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90 motor rebuild.
Posted by
Dutch_Rutter
on 24 Dec, 2013 13:04
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Finally got the motor that I'm swapping into my 85 frame. Unfortunitally I'm working till late tonight, so it looks like I'll be posting pictures of it up tomorrow. Just from looking at it it seems pretty usable, but I havent measured or closly inspected anything about it. SOOOOOOooo
How do I tell if my crank shaft is usable? or is that something that I should replace anyway since I have it tore apart?
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#1 Reply
Posted by
LT250RWV
on 24 Dec, 2013 16:02
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pull the rod up and pull to see if their play and a popping sound in the bottom bearing of the rod.
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Hers a few pics of my $150.00 motor.
crank looks and feels great.
but the head is kinda chewed up.
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Cases look pretty good, just two small spots were welded but nothing to serious.
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Cylinder looks alright, no gouges or anything but cant really see the cross hatch, maybe get away with just a hone.
What do you guys think, worth rebuilding and worth $150.00?
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opinions... anybody?
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#6 Reply
Posted by
LT250RWV
on 25 Dec, 2013 00:42
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Take some more pic of the cases mated together so we can see sealing surface. I probably rebuild the crank. Looks like a piston melted and they didnt clean it out. Check to see if the powervavle moves in the jug. Ive seen 2 be froozen from pistons breaking.
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thanks for the advice! I really have no idea what I'm looking for in this thing. a crank rebuild would still be far cheaper then a entire new crank.
I am able to move the power valve, (by using the adjustment knob) there is some scaring around the centers of the two cases where the crank would be. It did come with a pretty intact piston but thats not to say that they didnt replace a bad one.
Is a melted piston what would cause the dome to be all scared up?
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Detonation, wrist pin guts coming loose and banging as it goes through. Just some ideas.
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#9 Reply
Posted by
LT250RWV
on 25 Dec, 2013 11:04
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Yes in your case. What all American said is right to.
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When I was going through everything. I could not find the circlips. Everything else's is there except those. But the cylinder looks pretty clean. If the circlips came loose or there was other stuff that came loose woulnt it scar up the walls pretty bad, like my 86 jug?
Ill get some pictures of the case halves together today. Is there anything else that I should check out? All the internal components look clean, intact and all present.
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#11 Reply
Posted by
LT250RWV
on 25 Dec, 2013 13:30
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Just looks for cracks and loose bearings
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What do you guys recomend for bearing, gasket and crank rebuild kits?
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#13 Reply
Posted by
LT250RWV
on 25 Dec, 2013 18:54
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Oem or sgp parts seals Bearings gasket factory stuff is the best I got 91 bottom build thread il bumb for you.
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Thanks wv. Lots of good information in there.
Did you press in your crank bearings yourself?
And where were you able to find OEM bearings? This is the second time that I was told that OEM holds up better then aftermarket.
Ane how has she held up and ran since the build? Any problems at all?
This is going to be my first rebuild so I'm going to have A LOT of questions through out this project.
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#15 Reply
Posted by
LT250RWV
on 25 Dec, 2013 22:18
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Yea I pressed them first 2 times I rebuilt my motor but the second time inserts were bad. When i had them fixed I Jerry Hall do them since he done the inserts. Only the vibration from the crank wobbling only problem I have had. But inserts fixed that Problem. Smooth sailing since that. Jason from east Toledo Honda can get you all the stuff you need I forget his screen name on here. Im sure some will chime in.
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alright got some time to tinker on the motor today.. here is a shot of the cases set together. looks pretty good without a gasket between the two. all the bearings were solid, and other then the two repaired spots there were not any other cracks. I think it was a pretty good steal.
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There is no gasket between the case halves, you use 3bond. Also make sure to use the billet thrust washers and 99 rm250 piston pin bearing. Do not use the stock stepped thrust washers and wide bearings. The stock thrust washers break and could destroy your engine. The head damage could possibly be from the stock thrust washers coming apart.
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#19 Reply
Posted by
LT250RWV
on 27 Dec, 2013 15:31
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I have Jerry hall redo my cranks. You have to have a crankshaft jig and a way to true the crank. Not for most machine shop to do.+ Jerry knows these quads well. I would stay away from hot rods. Ive had good luck with the one I got but heard alot of bad story of them not be true and bearing going bad. The rod on your crank still could be good. Just a new bearing and retrued. Best to send it out and let them take it apart and diagnose what needs to be done.
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I agree on staying away from hot rods. Either Jerry or Iceracer(Carl) can do the crank properly not sure on pricing.
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thanks guys, I'll shot them a pm. I figure I'll be able to save some money on pressing in my own case bearings, they fit snug inside of the case now, so I think I'll be safe to do that. Is there a limit at to how much the bearings fit into the cases? or just tap till they stop/centered?
heres a rather depressing pic of how its sitting now..
I want it running.
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#22 Reply
Posted by
LT250RWV
on 27 Dec, 2013 17:43
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Just press them in till they stop. Now on mine the bearing pressed in tight. But the insert were shot. But it felt tight when I pressed Them. I have a hot rods crank in mine right now. Had Jerry redo it with new rod kit. Mine has held up good. But if I was in your shoes, it might cost a little more to do now. But I would send my cases have check the pockets put the bearings in let them scope the crank. So all your parts are their so you will know everything is right your very first time. So you dont waste any time or money.
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I think that is a GREAT idea. I would rather not have any problems with it once I get it back together. and its not like its my only bike to ride as well, I can live with it taking a while to get back together as long as it stays together.
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Heres a good tip, put the Bearings in a deep freeze for 48 hours, when your ready to drop in the bearings heat the cases in an electric oven for about an hour at 225-250, pull the cases out quick and the bearings should almost drop in. Note DO NOT USE YOUR WIVES NEW OVEN!!!!!
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