Flathead replica springer problem - The Jockey Journal Board

Go Back   The Jockey Journal Board > General Discussion > The Board

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-20-2009, 07:54 AM   #1
uwiik
Junior Member
 
Join Date: Aug 2009
Location: Jakarta
Posts: 12
Default Flathead replica springer problem

Hi all,
I am in the process of building my first semi custom bike (1997 heritage softail based).
I fitted a flathead springer replica on my bike (stock frame & springer length). Now everytime I apply front brake, the whole front end would try to fly up instead of diving like a normal shock would. The mech told me that all flathead replica have that tendency and it is normal. I personally dont like it and think it is dangerous. Is there any way to correct this tendency? Would fitting a friction ride control or shock absorber help?
Here is the specification of my suspension and tires:
F tire: 130/90/R16
R tire: 180/60/R16
Springer: 22" (bottom neck to bottom rear rocker hole)
Rear shock: stock height.

Thanks a million for taking the time to answer my questions, appreciate it.
uwiik is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 08-20-2009, 08:11 AM   #2
ironwigwam
Senior Member
 
ironwigwam's Avatar
 
Join Date: Jul 2006
Location: east coast, Lake View, MN, Bonneville, UT
Posts: 685
Default Re: Flathead replica springer problem

And my names Rocky and I like your introduction? Did you apply the time machine as well?
1957 S/VG
ironwigwam is offline   Reply With Quote
Old 08-20-2009, 08:18 AM   #3
uwiik
Junior Member
 
Join Date: Aug 2009
Location: Jakarta
Posts: 12
Default Re: Flathead replica springer problem

Sorry LOL... I was so frustated with this problem today and was posting in a hurry. Please look at newbie section. once again sorry...
uwiik is offline   Reply With Quote
Old 08-20-2009, 08:23 AM   #4
Danny F.
Senior Member
 
Danny F.'s Avatar
 
Join Date: Aug 2005
Location: Belgium (Europe)
Posts: 5,168
Default Re: Flathead replica springer problem

A picture from that front end with fitted brake would help a lot...
Why do you say "flathead" replica..?
Danny F. is offline   Reply With Quote
Old 08-20-2009, 08:38 AM   #5
uwiik
Junior Member
 
Join Date: Aug 2009
Location: Jakarta
Posts: 12
Default Re: Flathead replica springer problem

Thanks for the reply.. Here is some pics of the front end.... I am suspecting they screwed up the spring tension, or wrong front fork length?? the rocker angle position looks too slanted...



Sorry the pics is not too clear, it was taken with a blackberry...

Last edited by uwiik; 08-20-2009 at 08:43 AM. Reason: misspelling
uwiik is offline   Reply With Quote
Old 08-20-2009, 08:39 AM   #6
uwiik
Junior Member
 
Join Date: Aug 2009
Location: Jakarta
Posts: 12
Default Re: Flathead replica springer problem

I called it flathead replica because it was made by some local guy who happen to be really good at welding and He use stock hydra glide springer for measurement and shape.
can anyone tell me how to display my picture in good size. Mine looks way too big...

Last edited by uwiik; 08-20-2009 at 08:44 AM.
uwiik is offline   Reply With Quote
Old 08-20-2009, 08:52 AM   #7
Danny F.
Senior Member
 
Danny F.'s Avatar
 
Join Date: Aug 2005
Location: Belgium (Europe)
Posts: 5,168
Default Re: Flathead replica springer problem

No pictures yet..only 2 red stars are visible for me...mail me those pics now.. danny.hd@skynet.be

A Hydra-Glide has a Glide front end, not a springer, but I think you are just mistaken names here..
Danny F. is offline   Reply With Quote
Old 08-20-2009, 08:57 AM   #8
uwiik
Junior Member
 
Join Date: Aug 2009
Location: Jakarta
Posts: 12
Default Re: Flathead replica springer problem

Thanks a million for the heads up, I will try to fix the image.Yes I am mistaken. I meant early panhead with springer forks. Pictures sent to your email.
uwiik is offline   Reply With Quote
Old 08-20-2009, 09:04 AM   #9
uwiik
Junior Member
 
Join Date: Aug 2009
Location: Jakarta
Posts: 12
Default Re: Flathead replica springer problem



I hope the pictures showing now...
uwiik is offline   Reply With Quote
Old 08-20-2009, 09:04 AM   #10
uwiik
Junior Member
 
