Tuning How to get 70 BHP

[beanarillo]

see the thread about o ring heads:

[colinskillicorn]

bazmac

The 1.4 base gasket conersion only lifts the cylinder by 0.9mm as the std base gasket is 0.5mm so lifting the ports by this amount is sufficient

when the tuning is done by a profesional they lift the transfers by 1.0mm & redirect the angle which can give a substanial increase in power.Some tuners do & some don't lift the exhaust port as these engines aren't really safe over 13000 rpm

if you raise the transfers alone on a std engine you only get bottom end mid range improvement with max revs of only about 11250rpm so by lifting both you get more power through the rev range

when you do this mod you do slightly decrease the squish & raise the compression as the std head gasket is 1.2mm so the squish decreases by 0.3mm which on pump fuel is sufficient

Remember what it says at the begining of the thread which is "this is a basic tune" & the only machining you need is for the o'rings if you want more you need to go to someone like SS or bob farnham

When ever you make an imporovement in one area it is likely that there will be a loss in another that is why it is best if you do the whole tune with kit pipes & ignition when you get more power right through the rev range

Regards CS

[keean]

Beany, erm... okay you can cut and bond... (I forgot the outer seal is low pressure) - but how do you get the rind to stay in the groove whilst fitting the head?

Colin, what do you think causes the high rpm-failure of these motors? My guess would be ring flutter - there are however things that can be done about this... One I have heard of is an L-shaped ring, the other is a gapless ring on the bottom. Have you thought about any of these - if ring flutter is the problem, and it can be improved, the engine could be taken beyond 12,000/13,000 RPM?

[beanarillo]

good question and not one I have an answer for until I try !!!! I guess there is the same problem with the inner one. Maybe thats why some say its better to machine the cyl not the head ??????

[binitbob]

You could just wipe the o ring with a very thin layer of grease this should provide just enough stiction to enable the head to be inverted.

[thorsten-r]

another idea should be to champfer pistons.
that will also change port timing and you will not loose pre compression.

with thicker base gasket pre compression will be lower because of more unused room in crank case.

what also should be good is to close unused room in crank case.
also round edges.
for example a picture.



and to round edges from booster ports.
for better gasflow.

[colinskillicorn]

OK guys

Stop worrying about the outer O'ring just seal with RTV if its clean & dry you won't have any problems I have been doing this for 5 years now & not had one single failure

[keean]

Thorsten, I was under the impression you want to reduce primary compression (ie you will get mor HP with a larger crank volume, not a smaller one)

[thorsten-r]

thicker base gaskets are only used to lift boosters and exhaust ports.
by the way i am not interested in that because my bike revs high enough with the kit parts.
if you loose pre compression you have not such a good filling.
and therefore less to burn.
that will reduce power.
so dead room in crank case should be reduced.
on the other hand with less compression in burn room bike will also rev higher.

perhaps there are different ways.

i have sugaya kit pipes,23D10 kit box, "A" kit carbon fiber reeds and heads with another burn room design and other plugs.
these pipes have a higher resonanze frequenz and kit box matches with that.
also it produces more pre iginion to become a better powercurve in lower rpm.
and these parts together take my engine rev 13500 rpm.
so why should i lift cylinders?
a tuner in germany also said that he works with stock base gaskets because of dead room in crank case.
he doesn´t want to get more room there.

[bjoern]

thorsten, what material have you used to fill in the crancase?
is it aluminum epoxy?

looks good!


rgs
bjoern

[RGV John]

Thanks beanarillo. Im dropping my heads off at Martin's tomoro (26/8/04). And im also byeing some hangers off him


Has anyone tested this mod yet or im i going to be the first to get it running?

Am going to be useing RTV sealent as collin says, dose any one know where i can get it from?

[tasswipe]

my current engine has colins o ring mod,and i,ve just fitted some tygas.i haven,t run the new top end in yet[crap weather],i,ll dyno it when i,ve done it. it has .83mm squish and 12cc comb chamb vol.i,ve fitted 280/290 mains with af1 filter and slightly modded airbox lid.i sealed the water jacket on the heads with a loctite rtv,it hasn,t leaked yet after 4 heat cycles and 16 miles of test riding.
alan

[thorsten-r]

that is not my crank case.
i have only rounded edges so far.
with aluminium epoxy i feel afraid that that will come loose and destroy engine.
so i will make that out of solid aluminium and fix it with a screw.

[smokey_rs250]

Originally posted by tasswipe
my current engine has colins o ring mod,and i,ve just fitted some tygas.i haven,t run the new top end in yet[crap weather],i,ll dyno it when i,ve done it. it has .83mm squish and 12cc comb chamb vol.i,ve fitted 280/290 mains with af1 filter and slightly modded airbox lid.i sealed the water jacket on the heads with a loctite rtv,it hasn,t leaked yet after 4 heat cycles and 16 miles of test riding.
alan

I'm very curious !! Did you only machine the o-ring groove, nothing taken of the head (I think so)? I'm planning on doing the same, also tyga's so i'm very interested !

[bjoern]

thorsten
I understand your conserns about the epoxy comming loose. but filling crankcase this way is pretty normal, "ruffing" the surface using sanding paper or dremel, and cleaning the aluminum with thinner is a must.

what about using a block of plastic instead of aluminum, must be faster and easyer to work with?

keep the tuning work up
rgs
bjoern