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Post by poppysteve on Feb 4, 2014 19:39:59 GMT -5
Hi, SO now it begins.. Won't start, low compression ( ~60 ). Also the starter sounds like rocks in a blender, Pulled it out expecting nothing but shavings, but it looks ok, Did notice the lower bolt was finger tight, not sure if that's it.. Pulled the seat, and body panels off and found 20 lbs of eaten acorns I Believe it has a JOG90 Minarelli engine, the same as the Polaris.. Please advise if I'm off base here.. I'm learning.. It's a 2000 model, so I'm assuming a refresh is due anyway. I looked for a upgrade kit and found this.. get2itparts.com/index.php?main_page=index&cPath=115150_119101_1170_3090_4055I didn't see anyone mention that kit, so thought I'd ask before I drop $400. Also there are NO details, which make me nervous. This build will be a bit different as I'm more interested in Torque and trail use, then HP and top speed.. Hope you don't mind a 4 wheeler here, but this forum had the most relevant info I could find. I'll pull the head and cylinder and take a look this weekend. Thanks for all the info so far, and thanks for any advise going forward! Steve
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Post by skuttadawg on Feb 4, 2014 20:07:26 GMT -5
Check here to look up the engine stamp codes codes Also measure the bore with a caliper to be certain before ordering a kit . Compression should more than twice of what you have
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Post by moofus02 on Feb 4, 2014 20:44:19 GMT -5
Congrats on the new toydo you need another grandkid lol. First rule if you have that weird feeling hold onto your money unless research and reviews make you comfortable. And great buy. that should be 50 or 52mm bore x42mm stroke stock. A loose starter could make noise. Tighten it back down and see if it helps. Then check compression even if you have to use the kick starter. Those cast iron cylinders are real tough. If it doesn't pass compression test pull the top end and post pics of the Cylinder. A hone and a piston kit ($30) should get you back in business. I'm a fan of stroker cranks big bore kits and pipes but not for the young ones lol. A pipe will help with higher rpm power but good compression cvt and clutch tune and carb tune on a 90 should make a real good ride for the kids. Way Cheeper than 400. Check out 90gtvert project 90 thread and look in the tech section for related tuning info. Ask any questions you have. I likethe Leo vince zx on a scooter for a good all around pipe but I don't know what is available for the quads. Don't think a pipe is needed for kid play on a 90 if torque is what you are after. Bbk isn't much of a gain eitheron a 50 you jump by half to 70 on a 90 you gain 6cc. Not much displacement for the buck. If you have good compression and want a good rider cvt, clutch and carb tune is where I would spend my time. Be Cheeper also and probably a better ride for the kids Sent from my SPH-L720 using proboards
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Post by moofus02 on Feb 4, 2014 20:45:05 GMT -5
Forgot to say welcome
Sent from my SPH-L720 using proboards
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Post by 90GTVert on Feb 4, 2014 21:28:13 GMT -5
We're happy to have a 4-wheeler here. I'd like to hear how it comes together since I'm only used to these engines in scooters. If you do go with a BBK, Parts For Scooters has a 54mm that comes with a head for less. They also sell a whole jet kit for $15-16 instead of one jet for $10. kaseaparts.com is another good source for replacement parts and some performance parts. g-forcepowersports carries all sorts of racing parts. Like moofus, I'm not totally sure if you have 50 or 52mm bore, so measure it unless you're replacing with a whole kit. As he said, check it all out before you decide what to do. Getting the compression fixed and the carb and CVT dialed in may make you and the kids happy.
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Post by moofus02 on Feb 4, 2014 21:57:30 GMT -5
The other day I saw a 50mm Cylinder kit on eBay with high compression head for 50 or so plus shipping. Looked like a 8 port Cylinder from the pics pages.ebay.com/motors/link/?nav=item.view&id=171121732697I know it's not 54mm but the price is not much more than a piston and gaskets. I think the listing ended but they still had some Sent from my SPH-L720 using proboards
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Post by FrankenMech on Feb 5, 2014 0:05:21 GMT -5
Welcome!
Check the valve clearance B4 you tear anything apart. A simple adjustment may be all that it needs to bring the compression up. A tight valve may have caused damage also but it is worth a shot.
Edit- Of course if it is a 2T then that would not be a cause. I keep forgetting there are 2T and 4T engines in use.
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Post by poppysteve on Feb 5, 2014 9:04:01 GMT -5
Hi, Yes its a 2 stroke.. Been a while, glad to get to play with them again.. Actually I DO have another china quad with a 110 honda clone 4 stroke, but that's another project. The Kit is a 54mm bbk, + pipe + rollers + torque spring + gaskets + jet, clips, studs, bearings, and a plug. $374.99. I saw the 8 port 54mm on ebay, but not sure how many ports I have now Ya the 12 year olds don't need a bbk now, but us big kids Still can't find the engine number, found the vin near the tranny fill area B00F-YA005594. Pulling the exhaust is my next step, assuming it's been there for 14 years and all junked up. The exit hole has mud or something an inch or so inside.. not sure if its insects or wheelies. But a plugged exhaust won't help with compression..?? I'll take some pictures and post if there is interest... Thanks for the help and welcome!
