Proper way to test for compression?
Thread Starter
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Cruiser
Joined: Mar 2010
Posts: 133
Likes: 0
From: Oklahoma
Proper way to test for compression?
Hey guys,
I had SE-255 Cams installed recently and there's a chance they didn't get aligned properly, so I need to check compression to see if that's the case. I've read to remove both plugs and ground the plugs to the engine and also to remove the EFI fuse. Is this the correct method? Also, I looked at the fuse box diagram and all I could find was the fuel pump fuse...is the EFI fuse elsewhere or labeled something else? I plan on doing the test when I get home this afternoon, so any help or tips would be greatly appreciated!
Thanks,
Roger
I had SE-255 Cams installed recently and there's a chance they didn't get aligned properly, so I need to check compression to see if that's the case. I've read to remove both plugs and ground the plugs to the engine and also to remove the EFI fuse. Is this the correct method? Also, I looked at the fuse box diagram and all I could find was the fuel pump fuse...is the EFI fuse elsewhere or labeled something else? I plan on doing the test when I get home this afternoon, so any help or tips would be greatly appreciated!
Thanks,
Roger
Unofficial HDF Chaplain
Joined: Dec 2009
Posts: 21,157
Likes: 18,077
From: san diego
I don't go to all that bother, really. plugs out, throttle open 6 hits on each cyl. should be even (within10-15 lbs of each other, which is actually a pretty generous spread for all you spec freaks!) and should be above around 150 psi or so. if you have the cam timing off, comp will be pretty low, and bike will be very low on power and should be hard starting. don't know mileage or year of bike, all that comes into effect as well. why don't you take it back to the guy who did it and have him recheck the timing?
Elite HDF Member
Joined: Nov 2010
Posts: 3,846
Likes: 173
From: Simi Valley, CA
I'm certain the cams are aligned properly. Alignment of the timing marks is something I'm always certain of when doing a cam swap. But if you want me to tear into it and double check I'd be happy to do that. You can even watch if you'd like.
If upon inspection the cams are aligned correctly you will pay for the inspection. If they are not, I will correct it and refund every penny you originally paid me in labor.
To the OP... Why do you suspect that the cams are out-of-time? I understand that mistakes are possible, but any competent technician should NEVER make that mistake.
Now if the cams or gears are misground and that is throwing the cam timing off, that's a whole 'nuther story.
Thread Starter
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Cruiser
Joined: Mar 2010
Posts: 133
Likes: 0
From: Oklahoma
If I were the guy who put the cams in and you came back to me saying that you suspect the cam timing is off, here's what I'd tell you...
I'm certain the cams are aligned properly. Alignment of the timing marks is something I'm always certain of when doing a cam swap. But if you want me to tear into it and double check I'd be happy to do that. You can even watch if you'd like.
If upon inspection the cams are aligned correctly you will pay for the inspection. If they are not, I will correct it and refund every penny you originally paid me in labor.
To the OP... Why do you suspect that the cams are out-of-time? I understand that mistakes are possible, but any competent technician should NEVER make that mistake.
Now if the cams or gears are misground and that is throwing the cam timing off, that's a whole 'nuther story.
I'm certain the cams are aligned properly. Alignment of the timing marks is something I'm always certain of when doing a cam swap. But if you want me to tear into it and double check I'd be happy to do that. You can even watch if you'd like.
If upon inspection the cams are aligned correctly you will pay for the inspection. If they are not, I will correct it and refund every penny you originally paid me in labor.
To the OP... Why do you suspect that the cams are out-of-time? I understand that mistakes are possible, but any competent technician should NEVER make that mistake.
Now if the cams or gears are misground and that is throwing the cam timing off, that's a whole 'nuther story.
Road Warrior
Joined: May 2010
Posts: 1,348
Likes: 52
From: Central Illinois
It's suspect because it was running perfectly before the cams. I had the cams and a power vision installed at the same time. The power vision is using a tune Fuel Moto said is tried and true. The bike is really hard to start and runs like crap once it's running...never evens out. Jamie is the one who suggested I check compression.
Also, are the O2 sensors connected properly?
Thread Starter
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Cruiser
Joined: Mar 2010
Posts: 133
Likes: 0
From: Oklahoma
The O2 sensors looks to be connected properly, but they are the autotune ones which to my understanding aren't used to change anything on the fly.
I just went to check the compression and the compression gauge insert did not fit, it was too big. Anyone know what size I need for the bike?
Unofficial HDF Chaplain
Joined: Dec 2009
Posts: 21,157
Likes: 18,077
From: san diego
If I were the guy who put the cams in and you came back to me saying that you suspect the cam timing is off, here's what I'd tell you...
