98 zr 600 efi compression started by bigpiper223
	October 30th 2009 at 2:41 AM Post #1
	bigpiper223 Starting Member 11 Posts Group: Members Member Since: October 30th 2009
	can someone please tell me what the compression is actually supposed to be on a 1998 zr 600 efi. I just bought this sled and have paper work saying that the top end was rebuilt last year but i have compression of 102 on each cylinder. It runs VERY good and is actually pretty hard to pull to start it so I think the compression is ok but im new to the efi so im not sure. Any help is greatly appreciated. Thanks Rating: 0 Quick Edit Edit Topic

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	October 30th 2009 at 3:21 AM Post #2
	2L8ULuz Junior Member 235 Posts Group: Members Member Since: June 21st 2005 Location: Chicago, IL, USA Current Sled: 07 600cfi / 95 xlt
	Are you holding the throttle wide open when you are pulling the cord? If not have someone hold it when you pull. Usually you wont get the same low comp # if it was in need of a rebuild. Thats why I'm asking if you were holding it at WOT. Hows the comp gauge, new, old? Rating: 0 Quick Edit Full Edit

	October 30th 2009 at 8:40 AM Post #3
	constantiarider91 New Member 62 Posts Group: Members Member Since: October 18th 2009 Location: constantia, new york, USA Current Sled: 2001 xc sp 800 2008-2009 Miles: 4200 miles
	it should be 120 or 125lbs of compression in each cylinder because when my xc 500 had 102 lbs of compression it ran ok but it wasnt running at its peak Rating: 0 Quick Edit Full Edit

	October 30th 2009 at 9:22 AM Post #4
	440_jag 450 horse ditch bannger 1488 Posts Group: Members Member Since: July 30th 2007 Location: Galesville, wisconsin, USA Current Sled: 2002 zr 500 cce 2008-2009 Miles: 500
	102 is ok but its not the greatest. You should want to see about at least 115. If it had a recent rebuild, maybe the new rings and pistons haven't seated to the cylinder walls. Put about a TBS of gear oil in each cylinder. If the compression goes up you have blow by. 2002 Zr 500 CCE D&D pipe ported polished y 6 inch riser Acerbis Handguards Chrome winshield Pro-glider Rack Rsi pad Ripped graphics Fox snow pro shocks clickers Rating: 0 Quick Edit Full Edit

	October 30th 2009 at 5:38 PM Post #5
	powderforlife Average Member 721 Posts Group: Members Member Since: August 15th 2007 Location: Eagle river, Alaska Current Sled: 1999 Powder Special 700 2008-2009 Miles: 250
	yeah make sure you have the throttle pinned when you do a compression test it makes a big difference in the compression. 102psi is pretty low.. i would 115psi i was told is ok but you really want 120-125 atleast especially if its been just rebuilt. 1999 Powder Special 700 Super-Q can 4 inch fly risers Powdermad throttle Ext, With Fly Extn. Brake line billet adjuster blocks Fox Shocks all the way around surefoot grips Tunnel Braces With Pre-Filter material behind the hood screens 136 inch track with 2 inch paddle Making a custom Airbox.. Boyesen Power Reeds arrived! 1996 550 Cougar Mtn. Tunnel braces Fly Oversized handlebars with Rox 2'' risors. other family sled. The new edition. 1993 Storm 750 SKS. my sled "The Project" not running low compression 1998 Powder Special 600 EFI(stock) the dads sled Rating: 0 Quick Edit Full Edit

	November 1st 2009 at 2:34 AM  [ Modified November 1st 2009 at 2:46 AM ] Post #6
	bigpiper223 Starting Member 11 Posts Group: Members Member Since: October 30th 2009
	Thanks for the advice guys. I did not have the throttle wide open and the compression tester is an old one. The engine was rebuilt right at the end of last season and im not sure if it was ridden at all. i will try the things you have suggested. one more thing. what is blow by? Rating: 0 Quick Edit Full Edit

	November 1st 2009 at 11:58 AM Post #7
	bigpiper223 Starting Member 11 Posts Group: Members Member Since: October 30th 2009
	update: I tried everything that was suggested and im still getting the 102 rating. any other suggestions? Rating: 0 Quick Edit Full Edit

	November 1st 2009 at 1:01 PM Post #8
	440_jag 450 horse ditch bannger 1488 Posts Group: Members Member Since: July 30th 2007 Location: Galesville, wisconsin, USA Current Sled: 2002 zr 500 cce 2008-2009 Miles: 500
	Blow by is when you have compression that should be in the combustion space but BLOWS BY the rings into the crank case area. So if some air fuel blows by the rings there is less to compact on the compression stroke- so there will be less compression. So it might need to be broken in is what im saying. 2002 Zr 500 CCE D&D pipe ported polished y 6 inch riser Acerbis Handguards Chrome winshield Pro-glider Rack Rsi pad Ripped graphics Fox snow pro shocks clickers Rating: 0 Quick Edit Full Edit

