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Old March 28th, 2020, 10:06 PM   #1
dmarucci
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Name: Daniel
Location: La Puente, CA
Join Date: Mar 2020

Motorcycle(s): 2007 Ninja 250r, 2009 BMW R1200RT, 1968 Yamaha YCS-1

Posts: 4
Low Compression on 2007

Hello all, Dan here. First post on this forum. I picked up a 2007 Ninja 250 for my daughter last week. It has 20,400 miles on it. It was not running at the time, but was very clean. After I ordered a new battery (old one simply would not take a charge), I did the following:
1) Read quite a bit on Ninja250.org
2) Took off all the fairings
3) Thoroughly cleaned everything
4) Replaced spark plugs (old ones had enormous amount of erosion).
5) Verified spark (using another battery and jumper cables)
6) drained the fuel tank and removed valve and cleaned it. Lots of water, but tank had NO rust inside, rinsed it with alcohol and dried it. Valve opens with vacuum and does not leak.
7) removed carbs, soaked all jet and screws separately in Berryman Chem-Dip
8) soaked carb bodies (without diaphragms) on chem dip.
9) Blew carb cleaner through all openings, verified that it exited in the right place and reinstalled all jets and screws. 2 1/2 turns out on mixture screws. O-rings and washers in place correctly on mix screws. The carbs were not very dirty to start with.
10) Did a cold compression test (dry, throttle wide open). 55 left, 60 right.

This led to a mountain of concern.

11) Tore off valve cover and checked gaps. Exhaust was less than 0.002 inches on all 4 valves. Corrected this (and dropped a feeler gage into the cam chain gallery- retrieved with neo magnet and duct tape. All EX gaps are 0.005-0.006 inches. All intakes are 0.004 in.

Redid compression test. 60 left, 70 right.

Even spraying starter fluid into the airbox, this thing doesn't even kick, it just spins like the plugs are out.

It's too high to be a hole in a piston, but too low to probably run.
What does everyone else get on a stock cold compression test?

Next steps? How do I do a wet test to see if it's rings vs valves?
There's no oil in the coolant and the oil is not the typical milky brown you normally get from a blown head gasket.

What does everyone think? I hate to pull the head, but I may not have a choice.

Thanks!!!
Dan____
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Old March 29th, 2020, 06:31 PM   #2
DannoXYZ
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Hi Dan and welcome to Ninjette!

First, post picture of your compression gauge. If it has release valve out near gauge, entire volume of hose up to that valve will be considered part of combustion chamber, resulting in low reading.

To do wet test, remove plugs and squirt in about 1cc of oil. I use little squeeze bottle of oil I use to lube lathe and mill machining projects. Also cold engine will always yield low compression wet or dry.

When you measured valves clearances, did you check valve timing? That is all the marks on crank and each cam lines up properly?

Most likely, lack of fuel due to dried petrol clogs may be preventing starting. Dried petrol turns to plastic when sitting for over 3-months and requires mechanical scrubbing to remove as it will not dissolve again. You'll need ultrasonic cleaning with caustic radioactive solvents for weeks on end. Scrubbing all fuel passages with brushes of appropriate size (follow fuel-flow from beginning to end). Finish with micro soda-blasting at 10000 psi. Along with some other maintenance steps, then your carbs may be factory-fresh clean and run like it just left showroom floor.

Do search here for "clean carbs ducatiman" for photos and procedure on what's needed to thoroughly clean carbs. Good luck!
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Old April 1st, 2020, 08:44 PM   #3
dmarucci
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Name: Daniel
Location: La Puente, CA
Join Date: Mar 2020

Motorcycle(s): 2007 Ninja 250r, 2009 BMW R1200RT, 1968 Yamaha YCS-1

Posts: 4
Danno,
Thanks for the reply. I'm pretty sure the compression numbers are accurate. The spark plug end of the hose also has a check valve on it. After a few rotations it maxes out. The cylinder doesn't have to recompress the hose volume on each stroke. (see pics). My head gasket and all the other associated new gaskets and stem seals will arrive tomorrow. I've got my valve spring compressor waiting in the wings. We're gonna tear the head off tomorrow, after we do a quick wet compression test.

I'm hoping for a blown head gasket, and not burnt or bent valves. if it is the head gasket, I'll replace the stem seals for good measure, then lap the head and put it back on. If it turns out to be the pistons, then I may opt for new ones with a slightly higher compression ratio (maybe like 10 or 10.5) My BMW R1200 RT is like 12, but it requires premium unleaded.

Wish me luck and thanks again!!!
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Old April 5th, 2020, 01:28 PM   #4
dmarucci
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Name: Daniel
Location: La Puente, CA
Join Date: Mar 2020

Motorcycle(s): 2007 Ninja 250r, 2009 BMW R1200RT, 1968 Yamaha YCS-1

Posts: 4
Interesting development

Danno,
So, After all my new gaskets arrived, I did a wet compression test:
2 ml of Valvoline 20W50 full synthetic motorcycle oil in each cylinder via a syringe and a rubber hose (right at the edge of the piston)
Rotate with 14mm socket by hand through a few rotations.
Compression test each cylinder open throttle.
Both went up to 125 psi - exactly.
This bike only has 20,400 miles and I know the owner for its entire previous life. He says he was very good about oil changes. There's no way the bores / ring / pistons are THAT worn. I'm thinking the rings are stuck from sitting.

Thoughts?

I'm going to try the piston ring soak method you outlined here:
https://www.ninjette.org/forums/showthread.php?t=343925

It's not looking too much like a head gasket or valves anymore. I guess only a leak-down test would tell.
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Old April 5th, 2020, 05:54 PM   #5
DannoXYZ
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MOTY - 2018, MOTM - Nov '17
Sure, wouldn't hurt to do piston soak. I've brought back cylinders in 60psi range back up to 195psi with soaks (oil-burning Celica).
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