Fork springs, flywheel weights, & jetting

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#1
G'day everyone, I just wanted to pass on to you a couple of points of interest.

I just put after market fork springs in; .41 eibachs to suit an XR400, to be exact. WHAT A GLORIOUS DIFFERENCE ! I am now moving a LOT faster, and I can hit ruts and whoops hard without losing the plot. Highly recommended !

I also fitted a steahly flywheel weight. My bike is ported for top end and has a rad valve and FMF rev pipe, and rear wheel spin was the order of the day. I wasn't too sure if the flywheel weight was going to be worth the money, but I'm pleased to report that it is. I have noted a much better increase in traction off the start, and it lugs a lot better up those snotty hills. If you're thinking of getting one of these babies but you can't make up your mind, DO IT!

one last thing, I was suffering from what I thought was a sticking throttle at High revs, under load (eg up a hill). I tried everything to no avail, wondered if my jetting was a tad lean so I went up from a 145 to 148 main. NO MORE PROBLEM! anyone shed any light on this? Can a 2 stroke "run on" like this if it's too lean?
 

MADisher

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#3
From whom did you purchase your: .41 eibachs ?? and how much were they ?

Aren't you about my size ? 6'0 ish 200 lbs ?

:eek:
 
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#4
hey matt, I'm in australia, I got 'em through a parts warehouse that happens to be an eibach distributor. They cost me AU$150 (about US$75)

I'm about 80 kg's with all my gear...
 
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canyncarvr

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#5
andrew:
What did you use for preload on your longer springs? Did you keep the OEM spacer keepers (washers)?

I run XR 400 springs..not aftermarket, but honda springs (.40s). The least amount of preload I could get due to the washer configuration was 10mm. A bit more than I wanted, but I wanted to keep the OEM keepers in.

They are great springs, aren't they? I had both aftermarket .40s (stock length..470mm) and the longer (532mm) .40 XR springs. The longer springs were a huge improvement!!
 
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MADisher

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#6
So if you put the XR springs in, do/did you cut down the stock spacers ?

Can you buy spacers ? I'd want to be able to go back if I didn't like em.
 
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#7
Spacers? How about PVC conduit pipe? Don’t know what is avail over there but I found the perfect diameter stuff at the local hardware. Its light, very strong axially, easy to saw lengths & stupidly cheap so you can experiment away several times for a few bucks. :cool:

PS the same stuff but larger diameter & a couple of foot long makes an excellent fork seal installer. Comes in just the right sizes over here -guess it might be std world over?
 
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#8
Great idea on the fork seal tool.....Goog timing, Im about to replace mine. Looks like a trip to Home Depot......Thanks...
 
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#9
Yeah just make sure the size is right for pushing on the outside of the seal (can’t remember off the top of my head) & smooth the end after you cut it.
 
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#11
spacers for fork springs

The Eibachs shipped with a length of PVC pipe of the correct diameter. It had nice thick walls too, not that thin-walled stuff you normally get from the hardware. I made up 10mm spacers. They also shipped with 4 washers to place at either end of the spacers. I kept the OEM clip thingy that goes on the bottom of the springs - I just had to bend the tabs out slightly for a snug fit.

BTW, the springs were 510mm long, compared to the 470mm stockers. The extra length seems to be that much better.

I too use a length of PVC pipe as a fork seal driver. Works great.
 

canyncarvr

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#12
The 'thick walled' PVC pipe is schedule 40, the thin is schedule 20. I've never been in a store that carried such stuff that didn't have both types. Schedule 20 is good for absolutely, positively nothing whatsoever.

Curious why the Eibachs for the XR are so much shorter than the OEM honda springs.

What was the preload with the 10mm spacer you used? I set my PREload to 10mm, which put my spacer at about 4mm in length.

The extra length is great. I don't know why that idea isn't more prevalent. It WORKS !!
 
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#14
PRE LOAD

Dunno why the discrepancy in length between stock XR and eibach units; maybe different year models had different lengths?

Anyway, I found that those eibachs came to about the top of the fork tube or just a smidgen below, so I figured that 10mm long spacers would be just right. I wanted not too much preload because of the fact that they're quite stiff already (.41), but I was afraid of having too little...guess I could have measured it a bit more accurately at the start, but they feel pretty darn good so maybe I jagged it...I'm not going to mess with it now !

Cheers,
 

gonzodog

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#15
Andrew - maybe there's no choice, but what weight did you get for the flywheel?

88RM250 - we make our 'tater' guns out of Schedule 40 - I think 'cause the hair spray's stronger here in Pennsylvania!

Thanks,

Jim