who knows about 92-01 honda cr250s cylinder cracks ?

[terrobelone]

hey guys i know this might be to specific for this forum but who has ever heard of cracks forming on 92-01 cr250s sub exhaust ports here are some pics of mine i was told this was common and ok to run ( some of you might have seen my other thread)

<a href="http://s1009.photobucket.com/albums/af220/matt11_bucket/?action=view&current=cylendeycrack.jpg" target="_blank"><img src="http://i1009.photobucket.com/albums/af220/matt11_bucket/cylendeycrack.jpg" border="0" alt="Photobucket"></a>

<a href="http://s1009.photobucket.com/albums/af220/matt11_bucket/?action=view&current=cylender.jpg" target="_blank"><img src="http://i1009.photobucket.com/albums/af220/matt11_bucket/cylender.jpg" border="0" alt="Photobucket"></a>

<a href="http://s1009.photobucket.com/albums/af220/matt11_bucket/?action=view&current=USCHROME.jpg" target="_blank"><img src="http://i1009.photobucket.com/albums/af220/matt11_bucket/USCHROME.jpg" border="0" alt="Photobucket"></a>

any responses will help thanks !

Edited January 30, 2012 by terrobelone

[terrobelone]

sorry hears the pics

[terrobelone]

anyone ?

[Keith72]

My 97 cracked in the exact same place. I found out about them from my local repair guy when I took it to him to get honed for a fresh piston. He looked at it for about 30 seconds when I handed it to him and saw them right away. Must have known what he was looking for cause he saw them right away. He told me to just buy a new cylinder.

[mynewcr250]

ive actually never heard of this until you posted those pics in your last thread. since then ive heard people chime in on this and it looks like its very common. ill have to check mine out next time i have it apart. A new cylinder isnt bad, its just a problem when they arent available like they werent a little while ago.

I definitely wouldnt feel safe running it. Its one thing when its in a cart, or something that isnt flying through the air on 2 wheels

Edited January 31, 2012 by mynewcr250

[CamP]

ive actually never heard of this until you posted those pics in your last thread. since then ive heard people chime in on this and it looks like its very common.

It happens occasionally, but it isn't very common.

[CRPilot]

For a short term fix you can recess the crack slightly with porting tools to make sure the ring doesn't catch. I ran one like that for well over 2 years without any issues (recessed though).

The issues is that due to the amount of material there vs other more solid areas, you can get different rates of expansion as the cylinder heats and cools. Sometimes it will crack.

Longer term you'll want to replate or replace.

[terrobelone]

it has been replated, i will get a new cylinder once i get my taxes back but for now im going to run it, the cracks look alot worse in the pics than they really are, i have spoken with several pro's about this including U.S Chrome ( cough) and Powerseal USA both said i should be fine to run it but should get a back up cylinder and keep and eye on it. The last piston to come out of the bike didn't have any marks what so ever on it from that so i think ill be ok for a good 30hours or so ....the problem is my cylinder is ported so i guess i will just port the new one myself ?

[terrobelone]

power seal also told me the shifter cart guys snatch up all the 01's cylinders every time they make a batch of them so i just have to keep my eye out for one, i am considering getting the 99 cylinder as i ride woods but i don't want this bike to be a dog i love the 01 porting any thoughts

has anyone run a 99 and an 01 who can relate the differences to us

[36MotoMarc]

I've seen a bunch of them crack there, not sure why. Because the subexhaust valves run there it really complicates repairing them. Probably is cheaper to /better to just replace. I ran a cracked exhaust bridge for 20+ hours without it failing, but the machine was strictly used for iceracing, I wouldn't trust it pinned up to a do-or-die double etc.

Opinions will vary but I think the best years were 01, 95, 96, 99 in that order. 01 revved harder 99 burlier down low.

[shrubitup]

Pick up a slow '99 and then sell to me for $100. ?

[terrobelone]

Pick up a slow '99 and then sell to me for $100. ?

you want the 01 cylinder i have ?

[shrubitup]

you want the 01 cylinder i have ?

Not if it's cracked. ?

[Piney Woods]

I have had an 86, 91, 93, 95, 2000, and still on my 01. Never heard of it. Guess I have been lucky.

[CamP]

I have had an 86, 91, 93, 95, 2000, and still on my 01. Never heard of it. Guess I have been lucky.

Not lucky. If I was going to speculate on the percentages of cracked CR250 cylinders, I would say it's less than 1%, but it's easy to blow things out of proportion on the interweb.

[terrobelone]

Not lucky. If I was going to speculate on the percentages of cracked CR250 cylinders, I would say it's less than 1%, but it's easy to blow things out of proportion on the interweb.

well then looks like im the 1% ...although ken oconnor cleaned up the ports for free and it was just replated and approved i might just throw the old wiseco piston in it for now while i wait for the new cylinder to get here, then throw the spare new pro-x top end kit in the new cylinder .... thoughts ?

[H4L]

owned 93, 97 & 01 also a friend owned a 96 & 01 we raced & rode the bikes pretty hard & never had any cracks on the cyl's. I don't remember hearing anything about it back in the 90's that the cyl's were prone to cracking. The local tuner that worked on our cyl's did porting on them & he never mentioned anything. Does the cyl. have a lot of hrs. ?

Edited February 4, 2012 by Hondasforlife