going case inducted!!!

[Theon]

I got a new barrel today, and although advertised as an f80 barrel, I received another A80 (small port) barrel, so decided just to make it work.
First I carved a 20mm wide and 5mm deep boost port to the height of the original transfers.
Plugged the intake port,
cleared the transfer ports,
widened and polished the exhaust.
And chamfered everything.
I havn't checked the port timing yet, but will likely raise and deck the jug.
I also borrowed a KTM50 expansion chamber, liked the way it fitted (with slight mods) and so ordered one from Ebay.

 

[Davezilla]

Nice work on the jug!! I see you did a good job making the plug for the intake port, that'll work just fine.
Yeah, that's annoying when they send the wrong part, my original jug is the small port with the flat transfers but I got a spare that I've been cutting on that's got the bigger ports and the slanted transfers.
I'm starting to like the look of the KTM50 expansion chamber, was looking at the KX60 but the KTM has that extra bend right where I need it to fit my tiny frame.

 

[Theon]

Cheers Dave,
The only large port barrel I can find in all of OZ is $60.
This one was only $25 or $30, can't remember, but it said it was a F80!
Even has F80 written on it in Nikko Pen.
It looks to be a good barrel though, no weird defects!
There's a KTM 65 Pipe on Ebay In the states at the moment,
http://www.ebay.com.au/itm/1998-200..._Accessories&hash=item258b70bf31#ht_97wt_1164
$30. looks good.

 

[Davezilla]

Yup.. $30 looks good... somebody snatched that one up quick... sold... lol
There are more at close to that price tho, but it does look like less modifying needed than the KX60 pipe

 

[Theon]

I think the time just run out on that one, don't think it sold, I'd try contacting the seller if your keen.

 

[Davezilla]

Can't buy it today anyway... gotta hold onto my funds a little bit more until I get my shop open over here... collecting unemployment for being laid off from my work, but I'll have enough money from my severance pay and my 401k account to open my own shop so they actually did me a favor by laying me off, but I gotta wait a few weeks for all the money to become available to me.

 

[mech_engineer]

Looks good i will post photos of my expansion to night ktm 65sx. My engine have the big port too but the replacement is the small one

 

[Ron344]

Theon, Nice work on the cylinder that took some time to do. I made my own expantion chamber from hydro forming a guy from Australia told me how to do it when I went to Bonneville last year. It works great.

 

[Ron344]

Theon I was just wondering if there was a way to port the cylinder without cutting the cylinder wall? Maybe you could cut a section out from the intake port tot he bottom of the cylinder and cover it with a plate and screw it in place. leaving the cylinder wall in place would give more crankcase pressure. Just a thought.

 

[mech_engineer]

Is posible but we need to machine a port on a aluminum billet and then need to be bolted to a modified cylinder to accept the billet port

 

[mech_engineer]

 

[Theon]

That 65 pipe is a bit longer in the belly than the 50 pipe, should be better.
looking good, you will likely have to change your front forks to get that disc to fit.
What hub are you using on the back?

 

[mech_engineer]

A free wheel hub.. the clearance between the rear caliper and the chain will be milimeters

 

[Davezilla]

That pipe does look wicked on there like that... How's your front wheel to pipe clearance?

 

[Theon]

Caliper inside chain stays?

 

[mech_engineer]

The front wheel clearance is .75"... the clearance from the caliper and the chain on the rear sprocket is like 1 or 2 mm if tje chain get loose it will damage the caliper... for the front fork i need a custom bracket welded to the fork the clearance of the disc and the fork is ok

 

[Davezilla]

Those clearances should be fine, just inspect everything regularly and don't let the chain work it's way loose etc... I've run close fit clearances like that on my Harley for years with no trouble

 

[mech_engineer]

Recommended max comp ratio? The only stock bearing is the lower rod bearing

 

[Theon]

Depends on the fuel,
I like 150 Psi.
Which runs fine on 91.
But I havn't worked out what that comes to in head cc's.
Around 6cc from rough measurments.
With a 5.3cc fred head and 1mm squish, you should be getting at least 150Psi.

 

[Davezilla]

Just put mine back together and I'm getting about 135psi from a 6cc Fred head with the squish set to 1mm, running just fine on 93 octane if that helps. I can definitely feel the increase in the mid range and it likes to rev insanely high.