Author Topic: Thoughts on performance cam  (Read 1741 times)

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bthtony55?

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Reply #15 on: December 06, 2022, 06:53:25 pm
The squish mod compression increase should not require mixture change, but it may tolerate a slightly leaner mixture due to more complete burn.

Thanks Ace. Will the standard pushrods be ok if 1-1.5mm is taken off the barrel or will I have to shorten them. Second, will retarding the std inlet cam a tooth make any difference with the increase comp ration or best to leave it std timing?. I assume you have been down this road.
 Thanks.


ace.cafe

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Reply #16 on: December 06, 2022, 07:13:27 pm
Thanks Ace. Will the standard pushrods be ok if 1-1.5mm is taken off the barrel or will I have to shorten them. Second, will retarding the std inlet cam a tooth make any difference with the increase comp ration or best to leave it std timing?. I assume you have been down this road.
 Thanks.
The pushrods will need to be shortened by the amount you machined off the barrel for best results. You can sink the stock pushrods deep into the lifters, but there would be more risk of lifter pump-up causing damage.
You want about half of a mm preload into the lifter, so the hydraulic function can work correctly with no concern about lifter pump-up problems.
The squish mod requires that the piston comes up flush to the top of the barrel at TDC. It cannot be down in the bore at all, and it cannot stick up out the top of the bore. That establishes the squish distance as the thickness of the head gasket, which is normally about 1mm thick which is a good squish distance. Failure to establish correct squish distance can negate the benefits if piston doesn't come up close enough to the head, or the piston could touch the head if it comes up out of the bore. Get it flush at TDC and you're good to go.

IMO, the factory UCE does not benefit well from the one-tooth inlet cam retarding because the overall duration is short and it loses too much overlap on the inlet side and pushes the lobe center too much later for my preference. It does give a top end boost from later inlet valve closing timing, though.
If you want to try it, retarding the cam(up to one tooth) is quite safe to do without risk of clashing any internal parts. Personally I think that it shifts it too far, so it's not my cup of tea. But BW seems to like it.
YMMV.
« Last Edit: December 06, 2022, 07:38:54 pm by ace.cafe »
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gizzo

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Reply #17 on: December 06, 2022, 09:25:44 pm
The pushrods will need to be shortened by the amount you machined off the barrel for best results. You can sink the stock pushrods deep into the lifters, but there would be more risk of lifter pump-up causing damage.
You want about half of a mm preload into the lifter, so the hydraulic function can work correctly with no concern about lifter pump-up problems.


I thought I'd killed my engine after a lifter pump up following the squish mod  ;D but it bled back down and ran normally again.

I made a pair of shims from some 0.6mm (IIRC) brass sheet I had laying about. They go under the rocker blocks to lift the rockers up a bit. Saves having to have new pushrods made. Seems to work fine.
simon from south Australia
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ace.cafe

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Reply #18 on: December 06, 2022, 11:51:30 pm
I thought I'd killed my engine after a lifter pump up following the squish mod  ;D but it bled back down and ran normally again.

I made a pair of shims from some 0.6mm (IIRC) brass sheet I had laying about. They go under the rocker blocks to lift the rockers up a bit. Saves having to have new pushrods made. Seems to work fine.
If the lifters are pumping up and temporarily holding the valve off the seat, it means that the valve springs have lost control over the valve, it is oscillating, and the lifter pumps up to take up the excess lash. It happens when overrevving the ability of the valvetrain. As you mentioned it will usually bleed back down after a little bit of slowing down.

As long as the lifter preload is less than the piston-to-valve safety margin clearance at TDC, maximum lifter pump will not clash the valve into the piston.
That's why we like to keep the preload limited to less than the p/v safety margin when we assemble the engine.
But preload must be enough to take up the normal lash created from a warmed-up engine, which is about .010"(.25mm) or it will have valvetrain clatter.
« Last Edit: December 07, 2022, 12:22:22 am by ace.cafe »
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gizzo

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Reply #19 on: December 07, 2022, 12:27:29 am
If the lifters are pumping up and temporarily holding the valve off the seat, it means that the valve springs have lost control over the valve, it is oscillating, and the lifter pumps up to take up the excess lash. It happens when overrevving the ability of the valvetrain. As you mentioned it will usually bleed back down after a little bit of slowing down.

Yep. It occurred the one time after it was on the rev limiter for a few moments (had just swapped over from a revvier bike  ;D) but it settled down soon enough. All good.
simon from south Australia
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bthtony55?

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Reply #20 on: December 07, 2022, 09:08:11 am
The pushrods will need to be shortened by the amount you machined off the barrel for best results. You can sink the stock pushrods deep into the lifters, but there would be more risk of lifter pump-up causing damage.
You want about half of a mm preload into the lifter, so the hydraulic function can work correctly with no concern about lifter pump-up problems.
The squish mod requires that the piston comes up flush to the top of the barrel at TDC. It cannot be down in the bore at all, and it cannot stick up out the top of the bore. That establishes the squish distance as the thickness of the head gasket, which is normally about 1mm thick which is a good squish distance. Failure to establish correct squish distance can negate the benefits if piston doesn't come up close enough to the head, or the piston could touch the head if it comes up out of the bore. Get it flush at TDC and you're good to go.

