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Found 59 results

  1. Colt Hillis

    Yz125 jug

    How can i fix this? Why is this happening when everything else if fine? Took it to a machine shop guy said 100 in labor to do sleeve and he said he didnt know if they made sleeves but they do. Im considering on buying a brandnew cylinder but lots of money didnt know if cylinder could be fixed or this will happen again. Heres the piston, then top of jug has chips taken out 30-50 thousandths
  2. Greets to all. I'm about to install an Athena BB kit on my S. Kit comes with a single layer base gasket an gives 12.3:1 compression ratio. I've been thinking about bumping up the compression a bit. No budget available for a hi-comp piston, so I was thinking of machining the cylinder face down a couple of tenths of a millimeter. I have access to machinery needed for the task, so cost is out of the question. Will check piston-to-deck height and all before proceeding. My main concern is the nikasil coating, actually the point it "finishes" at the top of the bore. There's a chamfer right there, measures over half a mm high, so could easily be ok. But I need confirmation, wouldn't want to ruin my BB. Anyone done that before? Any problems with it? Thanks in advance. Lefteris.

    Cr80r Cylinder problem

    HI. So i am in the process of putting new studs on the cylinder in my 2001 CR80r! I am just wondering if i need to torque the studs if so what is the torque spec?
  4. I have a 99 kx 250 that needs a cylinder. I need to know if a 94 kx 250 cylinder is compatible with the 99 model assuming I use the 94 power valves? the bidding ends in a few hours
  5. 1995 cr250, had cylinder bored and sleeved with la sleeve. Sleeve not installed right and ports on cylinder do not match sleeve ports turned about 1/8 from being lined up. Can it be fixed or is it permanent? Please give useful advise, much appreciated.
  6. Hello all! Long time lurker here, great site! Long story short, I pick up a bike with low compression for a little project. I notice "FMF" on the side of the cylinder ask him if he knows anything about it? He replies "the guy I got it from said it was an FMF race bike, but I don't think so. Figured someone just carved that in the side." I have never had my other yz250 apart, looking at the ports and comparing them to the few pictures I have found, it does not seem the cylinder was ported. Admittedly, I very inexperienced when it comes to any 2 stroke porting. Stock rebuilds is how I have always rolled. Also, I noticed the "c12 only" but the head only looks lightly milled, if at all. Any expert eyes out that have some input? I am trying to keep this rebuild reasonable since the holidays are around the corner. There is a gouge in the cylinder from the ring breaking. Last time i sent a cylinder off for repair it was 350ish. If it is a stock cylinder I may try to find a used one in good shape a little cheaper. Any help or suggestions would be great appreciated!
  7. So I have an 07 cr 125 fouling plugs before the bike even has a chance to warm up, plugs come out wet and oily on the tip. had both crank seals replaced last season because my main drive side seal blew. While it was split I had a new crank put in, we noticed my cylinder plating was pooched so I sent my cylinder off to be re-plated, put a new piston in the shiny new looking cylinder put the old warped head back on and called it a day. then rode it all season having absolutely no idea about the warped head because I overlooked it when I was excited to put my bike back together and ride. Its now winter, snows on the ground. I recently went to go for a put and fouled a plug before I could get to the end of the street and back. I was also smelling coolant so checked the rad while running the bike, lots of movement and tiny bubbes. Pulled the head off and sure enough it was warped to the point where I could rock it back amd fourth on the mirror and see a small gap... so NOW after I replaced the head my problems persisted and I can still see little bubbles swirling around vigorously in the rad if I rev it with the cap off, I've had boiled it down to my cylinder probably being warped then I found a leaky hose by the exhaust that was dripping coolant onto the outside of the exhaust port. Which brings me to what I think may be an incredibly stupid question, could it just be the loose hose sucking in air that is causing my rad fluid to have small bubbles in it? And maybe im just experiencing increadibly rich jetting now that my head is actually sealed properly? over and out.
  8. jason0827

    millennium tech

    i sent my cylinder in to be plated and i was wondering if anyone could tell me how long it took to get yours back and reviews on millennium.
  9. Chiofalo11

    What could have caused this?

    Hello, my dad and I just re-did the top end on my 2014 Kx250f. We used a new cylinder with a wiseco piston and rings. Everything went smooth and had no problems putting it back together. It started right up and ran great as we let it idle for a few. Then the rpms jumped up quite a bit so we shut it down. When we went to start again it kicked over smoothly but wouldn't start. My dad brought it into the basement and kicked it over a few times and all of a sudden it wouldn't turn over at all. He said it appeared to be seized so he pulled the head cover and checked for oil circulation which was good. Today we pulled the head and cylinder and found that the upper oil ring was splintered. Now the piston, cylinder and rings are trashed. Oil circulation does not appear to be the issue and plenty assembly lube was used. Rings were also installed just as indicated in the instructions. What could have caused this to happen??? Thanks for any help, Danny
  10. cerialsledder

    03 cr250 cylinder worth anything?

