I'm jealous too Swiffer. fing02.gif Does compression go up as well with the kit? Looking forward to some dyno results,... Francine's gettin some attitude! beer.gif
While some of the engine internals (crank, rods) are on a trip to get balanced, I keep myself busy in my wrenching cave.
The engine mods use up most of my money so I don't have enough to get aftermarket plumbing. I just have to clean the stuff I have, for now, and send it away for heat resistant coating. While I'm at it I take away the first internal welds in the headers, in a desperate attempt to increase gas flow a tiny bit (must have too much time on my hands).
[image: user posted image] DIY exhaust cosmetics
I bought a set of heads off e-pay. Noone else seemed to want them so it was almost for free (shiping was more!). I've been wanting to port a set of heads "MOTOMAN style", epoxy and everything, for quite some time. According to my racing friends quite a few on the Swedish roadracing circuit do this or something similar. The beauty they say is that it adds torque over a wide RPM band. Check out his site at "Mototuneusa" or something. The guy seems to be a nutcase and his site is allmost unbarable but apparently Stigefelt and Harms' Honda 600's in the world supersport 600 DarkDog team had their bikes prepared in this spirit. Anyhow - gotta try!
First, however, I have to do the regular "sneak porting" or "polishing". Meaning taking away the edges and sudden changes in diameter that the unprepared stock ports have.
[image: user posted image] PICT1938b.jpg
Its hard to see in the pic but there is a 1 mm step at the arrows before porting (no, don't worry, they are not done in this pic). Its even more in the exhaust ports. What I don't have a pic of is the process of taking away the the same kind of edges between the intake rubbers (nomenclature?) and the head/carbs.
I just Dremel away until there are no edges that can be felt with my fingers. [image: user posted image] porting away
It takes quite some time since there are no room for error - one slip and you may have to cut new seats. After a while you are almost in a meditation like state. OooM!
Just in case you were unaware: Years ago, port and POLISH was the watch words. Then someone discovered that the sanding marks caused a slight turbulence that caused better atomization of the air-fuel mixture. I haven't seen polished ports in years. The short turn radius is the critical one. Be very careful what you do there. If you have access to pictures of airflowed ports so you could copy the design, I'd highly recomend such.
I tend to agree with Dr.Toto. In the 70's a good port and polish on my two-stroke Suzi 380 resulted in a somewhat rough intake tract and smooth exhaust. Has it changed over the last 30 years?
Some years ago, there used to be a service available where they pumped this slurry-like substance mixed with an abrasive media, through the ports of your engine's head which smoothens the intake and exhaust tracts and ports, Haven't heard much about it for a while. Is it still done out there?? It could provide the quickest turnaround time for porting your heads.
Beck, Jan 5 2006, 09:15 PMSome years ago, there used to be a service available where they pumped this slurry-like substance mixed with an abrasive media, through the ports of your engine's head which smoothens the intake and exhaust tracts and ports, Haven't heard much about it for a while. Is it still done out there?? It could provide the quickest turnaround time for porting your heads.
dr.toto, Jan 5 2006, 05:40 PMJust in case you were unaware: Years ago, port and POLISH was the watch words. Then someone discovered that the sanding marks caused a slight turbulence that caused better atomization of the air-fuel mixture. I haven't seen polished ports in years. The short turn radius is the critical one. Be very careful what you do there. If you have access to pictures of airflowed ports so you could copy the design, I'd highly recomend such.
There are several theories why slightly rough port surfaces gives more power, increased atomization is one I've heard, to create a boundary layer (pretty much like the reason for honing a cylinder) is another. A guy here in Sweden ports Suzuki heads for dragracing. He uses 120 grit paper in a right angle motion as a finish, so it's pretty far from polished. Sorry for misusing the term. Smoothing is maybe a better one. As for air flowed ports, check the MOTOMAN site.
I have read that the rough finish on the intake side helps atomize the fuel air mixture. Rough as a ooposed to smooth on the intake side helps mix the fuel and air together. Have you noticed a difference? Dyno or seat of the pants?
HispanicSlammer, Mar 31 2006, 10:48 PMI have read that the rough finish on the intake side helps atomize the fuel air mixture. Rough as a ooposed to smooth on the intake side helps mix the fuel and air together. Have you noticed a difference? Dyno or seat of the pants?
Yeah that seems to be the theory embraced by most people nowadays. And since I'm an amateur I need to pick the experts to believe rather than figuring it out for myself. I do have some problems with people combining the atomization theory with the boundary layer theory since I can't see how they both can be true at the same time...
This is how far I am from any kind of evaluation yet:
[image: user posted image] back home
But at least they are home. Take a look at the liner [image: user posted image] not much left of the liner
The shop had some problems when boring since the cylinder bore wasn't centered in the liner! They had to re-center it not to leave too little of the liner on one side.
Another finding was that one of the con rods were pretty much off (3 grams), all in the big end. A balancing was due! [image: user posted image] now in balance
Now i need to get my priorities straight that damn Ratfink got me goin' biggrin.gif [image: user posted image] Ratfink style on its way
It was about time that I got around to put the stuff together. First, oil clearance check with plastigage to see that the new bearings are the right size. These are the strips of plastigage before trial installation [image: user posted image] Oil clearance rod/crank
The same strips after the end caps have come off again. Ingenious stuff!
[image: user posted image] sqeeeezed plastigage
[image: user posted image] now crank/case clearance
When all the plastic is squeezed and the clearances are within the limits its time to check piston ring end gap.
One good thing about having cleaned all the stuff to the extreme is that you can choose a more cosy wrenching environment (and anything beats my usual wrenching cave). And since I'm obviously totally exhausted by all this I take a well earned brake to see what you guys are up to.
It is funny how demystified these things are once you tear into them at that degree, they seem to become more down to earth and easy to understand. Its not so complicated at that level anymore, really its just a bunch of nuts and bolts.
HispanicSlammer, Apr 16 2006, 12:04 PMIt is funny how demystified these things are once you tear into them at that degree, they seem to become more down to earth and easy to understand.� Its not so complicated at that level anymore, really its just a bunch of nuts and bolts.
True, and with the service manual and Haynes available it's really down to being thorough! (famous last words...? biggrin.gif )
The oil passages are slightly worrying though. One of them blocked somewhere and the engine is ruined!
Swiffer, Apr 16 2006, 06:08 AMTrue, and with the service manual and Haynes available it's really down to being thorough! (famous last words...? biggrin.gif )
The oil passages are slightly worrying though. One of them blocked somewhere and the engine is ruined!
Keep the peanut butter and jelly sandwiches away from the work area! biggrin.gif
Can't wait so see the finished product and find out how it runs! lurk.gif