ESE's works engine tuner

[speedpro]

Normally there is a form of cushdrive built into the rear hub of the clutch basket. You should be able to see the springs it it uses springs though on smaller ones I've seen they use rubber blocks.
A bike I built years ago made so much torque it was smashing the cush drive up against the stops which were the rivets holding the clutch basket to the hub etc. The springs actually coil bound and shattered spreading little bits of spring all through the engine. I've rebuilt it a few times and now have extremely strong springs in the cush drive plus a beefier backing plate and upped the rivet size. It buzzes at part throttle because there's no give at light load but I've used it a bit without getting pieces of spring stuck to the sump plug.
Whip the clutch out and have a look. Generally there will be 3 rivets holding it all together. If you grind the heads off it will all come apart and you can check it out. If your bike is making lots more torque than the clutch was designed for the cush drive could be bottoming out transferring shock loads to other transmission parts.

[teriks]

Something like this?
http://pro50parts.neto.com.au/buy/pw...ive-gear/PW084
Now, a PW50 is not exactly a high performance bike...

[wobbly]

Frits does mean rubber shock absorbers in the back of the outer clutch basket, most engines have this.
Another pointer is to get the stock gears cryo treated, the hardening process for production gearbox parts is shortened to the least possible.
This means there is a heap of incompletely converted martensite within the structure - the cryo converts this remnant material and helps part strength immensely.

[SwePatrick]

Thanks for the tips Frits.
Just a couple of words,, I´m skipping info cause i thought you´d understand better than the normal internet troll.
What i meant with more revs on engine is to keep the poweramount i have, but move it more upwards in rpm band.
that will end up in less torque, but the same amount of work is beeing done.(the work is a product of torque and movement, therefor called effect(effekt in sweden, equals to what torque and turning have produced))

My dynosheet says to me i am on a good track with power, it ended up in 21.34hp at 8600rpm(due to carb problems), but engine revs about 15k.
That should be around 23-24hp in engine on that rpm(8600). that is as i see it quite good.

And the third way you are talking about,, the engine has rubbercushions on clutch, i have just inspected them, no problems there.
And the gear shredded going upwards in rpm band, no clutch no shifting, just torque pulling hard.

Bear in mind, the gearbox is designed for about 15hp engines.
I just find it as a receit that i have succeded with something.
No hanging head here.. just laughing at the shredded gears.
Quite comfortable problem i might say

[SwePatrick]

Frits does mean rubber shock absorbers in the back of the outer clutch basket, most engines have this.
Another pointer is to get the stock gears cryo treated, the hardening process for production gearbox parts is shortened to the least possible.
This means there is a heap of incompletely converted martensite within the structure - the cryo converts this remnant material and helps part strength immensely.

Yes, cryotreatment could give me some more marginals.
But, look at the gears again.
The cogs are just fine, no problems.
i just kind of cut the gear in 'half'

Later watercooled CR80´s have the 'dogs' on gears 'closed' at one side of the gear, this should be much harder to 'cut in half'
and the gears do fit in the gearbox with small mods.
Even early Elsinore 125, around 1975 can fit with small mods.

Rgds.


edit: what i talked about with 'closed' dogs.


the MT8 gearbox i have just shredded is the dogs all the way thrugh the gear, thus making it very weak.

[dinamik2t]

It's what I used to know as cushions then. Here:



I guess those two springs-shocks are what you guys described earlier.
And since Patrick is dealing with CR80 parts, here's its clutch basket:

[husaberg]

Yes, cryotreatment could give me some more marginals.
But, look at the gears again.
The cogs are just fine, no problems.
i just kind of cut the gear in 'half'

Later watercooled CR80´s have the 'dogs' on gears 'closed' at one side of the gear, this should be much harder to 'cut in half'
and the gears do fit in the gearbox with small mods.
Even early Elsinore 125, around 1975 can fit with small mods.

Rgds.


edit: what i talked about with 'closed' dogs.


the MT8 gearbox i have just shredded is the dogs all the way thrugh the gear, thus making it very weak.

