antidives and fork oil service

[garyS-NJ]

Getting to some of the finer servicing on my recently resurrected 1984 xvz12DL, I'm looking to service the fork tubes.. I have the wheels off for tires and figure this is a good time to do this. Some time ago I met a guy with a 1980's Honda V4 something which had hydraulic antidives and he said that he took them off a bike he bought used and found the antidives full of crud. He had some odd front tire wear and attributed it to most likely the left and right antidives not working the same...

 

So back to my bike, the front forks seem to dampen OK just grabbing the brake and pushing to actuate the forks and it rides ok too. But with the old tires, I noticed the front end seemed to hop a little over grooves in the highway. Just a tad unnerving. So I was wondering if perhaps differences in how my antidives were working might be the cause.. I recently split the bakes and have two lines coming off an '87 front master cylinder to the front calipers.. That seems OK but the front braking is lacking and kinda soft.. (the rears now skid very easily but at least I don't have the front end diving when I step on the rear brake).

 

I think I'll get a ride on the new tires first but then do most folks remove and clean out the hydraulic antidives when changing for oil on an old unknown bike?? any links for how-to's? Or should I start with just a fork oil change per the manual and set the air pressure??

[OutKast]

The most common fix is to replace the springs with progressives, cut the spacers to suit, then disconnect or blank off antidives. if you are not into that, guess you just clean them.

[garyS-NJ]

Just installed the progressive springs and btw fork oil. I like it. Left the anti dives alone

 

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[Marcarl]

Road snake issues will have more to do with your choice of tire than with the forks, unless the forks are toast of course. Anti dives only work when you pressurize them when you apply the brakes. I found the best solution for spongy front brakes is stainless steel brake lines and properly bled.

[garyS-NJ]

Whoops, I tightened up the neck bearing a little and it does seem better. But i still feel more than if like and tires makes sense! I got the shinko 777's because they looked good for rain (&I have shinko tourmasters on my xj550). The 777s are HD load rated but maybe just not right for this bike. Not too many people are running them.

 

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[bongobobny]

Yup! What Carl said, the anti dives only work with brakes applied!! All they are is a solenoid that restricts the flow of shock oil when the brakes are applied. This restriction limits or stiffens the front shock's downward travel when braking. On your MK1 the anti dive solenoid is hydraulic, on the MK2 they are electric solenoids that activate with the brake light. Both do the exact same thing.

 

I suppose if the solenoid were filed with sludge especially on the hydraulic ones the solenoid could not properly disengage but that would result in a stiffer, more sluggish shock...

 

Now to address your issues, yes the condition and tread pattern of your front tire will indeed affect how the bike handles different road conditions! Now as far as delinking brakes, keep in mind now your front master cylinder has TWICE the load it was originally designed for!! Even the "larger" MK2 front master was designed for only one front caliper!! What you want to do is upgrade to a second generation front master or even better the 14mm master found on newer Yamahas so you get the proper volume of brake fluid delivered to the front calipers. Now you have the same issue in reverse for the rear calipers, you are now using a master cylinder that delivers twice the volume to now just one caliper resulting in very little brake pedal travel before it engages, but due to the bigger bore you really have to step harder on the pedal to get braking power!! With your master cylinder it's all about piston diameter vs stroke for power! The smaller the diameter, the longer the stroke you need to get the same VOLUME, but the smaller the diameter, the greater the PSI which is what gives you greater braking POWER. You might want to try McGuiver'ing a 2nd gen rear master cylinder, I have a spare one laying around if you want to experiment, but I do not have a spare reservoir, you will have to use your existing one...

[garyS-NJ]

Oh wow, this is an,old thread from last year. Since then I put on the new tires and that dramatically improved the highway ride over grooves. But at high speed, I had too much road snaking where if the front felt light, easy to upset, slow to dampen out... Felt like she might go into death wobble. I first noticed over 100mph but within months felt it at 70 mph. After the tires, I also fixed the class air pump. Yes I know how the antidive work and imagine they rob brake power but was worried they might be crudded up and make forks act different than each other... I'm sure a set of stainless lines will improve the brakes a goodly amount.

 

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[bongobobny]

OK while I was typing you just gave your Shinko response. I am not sure, but I really don't think the Shinko is really load rated for our really heavy 900 lb bikes! They may be load rated for a lighter "touring" bike like a Harley, but they are a couple hundred pounds lighter...

[garyS-NJ]

I had it up to 85mph last night and she felt good but somehow less stable up front than my other bikes. Gonna get some miles on her but I'm thinking now these shinkos might not be the best tire for this bike. For the price I would like them to be.. My other choice was the sons but I felt this shinko was a better rain tire.

 

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[bongobobny]

Yes, the hydraulic anti dives do rob HYDRAULIC power from the front brakes! One of the two reasons I switched to MK2 forks, the second being MK1 brakes are anemic at best...

[bongobobny]

I'm a Dunlop Elite fan but to each their own, no two drivers ride exactly the same...

