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Found 40 results

  1. Hey Guys, I am posting to see if anyone else on here has done the 300sx top end kit on their 250sx. I installed the kit last week to my 2014 KTM 250SX with 40 hours on it and wound up with a really bad vibration, the bike shakes so bad when you twist the throttle at idle that the foot pegs jump and the bars get a 3/8" oscillation to them. Before anyone says "its a 2 stroke they vibrate" I also have a 2014 300XC and it is 1/8 of the vibration that this thing has, also It didn't vibrate all that bad as a 250. Has anyone insalled this kit before, did it drastically increase vibration? Is the 250sx crank the exact same crank as the 300xc or is it a diffrerent crank with different balance? Has anyone gotten a crank for a 250sx balanced to the extra weight of the 300 piston? hoping someone has been through this before. Thanks, Jordan
  2. GeneralConfusion

    XR250 78mm bore jetting?

    What jetting should I use for a 78mm big bore on an '02 XR250. Currently have 135 Main jet and a 48 Slow with opened air box, K&N filter, ground headers and opened up pipe. (Elevation is varies greatly from 400'-3,000+' though mostly above 3,000')
  3. Dr.dualsport

    Bought a gem of a Dr350

    Hello TT! First post on this forum, only because someone has already answered every single question I've had in the past year. Seriously you guys F'n rock! Very anxious for the snow to melt so I figured why not share my Dr with the world in the meantime. I wanted to pick up a thumper last August to have a dualsport to take to class and mess around trails when I was up at school. Nothing nice, just something dependable with mostly original hardware for under 2k (broke college kid budget) did my research, it had to be a Dr. So I trekked from southern NH up to Maine to look at a '99 Dr350se with 14K on the OD... I know 14K is a lot, but the pictures looked great. The guy selling it, who was only the 2nd owner, said it had just about no rust and he had only done 1000 mi on her in the 2 years he had it (which was actually true I have the title) The bike looked perfect when I got there other than that blowby on the tail. But for a '99 with high miles I figured she would at least need rings and gaskets soon. Wicked cool guy no BS, he never touched a thing on the bike besides battery and registration stickers, the thing just ran. He insisted I take it for a test ride before I even consider making an offer so took a little cruise up the dirt road and left my girlfriend to lay down a little pre-negotiation charm on him the wife. By the time I left wifey was bringing me to the shed to grab all the free spare tires and wheels the four of us could carry, and they were all in usable condition. Next hands me 3 soft binders, one was a general maintenance manual, one a model year specific manual, and one stacked full of documents, receipts, title and handwritten parts lists ended up taking everything home for $1200, $200 lower than the asking price just because he thought I was a good guy. (Total wheels and tires I got for free was a complete front and rear set each with 50/50 on/off tires mounted, as well as 2 rear on/off tires and 1 spare front mx tire) But wait there's more... Of course I'm dying to see what receipts are there so lets have a look... Everything with a receipt was dated from 2008-2013 (could be worse right?) we've got: Both sprockets (stock gearing) Chain Discs & pads Fork boots Front fork seals Clutch Clutch cable Now I start getting into the nitty gritty... no receipts or dates but after doing a little sleuthing: DynoJet stage 2 or 3 kit (found the 'in box' installation instructions, plus the jet sizes are scribbled down on that paper i mentioned) 1 1/2" exhaust mod (found email printouts so I go check the bike, sure enough 1 1/2") and for the Holy Grail... Yes that's right ALL of the emails back and forth regarding shipment for the 440 big bore and sleeve May I add, when that guy said no rust he wasn't joking. There's a flake or two on the exhaust but everywhere else is paint. Every nut bolt and connector on the Dr440 is completely stock, right down to the alien antenna mirrors. The bike obviously couldn't have been ridden that hard, I broke those mirrors off that first week... Airbox has the big ol holes of course. It has a K&N reusable air filter pretty sure that is not stock correct? It had motard tires when i first got it (in that pic by the river) but I am taking this spring to gear her a little more for more dirt. I just wrestled a brand new DOT track tire onto the main rim and I have that mx tire mounted on a spare rim sitting on deck. It'd be awesome to get some input from you guys, maybe do's and don'ts on modifications I can make from here? Also let me know what you think of my plans, I'm open to all (most) input. Right now my grocery list is as follows: -1 in the front (currently sits at 15/44) FMF pipe (what's the best option for Dr? is there a full FMF system for a '99 Dr or just slip ons?) DynoJet Stage 3 (if I don't have it already, how would I go about checking the jet size?) RaceTech rear shock spring ( 7.2 kg/mm or 7.6 kg/mm constant rate? suggestions?) POSSIBLY swap for RM fork or just revalve? (is it still worth doing rear and not front?) Thanks a bunch guys, I'm dying to hearing what you think
  4. bianco013

