Author Topic: CycleX pistons "for chopper or bobber". (Read 26285 times)

N30R3L0AD3D · « **Reply #50 on:** June 09, 2011, 08:50:55 AM »

HondaMan, that a bad thing? I am buying it from cyclex. They claim it will work with factory valve springs in a stock motor.... I called webcamshafts, they too confirmed their cam will work in a stock motor with the same specs... And from what little research I've done, this is the weakest street cam you can get "new" anyway.

From their site:

"Broad power range. This cam will bolt right in stock engines. You will notice good power increase with this one. This camshaft profile was used on tight road-race tracks. You will like it. .360 valve lift and 270 degree duration."

Basically this is what all I am doing:

Replacing rod bearings
Replacing crank bearings
New heavy duty cam chain
New cam chain tentioner and rollers
New exhaust valve guides
New cam (stock one has a weird wear on one lobe from orig owner not ever adjusting cam chain tentioner)
Cam tower modification (top secret)
Port polish
All new seals
Oil pressure gauge (need to find one yet)
50 over piston kit (cycle X)

Some things I've already done to the bike prior to teardown:

Aftermarket Andrews ignition coils + new wires + plugs
530 chain conversion (18 front, 45 rear)
New rear dual damper shocks
Mac 4 into 1 exhaust (I had a kerker but the baffle disintegrated)
Put 120 jets in the carbs
Veshra clutch springs and disks
New Swing arm bushings
New brakes (rear)

Really the only reason I needed to rebuild the motor was cause some dumbass local machine shop, on a stock rebuild I did prior didn't hone one of my cylinders right and took too much off my #1 cylinder and caused over a 20 PSI compression loss in it. It ran ok, but I kept fouling a plug in that cylinder occasionally. Mind you I put new factory rings in it. And it was definitely not valves, poured a cap full of oil in the cylinder and compression shot right up to around 145 with the rest of the cylinders.

MCRider · « **Reply #51 on:** June 09, 2011, 08:59:27 AM »

You called RC Engineering? Really?

N30R3L0AD3D · « **Reply #52 on:** June 09, 2011, 09:12:49 AM »

Sorry, I meant webcamshafts

webcamshafts.com

MCRider · « **Reply #53 on:** June 09, 2011, 01:12:09 PM »

Quote from: N30R3L0AD3D on June 09, 2011, 09:12:49 AM

Sorry, I meant webcamshafts

webcamshafts.com

Thought so

Just wondering if you knew something I didn't.

Sounds like the same cam I've got: WebCam #41. Can't wait to get it running.

re: my comment about Yoshimuras cams being wimpy: I think that the drag boys were making massive lobe sticks to beat the pavement with. Like the chimps in 2001. While the roadrace guys were looking for revs and longevity. The cam was wimpy in statistics, but more attention was paid to the porting, carbs etc., and the engine would last flat out for 200 miles. It would also work well in an unbuilt engine.

The big bump cams would beat the engine to death in 20 to 30 runs down the strip. Somehting like that.

Or so i think.

voxonda · « **Reply #54 on:** June 09, 2011, 02:42:11 PM »

I run a 41a in my test-rig and it runs suprisingly good on it. It's a F2 engine. Love riding it on track.

Rob

N30R3L0AD3D · « **Reply #55 on:** June 13, 2011, 09:16:09 AM »

My only concern with the cam I've chosen is whether or not it will work with factory valve springs and a mostly stock bike. My motor is a K4 I believe.

360 valve lift and 270 degree duration does seem like an awful lot.. I don't intend to race, but do plan on putting some highway miles on it.

MCRider · « **Reply #56 on:** June 13, 2011, 09:43:05 AM »

Quote from: N30R3L0AD3D on June 13, 2011, 09:16:09 AM

My only concern with the cam I've chosen is whether or not it will work with factory valve springs and a mostly stock bike. My motor is a K4 I believe.

360 valve lift and 270 degree duration does seem like an awful lot.. I don't intend to race, but do plan on putting some highway miles on it.

As you've already mentioned, WebCam says yes and its the puniest cam they've got. What choice do you have, next thing lower is stock. Shuould be fine, I itenc to tour mine as well.

voxonda · « **Reply #57 on:** June 13, 2011, 02:33:20 PM »

I also use the oem springs, retainers etc. But keep in mind the springs in your bike are around 35 years old and probably have had a 'life' behind them. But for 'normal' use it should do.

Rob

N30R3L0AD3D · « **Reply #58 on:** June 15, 2011, 10:47:25 AM »

I know this is a bit off topic, but to those who are looking to replace crank and rod bearings.. Mine were all green according to the crank and case.. Your looking at $249 bucks. Ouch

N30R3L0AD3D · « **Reply #59 on:** July 09, 2011, 11:44:36 AM »

Update.

Took the jugs to a machine shop to have it bored out with the 50 over kit from cycle x. The machine shop called me later on and wanted to know what the clearance was on the pistons, so I called cycle X. They told me .001, and also talked to the machine shop guy. While I was checking out, the guy at the counter warned me this engine would seize up, and they would not be liable. I asked the guy at the counter what he thought it should be, and he told me .008

........

I thought the clearance was .0004 to .0016 or something like that...

HondaMan · « **Reply #60 on:** July 09, 2011, 10:29:26 PM »

Quote from: N30R3L0AD3D on July 09, 2011, 11:44:36 AM

Update.

Took the jugs to a machine shop to have it bored out with the 50 over kit from cycle x. The machine shop called me later on and wanted to know what the clearance was on the pistons, so I called cycle X. They told me .001, and also talked to the machine shop guy. While I was checking out, the guy at the counter warned me this engine would seize up, and they would not be liable. I asked the guy at the counter what he thought it should be, and he told me .008

........