	November 2nd 2009 at 11:31 AM Post #9
	bigpiper223 Starting Member 11 Posts Group: Members Member Since: October 30th 2009
	thank you very much for the advice. what can i do to break it in with out breaking it? if i start it in my garage and let it run will that work? Rating: 0 Quick Edit Full Edit

	November 6th 2009 at 4:17 PM Post #10
	OldCatRider Advanced Member 1975 Posts Group: Members Member Since: August 27th 2006 Location: Groton, NY, USA
	You have to take it out and run it at varied speeds for at least one tank of gas. It is not recommended that you mix any oil in the gas with EFI. You do tie the oil pump lever up so it runs more into the engine. The low reading may also be a symptom of the gauge itself. Try a good screw in one before getting into the engine at all. '93 wildcat 700efi w/Comet Pro-4 clutch & 01 ZR skid '85 indy trail 440 '90 Wildcat, project in progress junior warden, Dryden Lodge #472 F.&A.M. Trail Boss: Dryden to Groton area www.dcdrifters.net If I get to doing any better I am going to have to hire someone to help me celebrate. Rating: 0 Quick Edit Full Edit

	November 7th 2009 at 1:12 PM Post #11
	bigpiper223 Starting Member 11 Posts Group: Members Member Since: October 30th 2009
	The tester i was using was a screw in type but it is pretty old(father inlaws) and hes old and i dont know how long he has had it but its for sure not new. Rating: 0 Quick Edit Full Edit

	November 7th 2009 at 6:35 PM Post #12
	cat-sass Average Member 581 Posts Group: Members Member Since: January 15th 2005 Location: Gladstone, MI, USA
	Quote originally posted by bigpiper223 The tester i was using was a screw in type but it is pretty old(father inlaws) and hes old and i dont know how long he has had it but its for sure not new. Maybe you need a younger father-in-law, with newer tools Sorry, I had to Is your 102 reading on a cold motor, or a warm motor? Run it for a couple minutes and check it, with throttle wide open. Seems unusual to me to have both cylinders reading exactly the same, I'd ask around to borrow another gauge, or try this gauge on something else and see if it will go above 102 lbs. If you're not livin on the edge, Then you're takin' up space! Rating: 0 Quick Edit Full Edit

	November 8th 2009 at 1:09 PM Post #13
	bigpiper223 Starting Member 11 Posts Group: Members Member Since: October 30th 2009
	I took the readings on a cold engine Rating: 0 Quick Edit Full Edit

	November 8th 2009 at 2:28 PM  [ Modified November 8th 2009 at 2:28 PM ] Post #14
	OldCatRider Advanced Member 1975 Posts Group: Members Member Since: August 27th 2006 Location: Groton, NY, USA
	With throttle wide open and 5 to6 pulls? '93 wildcat 700efi w/Comet Pro-4 clutch & 01 ZR skid '85 indy trail 440 '90 Wildcat, project in progress junior warden, Dryden Lodge #472 F.&A.M. Trail Boss: Dryden to Groton area www.dcdrifters.net If I get to doing any better I am going to have to hire someone to help me celebrate. Rating: 0 Quick Edit Full Edit

	November 8th 2009 at 10:38 PM Post #15
	bigpiper223 Starting Member 11 Posts Group: Members Member Since: October 30th 2009
	Throttle was wide open and I did 2 pulls and got the same reading. Does it matter if the engine is cold or warm? Rating: 0 Quick Edit Full Edit

	November 9th 2009 at 4:00 PM Post #16
	OldCatRider Advanced Member 1975 Posts Group: Members Member Since: August 27th 2006 Location: Groton, NY, USA
	Both plugs out too? Even cold, you should be getting at least 120. Try again and give it 5 pulls. '93 wildcat 700efi w/Comet Pro-4 clutch & 01 ZR skid '85 indy trail 440 '90 Wildcat, project in progress junior warden, Dryden Lodge #472 F.&A.M. Trail Boss: Dryden to Groton area www.dcdrifters.net If I get to doing any better I am going to have to hire someone to help me celebrate. Rating: 0 Quick Edit Full Edit

	November 10th 2009 at 12:24 AM Post #17
	bigpiper223 Starting Member 11 Posts Group: Members Member Since: October 30th 2009
	no i didnt have both plugs out at the same time. i took one out then checked it and put it back in and did the same on the other side. Why would that make a difference? Rating: 0 Quick Edit Full Edit

	November 10th 2009 at 8:04 AM Post #18
	OldCatRider Advanced Member 1975 Posts Group: Members Member Since: August 27th 2006 Location: Groton, NY, USA
	Yes, it will slow down the rotation of the engine. '93 wildcat 700efi w/Comet Pro-4 clutch & 01 ZR skid '85 indy trail 440 '90 Wildcat, project in progress junior warden, Dryden Lodge #472 F.&A.M. Trail Boss: Dryden to Groton area www.dcdrifters.net If I get to doing any better I am going to have to hire someone to help me celebrate. Rating: 0 Quick Edit Full Edit