IMO, the factory UCE does not benefit well from the one-tooth inlet cam retarding because the overall duration is short and it loses too much overlap on the inlet side and pushes the lobe center too much later for my preference. It does give a top end boost from later inlet valve closing timing, though.
If you want to try it, retarding the cam(up to one tooth) is quite safe to do without risk of clashing any internal parts. Personally I think that it shifts it too far, so it's not my cup of tea. But BW seems to like it.
YMMV.

Thanks ACE. While I have the top off is it worth changing the std valves especially the exhaust for Hitchcocks better quality ones. Or are the std ones ok. Im not after huge performance just making mid range running more efficient. Any other little tweaks while the tops off like clean the inlet port up a little and unmask the valves in the combustion chamber?. Just appreciate you thoughts with your experience.
thanks. Tony


ace.cafe

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Reply #21 on: December 07, 2022, 05:21:54 pm
Forum member "Guaire" sells our Ace one-piece Stainless valves that we use ourselves for very reasonable prices, and also out valve spring kits. You could contact him about it, or Hitchcock.

I don't think the port or chamber needs to be worked at this stage of tune, but a high quality 5-angle valve job from a good performance machinist always pays a good dividend. Factory valve jobs are poor, so there are gains to be had there.
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bthtony55?

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Reply #22 on: December 07, 2022, 05:37:49 pm
Forum member "Guaire" sells our Ace one-piece Stainless valves that we use ourselves for very reasonable prices, and also out valve spring kits. You could contact him about it, or Hitchcock.

I don't think the port or chamber needs to be worked at this stage of tune, but a high quality 5-angle valve job from a good performance machinist always pays a good dividend. Factory valve jobs are poor, so there are gains to be had there.
Thanks Ace good advice.
Tony


Guaire

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Reply #23 on: December 08, 2022, 09:27:23 pm
Thanks Ace good advice.
Tony

Hi Tony - With the stainless steel valves, you won't have to worry about the valve head separating from the stem. The intake valve is 1mm oversize from stock. This gives you an intake boost even if you don't do anything else.
I'm running my B5 with these valves running with the beehive springs. The ACE cam is in there too.
ACE has designed all these parts for 'street-able' performance. The rise in the power band, runs through the whole power band.
« Last Edit: December 08, 2022, 09:35:53 pm by Guaire »
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bthtony55?

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Reply #24 on: December 09, 2022, 09:22:30 am
Hi Guaire.
Not planning to use the cams, I just want a bit more all round and a safe engine.
I read sometimes the std valves last for ever and others fail at very low miles. I would have thought if the valves were 1mm bigger that the seats would need opening out the same amount which could mask one side of the valve more in the combustion chamber.

As the ECU cuts off about 5200rpm ish I would have thought the original springs would have controlled the valves at that. Its not revving very high but it only has one spring. Did you use the Beehive springs for more valve spring pressure with the upgrade cams ?. I have no plan to rev mine to the maximum so may just put better valves in while the heads off for a skim.
Thanks for the reply. Tony


Guaire

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Reply #25 on: December 09, 2022, 02:36:26 pm
Hi Guaire.
Not planning to use the cams, I just want a bit more all round and a safe engine.
I read sometimes the std valves last for ever and others fail at very low miles. I would have thought if the valves were 1mm bigger that the seats would need opening out the same amount which could mask one side of the valve more in the combustion chamber.

As the ECU cuts off about 5200rpm ish I would have thought the original springs would have controlled the valves at that. Its not revving very high but it only has one spring. Did you use the Beehive springs for more valve spring pressure with the upgrade cams ?. I have no plan to rev mine to the maximum so may just put better valves in while the heads off for a skim.
Thanks for the reply. Tony

Hi Tony - That's sounds like a reasonable plan.
"...bit more all round and a safe engine."
ACE can tell you more about how stock valves have failed, more experience there. But, I know they are a 'friction welded' set up. ACE told me that fails have come from an overheating exhaust valve that separates.
   Only the intake is 1mm oversize.
Since I have owned my B5, it has had three successive heads. One, was stock.
Two, was our Clubman Kit 1. The head was re-conditioned. Either parts were checked and kept, or made new. Yes, the intake seat was modified for the new valve.

Third, Clubman Kit 2, Beehive springs, new valves. ACE cams. Oil seals. Retainers. Guides were replaced if needed. Seats mated to valves.
Cams; ACE's performance design were installed.
Also, I was running a modified Harley Davidson Sportster 'silencer'. The coil was replaced by one of our 'Ignition Kit' specials.
The PowerCommander V was set up using the AutoTune device. It attaches on the header to monitor the exhaust gas. The profile was changed as per the AutoTune trims.

Yes, the beehive springs make sure there isn't any problem controlling the valves.
  I don't like bouncing off the rev limiter myself. The two valve big single motor is supposed to get power from torque, not revs. This bore & stroke two valve responds well to better head flow design.
I really like this set up. No, you don't have to do everything I did, but I believe your approach to mods is a good one.

