the plug threads, but still have the wall to stop flow short circuiting over the head.

[TZ350]

A nearly definitive comparison of a RS125, Honda MC16 and MC21 frame weights.



RS125 = 11.5Kg

(I estimate 12kg if it still had the rear axle adjusters swing arm bolt and other equivalent engine mount hardware thats still on the other frames)



MC16 = 14Kg



MC21 = 17Kg.

[richban]

A nearly definitive comparison of a RS125, Honda MC16 and MC21 frame weights.



RS125 = 11.5Kg

(I estimate 12kg if it still had the rear axle adjusters swing arm bolt and other equivalent engine mount hardware thats still on the other frames)



MC16 = 14Kg



MC21 = 17Kg.

But which one will give you the best lap times?

[husaberg]

I was going to ask about the frame now you have so many. But don't you have a NX4 in the ESE armory as well.
You may see what i mean about the MC16 being the pick of the Honda frames to mod.
Those straight rails scream (channel me) a
The MC22 CBR250 swingarm is within a couple of mm of being a bolt in as well to the MC16 (for that Doohanesk look) shame its a bit longer.
Interesting thing with the NF4 is the steering bearing size weird as. Plus i don't think Hondas planing on making any soon either.

Well got it today. Surprised how light it all is. Fame, Swing arm, Forks, Rear shock all bolted up is 23kg.

?NF5?

[kel]

But which one will give you the best lap times?

My monies on the 16. The NF4 is too small for anyone over 5'6, and the 21 is made for 60hp.
More than 1 NX4 Husi.

[Ocean1]

Well while we are talking about cooling I’ll throw in my radiator questions.

Got an oil cooler in there somewhere?

[husaberg]

My monies on the 16. The NF4 is too small for anyone over 5'6, and the 21 is made for 60hp.
More than 1 NX4 Husi.

weight comparison is?
My moneys on the NX4 but the problem with the MC16 is the real lazy geometry in std spec.
But the rider is far more important it comes down to a total package.

Got an oil cooler in there somewhere?

I PM'd him about adding a marine cooler as a supplementary cooler. i just Know he will hate it.
But size wise they are bloody efficent yeah will need a extra small rad and electric pump somewhere but if you shop around they are available for basically nothing

[jasonu]

A nearly definitive comparison of a RS125, Honda MC16 and MC21 frame weights.



RS125 = 11.5Kg

(I estimate 12kg if it still had the rear axle adjusters swing arm bolt and other equivalent engine mount hardware thats still on the other frames)



MC16 = 14Kg



MC21 = 17Kg.

Hey Chris, how about weigh my NX4 frame and SA and post the results.

[richban]

My monies on the 16. The NF4 is too small for anyone over 5'6, and the 21 is made for 60hp.
More than 1 NX4 Husi.

Unless you mod it to bits. ( probably easier to make a new frame ) you are dreaming. Check the spec. lazy pig I think you will find. Best option is to just lighten the shit of of the monster 21 swing arm job done. Also the fame can be lightened heaps. Already got dibs on the 21 if rob wants to let it go.
MC16
Castor:26°
Trail: 103mm
18" rear wheel

MC21
Castor:23° 15'
Trail: 87mm
17" rear wheel

[F5 Dave]

Yep, thats exactly what its got = crossflow radiator, right hand tank split.
The other issue is the dumb water flow regime that came from the original RZ/Banshee.
Only way to help this is to machine inserts that allow some water next to the plug threads, but still have the wall to stop flow short circuiting over the head.

Beauty! I've never cut a rad open so didn't know how the bigger ones worked. Seemingly they are just made big enough, but I'm glad the split idea works, I'll do that. I'll give you a buzz for a sht cct thermo when I have some bills sorted out, unexpected trips to Auckland etc.

I'll pull the head off too so it can meet mr lathe. Do you think com ratio is worth pulling back?

[F5 Dave]

If I had room I'd plumb another small rad under the pillion seat blanking cover & mesh it, but running rad hoses about the bike, - well there just isn't room. Its in a RG250 chassis which is heavily braced.

[TZ350]

But which one will give you the best lap times?

That is the million dollar question.....

For completeness I weighed up a FZR250 3LN frame like mine.



Because the frame still had the triple clamp on it and I wanted a truer apples for apples comparison with the others.



I weighed the frame with a spare triple clamp sitting on it then without and deducted the difference to get the comparative frame weight.

Yamaha FZR250 3LN 15.5 Kg

So now we have:-

RS125 = 12.0Kg
MC16 = 14.0Kg
3LN = 15.5Kg
MC21 = 17.0Kg

MC16
Castor:26°
Trail: 103mm
18" rear wheel

MC21
Castor:23° 15'
Trail: 87mm
17" rear wheel

[Buckets4Me]

For completeness I weighed up a FZR250 3LN frame like mine.



Because the frame still had the triple clamp on it and I wanted a truer apples for apples comparison with the others.



I weighed the frame with a spare triple clamp sitting on it then without and deducted the difference to get the comparative frame weight.

Yamaha FZR250 3LN 15.5 Kg

So now we have:-

RS125 = 12.0Kg
MC16 = 14.0Kg
3LN = 15.5Kg
MC21 = 17.0Kg

can you re weigh the 3ln without the side stand and back brake master cylinder etc I'm sure there is another kg or 2 to loose there

[husaberg]

Unless you mod it to bits. ( probably easier to make a new frame ) you are dreaming. Check the spec. lazy pig I think you will find. Best option is to just lighten the shit of of the monster 21 swing arm job done. Also the fame can be lightened heaps. Already got dibs on the 21 if rob wants to let it go.
MC16
Castor:26°
Trail: 103mm
18" rear wheel

MC21
Castor:23° 15'
Trail: 87mm
17" rear wheel

Yokes with more offset sort the trail (and Visa Versa) no problems the steering head angle should be remembered is also an attribute of the set up with the respective ride heights and tire profiles by juggling both the geometry can be sorted.
The weight distribution is more problematic the reason i chose the MC16 frame (Rob has it now) was its straight narrow rails that made a simpler proposition to shorten correct the geometry.

I planned to jig a std NX4 frame to get the correct geometry. Then make the MC16 fit the jigged positions.

In the end i came across a NF4 frame not ideal (i would much rather have a NX4) chassis, but beggars can't be choosers.
Honda only made about 500 per year.

That is the million dollar question.....

For completeness I weighed up a FZR250 3LN frame like mine.
I weighed the frame with a spare triple clamp sitting on it then without and deducted the difference to get the comparative frame weight.

Yamaha FZR250 3LN 15.5 Kg

So now we have:-

RS125 = 12.0Kg
MC16 = 14.0Kg
3LN = 15.5Kg
MC21 = 17.0Kg

Actually surprised at the FZR esp considering it has the side stand still fitted.
Weight of course is only one factor. Yes you wont get it to the weight of the NX4 though because they are real light gauge.
The Alloy used in the MC16 also won't require heat treatment after welding. the very late model Honda's supposedly do. Not sure re the MC21 though.
MC16's are also cheap and readily available.

I have glossed over eccentric inserts trail adj yoke yokes with the steering stem re-angled etc