ESE's works engine tuner

[richban]

I am very impressed with your setup and the dial gauges for checking flow at different valve lifts.........

Yep big brothers workshop is wonderland for petrol heads. That engine will be stroked 1.5 up and runs a standard piston size takes it to 156. Hoping to gain some toque over the other engine. Also finished the megaphone that I tested at BOB. It sounds rather angry and added some nice mid and top end power on the track. Needs a dyno comparison to make sure I wasn't just dreaming. Then the ignition and we are ready to take on you 2 stroke lads.

[Yow Ling]

Is increasing the stroke to allow 156cc within the rules ?
the way the rules are written the capacity limit is 150cc with allowance for overboring.

Stroking and overboring are different fish

Is this mod within the rules , or just outside?

I realise plenty of people run +2.0mm pistons as that is a bit of an oversight in the rules, be interesting to hear others take on it

24.2.3 The maximum capacity for rebored engines shall be:
F4 2 stroke 55-100cc - 104cc
2 stroke 55-125cc air cooled - 130.5cc
4 stroke 55-150cc – 158.09cc
F5 2 stroke 0-50cc - 53cc
4 stroke 0-100cc - 104cc

[Bert]

Is increasing the stroke to allow 156cc within the rules ?
the way the rules are written the capacity limit is 150cc with allowance for overboring.

Stroking and overboring are different fish

Is this mod within the rules , or just outside?

I realise plenty of people run +2.0mm pistons as that is a bit of an oversight in the rules, be interesting to hear others take on it

One would suggest at as long as the maximum capacity isn't breached then all good.
Technically you could argue that Rich has stroked his motor (sleeve down the bore then gone out to the second/third rebore; that happens to be the same size as the original)....
There is nothing in the rules that state that a motor has to stay the same spec's as it was first constructed.

Plenty of us have gone the other way and de-stroked two stroke motors to run larger pistons and stay'ed within the 104 limit.

Maybe Speedpro could comment on this?
(or read http://www.kiwibiker.co.nz/forums/sh...68694-6/page21)

The biggest issue I see is that fact that us poor suffering 100cc two stroke riders are really constrained by the 104 limit; 106-108 would open up plenty of very cheap piston options (i.e. Kart pistons; ~$45-$55) without the need for serious stroke changes (would still require significant engine work but)...
and really would it make any real extra power??? Surely <1HP max... but it would bring the cost down; anyone brought a RG400 piston lately?

Maybe a rule change could be no more than 8cc oversize for all F4 motors that would be fair wouldn't it?
especially given the fact that 150cc to-158cc is nearly 10% of our entire motor size!!!

[TZ350]

It sounds rather angry and added some nice mid and top end power on the track. Needs a dyno comparison to make sure I wasn't just dreaming. Then the ignition and we are ready to take on you 2 stroke lads.

Take on us 2-stroke lads....... what..... we are already running, trying to catch you 4-stroke guys up......

Maybe a rule change could be no more than 8cc oversize for all F4 motors that would be fair wouldn't it?
especially given the fact that 150cc to-158cc is nearly 10% of our entire motor size!!!

I agree, 8cc would put more inexpensive piston options within reach, like the KT100 cart piston for 106cc on a GP100.

Spreedpro uses an offset bigend pin in his MB100 engine thats running a KT100 piston to keep within the capacity limit...

[SS90]

I don't think it will be too long before the two strokers disappear from the diesels, but like Burt writes, an issue is cost..... Piston selection for the current displacement limits things somewhat, its not so much the dispacement that is the issue, but rather the production of suitable pistons for the bore/stroke ratios.

Just make it 110cc and open carb... And 133cc 24 mm carb...problem solved.

[richban]

Is increasing the stroke to allow 156cc within the rules ?
the way the rules are written the capacity limit is 150cc with allowance for overboring.

Stroking and overboring are different fish

Is this mod within the rules , or just outside?

I realise plenty of people run +2.0mm pistons as that is a bit of an oversight in the rules, be interesting to hear others take on it

24.2.3 The maximum capacity for rebored engines shall be:
F4 2 stroke 55-100cc - 104cc
2 stroke 55-125cc air cooled - 130.5cc
4 stroke 55-150cc – 158.09cc
F5 2 stroke 0-50cc - 53cc
4 stroke 0-100cc - 104cc

I don't see a problem with the stroke. As Bert says plenty of 2 strokes have been stroked for piston changes over the years. As long as it wasn't a 160 like it almost was with the wrong size crank pin. 2mm each way.

