Port Clean Up

[Power Stand]

Guys, my version of port cleaning/ matching ports where the casting meets the sleeve and general tidy up. The casting on this barrel was ordinary, alloy ridges were sitting up and generally ruff which cause turbulence and poor engine performance. (Eddies & vortexes with the gas flow producing poor scavenging and lessened performance).

I burred back, sand blasted the wet side but smoothened (polished) the exhaust port. I am sure we are all aware that you don’t polishing the induction side/ ports due to the fuel condensates on smooth surfaces where we need the fuel to stay atomized.

Have a look at how bad the exhaust port married to the flange, I ran a marker around and burred out.

I have showed the tools & products used FYI.

I didn’t take any before photos to show the condition from the start but did take a few mid way through.











[size=16]Exhaust port before cleaning up.[/size]


[size=16]After clean up[/size]


[size=16]Taped up for blasting, the Gaffers 357 tape is best for protecting the sensitive areas and any where you don’t want to blast.[/size]






 



[size=16]Start of the sand blasted photos[/size]







[size=16]Tools used[/size]

[oldyzman]

Looks like a tidy job, can i ask how long it took to do the matching and porting etc? And is that the only tooling you had?
Brett

[Lozza]

Polishing ANYTHING  in a cylinder is simly a waste of time, and you have eliminated you pipe step which has lost you a couple of HP. Sorry for the bad news, don't take it as a slight on your workmanship though.

[vandy010]

i like your home made blast booth. very creative
i've blasted a few engine parts over the years and can't stress the importance enough on washing the parts thoroughly afterwards. that grit seems to get into everything and hides in the most unlikely places.

[Mick D]

I agree Vandy,  one peice of grit to an engine builder is like a brain surgen leaving his scouple inside a crainiel cavity :'( This my parts was washer. First I hose them, then wash them in the kitchen sink, then air blow them, then into the washing machine for an hour each item. Then invert them for another hour in the washing machine, so that blasting grit has a chance to fall out of all the blind holes etc.


Then a rinse in the bath tub before leaving to drip dry on the ultra high tech weldmesh drip dry rack.

At last pictures

[Nathan S]

Mick, you must be a single man.

[Mick D]

Mick, you must be a single man.

Yeeaaaah sort of Nathan, she live's nearby in a seperate house
It sometimes seem's like I have wasted allot of my life in an attempt to get her with the "Mick program" Poor thing, she still has allot of difficulty seeing the light
She just doen't see that when it comes to investing in household infrastructure one must maximise that investment by multi tasking every item's potential application
Any how I have just realized that you must be http://www.concourseparts.com.au
so I will PM contact you about some race plates now.
Incidently this is a YZ125 my neighbour picked up for $800. It is a "C" model
 
I'am rebuilding the engine now, which actually turned out to be a DT175 Engine
 

[Power Stand]

can i ask how long it took to do the matching and porting etc? And is that the only tooling you had?
Brett

Yep, about 6 hours and all you see is what I used, when saying matching I mean just making the cast meet the standard port lips. This barrel was slightly out when manufactured and it had a slight step/ over lay that would have caused a gas flow disturbance when transferring, shame I didn’t take photos before modifying for all to see. All I did was align the cast to the port. I didn’t bother with raising or widening the ports. Its 500 two stroke so it has plenty of power with out me stuffing it up. I just trimmed and added radiuses in some places.

The bits used in the die grinder are Preferred brand. Use CRC, Kero as a lubricant to stop them from clogging. The bits I used are for fine toothed steel burrs for fine trimming compared to course ally ones. These tools can do a lot of damage, if it takes off it tends to stuff what ever it hits. They are also prone to taking out a lot of material quickly and sometimes more than intended. A firm/ steady hand is needed and tiny cuts at a time. The Gaffer tap protects the bore and sensitive areas so I added a number of layers.

Lozza, I only wet and dried the exhaust port, inlet and transfer ports were left sand blast finished so I think it will rip, plus if unfortunate I can spare a horse or two.

Vandy010, good point & I totally agree, garnet is bad stuff, I blew in out/ washed it / blew it out/ washed it / blew it out and licked it clean, so I am feeling rather satisfied after all that