    97 CR125 bore size

    NOT ANOTHER BIG BORE QUESTION!!! Ok, ive searched high and low but cant seem to find concrete answers. I have a 97 Cr125 that been sleeved and bored twice over already. i blew the top end at the end of summer and am getting around to the maintenance. I plan on sending the top end into Millennium Technologies to have it bored out and the powervalves gone through. My question is... how big can i go? I have found a 56mm overbore kit on ebay.. will this be too big? its cheaper to buy thr rebuild kit myself and just send them the top end for machine workThanks for the read and the help
  5. I'm currently looking at moving with work to Andalucia in Spain, just across the water from Morocco and am looking at building a new DRZ-400 into a Rally bike to take with me. I looked at getting a KTM or Husky or other 450cc, but the maintenance would be a killer, so my intent would be to build a DRZ-400 engine under 450cc which can put out a reliable 50+HP. The only must have's on this beast would be kickstart, a capacity smaller than 450cc to stay in the lightweight class and ability to work in hot n high environments. I'm guessing I'd build it using a set of wide gears? I get that the DR Rally bike will be heavier and I'll have to change a lot of the components like brakes and suspension to make it onto the same playing field as a KTM 450 EXC, but the key for me, is having a bike which means I can actually focus on the riding during a 4/5 day event and self deploy to the event, meaning I can start racking up experience. As well as Morrocan based rallies, I'd be looking at competing in the Rally Albania and Greek rallies and maybe getting off-road in the Sierra Nevada's. Thumper Hive Mind, hit me with your opinions and suggestions on how to achieve this goal.
  6. I currently have a 2015 DRZ400S with 5k miles on it. I have the 39mm FCR carb installed, the airbox mod, and the MRD exhaust. I am looking to do the big bore kit with a set of hot cams to probably finish off the mods that I plan to do on the bike. My question is, with this bike at this mileage, is it necessary to replace or change anything else when doing a BB kit and cams? or is the bike still new enough and low mileage to get away with just bolting the kit and cams on? I just want to do it safely without risking anything, but also do not want to waste money on things I dont need. Thanks in advance for the input!
  7. 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
  8. Ben Riley

    Athena 480CC big bore kit

    Hi TT, Has anyone had experience with the bigger CC kits before? Im installing a Athena 480CC big bore kit on my WR450 and im wondering if a jetting upgrade is required or if i can just tweak the air/fuel mixture? Any help is appreciated. Thanks Ben
  9. I’m currently at stock jetting on my 2003 yz250f. I’m rebuilding the top end with a 269cc big bore kit and installing an FMF power core 4 with megabomb exhaust. Current elevation is 700’ above sea level. Where should I start with my jetting? And where can I buy individual jets so that I don’t have to buy an entire assortment? Currently: 178 main 42 pilot needle is 4th Clip from top (stock)
  10. All, I just bought a 1982 XT250 project bike. We had one of these in the family in the 90s, so I know the model fairly well already. I guess my plan is just to have a small, simple bike for shorter local trips, and maybe some light trail touring. I do know it has some known weaknesses, i.e. suspension, brakes, 6V electrics, corroding mufflers, and open frame/exposed engine cases. So I am looking for tips regarding big bore/ higher comp pistons, camshaft (Web Cam) stiffer shock, fork springs, 12 V upgrade, and so on. I was also thinking about fabricating a stepped SS headpipe, and use a 1 1/2" inlet Supertrapp IDS2 muffler. I guess the weight saving will be replacing heavy stock parts with lighter parts in alloy etc (Sprocket, handlebar, rear fender reinforcement for tail light etc), and using smaller/ lighter tail light, indicator lights. And also replacing the stock instruments with a digital dash from KOSO, Trailtech etc. Any and all tips are welcome!
  11. I know the throttle body is 38mm (2mm up from 2016) also a revised air-box, reshaped air boot, new muffler design and a larger-diameter exhaust head pipe. my question is can you install a big bore kit on this? i haven't seen anything stating that it will work for the 2017 model (my guess is it will but i'm not an engineer). Thanks for the help.
  12. buffalorider

