Author Topic: Rear Motor Clearance Issue (Read 7661 times)

Grande huevos · « **on:** March 28, 2016, 02:55:56 PM »

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

zcarlson12 · « **Reply #1 on:** March 28, 2016, 03:28:15 PM »

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.

Skeans1 · « **Reply #2 on:** March 28, 2016, 03:37:06 PM »

I wonder if Lonestar used to thick of a bearing tube

rk88r · « **Reply #3 on:** March 28, 2016, 04:11:29 PM »

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.

Grande huevos · « **Reply #4 on:** March 28, 2016, 05:40:57 PM »

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

huntertools · « **Reply #5 on:** March 28, 2016, 08:00:22 PM »

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.

Aceman · « **Reply #6 on:** March 28, 2016, 09:12:37 PM »

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!!

thesmith87250r · « **Reply #7 on:** March 28, 2016, 09:41:10 PM »

I have a 88 with a lonestar swinger, no clearance issues.

2ndmoto · « **Reply #8 on:** March 28, 2016, 10:09:24 PM »

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.

Grande huevos · « **Reply #9 on:** March 28, 2016, 11:19:21 PM »

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

2ndmoto · « **Reply #10 on:** March 28, 2016, 11:33:02 PM »

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?

broken1 · « **Reply #11 on:** March 29, 2016, 12:53:25 AM »

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?

Grande huevos · « **Reply #12 on:** March 29, 2016, 08:39:08 AM »

Quote from: broken1;66077

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

dem3500 · « **Reply #13 on:** March 29, 2016, 10:07:03 AM »

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

JesseA420 · « **Reply #14 on:** March 29, 2016, 10:30:44 AM »

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.