[richban]

I don't think it will be too long before the two strokers disappear from the diesels, but like Burt writes, an issue is cost..... Piston selection for the current displacement limits things somewhat, its not so much the dispacement that is the issue, but rather the production of suitable pistons for the bore/stroke ratios.

Just make it 110cc and open carb... And 133cc 24 mm carb...problem solved.

Well if Speedpro is making 29.2hp within the rules then you 2 smokers can stay where you are. I am heading to the US to live soon and the loacal rules in Porland are 105cc water Cooled 2 stroke...Unlimited Mods 210cc air cooled 4 stroke ....Unlimited Mods 150cc water cooled 4 stroke ....Unlimited Mods They don't even have an air cooled option from what I se they are running dirt bike engines in everything. KX CRF ect

[Bert]

....I am heading to the US to live soon and the loacal rules in Porland are 105cc water Cooled 2 stroke...Unlimited Mods 210cc air cooled 4 stroke ....Unlimited Mods 150cc water cooled 4 stroke ....Unlimited Mods They don't even have an air cooled option from what I se they are running dirt bike engines in everything. KX CRF ect

the two strokers are mainly based on 85cc MX motors taken out to 100cc ish.. Almost the same rules as Australia..
one has to remember that there was not a lot of little Japanese road bikes imported into the US to make an aircooled rule with...

Maybe 85cc are the way of the future of F4 (my annual rant that will shot down again for the sixth year running)

[SS90]

Well if Speedpro is making 29.2hp within the rules then you 2 smokers can stay where you are.

Im really not doubting this but, I have to say that 29 ps from 100cc is VERY impressive, by anyones standards.

Is there a dyno graph of this?

Totally feasible for sure, but still impressive.

Looking at the pipe design from the images he has posted, I am surprised.

[ajturbo]

Maybe 85cc are the way of the future of F4 (my annual rant that will shot down again for the sixth year running)

bert,... you paint your own target on yourself.... and i know where to get a paintball gun from.........

in saying that.. can i bore the poor old RG50 out to 85cc???

[ajturbo]

hey guys... i sooon will be living up your way... i will have to pop around one day... with the mighty GT...

oh and i have a FXR (?) frame that just could hold a GT125 engine in it one day..........

.

The boys have been busy dynoing Neds bike so that we have a base line to work too.

We know we can make hp like Neds, but we realy need power spread to be able to compete with the FXR's and bikes like this South Island one........

And the new light weight frame, from memory I think the whole thing is around 80kg's...

Attachment 223284

Marsheng kindly sent me his dyno graph too.........

Attachment 223277

I would love to see some other 4-stroke graphs, just to see what we are up against.............

We have been a bit distracted before chasing hp, power spread is the way forward for us at Mt Welly I recon.......

[richban]

.

Is there a dyno graph of this?

.

He was tricking.

[Bert]

bert,... you paint your own target on yourself.... and i know where to get a paintball gun from.........

in saying that.. can i bore the poor old RG50 out to 85cc???

1. yeayea i know (paint balls at 10 yards); but change will never happen unless someone sticks there hand up...

2. no, but I believe a early water-cooled RM80 barrel will fit the studs.,.
or
have a look at this:
http://www.cokerraceproducts.com/tuning.htm

[Kickaha]

I don't see a problem with the stroke.

I do, which is what Yow Ling was pointing out

24.2.1 Solo motorcycles shall have two engine capacity classes:
F4 2 stroke 55-100cc
2 stroke 55-125cc air cooled
4 stroke 55-150cc
F5 2 stroke 0-50cc
4 stroke 0-100cc air cooled

So F4 has a capacity limit of 150cc

24.2.3 The maximum capacity for rebored engines shall be:
F4 2 stroke 55-100cc - 104cc
2 stroke 55-125cc air cooled - 130.5cc
4 stroke 55-150cc – 158.09cc
F5 2 stroke 0-50cc - 53cc
4 stroke 0-100cc - 104cc

The key word is rebored there is no allowance for going over the 150cc limit with stroking

[ajturbo]

yeah.. have seen that already.. but as i have not blown the thing up yet (not from lack of trying!!!) i'll still be punting it around, giving some of the 100cc+ bikes a run for their money....

nothing like a stock std bike to get people pissed off with me...

1. yeayea i know (paint balls at 10 yards); but change will never happen unless someone sticks there hand up...

2. no, but I believe a early water-cooled RM80 barrel will fit the studs.,.
or
have a look at this:
http://www.cokerraceproducts.com/tuning.htm