TRX250R.ORG
Workshop => Suspension and Chassis => Topic started by: Grande huevos on March 28, 2016, 02:55:56 PM
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Has anybody ever had a Clearence issue with the back of the motor and the swing arm??... I've completely rebuilt the swing arm and the rear linkage, bought new front motor mounts and just had a new motor build and my cases welded and when I went to install my motor it was touching the swinger! All the holes line up and the bolts go right in. Not sure what to do but it's killing me! I have a lone star swing arm and oem 89 frame
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You could possibly put a thin piece of rubber between the two to help cushion it. I know mine is very close but never hits. I wish I had a better answer for you.
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I wonder if Lonestar used to thick of a bearing tube
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I would consider grinding the swingarm for clearance. You could use silicone to seal the tube to the crush tube if you have to go that far. I would not want it touching the cases at all.
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I can't think of any other possibility of why it could touch. I def do not want it to touch because then it's just a matter of time before it breaks again and leaks oil everywhere. Like I said I just got this motor back from being built and won't run it intil I find a fix..... I had thought about taking a grinder to the swing arm but I wasn't sure how good of an idea that is, but then again it may be the only possibility. I might try that tonight and see what happens
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Have you tried loosening all bolts for motor and frame then push the motor forward? (Don't forget head stay)There might be enough clearance in all holes combined to give a little more space. Mine only has about 1/8 inch and has never touched.
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Before I did anything, I would call Lonestar to get their input. I would absolutely not grind or touch a thing before that phone call!!
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I have a 88 with a lonestar swinger, no clearance issues.
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Pull the pipe and carb off , loosen all the mounts and see if you can move the motor for clearance. You definitely want a few millimeters of clearance, because the chassis and mounts will flex when ridden hard.
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I couldn't bring my self to grind on the swinger to afraid it weaken it too much.... And it's a new motor so there isn't pipe and carb on yet. With all bolts loose and 2 guys we couldnt get it to not touch on the stator side. Looking into doing some minor fabs to the rear mounts to squeeze the space out
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Seems like it's twisted if it's not touching on one side. Did you try and push the front mounts down a bit? Mounts look twisted or bent?
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How does the hole for the swinger bolt look? Those can get pretty wallowed out if the swinger ever came loose & got left like that. Was the case welding you mentioned on the back by the swinger?
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How does the hole for the swinger bolt look? Those can get pretty wallowed out if the swinger ever came loose & got left like that. Was the case welding you mentioned on the back by the swinger?
Yes we have taken the swinger bolt out and checked it and looks good.. Nothing is twisted or bent but after messing with it last night it appears that the weld is the only part touching, the rest is very close maybe the thickness of an index card. I'm afraid to leave it how it is though and have it break again
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im with all the other guys, something is not right. maybe your frame is bent. you could try taking measurements from a few different places on the frame and compare them to a known good frame. i have a 86 and 88 bare frames. i could help you compare measurements. i wouldnt grind anything as a few others have said. snap some pics
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u mean the weld that u just had done, is touching it? was this weld to repair damage caused from the engine vibrating against the swinger to begin with?
the motor does sit close at the back, but ill bet the problem is a slightly obrounded swingarm bolt hole. measure it with calipers it might not be too noticeable by the eye.
if you are only an index card thickness away from your swingarm as it sits, you only need a index cards thickness of slop in the hole for it to smack it.
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u mean the weld that u just had done, is touching it? was this weld to repair damage caused from the engine vibrating against the swinger to begin with?
the motor does sit close at the back, but ill bet the problem is a slightly obrounded swingarm bolt hole. measure it with calipers it might not be too noticeable by the eye.
if you are only an index card thickness away from your swingarm as it sits, you only need a index cards thickness of slop in
the hole for it to smack it.
Yes originally I noticed the engine leaking oil so I pulled the motor and it had a crack and a noticeable rub point on the left case and the swing arm. When I had my new motor built he bored my cases and welded the crack to repair it. The weld seems thick. I have replaced the pivot bolt bearings and the rear linkage with a kit from pivot works. All the holes line up straight the bolts go in with out much effort and the chain lines up perfect with the sprockets.... I've had several people send me pics of the engine mounts and Clearence and it all seems normal. I'll try and take some pics this evening and post them up
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The stock frames flex and bend. I have seen a lot of broken cases that show signs of touching the swingarm but they often had over 1/16" of clearance between the cases and swingarm when you inspected them. The majority of the bikes that showed signs of contact between the cases and swingarms were race bikes that really got pounded on the track, fat guys that did a lot of jumping or the bike had insufficient suspension for the abuse the bike was taking.
The 250R frame has basically an isosceles trapezoidal shape. 4 sided structures are not very resistant to collapsing when loaded from any side if they do not have triangulation from one corner diagonally to the opposite corner of the trapezoid. The head stay used the engine to add some very crude triangulation. The head stays were always breaking indicating they were trying to prevent the 4 sided structure from collapsing. Not running the head stay allows the frame to bend and flex (collapse) allowing the swingarm to move closer to the cases.