I thought the clearance was .0004 to .0016 or something like that...

The guy at the counter is WRONG. The proper clearance is 0.0008" to 0.0012" when new. I don't know of ANY engine that uses 0.008" clearances. Ever. The forged pistons, like Wiseco, use about 0.0020", but that's the largest. Even auto engines uses 0.0015" to 0.0022" spec. I think that guy should not be working in a machine shop?

Sadly, I have also had to fix several 750 engines in the last few years that came from loudmouths like him. They don't understand the fundamentals of the steel-sleeved, aluminum-finned, cast-piston engines, and they talk their customers into this nonsense. The end result is blown pistons (seized from lack of lubrication and contact with the cylinder walls.

Here's how it works:
The cylinder wall must trap the oil film between the piston skirt and the wall so the heat can transfer from the piston to the cylinder. If there is too much clearance, the oil will not make contact (because it can flow away from the contact areas area too easily) and the piston will overheat. This is what grows and seizes the piston. Very simple.

MCRider · « **Reply #61 on:** July 10, 2011, 05:19:48 AM »

HM: When I first read the post on the cylinder piston clearance, I googled "piston clearance" and came up with the same arguments. The piston manufacturers were calling for 1 to 3.5 thou (J&E) , certain machinists said no it should be 8. Interesting.

N30R3L0AD3D · « **Reply #62 on:** July 10, 2011, 05:50:03 AM »

Glad I stuck with .001 clearance then. I think from now on I will just ship my stuff out to a reliable machine shop. Unfortunately, the area I live in doesn't have good machine shops. Don't get me wrong, I think the shop I took my jugs into did a good job but when ya got a guy at the counter telling me things like this, I'd agree he doesn't belong there.

Just curious Hondaman, what was the ring gap at with your kit?

HondaMan · « **Reply #63 on:** July 10, 2011, 08:48:13 PM »

Quote from: N30R3L0AD3D on July 10, 2011, 05:50:03 AM

Glad I stuck with .001 clearance then. I think from now on I will just ship my stuff out to a reliable machine shop. Unfortunately, the area I live in doesn't have good machine shops. Don't get me wrong, I think the shop I took my jugs into did a good job but when ya got a guy at the counter telling me things like this, I'd agree he doesn't belong there.

Just curious Hondaman, what was the ring gap at with your kit?

Mine came in at 0.008" to 0.010" across the whole set, not bad. Honda's limit is 0.027" (very generous!), and low end should not be less than 0.006". With the inexpensive 836cc (65mm) piston kits we've recently seen, I had to open the gaps a little on several of the top compression rings, as they were about 0.002" with piston clearance of 0.0012". I put them in at 0.008", seem to be running fine.

N30R3L0AD3D · « **Reply #64 on:** July 10, 2011, 09:59:42 PM »

I'll check mine if I get the bottom end finished.. While putting the new rod and crank bearings in today, I discovered I had a bent rod. Funny thing was is it must have been this way since I bought it. The guy never adjusted the cam chain in 17k miles. I did notice 2 valves were not sealing right on #1 and #4 the first rebuild, so I put 2 new ones in and it ran fine. I never noticed this cause when I did the first rebuild, I didn't take the pistons off the rods. Rode it like this for awhile, ran fine other than a slight rough idle (acted like a carb was out of sync) I just assumed it was due to bad machining the first time around, taking too much material off from honing with new factory rings causing low compression.

Luckily for me, my dad has saved several sets of stock rods, so I was saved. Everything plastigauged out fine with new green bearings.

1974cb550k · « **Reply #65 on:** February 07, 2012, 07:02:04 AM »

I just bought a set of these from cycle X. I am unsure of what you mean by "flash" also how am I to "finish" the surface of the skirt ring. The quotes below were taken from hondamans orig post. Thanks

"They have some flash that must be removed before you use them, lest it end up inside your oil pump, which will cause significant pump damage. Pictures below: the flash is around the oil holes that are just below the oil rings.
3. The surface of the inside skirt ring is not finished: you must finish this yourself or it will end up like the flash in #2 above, and will pass through the oil pump."

N30R3L0AD3D · « **Reply #66 on:** February 09, 2012, 12:32:04 PM »

On my pistons, there was no excessive flashing. I got about 400 miles on my bike since the 50 over kit, and I got around 125 psi compression across the board. I had some issues with the wipe ring, and couldn't find an arrow or anything indicating up or down. Called them, and they said it was universal, which had me scared but I took their word for it and it seems ok. They did an ok job on the head, although there was some milling issues and I was not impressed with the head gasket that came in their gasket kit. Grade A valve job though.

N30R3L0AD3D · « **Reply #67 on:** April 10, 2012, 08:58:37 PM »

Just wanted to update on my previous post from a little bit ago. I now have 150 compression across the board with a new headgasket from veshra.

HondaMan · « **Reply #68 on:** April 11, 2012, 01:23:32 PM »

Quote from: 1974cb550k on February 07, 2012, 07:02:04 AM

I just bought a set of these from cycle X. I am unsure of what you mean by "flash" also how am I to "finish" the surface of the skirt ring. The quotes below were taken from hondamans orig post. Thanks

"They have some flash that must be removed before you use them, lest it end up inside your oil pump, which will cause significant pump damage. Pictures below: the flash is around the oil holes that are just below the oil rings.
3. The surface of the inside skirt ring is not finished: you must finish this yourself or it will end up like the flash in #2 above, and will pass through the oil pump."

On those first sets I got, there was thin metal flash and some large sharp edges on the ends of the skirts. I have not bought more of those since then, instead I get the "finished" version of them from Z1 Enterprises now. They started carrying them for the forum at our request, so I use them quite a bit.

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Author Topic: CycleX pistons "for chopper or bobber". (Read 26285 times)