At the first start of the day, I like to use the kick starter. One kick to get some gas and the second kick starts up. The strong spark helps the first start. Its idle is steady and sure. I did not mention I use an iridium plug, Nippon Denso, an NGK zero ohm cap, zero ohm plug cable and a super coil.
As you would expect, the torque is strong on take off. But, instead of tailing off as the revs climb, the power keeps on coming more, but evenly. It's like having one big giant mid-range from off idle to the top rev.
My local dealer is Cycles of Silver Spring (Maryland). Rush Branson is chief mechanic and co-owner. Once I got my bike set up, he did a test drive on my Bullet. His comment was 'good mid-range'. That's what we were after.
Not weak off idle, no 'where's the power?' in the mid-range, while you wait for the big hit off the radical cam. One big mid-range throttle means there's strong power all through the gears.

Well I just wrote the whole biography of a B5!
Cheers,
Bill G.
ACE Motors - sales & administration


bthtony55?

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Reply #26 on: December 10, 2022, 10:56:44 am
Wow Bill, you have invested some time and money. It looks like you are reaping the rewards. Its really interesting what folks do and the improvements they make, thanks for sharing. Its a great forum.

Mine has an aftermarket Goldie silencer from Hitchcock with a baffle in the end, its a 500 Classic 2017. After market air filter and the iridium plug.

 It runs well with no backfire on the over run and clean fuelling. I have changed the primary chain from the India one to a better quality and the rear is DID chain. I want to avoid the valve problem reported in some motors and do the compression mod on the barrel next. I don't have a Power Commander and have no plans for one. I will check the voltage on the Throttle position censor, but as the exhaust is not discoloured I don't think its weak on fuel. I get about 100MPG (UK gallons) at about 60mph ish. Mid range and torque is the thing and with a few more mods may be able to put another tooth on the gearbox sprocket.

I live in the UK about 10 minutes walk from the Triumph factory and about 1/2 hour drive from Hitchcocks, so I will pop over there for the valves etc after Xmas. Like you, I usually start first time on the kick start in the mornings then the electric starter after. I have a machine shop at home so I do all mods myself. I also have much modified Norton single and Ariel single and a home made Ariel V twin which I have made.
Cheers Tony


Captain Bob

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Reply #27 on: December 10, 2022, 02:52:15 pm
Wow Bill, you have invested some time and money. It looks like you are reaping the rewards. Its really interesting what folks do and the improvements they make, thanks for sharing. Its a great forum.

Mine has an aftermarket Goldie silencer from Hitchcock with a baffle in the end, its a 500 Classic 2017. After market air filter and the iridium plug.

 It runs well with no backfire on the over run and clean fuelling. I have changed the primary chain from the India one to a better quality and the rear is DID chain. I want to avoid the valve problem reported in some motors and do the compression mod on the barrel next. I don't have a Power Commander and have no plans for one. I will check the voltage on the Throttle position censor, but as the exhaust is not discoloured I don't think its weak on fuel. I get about 100MPG (UK gallons) at about 60mph ish. Mid range and torque is the thing and with a few more mods may be able to put another tooth on the gearbox sprocket.

I live in the UK about 10 minutes walk from the Triumph factory and about 1/2 hour drive from Hitchcocks, so I will pop over there for the valves etc after Xmas. Like you, I usually start first time on the kick start in the mornings then the electric starter after. I have a machine shop at home so I do all mods myself. I also have much modified Norton single and Ariel single and a home made Ariel V twin which I have made.
Cheers Tony

Tony,

It is amazing what folks are doing to their Enfield singles.  I have just started playing with my 2014 CGT 535 and am learning what others have done.  Quite impressive!  Mine still has pretty low mileage (under 1K) so I have only added a Hitchcock's muffler, hi-flow air cleaner and a Dobeck Electronic Jet Kit.  Down the road, I will get more serious about modifying the bike.  Would love to see some pics of your bikes.  If you get a moment, could you please post them?

Thanks/Bob
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bthtony55?

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Reply #28 on: December 10, 2022, 05:37:20 pm
I'll try and figure out how to post a couple of pictures Bob. I don't know how at the moment. Could somebody tell me please. I know they're not Enfield ones so I hope I don't get told off. Its great to have a play with theses things.
Tony
« Last Edit: December 10, 2022, 05:41:59 pm by bthtony55? »


Captain Bob

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Reply #29 on: December 10, 2022, 07:15:51 pm
I'll try and figure out how to post a couple of pictures Bob. I don't know how at the moment. Could somebody tell me please. I know they're not Enfield ones so I hope I don't get told off. Its great to have a play with theses things.
Tony

When you make a post, just below the text box are the words "Attachments and other options".  Click on that and you will see an area to "attach" pics.  You will need to have the picks downloaded on your computer first of course.  I usually put them on the Desktop.  I also resize them to the smallest pixel count I can.  Usually, if you are looking at the pic on your computer and with cursor on the pic, right click.  If you are using Windows, you should see an option to resize the pic in the drop-down menu.  Hope this helps.  I do not think posting a pic is going to be a problem.
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11 Kawasaki KLR 650