shock mount position questions 76 Cross Country

[Mike Stephenson]

Hello again everyone, I have been quietly lurking here, learning and am now finally starting to look into the needs of my 76 Cross Country 250.  The stock 'zoke shocks need rebuild/replacement. I understand many of you run shocks longer than the stock 13.5" to sharpen up the steering a bit.  With that in mind, i have decided to replace to get something a tad longer.

My questions are as follow (most of which really apply regardless of shock length)

1)  The frame is set up with 2 upper shock mounting position, and 6 lower positions on the swing arm.  Are there any combos of this that are a no no...ie...clearly using the lower upper mount, with the farthest forward bottom mount would not work.  But what about the second to last (towards the rear) lower mount?  Or  is the lower upper mount reserved for only the rearmost lower mount?

2) What impact does the various mounting positions have on shock action and spring rate needs?  I would think the more verticle the shock, the stiffer you will want your springs - (ie - will make a given spring and dampening feel softer).  Is this true?  I am not sure about the impact of using the more canteleverd positions however.

3) And finally - given that I do want to sharpen up the steering, I am assuming I will want to go longer.  I see mentions of anything between stock 13.5 and 15" being used.  What lengths and what mounting positions are you guys using, or would you recommend?

And, I guess related to all this, is a question of spring rates?  

FWIW - my intended riding on this bike will be typical Michigan woods rides - a few Family Enduro Series events with my kids.  Who knows, I might take in a vintage race - but wont really pursue it seriously.  I am about 190lbs without gear.  Oh, and I absolutely will be doing some riding with Young Ted!  (April 4th or thereabouts......right Ted?)

Mike Stephenson
Atlanta, Michigan
Penton Newbie - thanks to Young Ted!

[Kip Kern]

Mike  The easy way to know is to get a copy of the later Hi Point catalog and it will show the various angles and spring rates as well as the shock lengths that are to be used in the different positions.  This is also shown in a 250 400 Penton repair manual but the Hi Point catalog is more in depth.  CIAO

[Big Mac]

There are some very sharp engineer-types who will give you lots of exact detail for a spot-on setup with high-zoot shock technology, if you want to spend the bucks. A call to Works Performance is a good start in that direction.

For low-budget, have-fun riding, I go low tech/old school: 14-3/8" Curnutts, from Ebay or ask around, usually $50-$60 unless you get in an e-bid-war. Fairly easy to take apart and replace the standard and readily-available seals and o-rings, most sets out there seem to have mid-weight progressive springs on them, were built heavy duty with large shafts, chromed thick, and and don't seem to wear out. They work remarkably well.

You can buy "bull rings" at most any hardware store that are the right diameter to act as spacers, to stiffen up the springs. Run them in the holes for up/down position and it's just about perfect length for quicker steering. Maybe a bit much steering angle if you run them laid down, bottom in rear-most holes, and the extra leverage means you'll typically have to add spacers to stiffen. All the travel is cushy, but is too much to be legal for 4" max AHRMA rules for Vintage class (but on '76 GS, so are the ribbed Ceriani forks), and your chain slack needs to be sizable--best checked in full arc without the shocks on.

They bounce and spring rub is noisy when you sit in the garage, but they come to life well out in action. I run old Curnutts on 3 bikes in local MX and cross-country, and have made them work great for my 240lb girth.

Jon McLean
Lake Grove, OR

[Rocket]

Mike
Before you go with the longer shocks, what forks does your bike have, are they straight leg or leading axle?  If they are straight leg, the bike turns really good with stock length shocks, if they are leading axle, I would go with 14-1/4" long.
Just my opinion.
Rocket

[Mike Stephenson]

Thanks for the responses - I had someone else suggest the Curnnuts as well, and will see what i can find for sale.  I also look at the Legends shocks online - certainly less costly than others - maybe a viable option with out being a budget buster.  Any comments about the Legends shocks?

