Does My Cylinder Need Bored Or Not

[quadsrus1]

Ok here is my question i just tore apart my top end due to low compression.I did a compression test and only got 59psi.So i tore it apart when i look at the cylinder it don't have a nicks or anything it is stock bore.So would it be ok just to slap a new piston and rings in and go enjoy the bike.Also how do you clean a cylinder head and cylinder?Also is WSM a ok company to get a piston from?Here is the cylinder

Here is the head

 

[Prime]

Can't really see any scuffs in the cylinder...if there are any, run your fingernail across them. If you can feel anything with your fingernail, get a Wiseco .010 over piston and take it to a machine shop, where they can bore the cylinder to the piston.

 

[quadsrus1]

Can't really see any scuffs in the cylinder...if there are any, run your fingernail across them. If you can feel anything with your fingernail, get a Wiseco .010 over piston and take it to a machine shop, where they can bore the cylinder to the piston.

Ok there is no scuffs so i should be good to slap another stock one in there any tips on how and what to clean the cylinder and cylinder head with thanks for the quick response

 

[blasterdemon7]

If your going with new rings, you will need to get it honed to seat the new rings. Wash the bore real good with Dawn dish soap, dry it real good with papertowes till there stop getting dirty looking. Wipe the bore down good with some 2 stroke oil. Carb cleaner works good for the outside.

 

[quadsrus1]

If your going with new rings, you will need to get it honed to seat the new rings. Wash the bore real good with Dawn dish soap, dry it real good with papertowes till there stop getting dirty looking. Wipe the bore down good with some 2 stroke oil. Carb cleaner works good for the outside.

Im gonna put in a new piston and rings so i should get it honed and just curious what could happen if i don't get it honed i will if i have to its only 6 bucks at a local shop.

 

[blasterdemon7]

If you don't get it honed to go with the new rings, you will have low compression.

 

[jlsparky7]

Your compression wont last as long because your rings and cylinder wont mesh correctly.

 

[quadsrus1]

Correct me if im wrong a blasters compression should be between 140-160 psi correct?

 

[Surfrjag]

Compression should be about 125 on. A stock setup. Take the cylinder to the machine shop and they can tell you if you need a bore and what size piston to buy. If your clearances are out of spec you can break a piston skirt and cause it to destroy your bearings and possibly your cases. Good peice of mind to get it done right.

 

[quadsrus1]

Okl i see i will go get it honed i just ordered a standard bore piston kit

 

[Blaaster]

With 59psi compression it sounds like quite a bit of wear has happened, the bore may look good but could be sloppy, in which case will need a new piston and a re bore.

When replacing rings in a cylinder either new or used (not a smart idea) the bore should be honed. One of the reasons for crosshatch honing is to allow the cylinder wall to retain oil to lubricate the rings.
One reason for ring wear is from lack of lubrication on a smooth cylinder wall.

My advice is to take it to someone who knows and be advised by them.

 

[quadsrus1]

I think im gonna take it to go get honed at a local shop

 

[sicivicdude]

It may or may not be enough to simply get it honed. It may need a bore. The only way to tell if it needs a bore is to measure the cylinder diameter, taper, and out of round. The specifications for those measurements (and even the method for measuring them) is located in the service manual.

Did you already order the piston or you're looking into ordering a piston?

 

[yamaha28]

there is always a right way to do things.

there is always a sketchy way to do things.

Everybody just has to decided what fits them. If you don't want to spend the money to get a new bore and piston kit. That's perfectly fine. If you go get it honed and put new rings on then it might not last very long. Something happened that caused the compression to drop that far. There were a couple responses giving their advice to just hone it, others say to get the whole thing done with new bore and piston kit. Either way might work its up to you to decide when you want to redo the top end, now or later. If it was my quad I would do it now.

Sorry for the long post!

 

[Surfrjag]

It is kinda rare that you can just hone and re ring but I hope it works out. I also hope your cylinder is still on stock bore...

 

[quadsrus1]

OK my piston kit is ordered it comes with pistons, rings, pins, clips, needle bearings, head and base gaskets and intake and exhaust gaskets i plan on honing it out and yes it is a stock bore my thing is i just want to get it running good for the snow season then after snow season im gonna redo the top end and bore it out. What do you guys think

 

[Surfrjag]

Once you get it together and running you will want to listen for excessive rattling noise. Could be piston slap. What kind of piston did you get?

 

[Blaaster]

Ihate to seem like a defeatist, but.

Please, before you assemble it get the bore measured to see if it is within limits.

If the bore is sloppy (as I fear it could be with the compression figs you stated) the piston may slap around like a pea in a bucket.

If the piston you ordered is a cast type, the piston is invited to fail, and if it does be prepared to make a call to your bank manager.

 

[hudack]

OK my piston kit is ordered it comes with pistons, rings, pins, clips, needle bearings, head and base gaskets and intake and exhaust gaskets i plan on honing it out and yes it is a stock bore my thing is i just want to get it running good for the snow season then after snow season im gonna redo the top end and bore it out. What do you guys think

i think thats a very very very bad idea.
with only 59psi of compresion il bet my bottom dolar that it needs bored out.
i think you should see if you can cancel that order and get your money back.
take it to a shop have it mesured and everything checked out.
then you can go from there toherwise your going to have way more money into it then you want....

 

[quadsrus1]

I ordered a wsm piston kit i was told by local shop that it should be fine to hone it and put it in and here is another question if my exhaust wasn't on properly could that have made my compression that low as it was?