Many guys removed the head stay to prevent the head gasket from leaking and or breaking the head stay or breaking the head stay tab off of the head. This was just another indication the frame was flexing and head stay was trying to prevent this from happening.
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Well I can't seem to get my photo bucket to bring up my pictures which is really pissing me off. But I did do some measuring this week and the stator side rear mount was off a bit from the clutch side. Not much but maybe enough to make the difference... I did some welding and basically rebuilt the rear mounts and the middle botto
Mounts and reinforced them. I'm going to reassemble tonight and hope that she clears. I'm dying to get my bike back together and get this new motor broke in!!!
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I have this exact same issue on my '88 frame, changed everything out and it still rubs every once in a blue moon
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Mine touches when it's just sitting there, even after I fixed all this stuff. Pretty sure my issue is the weld that was just done by my builder.. Straight behind the front sprocket there is a half moon shape on the back of the case to form around the swing arm and mine is no longer visible and the weld actually protrudes a little past the flush point.. Time to grind some weld off I guess
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i just went and looked at mine, i have about a 1/4" between swinger and cases. without a doubt having the weld built up that far will make the weld touch it, but was the original cause of the swingarm bumping the cases to begin with extreme frame flexing, or worn out swingarm bushings? i kno this pic is an atc frame but the same idea applies, how much if any slop is in these holes i circled? (http://i1251.photobucket.com/albums/hh548/JesseA421/250r%20frame.jpg)
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(http://uploads.tapatalk-cdn.com/20160403/f5d0de5841030ef9671b3d487e2e3aa7.jpg)(http://uploads.tapatalk-cdn.com/20160403/a66b9b0d50bd0ed0d209f4e1831f4930.jpg)
This is on my puma I'd make dang sure it's not the swingarm
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Has anybody ever had a Clearence issue with the back of the motor and the swing arm??... I've completely rebuilt the swing arm and the rear linkage, bought new front motor mounts and just had a new motor build and my cases welded and when I went to install my motor it was touching the swinger! All the holes line up and the bolts go right in. Not sure what to do but it's killing me! I have a lone star swing arm and oem 89 frame
Could you throw up a few pictures of the area that's giving you issues?
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i just went and looked at mine, i have about a 1/4" between swinger and cases. without a doubt having the weld built up that far will make the weld touch it, but was the original cause of the swingarm bumping the cases to begin with extreme frame flexing, or worn out swingarm bushings? i kno this pic is an atc frame but the same idea applies, how much if any slop is in these holes i circled? (http://i1251.photobucket.com/albums/hh548/JesseA421/250r%20frame.jpg)
I took the dremel with a grinding wheel to the weld last night and put that "groove" back in it. I didn't make it as much as stock cuz I wasn't sure how to deep to go without messing it up and I finally got it to clear! I pulled my swing arm off when I welded the motor mounts and yes the main swing arm hole is perfect. Originally it did crack from bad bearings. I don't have quiet as much room as in your picture but it Should be all good now. I will re assemble everything today and get this beast running by the beginning of the week
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Could you throw up a few pictures of the area that's giving you issues?[/QUOTE
Is there a way to post pictures without photo bucket? That's hiw I've always done it but now all of a sudden I can't get it to pull up my pics. I have some build pics I want to post up too
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Could you throw up a few pictures of the area that's giving you issues?[/QUOTE
Is there a way to post pictures without photo bucket? That's hiw I've always done it but now all of a sudden I can't get it to pull up my pics. I have some build pics I want to post up too
Tinypic or tapatalk
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(http://uploads.tapatalk-cdn.com/20160403/f5d0de5841030ef9671b3d487e2e3aa7.jpg)(http://uploads.tapatalk-cdn.com/20160403/a66b9b0d50bd0ed0d209f4e1831f4930.jpg)
This is on my puma I'd make dang sure it's not the swingarm
Sent from my SAMSUNG-SM-G890A using Tapatalk
The issue was directly behind the front sprocket on the back side of case where the swing arm is closer to the frame. The case has a machined out crescent shape that allows the swing at
To fit.. Mine had a crack right there and when it was repaired it was very thick and you could no longer even tell that the crescent shape was ever there. That is where i did the grinding. If I get my photo bucket to start working I will
Load some pics
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you can just attach your photo directly to your posy by uploading the photo directly to the website I think
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(http://uploads.tapatalk-cdn.com/20160407/fe8a3a6f313b1bf89431dadf32585ac5.jpg)(http://uploads.tapatalk-cdn.com/20160407/b52af1828990db821545edcae9dd9261.jpg)(http://uploads.tapatalk-cdn.com/20160407/3c0155e63fab9d2c1959ca3df7668168.jpg)(http://uploads.tapatalk-cdn.com/20160407/15f1ac6cabd610ee3c604001b427c272.jpg)(http://uploads.tapatalk-cdn.com/20160407/a47118c57ef04288b953bc2633d7ac98.jpg)(http://uploads.tapatalk-cdn.com/20160407/28d2623a1b83ebbb4c32d5a8f1efa083.jpg)
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It's all good now got it to clear and she is back together
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