Porting advise for early 80's 430

I am searching for detailed information on what was changed on the 430 ports for performance improvement. I have gone through the data posted here and found some generic concepts that can be safely adapted to the 430 ports (clean up), but what I really need are diagrams, photos and measurements.

What I have:
Kinda fresh top and bottom with stock pipe, ports and Mossbarger reed valve with CF reeds. Carb is dialed in. Timing is set at 2.5mm BTDC. I may be going with a Pro-Form pipe in the next few months if I can swing it. The bike is powerful but not what I think a open class machine should be. (Timid compared to a 79 YZ400)

What I want:
Snappier throttle response, more midrange punch and a bit more over rev.

All responses appreciated.
Regards,

PC

What does 'kinda fresh' mean? You sure don't want to get fooled into thinking you need port changes when all you need is a fresher top end, right. That said...

You could try the mods in Husky service bulletin 8-097. I have it, but it's a .pdf and I don't know how to post it!! I have not done these mods, by the way, so I don't know how good they are.

What does 'kinda fresh' mean?

I have two seasons on a complete fresh motor. New bearings, seals, Eurorod, Wiesco piston, NOS 3rd gear, etc. Motor has about 20 hrs. Compression is not the issue. I have notice a small reduction in low end torque since installing the Mossbarger reed set. It also provides another 750-1000 usable rpm on top, so I plan to keep it. I did look at the 390-420 mod set and the others etc. I can lift the boost ports 1mm (Common for reed induction motors), but would like to know what was done by the old pros

Regards,
PC

See the service bulletin contained on this site for the '81/82 series 430 where they detail transfer, intake & exhaust mods. All work (did to my '82 430) & really makes a difference. I have a Mossbarger and you have to re-jet (up on the pilot & down on the main) before you can feel them. I also just started running a Pro Form pipe after having used a Vintage Iron one, like it a lot better as it adds more throughout the power band. Other stuff I've done that works: really work on the jetting & when it's great (snappy down low, not lean or blubbery elsewhere) then raise the exhaust port 1mm, get the squish set in the high .30"s to low .40s", run race gas, play with the timing a bit.

Hi Allen,
I have looked through all the reference material in the vintage section (I think) and did not find any related to porting the 430. There was a bulletin on updating the rear motor mount bushing and a warning about piston clearances, but nothing else that I saw. I will check again to be sure. If you could bring any information on specifics with you to the race at Perris in June (Are you going?), that may be enough to get me started. I need to try to put it all together between races.
I agree that I have not finalized the jetting on the Mossbarger, some of the snap is gone from down low but I am not unhappy with what I have considering the improvment in the top end.

Regards
Paul C.

Thank you guys!

Picklito, HuskT, and Leftcoast leftkicker -

This is exactly what I was hoping to find, answers some of the questions I had as to the differences between the XC/CR/WR cylinders, will allow me to identify which cylinder type I have before cutting (composite bike) and eliminates the need to plot my existing port timings with a degree wheel. (I may do it anyway.) I have downloaded the pdf file.

Thanks again.
PC

I had a similar idea... thought I could roughly identify cylinders by measuring the exhaust port height. Couldn't find any consistent measurement. I'm also finding the squish distance to be all over the map, as is compression ratio (kicking compression pressure, actually).

Glad to hear that you saw the service bulletin about early 81 430 pistons hitting the head... I bought one of those used and broken. It had smashed the ring groove just enough to grab the ring, so there was no compression, but not enough to really damage anything. And it still ran! So check that piston to head clearance, too.

My opinion: The 430 runs GREAT when it's correct, but it was built with pretty sloppy tolerances in terms of cylinder height, so squish, compression, port timing... vary quite a bit from motor-to-motor. These can stack up to make a pretty dull motor or a great one. So I'd recommend making sure all that's correct before grinding on any ports. Also, you could try bringing the timing back a touch, to 2.0-2.25 mm BTDC. That should help extend the rev just a touch.