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zx7r compression test results dry and wet advice help

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Real808
L Plate Warrior



Joined: 29 Sep 2011
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PostPosted: 19:30 - 29 Sep 2011    Post subject: zx7r compression test results dry and wet advice help Reply with quote

i had this bike now for 8 years unfortunately its spent most of that time off the road, i would really love to get it back just to road worhty standards to start with would be great and i have fell on hard times could really do with it for transport right now, i kept it because i have some personal reasons, just memorys really and centimental value i geuss, anyway for that reason it has become abit of a personal goal to revive it.

i have changed a few things new forks, exhaust system new calipers and a few small things speedo drive brake braided hoses ect, its still along way from being what i would guess would be a good example of one but i was happy with it for now an have no plans to ever sell it, anyway i finaly thought all i had left to do was the fairing it would defiantly benefit from some new paint and was looking forward to doing that last but just befor i booked it for its mot litterally the day i was aranging a friend to take it to the garage the one thing i thought was ok the engine, started miss firing and is now not starting, i have the carbs off now and in process of rebiulding them, something i proberly should have done along time ago they are stripped down and dont look in bad condition but then im not expert on this.

Anyway sorry for going on so much the reason im making this post is im hopeing you guys could help me i have done a compression test and would really appreashate any advice at all on the results i have spent last couple days researching about this but im really unsure what to do.

COMPRESSION TEST RESULTS
cylinders 1 to 4
dry
#1, 125 psi #2, 130 psi #3, 130 psi 4#, 125 psi

wet (about tea spoon of oil added through spark plug)

#1, 175 #2, 180 psi #3, 180 psi #4, 175 psi

It has been of the road around 3 years acasionally started up over this time, is this normal wear considering the age or is it maybe some kind of build up in the cylinders from being started and left to idal but not had a proper run for so long or am i just being desperate to convince myself its ok and it needs rebuild or new engine.

i would be happy to get just abit more life out of it untill i have the cash to find a good engine or rebuild it, its about a 35% 40% incresse on the wet test i read somwhere that somtimes after a rebuild it is normal to have upto 15% increese with a wet test, i dont know what to do could the compression results be causing the problem with starting? do i have no choice but a new engine or a rebuild? is it wishfull thinking to hope i can find the problem somwhere else get it running and after a good run the compression may come up abit higher.

i read in the manual and it says the usable compression is between 149 psi and 220 psi, i could write a book on all the stuff i have read about this and its just left me really confused please help...

Just wanted to add i had the carbs off and had a few pieces of cloth pluging the inlet holes to prevent anything falling in there which i temporarily removed and all the spark plugs when did this test, i hope thats correct way to do it i read you need to hold the throttle open when doing the test obviously with the carbs off i couldnt do that... also been wondering about this... on the engine number i saw kh1 where i thought the model number should be p1 p2 p3 p4 ect i thought it was a p2 engine am i looking in the wrong place or does anyone know what that means? i wasnt aware of a kh1 model this post is getting abit long i try not to add too many questions altho i have loads, please again any help or information regarding differences with wet and dry tests would be really appreciated
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serlant
Brolly Dolly



Joined: 06 Jul 2009
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PostPosted: 20:53 - 29 Sep 2011    Post subject: Reply with quote

new set of rings going by the compression results only.
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04 CBR1000RR, 1995 Husqvarna TE410, 1998 VTR1000(Sold), 1990 XJ600(sold), 1996 KH125(dead and sold)
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Livefast123
Nearly there...



Joined: 14 Mar 2010
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PostPosted: 21:01 - 29 Sep 2011    Post subject: Reply with quote

Personally I would just give the carbs a clean and put some fresh fuel in it then go from there. The non running is probably caused by sh*t caught up somewhere in the fuel system.

You should also do the compression test when the engine is up to temp otherwise you will get lower readings.
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MaybeGuy
Super Spammer



Joined: 12 Mar 2007
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PostPosted: 21:18 - 29 Sep 2011    Post subject: Reply with quote

the results show even wear with and without the wet test. That's good. did you do it at WOT?
Engine will be fine. After a run or regular use the seal will probably be better due to the rings being sealed better with oil from below.
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Blue_SV650S wrote: it was a sh1te wheelie, but it proves that he can get it up in 3rd and can do angles. In summery, mattsprattuk is a gobby little sh1tebag, dopehead tw4t, but sadly for all of us, he probably isn't THAT full of sh1te!! Mr. Green
Kickstart wrote: Hi I tend to agree with Matt. All the best Keith
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temeluchus
World Chat Champion



Joined: 01 Oct 2008
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PostPosted: 21:21 - 29 Sep 2011    Post subject: Reply with quote

for a cold test, those values look fine.
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