I'm certain the cams are aligned properly. Alignment of the timing marks is something I'm always certain of when doing a cam swap. But if you want me to tear into it and double check I'd be happy to do that. You can even watch if you'd like.
If upon inspection the cams are aligned correctly you will pay for the inspection. If they are not, I will correct it and refund every penny you originally paid me in labor.
To the OP... Why do you suspect that the cams are out-of-time? I understand that mistakes are possible, but any competent technician should NEVER make that mistake.
Now if the cams or gears are misground and that is throwing the cam timing off, that's a whole 'nuther story.
I'm certain the cams are aligned properly. Alignment of the timing marks is something I'm always certain of when doing a cam swap. But if you want me to tear into it and double check I'd be happy to do that. You can even watch if you'd like.
If upon inspection the cams are aligned correctly you will pay for the inspection. If they are not, I will correct it and refund every penny you originally paid me in labor.
To the OP... Why do you suspect that the cams are out-of-time? I understand that mistakes are possible, but any competent technician should NEVER make that mistake.
Now if the cams or gears are misground and that is throwing the cam timing off, that's a whole 'nuther story.
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Grand HDF Member
Joined: Mar 2007
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From: Deep in the heart of New Jersey
Have you checked the pushrods? Might have one or two out of adjustment, either hanging open or closed will make it run crappy.,,
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Elite HDF Member
Joined: Nov 2010
Posts: 3,846
Likes: 173
From: Simi Valley, CA
If I were the guy who put the cams in and you came back to me saying that you suspect the cam timing is off, here's what I'd tell you...
I'm certain the cams are aligned properly. Alignment of the timing marks is something I'm always certain of when doing a cam swap. But if you want me to tear into it and double check I'd be happy to do that. You can even watch if you'd like.
If upon inspection the cams are aligned correctly you will pay for the inspection. If they are not, I will correct it and refund every penny you originally paid me in labor.
To the OP... Why do you suspect that the cams are out-of-time? I understand that mistakes are possible, but any competent technician should NEVER make that mistake.
Now if the cams or gears are misground and that is throwing the cam timing off, that's a whole 'nuther story.
I'm certain the cams are aligned properly. Alignment of the timing marks is something I'm always certain of when doing a cam swap. But if you want me to tear into it and double check I'd be happy to do that. You can even watch if you'd like.
If upon inspection the cams are aligned correctly you will pay for the inspection. If they are not, I will correct it and refund every penny you originally paid me in labor.
To the OP... Why do you suspect that the cams are out-of-time? I understand that mistakes are possible, but any competent technician should NEVER make that mistake.
Now if the cams or gears are misground and that is throwing the cam timing off, that's a whole 'nuther story.
It's suspect because it was running perfectly before the cams. I had the cams and a power vision installed at the same time. The power vision is using a tune Fuel Moto said is tried and true. The bike is really hard to start and runs like crap once it's running...never evens out. Jamie is the one who suggested I check compression.
would not expect him to check timing, but I would expect him to see why its running bad, since he was the last one in. tag, you're it either the tune isn't right or possibly cam timing is off, one or the other, if he was paid to do the mods, he is responsible for the bike running properly after, unless he told the owner, before had that it wasn't going to work for some reason or another, this is a small modification, bike should run fairly well, op doesn't think its right, go back and let the tech tell him what is wrong
With the additional information in subsequent posts, I agree that the guy who did the work should have ensured the bike was operating properly before returning it to the customer, and should be responsible now to make it right.
The only caveat would be if the customer furnished his own parts and any of those parts turn out to be defective and the cause of the problem(s), then the customer needs to share some of the responsibilty.
Thread Starter
|
Cruiser
Joined: Mar 2010
Posts: 133
Likes: 0
From: Oklahoma
Ok. The original post didn't say anything about the bike not running properly or of any tuning performed. It simply stated, paraphrased, "hey I had some cams installed and the cam timing might be off", and that is what my initial post was in response to.
With the additional information in subsequent posts, I agree that the guy who did the work should have ensured the bike was operating properly before returning it to the customer, and should be responsible now to make it right.
The only caveat would be if the customer furnished his own parts and any of those parts turn out to be defective and the cause of the problem(s), then the customer needs to share some of the responsibilty.
With the additional information in subsequent posts, I agree that the guy who did the work should have ensured the bike was operating properly before returning it to the customer, and should be responsible now to make it right.
The only caveat would be if the customer furnished his own parts and any of those parts turn out to be defective and the cause of the problem(s), then the customer needs to share some of the responsibilty.