TRX250R.ORG
Workshop => Engine and Bottom End => Topic started by: sameltoe on December 11, 2013, 09:26:15 PM
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(http://i1347.photobucket.com/albums/p701/samw450r/20131211_200327_zps550f0812.jpg)(http://i1347.photobucket.com/albums/p701/samw450r/20131211_200437_zpsbe0bb734.jpg)(http://i1347.photobucket.com/albums/p701/samw450r/20131211_200346_zpsb3546b41.jpg)
So I have this engine and I'm wondering about these cracks as I'm inspecting it. Are these normal? Or is this back side about to have a blowout? I planned on sending this thing out to Neil for a rebuild an porting, but kind of curious.
I compared it to my Arens bike and it is smooth, but has these little cracks elsewhere. But more on the clutch cover.
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http://i1347.photobucket.com/albums/p701/samw450r/20131211_200327_zps550f0812.jpg
Mobile photobucket, Picture test, direct link
I don't see anything about resizing pics.
Sorry bout the size guys
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Those cracks are just surface cracks from when the cases were casted, these are usually noticeable in the inside crank area many times also.
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Thank you Sir!
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I vaguely remember seeing those on engine cases 250r and other. Looks more like a symptom/trait of the casting process as rss stated
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I vaguely remember seeing those on engine cases 250r and other. Looks more like a symptom/trait of the casting process as rss stated
Yeah, the same as the stock clutch basket. The casting marks appear to be cracks. Its your imagination getting the best of you.
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As noted, casting flaws.
One way to know for sure, get a can of spray carb cleaner (cheap Wal Mart brand) spray those areas to clean the surface, air hose them until dry, then sprinkle baby powder all over the areas.
Next, take a hot air gun & heat the areas of the cases & if theres a crack there, the oils in the crack will bleed up into the baby powder showing the crack. It kinda works just like having something magna fluxed for cracks, where when the metal is magnatized, the metal powder follows the crack line.
Works real well with bead blasting dust, like the welding slag type.
Now dont go telling everybody this little trick, ya'll be put the automotive shops out of the magna fluxing business.
:popcorn: Neil
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well some maybe cast marks but some are actual shallow surface cracks that can on occasion flake off like I have had in the crank area.
This happens from the fast cooling at the surface of the piece during the casting.
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well some maybe cast marks but some are actual shallow surface cracks that can on occasion flake off like I have had in the crank area.
This happens from the fast cooling at the surface of the piece during the casting.
I could see that happening.
Those outside pieces sticking up, probably from hair line cracks in the die molds from over & over use year after year.
Would have been nice, if Honda would have numbered their molds & left a number into the castings for us to search back & find out when the cases were cast.
Neil