I actually have a whole brand new "old stock" 76 CR125m (360 center code) gearbox. well at least 80% of one if not more.
kicking around in the shed.
But from what i understand Speedpros put 30 hp through his mb50 gearbox plenty people have put at least mid 20's through theirs without much issue is that the first one you have blown or is it one of many? I realise the drag racing is going to be hard on the box but just asking.
the 87 gearbox defiantly has in my experience closer ratios improved plates Steel rather than alloy and non pulp friction plates than the air cooled 80's but i seem to remember you saying the aircooled ones you had were closer ratios.

I wonder if the fact the gears are 30 years old and have possibly had a rough life as well.
The other option would be go to the 5 speed, These are a bit beefier as well.

[speedpro]

I was a bit surprised a cog broke as well due to my own experiance. My sidecar only made 19.9hp but the gearbox got heaps. You could really clutch it hard being a sidecar without it trying to spit you off which must have upped the load on the cogs. My bucket gearbox has been faultless apart from when I ran the oil a bit low at Taupo and scorched a few gears and selector forks. It's an MB50 gearbox, similar to a CR80 I understand, and designed for very modest power levels. My old 22.5hp bucket never had a gearbox problem and the 30hp one looked fine when I had it apart recently.

[SwePatrick]

I forgot to mention.

My Kawasakicylinder is stated '38hp' from factory, if true? i dunno
I know they were dynoed to 27hp at 11000rpm´s as std from factory at the rearwheel.
Now it is 132cc and way tougher tuned than when it left the factory.


Little setup:
40mm carb
V-forve reeds(ported)
15-1 compression
Cylinder tuned to make peak hp at ~13k, std is about 11k
Homemade pipe, with theories from old GP racer guy Peter Sköld.(R.I.P)

I dynoed 21.34hp at 8600rpm(at rear wheel) and engine running a bit lean just before it died.
If running dyno again now when carb is sorted out, i would figure i´d dyno about 23hp at the same rpm, and add a couple of hp´s to reach 'engine power'.
The engine pulls HARD all the way up to ~14km but i figure peakpower is at ~13k.
If one is allowed to dream,, i think engine power should be in the area of 40hp+

So why i shredded the gear isn´t hard to understand
My first post about the gears was mentioned to be a bit funny also.
But as i don´t smear down all my posts with smileys they can be misunderstood.

Rgds.

[speedpro]

I wouldn't take too much notice of the factory claims regarding horsepower. Pete Sale, a respected local tuner, and I used to have a few good laughs about the "real" numbers obtained on his dyno compared to the claimed numbers. Some of the "good" tuning stuff was bollocks as well, like FMF fatty pipes that he tested.

To quieten that sceptical little whisper I keep hearing it would be good to get your bike on a dyno and running properly and post some numbers.

[dinamik2t]

Actually, Patrick, no hard feelings, but 40 (you meant wheel, right?) hp from such an oversquare engine isn't a lot?
It would be around 47 crank or around 12.4 bar BMEP, which is manageable I guess; except the time-area needs vs numbers being large, especially at 13k rpm. I am no guru here, but it seems hard to accomplish.
Perhaps on a narrow-band, dragster basis?

[SwePatrick]

I´m talking 40+ at engine.. not wheel.
And yes, i find factorynumbers quite funny.
Therefor i say i have dynoed 21.34Hp at rear wheel at 8600rpm(running lean)
And the factory kawa wich i have taken the cylinder from has dynoed 27hp at rear wheel ad ~11000rpm.
(I don´t see it impossible on an oversquare engine, i have almost the same time/portarea as a GP racer engine.)

All the other number are 'daydreaming'.

I thought you figured that out also.

well well.
I´ll stop posting then if you can´t read my bad language skills.

[Frits Overmars]

Perhaps on a narrow-band, dragster basis?

Narrowing the power band down from its natural 'racing two-stroke' character will not raise peak power, but lower it.

[speedpro]

Geez. Don't take any of this the wrong way. Me personally, I want to see what it's making and then when you take it to the track how it goes against other competitors.

[SwePatrick]

What track?

I think you got it all wrong.. this is a 'moped' that is run at club mettings at 1/8mile straight line.
I just wanted to build an overkill moped.

And why that 'geez'?
Do you think it´s impossible to get 40+ hp at engine with hometuned 132cc engine?
If so, you need to look further than inside your box.

Such a lame statement..