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replating? rod play?

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ok finally took the cylinder off and found out that i need to get my cylinder fixed. cylinder if scored very bad below the exhaust port and some on the opposite side. i think this is because the kid before me never bothered to do maintenance on the bike and dirt got in it. i checked my rod and it didnt seem to have and play up or down but had about a half inch or so side to side. I also checked the flywheel and there was no play in that. is that side to side play normal or should i think about gettin a new bottom end too? think it would last a few seasons? anyone know where is the cheapest place to ship the cylinder to have it redone? whats my best option?

Thanks in advance guys

Edited by twalker2

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Powerseal USA did a better than OEM job on my cylinder. It needed repair so the total job was $230. Much cheaper than a new cylinder and it takes about 2 weeks. If it were me I would do the total rebuild. See if Wiseco makes a total rebuild kit for your bike which will include new crank, bearings, gaskets piston, rings at around $450 its a great deal and give you that extra insurance knowing that the motor is brand new. :thumbsup:

Powersealusa.com

Wiseco.com

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cylinderpics002.jpg

cylinderpics003.jpg

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ya thats what i was thinking about doing too would be nice to have a fresh bike. i got a new wiseco piston to put in it but when i found that my cylinder was scored i stopped. i also found a wiseco bottom end kit for 170 new off ebay with gaskets, main bearings and complete crank. for the bottom end do i need the case spitter and crank puller tool or can i get away with using something else? would the wiseco piston still fit after i get the cylinder done or would i have to get a new piston?

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Flywheel puller, yes...case splitter likely not, although still a good tool to have around...but what tool isn't?:thumbsup:

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I just had my 2006 yz 250 replated by US chrome , they did a good job , the only problem i had was they cross- threaded one of the cylinder stud holes and i had to put a heli-coil insert in it , that was 20 bucks from a machine shop. If you send them the new piston when you have it replated they can make your tolerances better than OEM. . If i had to do it again i would probably try powerseal or maxpower, just because of the thread damage. I think they all cost about $240 to have it done , which is cheaper than a new cylinder.

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I decided to get a new cylinder. I found a brand new one on ebay for $350, incl. S&H, and certain builders will pay $75 for shot cylinders. $275 brand new -vs- $240 + S&H to replate seemed like a no brainer to me.

BTW, a case splitter is important, IMO. That, a FW puller and a clutch holder, too.

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I am currently running a Wiseco Crank assembly and pro-lite piston in my 2002. The crank kit came with everything (gaskets, seals, bearings...).

I'm really pleased with it. It's been in there since August, no issues.

I would get the case splitter and crank puller. You really can't do it right without those tools. The flywheel puller is a good one to have too. You'll beat up your parts if you try using the wrong type puller.

Also, be careful installing the left main bearing into the left center case. Many people break that case by using too much force to install the bearing. It doesn't sit down flush with the inside of the casting when it's fully seated, so don't force it. Be careful and save yourself a $300 center case.

It cost me about $600 even to do the entire engine including transmission bearings. Makes these old two strokes really appealing.

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so i think my crank might be fine. has no up and down play but has side to side around half inch think sliding. how much side to side is too much? can i get another season out of it without any damage?

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I'm not trying to scare you here, just make sure you are sure.

When you say 1/2" I assume you mean at the small end (piston end) of the rod it will move 1/2" side to side.

The spec for side clearance is measured in between the rod and the side bushings down on the crank end. Any small amount of radial play in the big end bearing will allow the rod to wobble back and forth a great deal at the small end. That said, 1/2" at the small end still makes me think the big end bearing might be ready to go.

If the big end of the rod is moving 1/2" side to side (axial play in the big end bearing) that's way too much. If you can feel any radial play at all in the big end bearing, it's time to pitch that thing in the trash.

A quick way to check for axial play if you don't have the right tools is to clench a fist around the rod pulling it up with the crank near top dead center. now take your other hand and use your palm to smack the top of the rod. If you hear a little click, or feel some play, replace the rod and bearing, or the whole crank.

Check your main bearings, grab your flywheel and shake it up and down in and out. Any play you can feel or hear is due to bad main bearings. You need to check both ends, so repeat this on the primary drive gear side of the crank too.

If you have access to a dial indicator, you should use that to check for play in all the bearings, it's the technically correct method.

I always err on the side of new crank parts, replacing a crank is way cheaper than replacing a set of cases and or a piston/cylinder that shatter due to a broken rod & bearing.

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thanks for all the info. and ya its 1/2" play top of the rod by the piston. i checked the flywheel too and it was tight no play. rod had no noticeable up and down play. i think that the rod is just sliding on the bearing. i have to replace/replate the cylinder because when i got the bike the cylinder was scored badly right below the exhaust port so thats why i question how the bottom end is and what could still be in there. airbox was very dirty with sand/mud in it so just hope running a few cycles of gear oil will clean it out. if not i found a wiseco bottom end kit for 175 shipped which i would do but i dont have all the tools to split the case and take the crank out so id have to take it to a shop to have it done and dont know how much that would cost

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so i checked the play on the rod again and i was way off on how much it moves its only about 1/8th of an inch side to side. so it should be good. is there anyway to flush the engine if there happened to be some stuff in the engine like sand? other than taking the engine out?

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if there is 1/8" of thrust one of the washers is gone and the crank is trash. the upper clearance limit is .030. that is about the thickness of 10 or so pieces of printer paper. if you are going to measure the crank thrust, do it with a feeler guage.

if you look in this pic, you will see the rod pin at the 11 o' clock position. feel with the rod pushed all the way to one side and measure actual clearance.

it is worth the $5 for a feeler set

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