ESE's works engine tuner

**bucketracer** · 27th February 2012, 08:58

Attachment 258604

TeeZee I can see why your so keen to combine the two graphs, and with a power jet cut off as well, there is every chance the power spread could go from 8-13.5K, thats a massive 5,500rpm power spread. Thats unheard of from a stroker that makes any real power.

31 rwhp and 5,500 power spread now that would be a stroker with the same power spread as a std FXR150 and twice the power everywhere.

**husaberg** · 27th February 2012, 09:15

Originally Posted by 2T Institute

Suzuki built a water cooled disc valve 125 race engine (basicaly 1 cylinder off a RGB 500) was only raced a few times in Japan and Malaysia. There is a pic of it but do you think I can find it

Not the one you were talking about I thought there was a pic of it on this thread but i can't seem to find it.
but this below is similar ilk to quite a few local buckets.

Brent Jones in CHCH had something similar made in the late 70's early 80's pretty sure this UK version, has been posted before at of the start of the thread though somewhere
Attachment 258605 Attachment 258606 Attachment 258607
SCITSU
The bike was built by Nick Carpenter UK, it is one of only two produced.
The engine uses a Kawasaki motocross engine, disc valve with Suzuki RG500 cylinder.
Sounds a bit familar doesn't it.

Nice frame though.
Don't know about the carb poking out the side though i doubt it will catch on

Also seen this US one Suzuki 125 . I guess it is a RM125 motor though.
Attachment 258610
This bike is all hand built in 1978 to compete in the 125 gp wars against honda mt 125r, yamaha td and tz in southern california. it wound up being a skunk works project out of suzuki. world champion eddie lawson once rode this bike. (although never raced as he was under contact by kawasaki) the frame is all hand made out of 4130 cromoly and the tank and tail are hand formed aluminum. every part on this bike has been hand formed for the lightest possible weight and function. dry wight is 159 pounds! picture provided by jeff allen.

**Farmaken** · 27th February 2012, 09:37

Originally Posted by wobbly

A larger muffler ID exposes the wave fronts to more packing material area, thus reducing noise - a step back down from the perf core to a smaller exit tube will increase the wave amplitude and make MORE noise.
Stinger/muffler lengths/diameters are very hard to analyse,only way is to cut and try, but with small dia mufflers - generally shorter is better for power, but not noise.

Cheers Wobbly,(and Frits ) makes sense about the increased surface area. No end cap reduction for me then !!

**F5 Dave** · 27th February 2012, 10:39

Originally Posted by bucketracer

TeeZee I can see why your so keen to combine the two graphs, with a power jet cut off, there is every chance the power spread could go from 8-13.5K, thats a massive 5,500rpm power spread. Thats unheard of from a stroker that makes real power.
. . .

pah! my GG Trials bike has easily that spread, - the secret is no expansion chamber.

. . .by real power, I hope ~8 or 9 qualifies.

**dinamik2t** · 27th February 2012, 10:52

Hey, TZ, your primary transmission gears are heli or straight cut?
I remember reading over the net a long time ago, that straight cut gears produce more noise, while heli are quieter, thus used in mass production 'civil' engines.
I don't remember seeing heli on any race engine. Straights must eliminate the side loads on bearings I believe.

Anybody has an opinion, performance wise?

**F5 Dave** · 27th February 2012, 10:57

on something like a twin or triple with a long crank it is a good idea. On a single I wouldn't get too worked up about it. theoretically you should lose less power, but I doubt you would notice it on the dyno even if you did cleverly engineer a straight cut set onto an engine with helicals. . . . well at least I didn't see it.

**dinamik2t** · 27th February 2012, 11:10

Actually I have found that my clutch basket is the same with Cr80, which has straight cut gear (same teeth too). I found a few crank gears and one fits the distance and tooth pitch, but needs some machining to fit the crank. So I wondered whether it's worth it..
Clutch basket and gear is lighter than the stock one, perhaps that could improve something.

ps. your post is devilish 6666 OUU

OUUU

**wobbly** · 27th February 2012, 11:40

Straight cuts only make more noise if they are not cut properly - too much backlash and they will chatter,also being in an oil bath helps heaps as in a RZ sidecover.
They do reduce side load on the crank bearings, the graph shows a couple of Hp gain up to peak, nothing dramatic.
The real gain is in reducing the ratio and dropping the torque load on the clutch.

**F5 Dave** · 27th February 2012, 12:02

So those two runs were done on different days? Just looks like curve is affected by conditions, or otherwise one could draw the conclusion that straights will lose power after 10,000 rpm compared to helicals. Looks like a jetting or ign movement.

**husaberg** · 27th February 2012, 12:42

Originally Posted by wobbly

Straight cuts only make more noise if they are not cut properly - too much backlash and they will chatter,also being in an oil bath helps heaps as in a RZ sidecover.
They do reduce side load on the crank bearings, the graph shows a couple of Hp gain up to peak, nothing dramatic.
The real gain is in reducing the ratio and dropping the torque load on the clutch.

My guess it the Poms got it a bit wrong with the Morris's then. Not that i am complaining I would hate to sound like a winy bitch

One of the engine selection criteria for Vanessa was straight cut gears.

I am not sure if she does have them in her as they seemed to mix and match depending on the market.
but they are available on differing models.(non competition as well i might add) as well as different gear ratio's as well.

I doubt weather there is much in it but every little bit helps.

Most all Honda's have straight cut gears and they are not loud. Where as most of the other makes use Helical gears on primary drives on there road/trail and straight cut on the competition models.

Very few competition engines have gears that are not straight cut. They also have very narrow contact patches as well.
I love those beautiful knife edged gears you see in competition engines of yesteryear ESP the Italians.

Virtual Chocolate fish to anyone (bar Frits or Wob) that can name this engine i am pretty sure we have one still in NZ and it does have a New Zealand as well as a Italian connection.

Note it has a cassette box I didn't realise that before. Also a interesting center joint for the crankshafts.

**F5 Dave** · 27th February 2012, 13:19

yeah old Hondas & Kawis seem to run straight cut. Must be cheaper to hob.

**marsheng** · 27th February 2012, 13:27

Hi Husaberg

Which Robinson book is the last attachment from ? (page says 109)

**husaberg** · 27th February 2012, 14:31

Originally Posted by marsheng

Hi Husaberg

Which Robinson book is the last attachment from ? (page says 109)

It the er... 2 stroke one.

A lot of people don't like it but it has some relevant info if you read between the lines.
The carburetor section which i admit i had never seemingly taken that much head of does describe a lot of stuff.

Are you starting to think those four strokes are a bit boring?
Anyway this is the book. Is Hitech books still in CHCH.

**Grumph** · 27th February 2012, 14:45

Straight cut Vs Helical....if you've got helical primaries, don't stress, they can probably be narrowed as they'd have been designed for long life. If you're building a motor from scratch, by all means use straight cut.

I've been through this with a 4 stroke which comes with helical primaries. Substituting straight cut gears led directly to regular crankcase cracking. And yes, they were very well engineered gears. Checking with experts in the field revealed that you swap the small end thrust of helicals for a greater "separating force" between the shafts. Sometimes it can be surprisingly large.
On the motor in question I now narrow the std helicals from around 22mm wide to approx 15mm - haven't broken one yet, so I could probably go narrower again.