    Is a cylinder off a 2003 cr250 with a crack in the exhaust port bridge worth anything? I have one sitting on my shelf that I never did anything with. Thank you
  11. I recently purchased a basket case 2000 rm125, with this bike came a tub of misc. parts. I have a cylinder that has been sleeved in great shape. I was told all parts in box were for 1998-2000 rm 125. This cylinder does not look like my 2000. From what I can tell from suzuki parts finder it appears to be a 1991? I say this because the power valve rod chamber on top right of jug does not have vent nipple, 1993 and after do. Any help would be appreciated. It measures 54.01 inside, also numbers in pictures are 7wh7 S ON base of front, also 50 on right side and 124cm3 on left side. I circled missing vent area in the one photo. thanks in advance
  12. GearHeadBrady

    Jetting help CR250

    Hello guys, this is my first post on here as I am in need of some help, I have been following these threads for a long time now because they contain very useful information. nut i have never made a post of my own because I have normally been able to find the answers to my questions in existing threads. anyways, I have just finished rebuilding my 2002 Cr250, i used the crank that was already in it and just replaced the crank bearings,crank seals, all external oil seals, as well as sending my cylinder off to millineum technologies for a bore a re nicaseal of the cylinder(back to stock bore) as well as replacing the piston with a wiseco Pro-Lite piston(I drilled the holes for the exhaust bridge as I have always done).( a new OEM cylinder head was put on as well) so here's my problem, I believe my damage to the top end was due to air leaks thus a lean burn down of the top end. I have gone through my break-in procedure and done 4 heat cycles and then an idle run through of the gears. today I did a half throttle and then an about 3/4 throttle pull through the gears. the bike felt like it ran good and had good power except it felt like it fell a little flat in the top peak of the RPM(so there's problem number 1) my second issue is after these pulls the silencer and pipe silencer joint were covered in spooge.(i know a bit of spooge is to be expected after full days worth of riding but not after a 10 minute run through of the gears) the spooge problem led me to believe that the jetting was the issue and that the bike falling a liittle flat high in the rpms and the spooge were connected(i have a stock mikuni carb with the recomended jetting for a pro circuit pipe 380 main, 32.5 pilot stock needle on 3rd clip position)(i was running a 340 main and 30 pilot before the rebuild but i felt like that was a little lean) i then pulled the plug and looked at all of it and the coloration of the porselin is leading me to beleive the jetting is lean(even on stock jetting and 4 sizes up on the main from where i used to be) the plug looking lean scares me a tad as this is what i fekt like caused my top end failure before. so i really need help from the jettng gurus here that can give me good info attached are pictures of the plug,spooge and new top end any help would be appreciated, i would like to fix the spooge problem and the falling flat feeling high in the rpm, i just put alot of money into this motor and i want to do it right to prevent andy further problems.
  13. I messed up bad. I was looking at a couple jugs on eBay. I accidentally bought the wrong one! Didn’t realize until after I paid😩 so now I own a 92 cylinder for a 95 case. I have 6 children and can not afford this mistake! Please tell me how to make it work. The whole power valve assembly is different. I’ll buy the head too if it’ll work. 2 coolant ports too! Uhhghhhh.
  14. i know a lot of kx cylinders will interchange ( ive heard 93-04 will) but i know on a lot of those year cylinders the port timings are different. I have a 99 kx250 that i am looking for a cylinder. So my question is what year cylinders will bolt on and have similar port specs. Wouldnt a 99 run badly or not run at all if it had a cylinder with different port timings than what it was designed for?
  15. First-time poster here. I have a 99 YZ125 that's been causing me a whole lot of headache trying to dial in the jetting. I've given up and since ordered a Lectron Carburetor (waiting for it in the mail). After last weekend's ride I was doing some research into why my bike smokes a lot even with how much I've leaned it out (per JD jetting recommendations and then some). I learned that sometimes a faulty clutch-side crankcase seal can leak transmission oil into the crankcase and cause excessive smoking. This would make sense as last time I changed my oil a very small amount came out from the transmission. I've ordered a seals kit. With that knowledge, I decided to tear down the bike and inspect the top-end. Here's what I found. What is this milky, white substance? Coolant leaking? I've also ordered a water pump rebuild kit. ALSO, I discovered that the cylinder bolt next to the power valve linkage was completely off the dowel and wedged behind the power valve linkage. I torqued this bolt to spec using the Motion Pro torque wrench adapter. Do these need to be Loctited? Could this loose bolt be causing coolant to leak into the cylinder?? Other info: – Always clean air filter – Low (20ish) hours on the piston, rings, and gaskets – FMF pipe and silencer (packing looked good when I removed last night, will replace) – I did give the bike a good pressure wash (with muffler plug and airbox cover), so maybe it's water? – 91 pump gas with Maxima Castor oil – 10w-30 oil
  16. I would like to ask you for advice on rebuilding a Brembo clutch slave cylinder. I know that Maguras used to have a circlip and I was wondering how do you get the piston out from this one? Anything to watch out for? Thanks!
  17. Hey, new member here (been using the fourm for years) but just finally joined. I have about 8k miles on my 2015 DRZ400sm. I was riding about 80mph and felt a momentary loss of power, dropped off the throttle and it felt ok. At the next stop i could here top end noise like the piston was tapping so i tore it apart and found: The upper piston ring was ok, the lower was stuck in the groove (flush with the piston ) and unable to move around the piston. there was scuffing on both intake and exhaust side of the jug and piston. Before tearing apart i did a leakdown and could hear air from exhaust and from down by the timing chain. I will try to post pic and video with this post Bike was running great then had started puffing smoke when i get on it quick, and the idle would fluctuate a good bit 2015 DRZ- 3x3, k&n filter, FCR39 (with eddie mod) DRZ E airbox boot and exhaust header with drilled out stock SM muffler,
  18. Maksymilian Pizzochero

