Can you take piston cylinder off without messing with cam timing?

DualSport · 11-07-2018, 06:29 PM

I got parts from RPS to repair my dinged up piston and messed up valves and head, and am wondering if I can pull the piston cylinder without having to reset the cam etc..

I tried searching here and google for it being documented for either the Hawk or original CG 125 and came up with nothing.. I don't want to offset the cam, crank, and magneto and see that the cam adjuster is on the piston-head, but it looks like it's just in the cavity under the push-rod holes.

Thanks

ben2go · 11-07-2018, 07:51 PM

No. It usually turns just a bit while feeding the chain around the sprockets.

**JerryHawk250** · 11-07-2018, 07:57 PM

The CG250 is a push ROD engine so yes you can remove the cylinder without messing up the timing. No timing chain on the CG250.

NzBrakelathes · 11-07-2018, 08:50 PM

CG yeah cause cam inside bottom cases
Maybe add in roller rockers while you are there
Messing with cam timing can’t be an issue cause such a simple motor n line up the dots I assume

ben2go · 11-09-2018, 08:34 AM

Quote:

Originally Posted by JerryHawk250

The CG250 is a push ROD engine so yes you can remove the cylinder without messing up the timing. No timing chain on the CG250.

Forgot that that engine is a pushy rod type.

**JerryHawk250** · 11-09-2018, 08:45 AM

Perfect opportunity to throw in some roller rockers.

https://www.aliexpress.com/item/Bran...9-7f354bbbe4f6

Red Hawk · 11-09-2018, 12:59 PM

WOW I am seriously tempted to try those !
It's snowing here now

so im running out of dust to knock off the Hawk.

**JerryHawk250** · 11-09-2018, 01:16 PM

Quote:

Originally Posted by Red Hawk

WOW I am seriously tempted to try those !
It's snowing here now

so im running out of dust to knock off the Hawk.

Even though any performance gain will be very small if any at all. Less friction does equal more power. It's one of the mods that I would do only if I was already pulling the cylinder off. I wouldn't pull the cylinder just to install them.

Sochin · 11-09-2018, 02:07 PM

Porting the head is simply a must if you're already in there, smooth out and open the intake/exhaust will give you tremendous performance for the money. And port the stock exhaust header to match the opening, as it has a big arse weld inside, forming a doughnut restricting flow..........unless you have an aftermarket exhaust?

Megadan · 11-09-2018, 02:15 PM

I would be more interested in those rockers if they offered an increased ratio. For the dollar I think that would be the best "bang for the buck" if it could be done.

pete · 11-09-2018, 04:35 PM

if the cam lobe ramp angle is not steep enough to
require the use of a roller to climb it..
there is NO gain from a roller..

( if the cam lobe angle is steep enough it will try and
push a lifter side ways... then you need a roller)

but they are cheap..So why not put them in ..
i would just for the hell of it and because I can...

.

Weldangrind · 11-10-2018, 02:03 PM

I'm shy about using rollers, because the needle rollers are another point of failure. I've seen roller rockers grenade inside V8 engines, and those needles go places you don't want them. As Dan says, I'd be more interested in a different ratio.

DualSport · 11-10-2018, 02:08 PM

Can someone tell me why my rockers wouldn't be moving? Got the piston and new head installed(great compression etc...), and rotated engine with pushrods set in the rocker joints and they don't move.. Exhaust is really high up and intake really low, and cam is moving etc..

I have the rocker pin set with the bolt tightened I'm hoping I can fix this there instead of pulling up the piston sleeve. Even though doing work on the piston sleeve is surprisingly fast and requires no special tools.

pete · 11-10-2018, 04:31 PM

are the push rods the same length ?

..

DualSport · 11-10-2018, 05:37 PM

rods were same length they worked after I pushed harder on the exhaust rocker. I'll upload pics tomorrow of everything.

