ADVrider

Go Back   ADVrider > Bikes > Thumpers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 09-26-2014, 01:16 PM   #1
MATTY OP
ADV RIDER & DRIVER
 
MATTY's Avatar
 
Joined: Jun 2014
Location: THE BORDER ENGLAND
Oddometer: 204
Hydraulic tappets

I adjust tappets because i have to, and dont mind it, but if one of the round the world types needed to have a bike needing a little less maintainance, then i could understand where they were coming from.
One thing i have never worked out is these valve adjustments could be done away with by use of hydraulic tappets common place on cars etc , ok i only got old 10+ year old bikes myself so out of touch with modern things, but do any have hydraulic tappets these days and if so , which ones and why were they not in use years ago. Can any think of a practical reason hydraulic tappets could not have progressed in line with cars and the like.
MATTY is offline   Reply With Quote
Old 09-26-2014, 03:06 PM   #2
jeiff
Gnarly Adventurer
 
Joined: Jan 2007
Location: Top of the Hill
Oddometer: 242
Honda Knighthawks had them back in the 80's. And I think many big V-twins currently use them. My understanding is that they tend to limit RPM.
jeiff is offline   Reply With Quote
Old 09-26-2014, 03:55 PM   #3
RideFreak
Green Chile Eater
 
RideFreak's Avatar
 
Joined: Apr 2009
Location: County Lockup, NM
Oddometer: 5,492
Quote:
Originally Posted by jeiff View Post
Honda Knighthawks had them back in the 80's. And I think many big V-twins currently use them. My understanding is that they tend to limit RPM.
They did and were somewhat inprecise IRT maintaining valve clearances.
RideFreak is offline   Reply With Quote
Old 09-26-2014, 05:30 PM   #4
MATTY OP
ADV RIDER & DRIVER
 
MATTY's Avatar
 
Joined: Jun 2014
Location: THE BORDER ENGLAND
Oddometer: 204
Ok thanks i had no real idea what the score was with hydraulics, if they are not practical that explains why they have not been more generaly used.
MATTY is offline   Reply With Quote
Old 09-26-2014, 07:33 PM   #5
tHEtREV
Captain Awesome
 
tHEtREV's Avatar
 
Joined: Apr 2007
Location: Middle Park, Brisbane, Australia
Oddometer: 7,148
XLV750 had them.

Allegedly Honda built it to go head to head with the BMW at Dakar and wanted it to be as maintenance free as possible (Hydraulic tappets, twin sparkplugs, easily accessible spin on oil filter, shaft drive and easy access air filter.

But as far as I know they didn't make it onto any other off road bikes.



My understanding is that they are not very good for performance, and manually adjusted is much better (for proper running), really not that hard and shouldn't have to be done to often anyway.

And I thought cars had gone away from hydraulic tappets years ago (I may be wrong on that, I'm not a car person).
__________________
tEAM iDIOT.

KDX Super Fan!

My Spot HERE (active and on a trip).
tHEtREV is offline   Reply With Quote
Old 09-27-2014, 05:54 AM   #6
markk53
jack of all trades...
 
markk53's Avatar
 
Joined: Dec 2007
Location: Delaware Ohio
Oddometer: 7,749
The hydraulic valve set up Honda used was never an issue unless they got dirt in the rocker pivot - yes they used a hydraulic non-moving pivot, not a moving tappet. Of course the same is true with automotive valve trains too. Stick a lifter and they tick, also affecting performance some too.

The fact is the Nighthawk set ups along with all the other bikes Honda did with hydraulics (GoldWing/Valkyrie, Shadow 700-1100, and I think VTX) worked great, I had a Nighthawk S 700 and 10,000 was no issue what so ever. Technically the hydraulic set up holds virtually a zero clearance. When the cam presses they hydraulically lock, when not under pressure there is oil fed to them to keep them full and pumped up against the rocker.

The reason why they're not used off road - weight and complexity. The lightest set up is a cam on a shim-over- bucket set up. Next is the rocker arm set up Honda uses where there is a screw adjuster on the end for the clearance. The hydraulic valve set up adds weight and a bit more complexity to the bike. More parts/machining = higher cost.

There isn't enough value in doing the hydraulic adjuster set up over the solid set up for off roading.