    90's YZ 250 Cylinder Kits

    Hi, i was wondering if anyone could tell me if a cylinder kit for a 1990 YZ 250 would fit in a 1999 YZ 250. If anyone could help me out ASAP I would greatly appreciate it. Thanks, Maksym
  19. Callahan Scholtus

    Need new cylinder for a 1995 cr250

    I have a blown motor a 1995 cr250 and i need a new cylinder but cant find one for that year what year cylinder can i buy to replace that one and what year would be the best fit.
  20. Hello All I am in serious despair!, I have been waiting 6months to repair my crf450r 2012 after the big end breaking. I bought second hand left and right crankcases (from a 2012) and a hotrods stroker/cylinder works big bore kit from a eBay seller. this kit is advertised as bolt on!, after installation the piston locks just before TDC, after inspection I was shocked to see the the piston raises about 1mm above the cylinder ??? WTF!. I have searched the internet and found no other issues of this sort, I checked the boxes and they all say for a 2009-2012, the kit did have 2 base gaskets and 2 head gaskets :-k . any help would be much appreciated as the seller does not respond and I have no idea what I should do. thanks in advance, Lee
  21. well i bought a 2018 ktm 300 xcw on the 23rd and rode it 1.5 hours after i set everything to manual spec as of jetting and the pre mix and anything else needed. well after the first ride i had a leak out the rh side pv cover so i slid the pipe off while finding the leak and took a look up the cylinder and see vertical lines. under all the light scoring i can still see the cross hatch except in the thin parts in between the ports. is this normal for the first few hours on a newly plated cylinder? dealer said its fine but they could not even find where to check the oil on the bike so i dont trust them on a cylinder to not lock up the day after warranty. it has received a easy break in so far. ive owned many two stroke ktms and other assorted bikes before but as a second owner this is my first from the dealer bike so i never saw the initial few hours of break in on the plating during all the rebuilds ive done in the past at 80+hours hope im worried over nothing
  22. C_juve

    Cylinder head-reusable?

    I have a 2002 cr250 2 stroke that recently blew up. i believe it was due to low octane fuel and extended periods of holding it wide open. Mill tech already replated my cylinder, redid the power valves, and sent me a new piston with gaskets but i was wondering if i can reuse this cylinder head if i really clean it up. Any advice would be appreciated. I can buy a new cylinder head for about $85 if needed. i would like to reuse this one but i already have $600 into the top end by sending it to millennium and the parts alone so i suppose another $80 wouldn't be too bad. pic of cylinder head attached.
  23. So, looking for a little wisdom. I just rebuilt my bike last night and finished at 12:30 this morning. Last night i wanted to make sure i could get the bike to fire up and make sure everything is okay and begin the break in. As luck would have it, the HG is leaking coolant. what would y'all recommend i do. I have a cosmetic gasket because i have a cylinder works 269cc. P.S. it was running for 15 minuets with me modulating the throttle when i noticed it. It was a VERY small little line but its still leaking coolant with less than 20 minutes in the the motor. Thanks -Brandon
  24. I recently purchased my son a used 07 CR85 and have made it a project bike build. After rebuilding most of the entire bike, I came across these two highly stripped out master cylinder screws. I am stumped, how can I get these suckers out without ruining the reservoir. Like many ham fisted bike owners, these suckers are in very tight.
  25. ubercoper

    KTM top end advice needed

    I've been AWOL on here for a few years but I'm desperately in need some advice/ "expert" help... My 2000 KTM 300 grenaded with about 10 hours on a fresh top end. Here are the teardown pics. Piston is gonzo and the cylinder is going off to powerseal usa for repair. I'm wondering if this could be related to the horizontal play in the con rod? I may send this out to Andrew Cooksey to split cases and go deep ($$$) into a rebuild, but I'd like to save the expense if possible. Any and all advice would be appreciated. Thanks in advance! -Seb IMG_6216 by ubercooper2000, on Flickr