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CVO Technical => Twin Cam => Topic started by: Dan_Lockwood on November 21, 2015, 02:04:53 PM
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I know on cars it's common place to change valve springs or retainers without pulling the heads.
You just place an air plug in the spark plug hole and pressurize the cylinder to hold the valve in place and then pop off the retainer and change the spring.
Is this possible on our motors?
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I know on cars it's common place to change valve springs or retainers without pulling the heads.
You just place an air plug in the spark plug hole and pressurize the cylinder to hold the valve in place and then pop off the retainer and change the spring.
Is this possible on our motors?
Dan:
Yes. I had to do it on my Big Bore V-Rod when one of the inner springs broke (bad product) so all springs were replaced. There are some low profile tools that allow you to get the job done essentially the same way.
Good luck.
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We used to do the same on car motors by taking a small diameter rope and stuffing the cyl full then rolling the motor through by hand till it stopped. Piston would push the rope into the CC and hope the valves in place
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http://www.nubtools.com/product/overhead-valve-spring-compressor/
I have one of these..... Works as advertised
I've loaned it out a few times if interested
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we would you even want to mess with doing this?? 4 headbolts & pop the head off
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http://www.nubtools.com/product/overhead-valve-spring-compressor/
I have one of these..... Works as advertised
I've loaned it out a few times if interested
I have and use this tool as well. The only difference is I use the rope method with it still. Works for me.
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I have and use this tool as well. The only difference is I use the rope method with it still. Works for me.
I have always had a fear with the air method of hitting the valve just right and breaking the seal......Woops.... I just know my luck
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we would you even want to mess with doing this?? 4 headbolts & pop the head off
You know, just so you don't break the seal... I guess really the four bolts as you say isn't a big deal, but keeping everything where it's at without disturbing it seemed to be a good thought.
Thanks for all the comments and the Nub tool link. And thanks TorqueInc, if I decide to swap out my lifters this winter, I'll probably change out to beehive valve springs at the same time. If so, I'll be in touch with you.
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You know, just so you don't break the seal... I guess really the four bolts as you say isn't a big deal, but keeping everything where it's at without disturbing it seemed to be a good thought.
Thanks for all the comments and the Nub tool link. And thanks TorqueInc, if I decide to swap out my lifters this winter, I'll probably change out to beehive valve springs at the same time. If so, I'll be in touch with you.
no problem :2vrolijk_21:
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When working with cams that have larger lifts/timing specs........be totally aware to check valve to valve clearences...........that ain't gonna' happen with the heads left on the bike, nor will seat pressures.
As Kirby said, 4 bolts and it in your hands.
Scott
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http://www.nubtools.com/product/overhead-valve-spring-compressor/
I have one of these..... Works as advertised
I've loaned it out a few times if interested
X -2 Borrowed one from Steve @ GMR..works like a charm..
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We've never bothered to buy one.
Scott
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I'm glad I got mine. Great to use on customer's 120r without getting into the liability of ring seal, or base gasket issues. It can be more than just 4 bolts. Don't forget about the intake and exhaust that doesn't have to be removed to open rocker boxes. Base gaskets is another factor of changing or reusing. Now we are getting out ring compressors.
I personnel haven't had great luck with straight bores and good ring seal on those from the factory. One thing to say to do it correctly and completely, but the customer dictates that sometimes. The NUB tool allows me to avoid that rabbit hole completely.
There is always more than one way around the barn. The tool I own was given to me by a friend. I have no judgement for the ones that don't want to use it. I have found it useful is some situations.
Sent from my iPhone using Tapatalk
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I'm glad I got mine. Great to use on customer's 120r without getting into the liability of ring seal, or base gasket issues. It can be more than just 4 bolts. Don't forget about the intake and exhaust that doesn't have to be removed to open rocker boxes. Base gaskets is another factor of changing or reusing. Now we are getting out ring compressors.
I personnel haven't had great luck with straight bores and good ring seal on those from the factory. One thing to say to do it correctly and completely, but the customer dictates that sometimes. The NUB tool allows me to avoid that rabbit hole completely.
There is always more than one way around the barn. The tool I own was given to me by a friend. I have no judgement for the ones that don't want to use it. I have found it useful is some situations.
Sent from my iPhone using Tapatalk
Absolutely!
Of course there's much more labor required to remove a cylinder head than 4 bolts. And there's also the expense of gaskets and such. There's a time when it's necessary to pull the top end down, but when it's not necessary, it's nice to have a solution available... Some may chose to one road, while others may chose another. To each his own...
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I suppose if one assumes that the stem protrusions are where they are supposed to be, for correct seat pressures and tdc valve-to-valve is all hunky-dory........let-r-rip 'tater chip. :2vrolijk_21:
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Harleys valve stem protrusion is usually spot on so unless you are going outside of the typical bolt in cams or using springs that require more installed height....the tool is damn handy.
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You can check the spring packs with calipers, spring height checker, or inside mike, and adjust with shims if needed.
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You can check the spring packs with calipers, spring height checker, or inside mike, and adjust with shims if needed.
You sure can. Some common sense and experience comes into play as well. How many AV&V6500 spring sets in a 120r MVA head need to be done with the heads off before one starts doing them with the heads still installed? Just like any other tool out there. There isn't one for every job, but they all have their place.
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Our clients do not come here for just valve spring swaps.
That is established/installed when they are upgrading the rest of the engine.
If that tool works, that is very good. :)
Scott
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X -2 Borrowed one from Steve @ GMR..works like a charm..
For the job that wants to be done and nothing more . no issues to swap the springs on the bike with that tool.