[garyS-NJ]

I don't recall which used front master I bought but I think its 14mm (getting old, I should keep a logbook for reairs, maintenance and mods). So that explains the wooden feel to delinked back brakes. I read a post saying when delinking, after ditching proportionong valve, one should plug that hole and put rear brake line where the front one came off. Shinko 777HD has the same load rating at the Dunlop elites but that don't mean it would handle same way so yes, next set would be elites unless I find some high speed riders using the avons

 

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[garyS-NJ]

Yup! What Carl said, the anti dives only work with brakes applied!! All they are is a solenoid that restricts the flow of shock oil when the brakes are applied. This restriction limits or stiffens the front shock's downward travel when braking. On your MK1 the anti dive solenoid is hydraulic, on the MK2 they are electric solenoids that activate with the brake light. Both do the exact same thing.

 

I suppose if the solenoid were filed with sludge especially on the hydraulic ones the solenoid could not properly disengage but that would result in a stiffer, more sluggish shock...

 

Now to address your issues, yes the condition and tread pattern of your front tire will indeed affect how the bike handles different road conditions! Now as far as delinking brakes, keep in mind now your front master cylinder has TWICE the load it was originally designed for!! Even the "larger" MK2 front master was designed for only one front caliper!! What you want to do is upgrade to a second generation front master or even better the 14mm master found on newer Yamahas so you get the proper volume of brake fluid delivered to the front calipers. Now you have the same issue in reverse for the rear calipers, you are now using a master cylinder that delivers twice the volume to now just one caliper resulting in very little brake pedal travel before it engages, but due to the bigger bore you really have to step harder on the pedal to get braking power!! With your master cylinder it's all about piston diameter vs stroke for power! The smaller the diameter, the longer the stroke you need to get the same VOLUME, but the smaller the diameter, the greater the PSI which is what gives you greater braking POWER. You might want to try McGuiver'ing a 2nd gen rear master cylinder, I have a spare one laying around if you want to experiment, but I do not have a spare reservoir, you will have to use your existing one...

I'd take that second gen rear master if you think it would line up with an adapter.. But someone must have done this before so I'll post on that to check complexity (I'm the crudest machinest).

 

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[bongobobny]

PM me your mailing address and it's yours! You're on your own making it work! Does not come with the pushrod, I needed it for the conversion I did to power the Honda rear calipers on my trike using a larger car master cylinder...

[camos]

I don't recall which used front master I bought but I think its 14mm (getting old, I should keep a logbook for reairs, maintenance and mods). So that explains the wooden feel to delinked back brakes.

Not necessarily Gary. I remember getting the same thing many years ago when replacing the front pads on my Virago. I did the job at work one night in the parking lot during breaks and it was the very first time I ever done a pad replacement. It is my opinion a wooden feel can be the result of an improperly bled system although it could possibly be due to sticky pistons. I remember the pistons were very difficult to push back into the calipers. It took me the whole night using the various "tips" from the forum, not this forum, to get enough pressure on the brakes to attempt the ride home in the morning. It was that experience that made me decide to figure out how to properly bleed brakes. Since then it's been a piece of cake.

 

[garyS-NJ]

I think air in the system could only make them feel soft or squishy

 

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[camos]

I think air in the system could only make them feel soft or squishy

 

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I agree with that statement but there must be a condition where air can act like a vapor lock or something. Perhaps at the master cylinder or at the calipers. The front brakes on the Virago are very simple, one line split into two with no other devices inline, and yet that woody feel did happen so something caused it. The lever felt solid with no sponge at all but no matter how much force was used there was little change in braking power. After bleeding again, they worked perfectly.

 

So I can only suggest that if you are experiencing woody feeling brakes, check that the pistons are not jammed somehow and bleed it again.

[garyS-NJ]

I had working linked brakes and then delinked and removed the proortioning valve and then immediately notice the wooden feel to brakes. Very on or off, easy to skid. Because the master used to serve two calipers with the back off the proportioning valve.

 

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[videoarizona]

Gary, FYI... I'm running Shinkos Tourmasters on my 89 VR with no issues. Stable and smooth.

[garyS-NJ]

Gary, FYI... I'm running Shinkos Tourmasters on my 89 VR with no issues. Stable and smooth.

Do you ride " fast" on the highway?? And what about fork springs& air pressures? I think I bought the 777 instead of the 230 because it looked like a better rain tire. And I read somewhere better mileage than the 230 (& I assumed the higher price then would make sense). Looking again I see the Dunlop elite 3s have higher load rating (especially the front) and I wonder if my shinko front is just getting squishy and causing the weave snaking

 

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[videoarizona]

I routinely cruise 75 to 80 on highway. Not much choice out here...I would get run over otherwise. Do break the century mark,now and then, as the "Grin Factor" is hard to resist.

 

Fork air front and rear is on auto low setting when one up. Rear changed to auto medium two up. Tire pressures 2 lbs under max tire load pressures. 40 lbs. Rear to 42 two up.

 

Max load on 230 for our size fronts and rears was more than enough for two up load... when I bought them last year. Maybe they downgraded the tire though I would doubt that. I have never felt any squishy ness ... even on severe high speed corners two up. Got caught on a decreasing radius turn at 60 mph in the mountains... Had to lean way over (one of those..oh crap..trust the bike... moments.) something scraped during turn but got through fine. Lady woke up with scrape noise... She was sleeping!

 

As far as weave and snakes... Far less then the Metzler's on bike earlier.

 

I'm very pleased with 230's. I don't expect much mileage out of them.. But when they are due, the rear end will want some grease anyway....

[garyS-NJ]

Thanks. I noticed considerable more snaking with the front air set to auto low as compared to manual deflated. And I had the rear at medium

 

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