Honda TRX250R Forums banner

1 - 6 of 6 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter #1
Whatsup guys, this will be my first top end rebuild. Ive got a cylinder (HA2) thats got some vertical marks. None of which can be felt by fingernail but some visible vertical marks. Some cross hatches are still visible in certain areas.
My questions are, how do i tell if its nikisil plated, and if so what is the correct way of going about honing it before putting a new piston in it?

If it not and its a steal sleeve, can i just run a ball hone through it?

It also looked to me as if the exhaust side was getting a little more hung up than the intake side so ive got to get myself a good bore gauge and figure out if its out of round in which case i guess ill just bore it and either have it replated or sleeved ?

Attached are some pics of what the cylinder looks like.

Any of your input is appreciated thanks!
Mike
 

Attachments

·
Registered
Joined
·
208 Posts
You have what looks like a virgin 87 cylinder. The sleeve is steel & it can be bored, the next size up will be 66.25 or 66.5mm depending on measurements of the current bore. When you have it bored they'll hone it to. Be sure to take it to someone that knows 2-strokes & knows how to relieve the exhaust bridge & chamfer ports.
 

·
Registered
Joined
·
13,187 Posts
Nice OEM cylinder.

Not Nikasil, Steel Sleeve

Never run a Ball Hone

Never just Hone a cylinder after it has any significant running time or >5 hours (It will just oversize the bore out of specifications).

Exhaust & Intake Wear look normal

You will find the cylinder to be out of round

Go to the next piston size as stated; 66.25 or 66.50...should clean up at 66.25

Carlos
 

·
Registered
Joined
·
15 Posts
Discussion Starter #4
Nice OEM cylinder.

Not Nikasil, Steel Sleeve

Never run a Ball Hone

Never just Hone a cylinder after it has any significant running time or >5 hours (It will just oversize the bore out of specifications).

Exhaust & Intake Wear look normal

You will find the cylinder to be out of round

Go to the next piston size as stated; 66.25 or 66.50...should clean up at 66.25

Carlos

thanks Carlos.
I had it measured professionally being I don't have a dial bore gauge and it was in fact out of round. Clearance was .010 so it was definitely time. the piston in there was a 66.25 so its being bored and honed to 66.50 unfortunately.
thanks for input
 

·
Registered
Joined
·
15 Posts
Discussion Starter #5
thanks man, its being bored to a 66.50 now it was out of round a bit so Pistons on order !
 

·
Registered
Joined
·
13,187 Posts
thanks man, its being bored to a 66.50 now it was out of round a bit so Pistons on order !
Yup...always the case when you have just about any significant run time.

thanks Carlos.
I had it measured professionally being I don't have a dial bore gauge and it was in fact out of round. Clearance was .010 so it was definitely time. the piston in there was a 66.25 so its being bored and honed to 66.50 unfortunately.
thanks for input
No worries; at 66.50MM you have a lot of bores left...8 Bores with some .25MM sizes in between 66.50-69.50MM. Glad to see you had it done Correctly, "professionally"...:)

Carlos
 
1 - 6 of 6 Posts
Top