Join Date: Aug 2009
Location: Jakarta
Posts: 12
Default Re: Flathead replica springer problem

uwiik is offline   Reply With Quote
Old 08-20-2009, 09:07 AM   #11
michaelbarry
Senior Member
 
Join Date: Jun 2008
Location: Dandridge, TN
Posts: 263
Default Re: Flathead replica springer problem

Is it just me..or do those front legs look tweaked? May just be my eyes playing tricks on me with the angle of the pics.
michaelbarry is offline   Reply With Quote
Old 08-20-2009, 09:11 AM   #12
uwiik
Junior Member
 
Join Date: Aug 2009
Location: Jakarta
Posts: 12
Default Re: Flathead replica springer problem

No it is not tweaked. I have tried riding with it and it runs fine. The only problem is the extreme upward front end stop whenever I applied front brake. It feels like I am about to get thrown over the handlebar. I could only use the rear brake...
uwiik is offline   Reply With Quote
Old 08-20-2009, 09:11 AM   #13
Hoat69
Senior Member
 
Join Date: Dec 2008
Location: Alexandria VA
Posts: 131
Default Re: Flathead replica springer problem

hard to tell with those aweful pics and weird angles
Hoat69 is offline   Reply With Quote
Old 08-20-2009, 09:15 AM   #14
uwiik
Junior Member
 
Join Date: Aug 2009
Location: Jakarta
Posts: 12
Default Re: Flathead replica springer problem

I'll take better pics tomorrow and post it..
uwiik is offline   Reply With Quote
Old 08-20-2009, 09:23 AM   #15
Danny F.
Senior Member
 
Danny F.'s Avatar
 
Join Date: Aug 2005
Location: Belgium (Europe)
Posts: 5,168
Default Re: Flathead replica springer problem

Geometry from anchor rod should be looked after again...and make sure everything is working "loose" with the correct bushings at pivot points... when the frontend comes up while braking it usually means something is "to tight" that should be not tight at all...

Also read this..
http://www.jockeyjournal.com/forum/s...ont+brake+stay
Danny F. is offline   Reply With Quote
Old 08-20-2009, 09:26 AM   #16
uwiik
Junior Member
 
Join Date: Aug 2009
Location: Jakarta
Posts: 12
Default Re: Flathead replica springer problem

after comparing to so many different springer pictures, I noticed that the rebound spring (upper spring) is not compressed enough, so maybe when I applied front brake the momentum of the bike forced the front end to retract upward instead of diving because there is not enough pressure from the rebound spring..... Am I correct???
uwiik is offline   Reply With Quote
Old 08-20-2009, 09:27 AM   #17
uwiik
Junior Member
 
Join Date: Aug 2009
Location: Jakarta
Posts: 12
Default Re: Flathead replica springer problem

Ok I will check with the rebound spring factor and "too tight" factor somewhere in the joint..
uwiik is offline   Reply With Quote
Old 08-20-2009, 10:23 AM   #18
agarden
Member
 
Join Date: Mar 2009
Location: Vancouver
Posts: 55
Default Re: Flathead replica springer problem

Hey uwiik,

I just got done working out similar problems on my springer, although my setup is using a front drum. I think this is what is causing your problem:

Think of your front end as a parallelogram. two sides are the two fork legs on your springer. One side is the line from your rocker bolt to your axle. The final side is the line from your brake stay fork anchor and the brake stay disc anchor.

The fork sides of the parallelogram are parallel naturally as your springer was built that way. It is CRITICAL that you brake stay and rocker are parallel.

If they aren't then you will experience very odd behavior when you apply your brakes. What exactly will depend on what type of misalignment you have. In your case, when you apply the front brake, the forward rotational force of your wheel will put huge load on your brake stay and that force will be transferred to your springer leg then compressing your springs.

If your brake stay is parallel to your rocker then the regardless of your front-end movement they will remain parallel and the force applied to your brake stay when you apply the brake will be pulling "straight" on your fork leg and will prevent your brake from rotating, thus keeping your front-end true.

