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Should I strip the top end after a heat seizure?

Posted: Sun Aug 12, 2012 7:54 pm
by Muttlyoo7
My Rapido Classic 225 nipped up on the motorway. I'd recently had it dynod and jetted for touring i.e just on the rich side. Prior to this, and after a complete engine rebuild it had just clocked up 1000 trouble free miles. The scooter was nicely warmed up and I'd just given it its 1st flat out run of about a mile, and was just slowing down gently from 70 MPH i.e not closing the throttle fully when it happened. It was decelerating at about 60 MPH and 6000 RPM the head temperature hadn’t risen alarmingly.
After the seizure it started up and seemed to run fine with no nasty noises. Should I now strip the top end and give it a thorough check over? Or after checking for the usual causes of heat seizures i.e. air leaks etc keep using it, paying attention to any unusual noises or reduced performance?

Re: Should I strip the top end after a heat seizure?

Posted: Sun Aug 12, 2012 8:26 pm
by LI150
I would want to no why it seized and I would strip it

Re: Should I strip the top end after a heat seizure?

Posted: Sun Aug 12, 2012 8:37 pm
by paulmgreen
Yes definitely strip it mate. You could well have some alloy from pston transferred onto the barrel. Best to strip ad check it or else it will always nag in your mind and you wont have t full confidence in your motor.

Slowing down after a flat out run its worth blipping the throttle to help with lubrication...

Re: Should I strip the top end after a heat seizure?

Posted: Sun Aug 12, 2012 8:59 pm
by col68
I would strip it down mate . I had the same kit should think it is exhaust side mine always was . would check piston is still about 3.5 thow clearance to !! Got a ts1 now and no more nip ups !! col 8-)

Re: Should I strip the top end after a heat seizure?

Posted: Sun Aug 12, 2012 10:09 pm
by rosscla
That's a good advert for dyno set ups ... :?

Re: Should I strip the top end after a heat seizure?

Posted: Mon Aug 13, 2012 9:45 am
by nelson pk
rosscla wrote:That's a good advert for dyno set ups ... :?
I guess it could have developed an air leak since being dynoed but it probably just goes to show again that the dyno is simply a tool and what matters is the person using that tool ;)

Re: Should I strip the top end after a heat seizure?

Posted: Mon Aug 13, 2012 9:51 am
by nelson pk
Muttlyoo7 wrote:My Rapido Classic 225 nipped up on the motorway. I'd recently had it dynod and jetted for touring i.e just on the rich side. Prior to this, and after a complete engine rebuild it had just clocked up 1000 trouble free miles. The scooter was nicely warmed up and I'd just given it its 1st flat out run of about a mile, and was just slowing down gently from 70 MPH i.e not closing the throttle fully when it happened. It was decelerating at about 60 MPH and 6000 RPM the head temperature hadn’t risen alarmingly.
After the seizure it started up and seemed to run fine with no nasty noises. Should I now strip the top end and give it a thorough check over? Or after checking for the usual causes of heat seizures i.e. air leaks etc keep using it, paying attention to any unusual noises or reduced performance?
Definitely strip it. It could well have ally nipping your piston rings in after a seize and clean any ally that has deposited on the bore off with some fine wet and dry and make sure there are no high spots on the piston otherwise it will do it again and again and again even if you find the cause of what done it in the first place!
While its stripped you could get someone to check your bore clearance which is a must with any barrel/piston set up even if its brand new.
In theory if its new you shouldn't have to, but unfortunately it is often is required.

Re: Should I strip the top end after a heat seizure?

Posted: Mon Aug 13, 2012 7:27 pm
by Muttlyoo7
Thanks for all your advice. I guess I knew deep down that I'd have to strip the top end, but was just hoping that the advice would be otherwise. :roll:

Re: Should I strip the top end after a heat seizure?

Posted: Mon Aug 13, 2012 7:56 pm
by RICSPEED
nelson pk wrote:fine wet and dry.
i belive this can cause grit to get into the ally .. light use of a fine file my be better

Re: Should I strip the top end after a heat seizure?

Posted: Tue Aug 14, 2012 11:33 am
by GP Kevo
paulmgreen wrote:Yes definitely strip it mate. You could well have some alloy from pston transferred onto the barrel. Best to strip ad check it or else it will always nag in your mind and you wont have t full confidence in your motor.

Slowing down after a flat out run its worth blipping the throttle to help with lubrication...
What Paul said, and it sounds cool when you do it, an added benefit. 8-)