    Big Bore 550 MXC issues??

    Hello fellow big bore lovers...... If you have ANY information (good or bad) please advise as it may either help me save from making a $4000 mistake or spend it and be happy. I have a line on purchasing two KTM 550 MXC bikes in Colorado. I have not seen them yet in person. I've talked with the owner twice and this is what I DO know. He is an ex pro hill climb racer and raced AMA, NHA and others. I will try to post photos. One is I believe a stock 1994 in very very nice original condition and the other is a 1995 model that was his race bike. The stock bike has had a Nikisil coating and I'm being told it runs very well and pulls super strong. The '95 model was highly maintained but was raced. No engine work ever performed. It has custom bolt on swingarm extenders that are easily removable so the bike can go back to stock. Those alone were $500 to have them CNC'd for the guy. He wants $2000 each. I have read that these bikes had notorious issues with piston squish, stator electronic's and other things. Is this a good deal or should I steer clear? Thank you.
  13. Sunflash

    RTW 470

    So I have done lots of searching but can't seem to turn up the info I am looking for. So after a 25,000 mile run from Deadhorse, AK to Yaviza, Panama and back to my home in Alaska on a Rally Raid Level 3 CB500X..... I am now going back to my roots and picked up a 2004 DRZ 400 with about 2900 miles on it. Lots of reasons for it but the cut it short I know I was looking for something different for the rest of the ride around the globe. So my plan is to build a bombproof DRZ that can take me everywhere and back. To that effect I have already ordered an Athena 440 kit, will be going with the Hotrods +4mm crank kit, and the ACT wide ratio gears. Where my plan differs from most of the other power mongers is that I want to keep the compression low enough to run low regular fuel without going nuclear. That type of tuning runs a bit contrary to everything I can find info on. So who out there has done a low comp 470? Since the plan is a mild state of tune rather than the usual fire breather everyone else is trying to build does anyone have a good recipe for the spacer or gaskets to keep the compression low enough? Cams for the milder state of tune? FCR 39 going to be enough carb or should I be looking to the 41? My engine building has been limited to old air-cooled 4 cylinders and for max grunt not longevity on crap fuel. Lots more will be done to the bike but the motor spec is one of the ones leaving me a little out in the cold. Want the grunt of a bigger motor to pull the wide gears but not the short life of a rocket ship. Thanks for the help.
  14. I found a Magnum 290 kit on ebay for my 09 yz250f; thought I'd give it a try. It was $400, figured that's not too bad for cylinder, piston, and gaskets. Advice #1: After you take your current piston off; put the new jug on with the water jacket dowel and the two steel dowels in place to make sure everything is going to fit right. Make sure the castings are perfect so it fits down nicely and flat. Mine were a bit too tight in one spot, and I had to dremel just a tiny bit off a steel dowel hole edge for a good fit. Advice #2: Be super careful about stuff dropping into the motor, take your time, cover the motor very well. Advice #3: The four head bolts? they are different lengths, note which goes where. Advice #4: Put the exhaust cam on first, then the intake. Advice #5: Measure your valve clearances as you take your motor apart. Otherwise you have to put it together again, just to see you would rather have shimmed. Advice #6: Put those metal clips into the cam caps, then put the cams into the caps (carefully getting the cams into the clip properly), then hold the cams as you put them in the head Power does seem to be increased everywhere. It's a noticeable increase. I had heard that it signs off hardcore up top; maybe I didn't rev the crap out of it because it was the break-in ride, but I didn't feel that. Is it a mini 450? Is it a 450 slayer? No, I mean, in the right hands it could be; but a 450 is still faster and even if you can be even with them for a stretch, then you have to shift. Mine doesn't feel as fast as a Husqvarna 350. It feels like a strong 250f, but still a 250f. Maybe now you can be one gear tall coming out of a corner, but not almost any gear tall like on a 450. The increase is noticeable and welcome though. It felt strong and I liked how it ran. I recommend this kit, it felt great.
  15. 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.
  16. Friend has a 2014 ajp Pr3 which has an electric start zongshen 233 cc 5 speed engine in it,he loves itespecially the low seat height for his short stature. Only bitch is its slow as hell. Can he use top end performance honda crf230 topend parts,or rev box,carb,??? No room for bigger carb i am told as gas tank is behind engine. I have not seen bike as he lives 200 miles away,but would like to speed it up over winter[Northern Vermont winters are verrry long] Any input or info would be greatly appreciated.
  17. Nickhutton21

