slavens ported 500

was checking out a cylinder from a bike i bought and noticed it had a nice looking professional port and polish. was cleaning it up and noticed some engraving underneath

noticed it said "jeff slavens" then "500"....looked it up and it appears he has worked with ktm for a long time. said on the slavens site that jeff did alot of work for the factory husky riders in the 80s...anybody have any info on his involvement with husky? i find this kind of stuff very interesting.

heres more cell pics

bike and engine no indicate 85 cr500

What Year of Husky 500? I have a 87 430CR with a Slavens motor and has the same signature on the cylinder, also has modified oem WP USD forks with external N2 bottles. I think Jeff Slavens did most of the work on the factory Husky bikes in the mid eighties. Here is some pictures of my "Slavens" 87 430CR totally origninal unrestored.

very cool, how does it run? the bike i bought had been owned by non husky enthusiasts and had many areas of neglect and got taken apart and stored into whatever you want to call my "inventory". very neat finding out about slavens work

wonder if port timing is changed at all ?

Nice 87 CR

I love the looks of a professional porting job. It just screams fast. But with looks set aside it would be interesting to know the percentage of change in performance due to stuff like porting, exhaust systems, and carburation. I don't doubt that psychologically the power would increase.

ive had things ported before and it can be a postive difference if done right. all depends in the end goal..some port jobs trade power in one area for gains in another, others just enhance one area. after having my snowmobile ported with triple pipes installed it was a huge increase. there was no area that suffered, just your wallet..
of course there are many mods that do not seem to do much if anything. sometimes they lose power.

It runs and rides great! Compared to the aircooled 430's and my 420AXC's it is way smoother and has an ultra wide torque band. Certainly is responsive. It is quite an enjoyable bike to ride.

Yes, and in the process of doing the mods and losing power, the power delivery is often made more abrupt giving the false impression of more power. In my younger years I would get a new bike and before I even got used to it I would "throw the catalog" at it, even if it didnt need it. Some times it worked, but most of the time it just cost me a lot of money. Now I have gone the other direction, I am very careful before I modify a bike, especially a bike as well designed from the beginning as a Swedish Husky, its actually pretty difficult to improve on them.

Thank you!

wounder what it would take to talk him into doing one nowdays

if anyone cares here is one of the factory pipes from the late 80's 87-88 430

nice looking porting
just surprised it was not knife ported on the transfers
really woke up my 87 430
just the knife porting that is

u tube u utube... jeff slavens...he does lots of work and puts it up on utube.

He clearly knows his stuff like Paul Rooney here in aus, get a rooney cyl and it has a fat smooth band. slavens motors have good reports as well.

Jeff helped me reassemble my katoom 300 power valve..thanks Jeff!

very cool pipe premo, gotta love it when the big bores go hunting for some volume, pipes can take some interesting routes! yours looks to be tucked away from danger fairly well..too bad stuff like this is never found for sale.
also, the transfers are knifed, in a blunt way. he does them like a butter knife. thinking of building an engine around this jug, very neat to find stuff like this. thanks everyone for sharing.

luv the pipe & the jug porting. It leaves the port & heads vertical before heading sideways. It looks like it might be fatter & longer initially than my uptite pipe. For more bottom torque maybe?

Longer headpipe is for fatter low-mid range so the reason to go up first gives more length to work with

yup, that was what I was getting at

I had a 87 430CR & my 88 430WR never pulled like the CR did. The CR was apart a time or two before I owned it but I never had a reason to open it up. Now my WR pulls like my CR did! I raised the exhaust port, cleaned up the transfers, & slightly flared out the top of the intake ports. She flat out rips now! Gently roll the throttle on & it's like a direct link to the back tire breaking loose! (or the front end lifting)