Rocket - I have the leading axle 'zoke forks - so sounds like longer is the way to go.

I did some more searching - initally found not much...but amazing what added info you get when you search "shock mounts" vs "shock mounting" vs "shock positions"!  Anyhow, it sounds like the laydown position yeilds longest travel - which I think is what I want - I am not concerned with AHRMA travel limits etc.  But i get the sense that the laydown position is not suggested for woods riding?  why would that be?

Anyone have an online link to the Hi Point catalogs etc. that Kip mentioned?

Mike Stephenson
Atlanta, Michigan
Penton Newbie - thanks to Young Ted!

[sixdazed]

Mike,I have Curnutts on my 75 Harescrambler and they work fine after you hit some bumps to heat them up.They are in the near vertical position to be ahrma legal.Try and find some that came off a Penton as Charlie Curnutt set the Curnutts up for the Pentons a little stiffer because of the needle bearing swingarm having less drag then conventional bushings.The Curnutt Squeak is normal-if you are really good bouncing up and down on your bike in the garage you can play Led Zeppelin!Have Fun,Ric

ric emmal

[Mike Stephenson]

Rocket..i almost forgot - you should know what forks are on this bike...it used to be yours!

I went out to the garage to do some messing around.  Answered some of my own questions.  The cantelever upper mount will only work with the rear most lower mount.  I also measured the rear ride height with the shocks vertical position (upper top mount, furthest forward lower mount), vs in the cantilever postion.  Ride height increases by about 1/2" - which is the direction I want things to go.  Doing as Rocket suggests, with a 14 1/4" long shock, will really raise that rear end!

I also measured the distance from the upper upper mount (boy that sounds odd doesnt it!), to the rear most lower mount - comes in around 14 1/2" leaving the ride height the same as with the 13 1/2" shocks vertical. If I went to say a 15" or 15 1/2" shock, using that mounting position, I suspect it would yeild ride height comparable to the 14 1/4" cantelever position.  Would I yeild less travel though using the upper upper to rearmost lower mount vs cantelever?

sixdazed - I can just see it now...a bunch of Currnut equiped Pentons rockin and a rolling! []

Mike Stephenson
Atlanta, Michigan
Penton Newbie - thanks to Young Ted!

[tmc3c]

Hi Ktm Mike,I have a 1976 250gs and I was in the same shoes as yourself but I wanted to stay close to orginal as possible.I had "Rocket" Rod Gorzny rebuild my zokes and they are like new.I weigh well over your weight and have never had a problem.I rode the AHRMA cross country events last year and several fun rides also.Rod does excellent work!!



Thomas Carmichael


1970 125 Six Day
1976 250 Hare Scrambler

[shpclay]

You made mention of the curnutts. Where do you these rebuilt or where to buy the parts.

Steve Clay
76 250 Penton/73 Harescrambler
76 husky 250 WR
2002 Aprilia Futura
71 Honda Trail 90

[Rocket]

quote:Originally posted by shpclay

You made mention of the curnutts. Where do you these rebuilt or where to buy the parts.

Steve Clay
76 250 Penton/73 Harescrambler
76 husky 250 WR
2002 Aprilia Futura
71 Honda Trail 90

Steve
Not to sound like an advertisement, but I also will rebuild Curnutts along with the Marzocchi shocks.  Send me an email if you are interested in getting the Curnutt's rebuilt.
Rocket

[firstturn]

Rocket does nice work on shock rebuilds/restorations...just don't get him too busy he can't do mine;).

Ron Carbaugh

[shpclay]

Thanks for the reply. Its not for me but my friend I ride with has a 250 OR husky which has old curnutts, I'll pass this to him.

Steve Clay
76 250 Penton/73 Harescrambler
76 husky 250 WR
2002 Aprilia Futura
71 Honda Trail 90

[firstturn]

Who sells legend shocks?  Thanks.

Ron Carbaugh

[hrbay]

Rocket... Boge/Mulhollands too?

GC