    Increasing capacity of a 125

    Hello Chaps Nick from England here. First post so go easy on me :-) i wonder if if anyone can offer views on feasibility of increasing the capacity of a Chinese Suzuki GN125 derived engine beyond the "big bore" limit of 147cc. Following the advice found on this forum I've fitted a Chinese 147cc big bore kit, a VM26 carb and a DR200 cam...actually a Chinese QM200 cam, but I'm told they are the same thing. This is nice, but I would like to increase the capacity further, ideally up to 200cc. I know the stroke is longer and bore is wider on a 200cc variant so im guessing I would need a DR200 crankshaft, con rod, piston, barrel and head. But, in big handfuls, is this likely to be compatible with the 125 crank case and transmission ? ive posted here because there are (or were a decade ago) some guys who seemed to know everything about swapping bits between the small two valve Suzuki engines. Whereas other forums tell me I can get major performance increases by changing the air filter and spark plug :-) Thanks in advance Nick
  18. What can I expect as challenges to using the bigger fin cylinder from a ATC200X on a TLR200 Reflex engine. I want the extra cooling from the bigger fins. Am I going to have to also use the ATC 200X head and then use the ATC200X ignition parts? Help me if you have done this by telling me of your experience mating these to a Reflex TLR200. Thanks, Croatan AKA Tim
  19. Hello everyone, I've been away from the forum for a bit, after I ran the DRZ into the ground and couldn't fix it until now. I've read through many posts about big bores, but most of them are aimed at max HP and things like that. I'm not looking to make 55HP, but my engine is done so it needs everything. I ran the bike on the highway for too long, didn't check levels properly, vaporised all the oil and ruined the engine. The big end is gone, the cilinder wall is worn, the cams and chains are worn and even the valves are having issues. I ran it for a while with all these problems, since I had not other transport. Gotta love a bike on a budget.... For the last few weeks I've been looking for big bore kits and info on them. I want to build a DRZ that does a bit better on the highway, has more power overall but want it underpowered and overbuilt. Towards 50HP would be nice, but not a requirement. My budget is decent, but not endless, which gives me a problem: there are soooooo many brands and styles around, I can't see the forest through the trees. The prices differ immensely, as does quality. On top of that there are setups that just run on race gas, which I can't over here, so I'm looking for a streetable setup. Since I live in the Netherlands, Europe, I have to ship everything over, and to save money in the long run I would rather spend a bit more initially and get it right, instead of getting three different kits. Its a 2005 SM with a stock engine, I will get: Big Bore cilinder (not set on cc's, but looking around the 470 range) Piston Stroker crank/rod (crank is most likely done) Cams (don't need super hectic lift and duration) ACT gears Carb (39 or 41) All the consumables and bearings Its fitted with a Leovinci 3X, have the 3x3 mod, valve and other smog stuff is removed. Not a brand fanboy specifically, I've looked at and could find out about them: MaxRPM, both IceCube and the Stealth, looks great but pricey. CilinderWorks, not sure what their quality is but they're cheap. Athena, mixed reviews and medium pricing. HotRods cranks, famous name but no idea on durability. HotCams & Web Cams, I don't have a preference, whichever gets me the best cam. And a bunch of brandless cilinders, packaged with branded items. Impossible to find out what the level of quality is. Who can help me out on deciding on this setup? More top speed, more power over the whole range, but rather have less power and more reliability than maximum RPM. I know the best solution is OEM, but since I'm building it, I might as well add to it.
  20. Msteinbach147