As for cars, I've been reading a lot of car magazines in the past few years. In the early years road going cars all did hydraulics, but for performance the solid lifters were the thing. Now it seems roller hydraulics are handling at least up to 1000 hp engines. I can't remember having a car that required valve adjustment, indicating they all have some sort of hydraulic adjuster on them. An in the 70s I had a friend who could rev his Plymouth 383 to 10,000 without valve float using a hot hydraulic cam - of course the horsepower peak was way lower. He learned it could rev that when he missed a shift one day... thought it was pretty cool, so he did it again and a few more times.

Hydraulics can handle high performance in motorcycles and cars.
__________________
Ever get lost? You know, that good kind of lost - come to a dirt road intersection and you have no idea where you are or which way to turn? I like when that happens!

Mark - klx678
95 KLX650C w/Vulcan piston bigbore, Now an 09 KLX250S, selling my 90 Zephyr 550

markk53 screwed with this post 09-27-2014 at 06:00 AM
markk53 is offline   Reply With Quote
Old 09-27-2014, 08:28 AM   #7
Roadscum
Beastly Adventurer
 
Joined: May 2007
Location: SW Florida
Oddometer: 1,880
Shaft drive and hydraulic lifers would make me a happy, lazy, content, rider.....

H-D uses hydraulic lifters in their motors.... A modern motorcycle? You decide!

Paul
__________________
"One of the things that make motorcycling so great is because it never fails to give you a feeling of freedom and adventure." - Steve McQueen
Roadscum is offline   Reply With Quote
Old 09-27-2014, 12:43 PM   #8
BikePilot
Beastly Adventurer
 
BikePilot's Avatar
 
Joined: Jul 2005
Location: Tampa
Oddometer: 11,195
They are heavy and bulky. Not really practical on a bike (unless it's push-rod and you can put the lifter down in the case). Adjusting tappets doesn't have to be a big ordeal or something that's needed often. With a bit low rpm motor in non-race use valves go many tens of thousands of miles without moving. And when/if they do it can be a simple matter to adjust them. On an XR650R or XR600R it's a quick and easy thing via the inspection covers and screw-and-locknut arrangement. Even on the much-maligned CRF valves rarely move if you aren't on the rev limiter all the time and keep the filter clean, and with it's clever cyl head design swapping shims is quick and easy. I think it took me an hour total on the CRF the first (and only) time I had to swap shims. Probably would take half an hour if there were a second time.

It's not unheard of for modern-ish cars to not have hydro lifters. Many hondas of the 1990s had screw-and-locknut adjusters. Most owners didn't realize that and probably never adjusted them. My wife's 1993 civic has 230k miles and still hasn't needed an adjustment
__________________
'09 Buell XB12XT, TL1000S, H1F, M620, CR250R, KX100, XR650R, Cota 315R

Summer 2009 Ride Report http://advrider.com/forums/showthrea...1509c&t=507038
Summer 2008 RR. http://www.advrider.com/forums/showthread.php?t=367703
BikePilot is offline   Reply With Quote
Old 09-27-2014, 02:24 PM   #9
zap2504
Dave E.
 
Joined: Feb 2006
Location: Middletown, PA
Oddometer: 557
Quote:
Originally Posted by BikePilot View Post
Many hondas of the 1990s had screw-and-locknut adjusters. Most owners didn't realize that and probably never adjusted them. My wife's 1993 civic has 230k miles and still hasn't needed an adjustment
Hondas still do - even the 4-valve/cyl V-6s.
zap2504 is offline   Reply With Quote
Old 09-27-2014, 03:19 PM   #10
RideFreak
Green Chile Eater
 
RideFreak's Avatar
 
Joined: Apr 2009
Location: County Lockup, NM
Oddometer: 5,492
I repaired 3 nighthawks in one year under warranty for hyd valve issues, primarily collapsed lifters back in early 80s when I worked at a dealership, when they worked right they weren't bad but when they didn't you definitely knew it.
RideFreak is offline   Reply With Quote
Old 09-27-2014, 03:24 PM   #11
KustomizingKid
Studly Adventurer
 
Joined: Nov 2012
Location: Minneapolis
Oddometer: 675
RPM problem... Not a hp problem.
__________________
2000 Xr650r!
KustomizingKid is offline   Reply With Quote
Old 09-27-2014, 07:12 PM   #12
markk53
jack of all trades...
 
markk53's Avatar
 
Joined: Dec 2007
Location: Delaware Ohio
Oddometer: 7,749
10,000 no problem on Nighthawks.

