Banshee runs strong but Compression at 90psi and 100psi on the 2nd cyl

[Socalshee95]

First post here. My Banshee runs great, pretty strong, very good take off nothing out of the ordinary. I did a compression test today and got 90psi on the left and 100 on the right. Used a gauge from O Riley's, kicked until it stopped. When measured, throttle was NOT pushed down, the elevation is about 300p (don't think it matters at all but it's what it is) and my reeds are worn (if it matters.) Pistons appear healthy and are Wiseco (about 2yrs old according to previous owner). Bike does wheelies in 2nd gear without trying much. Any ideas? This beats me, low compression but bike runs fine. Never heard that before. 

[the boris]

Well tuned I suppose.

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[the boris]

Or your tester is toast

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[Deets]

Cheap Chinese tester is my guess. Do you have anything else to check the tester. And elevation does make a difference. 

[Socalshee95]

9 hours ago, Deets said:

Cheap Chinese tester is my guess. Do you have anything else to check the tester. And elevation does make a difference. 

I actually don't, rented it at O'Riley's. Reason I checked in first place was because the kick start felt "soft" but it starts without having to kick more than 2-3 times even after sitting for a while. I took it out for a spin, even raced a Camaro and the bike flies. I just can't seem to make sense out of it. Pistons are clean, Wiseco and non-issue there. Also let the gauge sit there for 5 minutes and lost no compression, stayed steady. I ve never seen that before 

 

[Deets]

23 minutes ago, Socalshee95 said:

I actually don't, rented it at O'Riley's. Reason I checked in first place was because the kick start felt "soft" but it starts without having to kick more than 2-3 times even after sitting for a while. I took it out for a spin, even raced a Camaro and the bike flies. I just can't seem to make sense out of it. Pistons are clean, Wiseco and non-issue there. Also let the gauge sit there for 5 minutes and lost no compression, stayed steady. I ve never seen that before 

 

The gauge won’t lose psi unless the Schrader valve is bad. I’ve seen cheap gauges read high or low of what actual comp is. I’d check with a different gauge, or you could pull it apart and visually inspect bores. I’d check ring end gap if your that far. 
 

But from the sounds of how it’s running, it’s Probly a faulty gauge

[the boris]

I guess 90 and 100 psi is not that bad, if it runs no need to fix it.

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[Ayesully810]

if it runs fine then run it.  a better tester with the right tip will give you a more accurate reading, plus with the throttle open.  if the compression was bad, it would start hard.

[Deets]

5 hours ago, Ayesully810 said:

if it runs fine then run it.  a better tester with the right tip will give you a more accurate reading, plus with the throttle open.  if the compression was bad, it would start hard.

Why does the throttle need to be open? 

[kawa110]

You will not get a accurate reading with “bad” reeds.

Throttle open to allow Maximum amount of air into cylinder to compress.


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[n2otoofast4u]

If it runs good, then run it! Don’t fix something that isn’t broke!

Buy your own tester! $30 or $300. Just buy one. Use it, and your procedure as a baseline. But, until it gives signs of slowing, run da fuck outta it, that’s what they are made to do.

Good gas, good oil, good warm up. Run it!

[the boris]

Why does the throttle need to be open? 

If you have 10psi of vacuum because your slides are all the way down you will have 10 or maybe even more psi less compression.
Now when you mentioned it, I'll run a test with full throttle and no throttle at all, just to see the difference.

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[the boris]

Just had a quick Web surf and the difference is from 10 to 20 psi with throttle open VS closed.

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