    2012 ktm 365 sxf

    I have a 2012 ktm 350 sxf with a cylinder work big bore in it looking to get a fuel tuner wonder if I should go the the jd jetting tuner or the wisco. Looking around those price range
  21. gmortie3rd

    So I did this

    I blew up my '14 drz S a few weeks ago. Started, and ran cold up to to redline one the highway. I know it was dumb. But i have since installed a big bore kit and stroker crank. I also had the head serviced with new SS valves and had it ported and polished at Fastheads. I was running the 3x3 mod, and a JD jet kit. Everything else stock. Wondering if the bike will run well with stock carb and pipe, and what jetting to use. If it will run like crap, what carb and pipe do I want to run? (I want a quiet pipe) Normal operation is at 600 ft and cool, but do travel to colorado often.
  22. Supermotofool

    Let's Build! Motor Teardown

    Alright good news. Had saved up a bunch of money expecting to owe a significant amount for taxes.. Turns out I don't owe nearly as much!! Time to put the money to good use and build a nice performance motor for my drz. I am planning on doing a full 470 kit from ebay (Stage 2 cams, +4mm Crank, 94mm Piston/Jug) Has anybody else done this big of a displacement change? If so how bad will this hurt my reliability? I know it wont be nearly as reliable as stock, obviously.. just wanted to get a few opinions before I jump into ordering everything. Also, if I follow through with it I would be doing the MX39 carb swap. I am running a new Yoshi RS-2 full system, but will swap to MRD if it will make a significant difference. Thank you guys, Brad
  23. Hey everybody, first post after years of lurking. Saturday I traded my johnboat for another bike. A very rough 2006 ttr125 with a 150 big bore kit. (no idea who made the kit). She starts first kick no matter what, idles and runs great until about 7/8 to full throttle where it proceeds to fall on its face until I let up. Bike has an "aftermarket" carb that i'm having trouble identifying. The only marking on it is an "M" cast on the side of the body. the insides look brand new but the jets dont have sizes on them. I can post pics as soon as I get off work but without knowing what size jets I have i'm not sure what kit to purchase. Starting to think a new mikuni would be the best course of action. Any Ideas or discussion would be great. Thanks a ton in advance. -Ricky
  24. I just picked up a 93 kx 250 traded my 125 since it need a piston no problem i thought so i went to find the piston size for it but mine is a big bored at 73.8mm i just don't know where to find the new piston i was told by the owner that i could just search 73.8 mm piston and buy any one but i highly doubt that so if anyone can point me in the right direction that would be great thanks. Posted some pic below to see if it helps.
  25. k-lent

    DRZ400SM Rebuild Questions

    My '05 SM had it's rod bearing go out at 15,000 miles and scored my cylinder so its time for a rebuild. I already have the engine out and cases split, just getting ready to clean and inspect everything and spend lots of money. Bike as of now has 3x3, full Yosh RS3 Off-Road exhaust, and JD jet kit. The plan so far is to get: Hot Rods Crank Assembly Cylinder Works Big Bore Kit Cam Chain MCCT FCR 39 (hey why not) My main question is if I should replace the engine bearings or not. I feel like I should since I have the engine apart and plan not to have it again for a while, but its around $200 for main, transmission, counter balance, etc. I could not find anything about inspecting bearings aside from feeling smoothness. Is there anything that indicates I should replace bearings? Should they be fine? Or dont risk it and replace all since I had metal running through the oil? Let me know what you think along with any recommendations for the build. I plan on skipping out on the stroker to eliminate challenges with compression and reliability and skip out on cams for the sake of $$$.