11-07-2018, 06:29 PM	#1
DualSport Join Date: Sep 2018 Posts: 173	Can you take piston cylinder off without messing with cam timing? I got parts from RPS to repair my dinged up piston and messed up valves and head, and am wondering if I can pull the piston cylinder without having to reset the cam etc.. I tried searching here and google for it being documented for either the Hawk or original CG 125 and came up with nothing.. I don't want to offset the cam, crank, and magneto and see that the cam adjuster is on the piston-head, but it looks like it's just in the cavity under the push-rod holes. Thanks
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11-07-2018, 07:57 PM	#3
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,561	The CG250 is a push ROD engine so yes you can remove the cylinder without messing up the timing. No timing chain on the CG250. __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel Last edited by JerryHawk250; 11-08-2018 at 07:27 AM.
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11-09-2018, 08:45 AM	#6
JerryHawk250 Moderator Join Date: Oct 2016 Location: Houma, La. Posts: 11,561	Perfect opportunity to throw in some roller rockers. https://www.aliexpress.com/item/Bran...9-7f354bbbe4f6 __________________ 2023 Lifan Lycan 250 Chopper 2023 Venom Evader 2022 Lifan KPX250 2020 Kawasaki Vulcan S 2004 Honda ST 1300 2016 Black Hawk 250 (sold) Keihin PE30 carb,125 main,38 slow.Pod filter,ported & decked head 10:1 CR,Direct Ignition Coil,15/40Sprockets,NGK DPR8EIX-9,De-Cat,Dual Oil Cooler,Digital Cluster 2016 Cazador180 XL 2014 Coolster150 JerryHawk250.com My YouTube Channel
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11-09-2018, 12:59 PM	#7
Red Hawk Join Date: Jul 2018 Location: NEPA Posts: 273	roller rocker WOW I am seriously tempted to try those ! It's snowing here now so im running out of dust to knock off the Hawk. __________________ 2018 Hawk P&P Decked .040 off the head. 17/43 D.I.D. 428, NGK Iridium plug, DeCat, Wrapped pipe, Custom S.S. Muffler core, Nibbi PE30 115/35, L.E.D. Lights, Digital Cluster, USB port, Cutting Bord skid plate, Oil cooler w/ custom CRF oil filter inline, 5Wt fork oil, Rear Shock, CNC Back Rack, 30mm FAT bars, Bark Busters, ProGrips, Adjustable levers, Shinko 700’s lots of Loctite!
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11-09-2018, 02:07 PM	#9
Sochin Join Date: Jul 2017 Location: Montucky Posts: 209	Porting the head is simply a must if you're already in there, smooth out and open the intake/exhaust will give you tremendous performance for the money. And port the stock exhaust header to match the opening, as it has a big arse weld inside, forming a doughnut restricting flow..........unless you have an aftermarket exhaust? __________________ 1991 Kawasaki KLR250
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11-07-2018, 07:51 PM	#2
ben2go Join Date: Jun 2011 Posts: 1,335	No. It usually turns just a bit while feeding the chain around the sprockets.
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11-07-2018, 08:50 PM	#4
NzBrakelathes Join Date: Jun 2016 Location: Hell Posts: 2,408	CG yeah cause cam inside bottom cases Maybe add in roller rockers while you are there Messing with cam timing can’t be an issue cause such a simple motor n line up the dots I assume
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11-09-2018, 02:15 PM	#10
Megadan Join Date: Apr 2017 Location: Omaha, NE Posts: 8,016	I would be more interested in those rockers if they offered an increased ratio. For the dollar I think that would be the best "bang for the buck" if it could be done. __________________ Hawk Information and Resource guide: http://www.chinariders.net/showthread.php?t=20331 2018 Hawk 250 - Full Mod list here. http://www.chinariders.net/showpost....62&postcount=1 2024 Royal Enfield Shotgun 650 https://chinariders.net/showthread.php?t=34124
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11-09-2018, 04:35 PM	#11
pete Join Date: Jan 2012 Location: ChCh , NZ Posts: 2,261	if the cam lobe ramp angle is not steep enough to require the use of a roller to climb it.. there is NO gain from a roller.. ( if the cam lobe angle is steep enough it will try and push a lifter side ways... then you need a roller) but they are cheap..So why not put them in .. i would just for the hell of it and because I can... . __________________ 09 XT660R ... 06 TTR250 ... 80 Montesa H6 125 Enduro... 77 Montesa Cota 348 MRR "Malcom Rathnell Replica"... Current resto projects.. 81 Honda CT110... 80 Kawasaki KL250A1... 11 Husaburg TE125 enduro... "sold" along with another 31... Lifan 125 Pitbike.. "stolen" ... KIWI BIKER FORUM...... http://www.kiwibiker.co.nz/forums/content.php All the best offroad rides in NZ... http://www.remotemoto.com/ E-mail... xtpete1@gmail.com
	1

11-10-2018, 02:03 PM	#12
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	I'm shy about using rollers, because the needle rollers are another point of failure. I've seen roller rockers grenade inside V8 engines, and those needles go places you don't want them. As Dan says, I'd be more interested in a different ratio. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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11-10-2018, 02:08 PM	#13
DualSport Join Date: Sep 2018 Posts: 173	Can someone tell me why my rockers wouldn't be moving? Got the piston and new head installed(great compression etc...), and rotated engine with pushrods set in the rocker joints and they don't move.. Exhaust is really high up and intake really low, and cam is moving etc.. I have the rocker pin set with the bolt tightened I'm hoping I can fix this there instead of pulling up the piston sleeve. Even though doing work on the piston sleeve is surprisingly fast and requires no special tools.
	0

11-10-2018, 04:31 PM	#14
pete Join Date: Jan 2012 Location: ChCh , NZ Posts: 2,261	are the push rods the same length ? .. __________________ 09 XT660R ... 06 TTR250 ... 80 Montesa H6 125 Enduro... 77 Montesa Cota 348 MRR "Malcom Rathnell Replica"... Current resto projects.. 81 Honda CT110... 80 Kawasaki KL250A1... 11 Husaburg TE125 enduro... "sold" along with another 31... Lifan 125 Pitbike.. "stolen" ... KIWI BIKER FORUM...... http://www.kiwibiker.co.nz/forums/content.php All the best offroad rides in NZ... http://www.remotemoto.com/ E-mail... xtpete1@gmail.com
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11-10-2018, 05:37 PM	#15
DualSport Join Date: Sep 2018 Posts: 173	rods were same length they worked after I pushed harder on the exhaust rocker. I'll upload pics tomorrow of everything.
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