Based on sheer numbers of Hondas with them, 3 is a drop in the bucket. Wings have used them since 1986. All shaft drive Nighthawks did too, along with the later chain drive 750s. we had a few that had gotten some crud in them and collapsed, but compared to the several hundred bikes sold with them, it was nothin.

As said, it is the weight and complexity for a high performance engine that makes them undesirable. I'd take them on a multi-cylinder road bike any day.
__________________
Ever get lost? You know, that good kind of lost - come to a dirt road intersection and you have no idea where you are or which way to turn? I like when that happens!

Mark - klx678
95 KLX650C w/Vulcan piston bigbore, Now an 09 KLX250S, selling my 90 Zephyr 550
markk53 is offline   Reply With Quote
Old 09-28-2014, 01:29 AM   #13
JohnDL
Gnarly Adventurer
 
JohnDL's Avatar
 
Joined: Mar 2011
Location: UK
Oddometer: 131
The new(ish) Royal Enfield unit construction engines have hydraulic tappets.

http://www.advrider.com/forums/showt...php?p=24354407

JohnDL is offline   Reply With Quote
Old 09-28-2014, 05:51 AM   #14
Murf2
Studly Adventurer
 
Joined: Feb 2007
Location: Kansas
Oddometer: 798
Yeah, I'm calling bullish!t bingo on the 10,000 rpm Mopar. He must of had a universal tach set on 4 or 6 cylinder. Anyway valve train weight is the big issue on hyd lifters.

Murf
Murf2 is offline   Reply With Quote
Old 09-28-2014, 06:57 AM   #15
markk53
jack of all trades...
 
markk53's Avatar
 
Joined: Dec 2007
Location: Delaware Ohio
Oddometer: 7,749
Quote:
Originally Posted by Murf2 View Post
Yeah, I'm calling bullish!t bingo on the 10,000 rpm Mopar. He must of had a universal tach set on 4 or 6 cylinder. Anyway valve train weight is the big issue on hyd lifters.

Murf

Call it what you want, I knew the car, I knew the driver, plus I was sitting in the passenger seat and watched the Sun Supertach climb from 6500 to 8000, building revs, then he mashed it and 10,000. No goofy tach tricks. Rev limiters didn't exist. Valve train was the rev limiter and with the high performance hydraulic lifters and heavy duty valve springs (Crower I believe) it didn't float. Normal shift when drag racing was 8000.

No way it was strong, it was way over-reving regardless, totally out of useable power. He thought the engine was tired and was pretty much running the snot out of it, figuring it was due to be torn down.

Besides if a 327 Chevy small block could spin 10,000 rpm legitimately making power (it was featured in either Hot Rod or Super Stock early 70s) why can't a Mopar spin 10,000 making power or not?

Even if the tach wasn't accurate at 10,000, it was damn close.

Whether you believe it is beside the point.

Now it's my turn to call bullshit -

Hydraulics can handle rpm, especially the Honda set up on the Nighthawk 550/650/700/750. They can rev on par with any solid set up - the adjusters (they aren't lifters) don't move, they're the fulcrum in the lever, the cam lobe pushes the center of the rocker down against the valve at the other end. The rockers are probably lighter than the adjustable ones with the screw and nut on the end, less metal and no screw or nut. It's just the added weight and complexity of more parts in the engine if it is about shaving ounces for a supersport or light weight - a pound is a pound and 16 lifters will be a couple pounds. They won't eat up any power since the mass of the adjusters aren't moving. That was Honda's big point in what they did. Low/no maintenance without performance penalty in the engine.

The 700 Nighthawk S was only a bit behind the 700 Interceptor in straight line performance and odds are the majority of the difference was due to shaft drive. The engine was in a lighter state of tune, down I think about 6 hp on the VFR. It and the 550/650 easily reved to peak horsepower, which was around 9500 rpm on the S, I think about the same on the 650 and 10,000 on the 550. I rode a demo 650 for about 2500 miles and my own 750 for near 10,000 miles. Great bikes, quick revs, surprising performance for standard UJMs.
__________________
Ever get lost? You know, that good kind of lost - come to a dirt road intersection and you have no idea where you are or which way to turn? I like when that happens!

Mark - klx678
95 KLX650C w/Vulcan piston bigbore, Now an 09 KLX250S, selling my 90 Zephyr 550

markk53 screwed with this post 09-28-2014 at 07:13 AM
markk53 is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
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


Times are GMT -7.   It's 03:28 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014