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Sporty blew

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mjohnsns

Member
I was wondering about the chances of rebuilding a 1200 top end. I know the front piston is
Broke and motor is locked up. I guess my question is the bottom end
Damaged also.
WAP.gif
 
Well, the "million (no quite) dollar" question is how old is the sportster, is it worthwhile to pull the motor and rebuild it depends of course on the conditions and circumstances. There are Sportster kits for upping the displacement which includes barrels, pistons and such.

And of course there is "E-bay" or the Internet to find used or short blocks in the classifieds for rebuildable "stuff". Are you able to do the majority of the work...i.e. R&R of the Engine, and no damage to anything else?
 
NEWHD74FAN said:
Well, the "million (no quite) dollar" question is how old is the sportster, is it worthwhile to pull the motor and rebuild it depends of course on the conditions and circumstances. There are Sportster kits for upping the displacement which includes barrels, pistons and such.

And of course there is "E-bay" or the Internet to find used or short blocks in the classifieds for rebuildable "stuff". Are you able to do the majority of the work...i.e. R&R of the Engine, and no damage to anything else?
Click to expand...

The bike is an 07 I haven't torn it down far enough to see the lower end
What has got me puzzled is why didn't the rev limiter shut it down before the bearing spun
And broke the piston
WAP.gif
 
mjohnsns said:
The bike is an 07 I haven't torn it down far enough to see the lower end
What has got me puzzled is why didn't the rev limiter shut it down before the bearing spun
And broke the piston
WAP.gif
Click to expand...

RPM's are not always the cause of a bearing spinning. A oil starved or overheated bearing (or bushing) will spin at any rpm, just won't cause as much damage.
 
WOW. sounds like the same problem as mine. how many miles have you covered. Im sorry to hear about your bike. Its possibly the crank pin. aparently the cranks on these newer rubber mount sportsters is non rebuilderbull. £1000 for a new crank in the U.K. and then the labour cost. my Engineer says he can rebuild it. all the best,
 
I would want to check the lower end as well, Do you have a manual?
 
I know a harley mechanic and he is going to come and get it and tear it down. i am hoping the lower end is fine fingers are crossed.

found out what happened! A bolt that was holding on the backing plate (for the air cleaner)came loose and got sucked down the throttle. What's left on the piston shows a threaded bolt pattern in it. The head shows the exact same imprint.
 
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