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arbowman

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About arbowman

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    Pennsylvania
  1. Hello! This is my first post and I am in need of some helpful opinions and advice from some very knowledgable members! Here is my situation: I purchased a 1990 CR500 with a damaged engine for $300 from a guy I know that needed money. I love people like that! The engine is repairable but the rest of the bike needs a lot of help so I have decided to do an aluminum frame conversion. I have already purchased a 2004 CRF450 with a blown up engine that is not repairable because the case halves are missing. They are missing because the guy I purchased it from had a roommate that was a junkie and the roommate stole the cases because they were the biggest pieces of aluminum in the box of engine parts that he could scrap for dope money. The entire bike is completely thrashed and was obviously abused and never maintained and crashed hard many times. The wheels, tires, suspension, brakes, plastics, seat cover, handlebars, controls, cables, radiators etc etc will all need to be replaced or serviced completely. So long story short, this bike will need at least $1000 worth of parts and whole lot of time invested into it to make it nice again. I only paid $400 for the whole bike and there isn't much left of the 450 motor that I can sell except for the carb, covers, exhaust, etc.. The cylinder, crank, head, etc are all completely trashed. The cylinder and head might be repairable but they are pretty much worthless as they are now. When it comes to the actual process of converting the aluminum frames to accept the 500 engine, the 02-07 CR250's are one of the easiest chassis to convert. The CRF450's require much more work than the CR250 to convert so that got me looking for 250s on Craigslist. I found a very nice looking 02 CR250 on Craigslist. According to the description in the ad, the bike needs some basic maintance work done to it like fork seals and a master cylinder rebuild. The engine runs good but has a slipping clutch. Hopefully the rest of the bike is nice and doesn't need much attention or new parts. The owner is asking $1200. The ad has been on Craigslist for awhile now so he would probably take $800-$1000 for it since it needs some work and it isn't riding season and Christmas is coming up. I figure I could sell the complete engine from that bike for at least $500-$800 on Ebay. I think I could convert this CR250 for the 500 engine and do the simple maintanence and be riding it without a whole lot of effort in a short amount of time without spending alot of $. Of course I will look over everything else on the bike to make sure it is in good working order before I ride it or even buy it. So here are my questions: What chassis is better overall? The 04 CRF450 or the 02 CR250? What are the noticable differences? Are they completely different or very similar? Which bike handles better? I will be doing mostly freeriding, hillclimbing, jumping, and some fast trail riding at Trevorton PA (check it out on youtube) with some occasional MX track riding and will eventually be making some trips to the Silver Lake sand dunes in Michigan. Also, I plan on making the bike street legal with all the lights and legal stuff and will be installing a set of Supermoto wheels and tires when I will be street riding. I am 6 ft tall and weigh 170 pounds without gear. I will be converting the CRF450 either way because I already have it and it will be tough to sell it because it is a total POS. I guess my biggest issue is whether or not I should even bother trying to get the CR250. I figure I could convert the 250 for the 500 engine and ride it kinda stock while I slowly build the 450 completely custom and badass and then swap the 500 engine into that and then either sell the converted 250 rolling chassis or find another 500 engine for it. Or I could build the 450 dedicated for only street use and build the 250 dedicated for only off road use but then I would have to find another 500 engine. To do that just seems to me like a lot of work and $ invested. I would probably make a couple thousand bucks in the long run if I sold the 250 but I probably would never sell it and then I would just have a bunch of $ invested in two bikes I never really needed! Uhh....too many options and decisions to be made....I need help some help making up my mind! Any opinions or advice about my entire situation is greatly appreciated! Thanks in advance! Sorry for the long post!
  2. Hello. I bought a 2003 JR50 that wasn't running. I took the carb apart and everything was dried up and clogged with residue. I need a new needle valve. They are $25 + shipping for an OEM valve for the 2000+ JR50's which to me is very expensive. I found a OEM needle valve for an 80's JR50 for $10. The carbs and needle valves for the 80's JR50's and 2000+ JR50's look very similar in the OEM parts diagram. So here is my question: Are the carbs and the carb parts the same for all years of JR50's from the 80's to 2000's? Will the needle valves swap from carb to carb from the early models to the newer models? I will be removing the intake and exhaust restrictors and drilling holes in the airbox cover and removing the second pilot jet. Jets R Us says typical jetting for a JR50 is 15 pilot and 52.5 main. The stock pilot is 15 and the stock main is 56.3 so Jets R Us is recommending a smaller main jet so I am assuming a bone stock JR50 is too rich with the restrictors in place. Please correct me if I am wrong. The author of this post is using a 17.5 pilot and a 67.5 main jet in Socal with the restrictors removed: http://www.thumperta...uki-jr-50-mods/ A 67.5 main is 3-4 steps higher than stock which seems very rich to me. I always thought 1-2 steps higher was a good start with main jets. What is typical jetting for a JR50 with the restrictors removed and holes in the airbox? I am located in the mid atlantic of the east coast. I really don't want to have to buy 5 or 6 main jets at $6 each to get this bike to run correctly. I am hoping to only have to buy 1 or 2 main jets but I need a good recommendation for a starting point. Thanks in advance!
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