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Author Topic: Yamaha SR250 Power and Temperature Testing  (Read 7404 times)

Offline sbruton

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Re: Yamaha SR250 Power and Temperature Testing
« Reply #90 on: Nov 30, 2016, 22:07:51 »
Badass.  As an engineer, I totally dig the thought process and mechanics of your testing procedures.  It will be very cool to analyze the results once you've had a chance to put your theories to test!

Offline JadusMotorcycleParts

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Re: Yamaha SR250 Power and Temperature Testing
« Reply #91 on: Jan 11, 2017, 16:19:12 »
The exhaust thread in the head of the Jadus Test Mule 1.0 finally gave out  :(  Swapping headers around and bolting down the clamp flange a few times did it.  If you look closely at the hole you can see the old bolt is actually still there - in the middle of where the new thread should have gone.  But sadly, the muppet that did this repair job failed to extract it and then just decided that a new M6 tapped hole, 3mm to the right at a 15 degree wrong angle was good enough.  Same person that bolted in a wood screw remember!  Gah. 

I took it as a sign.  I am going to do a full rebuild of this engine eventually and make a separate build thread of it.  I'll get that exhaust thread repaired properly with the head off - hopefully even welded up and re-tapped in the correct position.  I have lots of ideas for the build... Cam, high comp piston etc.  It's gonna be a killer.

In the mean time, plans go ahead to complete the testing on the Jadus Test Mule 2.0  ;D

Offline Tune-A-Fish©

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Re: Yamaha SR250 Power and Temperature Testing
« Reply #92 on: Jan 11, 2017, 17:14:49 »
If you made a drill jig to bolt to the other hole and went slow you could get a timesert in that head.


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"I didn't come here and I ain't leavin"  Willie Nelson

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Offline JadusMotorcycleParts

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Re: Yamaha SR250 Power and Temperature Testing
« Reply #93 on: Jan 12, 2017, 15:35:31 »
If you made a drill jig to bolt to the other hole and went slow you could get a timesert in that head.

That was my original thought too, but unfortunately, the new threaded hole is so far off centred and crooked that it has removed a lot of meat where the timesert would nead to go  :-\  So I think I will extract the bolt that is there and try have it welded up - def a job for a pro.  The jig is an awesome idea for the new hole though.

Btw, pros and cons for Timesert vs Helicoil?  I have used both and didn't quite evaluate if one was better than the other  :o

Offline Tune-A-Fish©

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Re: Yamaha SR250 Power and Temperature Testing
« Reply #94 on: Jan 12, 2017, 16:23:14 »
Helicoil is like a thread spring, sub par but will work. Timesert is a solid part and installed with a roll form tap that sets the od threads in the tapped hole with a shoulder to both stop it and provide a perfect opening for alignment.

I got a set that provides a four step process... drill, shoulder cut, tap and driver/thread roller.

Really better than new if installed in aluminum.








Sent from my iPhone using DO THE TON
"I didn't come here and I ain't leavin"  Willie Nelson

"love hard, live fast, die fun" Kacey Musgraves

"Like a Wreckin Ball!" Eric Church

Offline JadusMotorcycleParts

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Re: Yamaha SR250 Power and Temperature Testing
« Reply #95 on: Jan 13, 2017, 12:56:26 »
Ah sweet, that definitely looks like the way to go!  Have just read a bit more and it looks like these are the ticket for cylinder blocks and things too - perfect :)

Offline JadusMotorcycleParts

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Re: Yamaha SR250 Power and Temperature Testing
« Reply #96 on: Jan 14, 2017, 05:37:53 »
One of my favourite shows on Youtube (after MCM and Roadkill ;D) Engine Masters have done some pretty awesome tests with exhaust systems - both collectors, inch size and mufflers.  Although slightly different, a lot of this stuff is applicable to bikes too.  I have been inspired by their methods and love their enthusiasm!