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Post by 90GTVert on Feb 5, 2014 9:16:40 GMT -5
The ATVs don't always have a number like 1E40QMB. My Polaris 90 engine just has some sort of Polaris SN that means nothing to me.
A clogged exhaust shouldn't be the compression issue, but it should be cleared out anyway.
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Post by poppysteve on Feb 9, 2014 15:58:52 GMT -5
Had a chance to pull it apart.. It actually had 90 pounds after pulling the exhaust when I checked, but the cylinder and piston was pretty scored.. Put some pics on dropbox. www.dropbox.com/sh/5dvxc2y33vnkqxq/mK4puZR11EThe belt is a Bando 780 17 30 and I measured 16.78 width, is that still good? I ordered the ATV kit with everything but a stroked crank, will let you know how that works out.. Thanks!
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Post by 90GTVert on Feb 9, 2014 20:59:58 GMT -5
The service limit for that belt should be around 15mm, but to keep it tip-top you'll prob want to replace it by 15.5-16mm. The narrow belts sometimes make takeoff strong, but it may hurt top speed. If you don't go fast you may actually like the narrow belt.
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Post by poppysteve on Feb 19, 2014 13:08:01 GMT -5
Hi, Got my parts today! get2itparts.com/index.php?main_page=index&cPath=115150_119101_1170_3090_4055 Must say Get2itparts have been great to work with. They verified everything will fit, except the exhaust, and offered to take out the not perfect parts. I requested the pipe anyway, I don't mind making a bracket.. Also the shipment left SC just as a snow storm hit, and the 2 day priority ended up taking 8 days. They help track it down, and offered to send all new parts. Most with labels say Produced in Taiwan. Cylinder is a 6 port, so now off to find the files and clean up the ports. The new main that came with the kit is a #90, the stock card is a 19.12mm Sunworld. Think this carb will be ok with the bigger jet? Good news is I own a LM-2, so I'll find out Also will clear up the exhaust.. Chrome bonus, picture showed Black.. Some pictures.. www.dropbox.com/sh/2ty8n0vw6ter6h8/flSi8DsqHGWish me luck, I'm going in!
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Post by 90GTVert on Feb 19, 2014 13:52:40 GMT -5
You can get the air/fuel ratio correct, but a larger carb will improve cooling. Here's some data I collected with various carbs on a 96cc. This is not to say you must have a larger carb. Just info. 49ccscoot.proboards.com/post/44367Most stock carbs aren't as big as they are believed to be. The 19mm ID of the outlet doesn't mean it's really a 19mm. Most are more like 16mm at the venturi. Tough to measure because it's an oval and needs to be converted to it's equivalent as a round hole and that's difficult to be accurate with. At any rate, here's a stock carb (19mm outlet) next to a real 19mm carb (DellOrto PHBG) to get the point across better. Notice the difference in bore at the venturi. Also there are adapters for using widebands with 2Ts because they are quickly fouled by oil if used regularly. Consider an adapter or just using the wideband to get in tune and then plugging the bung. Koso AdapterGood luck and let us know if you need help or at least how it turns out!
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Post by poppysteve on Feb 19, 2014 18:40:36 GMT -5
cleaned up and chamferred the ports some.. Don't think I broke anything important yet Need a LONG dremmel bit.. Checked the ring gap, and ran the ringed piston up and down a few times, seems smooth.. Now Blow it all out and lube it up.. www.dropbox.com/sh/yqpknivdcn6p4x0/lyf63Fckqd
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Post by poppysteve on Feb 24, 2014 6:34:51 GMT -5
Got the engine assembled, had to remove the oil pump because the base gasket hit it. Was going to remove it anyway so just moved up the timing.. I found the starter grind problem.. www.dropbox.com/sh/r94ttx4bzm9j7mf/Yzf0wIxG3ACould get it to turn over without the plug in, but not with.. Will try a local source for a gear. Got it to run full throttle with the manual ( Pull ) start. Ya the Kickstart hits the rear tire, so they mount it backwards and you Pull up on it.. Lots of fun that.. I had the carb soaking, so need to play with the adjustments.. Probably got 5-10 seconds of run time at full throttle.. I'll look up some sane initial adjustments next. On to the plastic next, it has been sitting outside most of the time and has like mold or something all over it.. Will power-wash and hit with bleach and see what happens.. It was silver and red, now its silverish and pink, so we need to fix that.. It used to look like this.. atvs.rununtilsold.com/atvt/atvt-photos/1076280069.jpg I'm thinking silver becomes red and pink becomes black. More like the colors of my toy www.powersportstv.com/adminuploadedimage/400x200/2010_Polaris_Outlaw_525S.jpg Any recommendations on spraybombs to use or stay away from with plastic?? Thanks!
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