Engine builders??? Redoing a 250x topend and have questions.

[welpracing]

I am redoing a motor for my sisters trx250x cus of a broken case. I split the cases and replaced them and i am replacing the piston, rings, wrist pin, circlps while i am at it. Now when i do my YFZ i replace the cylinder to since they are only $200 but hers is $450 i just can't see spending all that when it didn't need it. now the cylinder looks great and had good compression.

should i hone this cylinder?

get it resleeved?

just put the new piston and rings in and go?

what would you recommend for the best outcome?

any help would be great.

Brandon

[REDRIDDER]

I'm not an engine builder for occupation but when i rebuild my exs engine i run my finger nail across the cylinder sleeve and if it catches any nics ill bore depending on its depth and if it doesnt ill just hone it.You should check for scoring,burrs and roundness witch you will need an inside mic to do but you should always hone a cylinder any time its apart using a crosshatch pattern to ensure proper ring seal.can you show us the pics of the cylinder it would be easier to judge what is really needed,but just sounds like a hone job,also you can go the route i did with my 400ex i sent it to LA sleeve to get a sleeve installed for my 426 kit,it costed me $83.63 for the sleeve and $119.00 for the install and $22.23 for the return shipping so a total of $224.86 thats not to bad and they can make a sleeve for anything just about right from scratch.LAsleeve# is (562)945-7578 you can buy the sleeve and have c&d install it or have c&d do the whole sleeve installation.But just by your description it sounds like just a hone job will be suffice.PS service honda has a whole cylinder with the sleeve for $287 bucks were did you get $450 from go to service honda for any oem parts their also the cheapest.good luck

[welpracing]

Well the cylinder is in great shape not knicks and super smooth. has the criss cross pattern in it that they do from factory.

I am almost certain it would need just honed. Just wanted to see what everyone else thought.

ok well i never honed one before. Do i use a small engine one (like a lawn mower) with pads that are 2 inches long or a automotive one that the pads are 4 inches long?

also what grit of pad?

do i need any kind of grinding compund to do this or do i used motor oil or nothing?

Then how do i tell when it is finished?

also any certian motion to use to get it right?

any other tips?

thanks Brandon

[REDRIDDER]

Brush Hone TOOL is a honing tool designed with a soft cutting action for superfinishing in any type and size of cylinder. The tool develops a surface on a metal part which is optically smooth and metallurgically free of any fragmented, amorphous or smeared metal from previous operations.This is what i use and you can get them any were they sell tools,i use new motor oil when i do it and be sure to do the cross hatch pattern.hoped to have helped you out.

[welpracing]

yes being of great help. ok how do i pick out a size?

I am in a napa tool book. and the smallest is 3" and largest is 4 1/8. Now i don't have my cylinder here to measure it but do you get one that is close in size. or will i need to go to the dealer and buy one?

put it in a drill and just go up and down in the cylinder till everything looks smooth and even (as in the gloss) keeping it lubed with new oil while doing it?

is the up and down movements what gives it the criss cross pattern with the circle motion of the drill then?

Thanks Brandon

[wilkin250r]

Have you already bought the piston?

This is one of those "knat's *****" type of operations. The clearances should be accurate down to a half thousands of an inch (0.0005"), about a quarter of the thickness of a piece of paper.

Did you measure the piston/bore clearance?

It's not impossible, but it helps to have experience, and it certainly needs the proper tools.

Cripes, it will only cost about $20 or so to have your local dealership check the clearances and hone the cylinder. You are going to spend more than that on tools if you want to do it yourself.

This is something that needs to be REALLY precise, but it's not that expensive. I don't know about you, but these factors combined would convince me to just let my local dealership handle this aspect.

[welpracing]

I understand all that. I have been looking at rthe prices of hones and the can range not to cheap. i guess i will end up taking ti to the dealer.

I was ust wanting to learn. I am trying to catch on to some of this stuff. guess i will have to buy a cappy cylinder nd try it some time. I mean a guy has to start some where right.

I didn't know a dealer would do it for only like $20.

yup prolly just have that done.

thanks for the help guys

Brandon

[REDRIDDER]

Originally posted by wilkin250r
Have you already bought the piston?

This is one of those "knat's *****" type of operations. The clearances should be accurate down to a half thousands of an inch (0.0005"), about a quarter of the thickness of a piece of paper.

Did you measure the piston/bore clearance?

It's not impossible, but it helps to have experience, and it certainly needs the proper tools.

Cripes, it will only cost about $20 or so to have your local dealership check the clearances and hone the cylinder. You are going to spend more than that on tools if you want to do it yourself.

This is something that needs to be REALLY precise, but it's not that expensive. I don't know about you, but these factors combined would convince me to just let my local dealership handle this aspect. i would agree it would be easier to let a shop do it but if your up to the challange buy the flex hone youll always have it and you can save money in the futrue instead of having to run to the shop every time.It is simple to do here any time you install new piston rings you need to hone the cylinder walls to break the glaze in order to allow the new rings to wear in and seat properly to minimize oil consumption. The hone has a flexible drive shaft and is typically driven with a 3/8" electric hand drill at speed under 1000 rpm. A pro shop might use a hone in a drill press to run it as straight as possible and to have better control over axial motion to produce a cross hatch pattern on the cylinder wall.

[welpracing]

well i just called the shop and they told me $5 so i was well duh ok.

but i still wanna learn so i will prolly end up buying one and practiceing on an old cylinder i have at hone and stick it in the drill press and go to town.


Thanks Brandon

[REDRIDDER]

Originally posted by welpracing
well i just called the shop and they told me $5 so i was well duh ok.

but i still wanna learn so i will prolly end up buying one and practiceing on an old cylinder i have at hone and stick it in the drill press and go to town.


Thanks Brandon there you go glad i could help.