Virago 920 XV cafe racer / custom

Checking the valve clearance was not as difficult as i thought. Removing the cylinder head and checking the piston looks like it is going to be challenging. I'm currently living with in-laws and my father-in-laws does not have an air compressor for a leakdown test.

Should i just pull the front cylinder and check the piston rings like the hanyes manual suggest? or are there other methods to determine if im headed down the right path to increase the PSI.

Symptoms
When i turn the engine by hand it becomes tight in one section.
I hear a hissing noise from the front cylinder when i do a compression test.
PSI is 90
 
Try to hear if the hissing is coming from the intake or exhaust valve. If they are still leaking clearance then there could be carbon build up on the seat or just a bad seal.

There might be something that you can use to soften up the carbon and turn the engine over until it seals right but any carbon that comes off the seat will be in the cylinder.

Sounds like you might be diving into the engine. If the valves are leaking you can take the head off and clean them up which should restore the seal. No need to remove the cylinder.

If that doesn't fix it your up for new rings and a hone.
 
Didn't you say earlier the compression went up when you squirted some oil in the cylinder?


Try that again - if it does then it means rings.....hopefully just a stuck one that will loosen up with a few heat cycles.
 
Last night I removed the cylinder head to see the piston rings condition. The gap looks extremely large. I have the Clymers Manual and Haynes Manual and it is unclear what the specification is and how im supposed to check it. Can someone please inform me?
What is the best method to clean the valves, bolts, cylinder head, and bore? Can I just dip them in mineral spirits or kerosene to clean them?
The manual says to hone the bore, where can I take the bore to get that done cheaply?
Should I spray the gears below with PB blaster while they are exposed?
This project is getting pricey quick. I’m assuming I need new piston rings, new O-rings and gaskets. Where is the cheapest place to purchase these items?
 

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The rings should be moving freely, and the free end gap doesn't mean much at all. The proper way to measure the correct end gap on the piston rings is to remove them from the piston (carefully, they are very easy to break) and insert them into the cylinder bore and down about 10-15mm, evenly. You can then measure the gap between the two ends, but this is mostly a tool to confirm that new rings are in spec before putting them on.

An engine machine shop will be able to measure the bore/piston for you so that you can compare it to spec. A cylinder hone should be fairly cheap to have done, you can also buy a hone for a cordless drill and do it yourself.
 
Hard to tell conclusively from a shadowy picture on the computer but your cam lobes look badly scored.
 
920 Bore to big for piston

I took the piston and bore to get measured at a machine shop. The clearance of the piston and bore has exceeded its specs.
I’m looking for the cheapest fixed without jeopardizing the quality of the motor.
Should I take my look with a cylinder jug on ebay? They do not make an over sized piston (92.25mm-92.5mm for virago anywhere on the internet.
I saw one case of someone some taking a virago 1000 piston and boring out the 920 jug.
Does anyone have any great ideas?
 
cut your losses and move on ,sad indeed, but the fact is its worn out .there is the issue of the cams and heads ,what kind of shape is the crank and big end bearings in ?its going to take a pile of money.period
for the bore to be worn out it was probably lack of proper mantainance as well,considering that, the big end is a worry
if you are stuck on a virago find a good runner with low miles,that engine is not a viable deal without a complete overhaul =$$$$$$$$$$$
 
Don't give up just yet.

Price a new motor, price new pistons, price new cylinders and price a new bike. Then work out which you think is best
 
After honing cylinder, new gaskets (except head gasket), relapped valves, and a good cleaning i have 110 psi. Manual says minimum 128psi. Is 110 good enough?

The rear cylinder was not torqued to specs, does that have any relationship to front cylinder.

Sent from my SM-G920V using DO THE TON mobile app
 
So did you replace the rings and head gasket?

You may find a very slight increase after running it for a little. That is due to the hone and carbon buildup.

I would use a new head gasket at the least. You may find it helps.
 
Of all the gaskets you should replace - the head gaskets are number one.


By this I mean they are not to be re-used.
 
I got new piston rings. I did not replace the head gasket. Does anyone have any experience removing a head gasket for a virago 920?
 
its a ring right ?
called a fire ring sometimes
generally they are built in to a more normal looking gasket,not seperate
you just pick it out an icepick would work great just dont jab down into the mating surface you dont want to knurl it up
and then clean gasket surfaces back to metal no residue at all should be left
but if you havent taken it back apart find out for sure if a leak at head gasket was contributing to gauge reading
you can pretty much cover it test wise with soapy bubbles test
 
I just pulled the head of the Virago I am working on the previous mechanic thought there was no head gasket because the old one was black and looked like part of the jug, it comes out easy with a flat screwdriver, Yamaha puts a slot on the ring it sits in for removal and it has to be replaced because it won't re-seal after the first time it is torqued. My guess is the old gasket is your cause of low compression. They come in any of the aftermarket top end kits. worth getting the kit as it has gaskets for all the other bits you need to pull and fresh gaskets are good to keep oil seep at bay from covers, tensioner etc. on the heads. You can see the empty slot where the gasket goes in the pic below, the arrow points to where you can use a flat screwdriver to pry out the gasket. and the old gasket is the circled in red in the bottom of the pic.
 

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Thanks for the pics. My gasket looks like it is apart of the jug. I will remove the top cylinder and try to fish out the old gasket. I have the gasket kit i just hope i just hope the old gasket comes out quickly.
 
It should pop right out with little to no effort. Clean the ring surface really well after but don't remove the carbon ring that is at the top edge inside the bore, my manual made that really clear for some reason. My guess is compression help. Also if you don't have the service manual, they can be googled and downloaded for free. I see you said you have the manuals.
 
I just went back a screen and see your jug doesn't have the pry spot so like XB said an Ice pic would be best probably.
 
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