Hope that makes sense! I don't have time to sketch out diagrams for you this morning but if you're still stuck I'll cad it out later today.
agarden is offline   Reply With Quote
Old 08-20-2009, 10:33 AM   #19
Dragstews
Banned
 
Join Date: Mar 2008
Location: Also Lost in the Sixties
Posts: 7,717
Send a message via Yahoo to Dragstews
Default Re: Flathead replica springer problem

The brake mount to the axle must float on the axle....Make sure that it does.
Dragstews is offline   Reply With Quote
Old 08-20-2009, 10:43 AM   #20
panhead_pete
Senior Member
 
Join Date: Apr 2007
Location: Auuuuuuuuuusralia
Posts: 2,191
Default Re: Flathead replica springer problem

You guys made that front end from scratch? Cool.
panhead_pete is offline   Reply With Quote
Old 08-20-2009, 11:10 AM   #21
little d
Senior Member
 
little d's Avatar
 
Join Date: Dec 2007
Location: midwest
Posts: 2,636
Default Re: Flathead replica springer problem

+1 on what agarden said, here is a pic of a stock stay on a springer. look at how it runs parallel with the rocker.

__________________
"Apparently, any asshole can wrench on a newish, un-fuckered bike. Takes a goddamn genius to take this shit on."-Liam.
little d is offline   Reply With Quote
Old 08-20-2009, 01:24 PM   #22
LTW
Senior Member
 
LTW's Avatar
 
Join Date: Jan 2008
Location: oakland, ca
Posts: 110
Default Re: Flathead replica springer problem

that brake stay/rocker parallel thing makes sense. seeing your home built springer is inspiring, but maybe you could move that anchor for the brake stay on the rear leg up towards the stem a bit. that should make the brake stay rod jut out parallel to the rocker. the fact that the stay rod is currently pointing up, away from the rocker would explain why you get that rising sensation when you brake.

good luck.
LTW is offline   Reply With Quote
Old 08-20-2009, 02:30 PM   #23
BORED
Senior Member
 
Join Date: Jun 2005
Location: Hill Country,Tx.
Posts: 504
Default Re: Flathead replica springer problem

[quote=Danny F.;521309]Geometry from anchor rod should be looked after again...and make sure everything is working "loose" with the correct bushings at pivot points... when the frontend comes up while braking it usually means something is "to tight" that should be not tight at all...

...What Danny F said, I think the Anchor rod geonetry he refers to are the pivot point on front of the rocker and axle point in relation to the rear pivot point on the rear springer leg"anchor" To "Rock" the front pivot point should be 1/8 to 1/4" higher (measruring vertically from the ground when the bike is standing with the wheel straight. If not, that combined with the nuts too tight or improper bushing fitmit, size, greasing can make the bike "Pogo" when it hits a bump on in breaking. Instead of the rocker "rocking" and compressing springs it "drives" the whole front end upward...or at least that 's what happended on mine.
ted
__________________
"I would never want to belong to a club that would have me as a member"
BORED is offline   Reply With Quote
Old 08-20-2009, 04:43 PM   #24
ampdesign
Senior Member
 
ampdesign's Avatar
 
Join Date: Oct 2007
Location: Philly
Posts: 410
Default Re: Flathead replica springer problem

I think everyone is looking to much into this problem, is it me or do those springs look like they are not compressed at all. If you press down on your bike, is the front end real squishy? It looks like both the top and bottom springs need to be tighter, or "pre loaded" so that its not so loose.
ampdesign is offline   Reply With Quote
Old 08-20-2009, 07:38 PM   #25
Destralo Roach
Moderator
 
Destralo Roach's Avatar
 
Join Date: Aug 2006
Location: Tera Firma WA
Posts: 6,976
Default Re: Flathead replica springer problem

All springers will post up when ya hit the front break, if you dont like it, put the Hydraglide back on, only Hydraglides dive when ya hit the break....Roach.
__________________
The Road to success is covered by the Backs of Many! I chose the Hard way!!!!
Destralo Roach is offline   Reply With Quote
Old 08-21-2009, 01:15 AM   #26
geasy$
Senior Member
 
geasy$'s Avatar
 
Join Date: Nov 2006
Location: oregon
Posts: 646
Default Re: Flathead replica springer problem

Move the brake stay up on the back leg as stated several times already. The rod should be parallel to the ground. As it sits, when you apply the brake, the reaction you are feeling is from the rod, as it is being pulled foreward, it wants to "level out". If the rod was already parallel to the ground, it would be pulled foreward, instead of UP, which in turn forces the back leg UP, and you feel the bike going UP, as you brake.

Hope that explains it a little better.
__________________
Support Your Local Jockey Shifters............OG

"I hope I don't poop before we get home" ........BFG

Last edited by geasy$; 08-21-2009 at 01:17 AM.
geasy$ is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -5. The time now is 02:54 AM.