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Laser Engines - Technical questions

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Jon - Laser Engines17/01/2019 10:19:24
5560 forum posts
270 photos
Posted by Gary Spicer 1 on 15/01/2019 10:45:56:

Just to follow up on Jon link a page back this is t he Fastrax remote glow fitted to my Laser 70, its a Precision fit and work well.

laser70.jpg

Has your exhaust clamp shed its retaining bolt Gary? it appears to be missing and could cost you an exhaust!

Chris Walby17/01/2019 12:48:03
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1276 forum posts
315 photos

Looks good and will be especially useful on my inverted engines like the mossie where I have to start the port engine and then stretch my arm under the nose to unclip the glow starter, then start the starboard engine, if I reach from behind I burn my fingers on the exhaust!

Thanks guys for the lead on this (pun intended).

Former Member17/01/2019 13:06:28

[This posting has been removed]

Gary Spicer 117/01/2019 14:57:02
46 forum posts
3 photos
Posted by Jon - Laser Engines on 17/01/2019 10:19:24:
Posted by Gary Spicer 1 on 15/01/2019 10:45:56:

Just to follow up on Jon link a page back this is t he Fastrax remote glow fitted to my Laser 70, its a Precision fit and work well.

laser70.jpg

Has your exhaust clamp shed its retaining bolt Gary? it appears to be missing and could cost you an exhaust!

Thanks Jon, I cant check for a few days, but it looks like it is missing!!

Jon - Laser Engines17/01/2019 15:35:14
5560 forum posts
270 photos

They dont call me hawkeye for nothing

Manish Chandrayan31/01/2019 10:11:52
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645 forum posts
73 photos

Call for help!

Confession!! I am guilty (before some of you choose to berate).

I have some how managed to round off the hex recess on one of the screws that hold the rocker cover on my 150. Current situation being neither a metric nor a SAE allen key is able to get a grip. And no, the keys themselves are fine as they work perfect on the other screw.

Any ideas on how to open the screw that has the knackered hex head ?

Edited By Manish Chandrayan on 31/01/2019 10:12:27

Paul james 831/01/2019 10:16:34
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174 forum posts
48 photos
Posted by Manish Chandrayan on 31/01/2019 10:11:52:

Call for help!

Confession!! I am guilty (before some of you choose to berate).

I have some how managed to round off the hex recess on one of the screws that hold the rocker cover on my 150. Current situation being neither a metric nor a SAE allen key is able to get a grip. And no, the keys themselves are fine as they work perfect on the other screw.

Any ideas on how to open the screw that has the knackered hex head ?

Edited By Manish Chandrayan on 31/01/2019 10:12:27

If you can find a pin punch that is the right size to fit the head of the screw, give it a sharp tap with a light hammer and it will very often allow you to unscrew a screw that has this problem. If it is still difficult you might try an "easy out". I've got a good selection of those if you get stuck.

Martin Harris31/01/2019 10:22:17
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9409 forum posts
255 photos

There is a product called Screwgrab which has worked very well for me in the past but the cheapest way would be to drill the head off - use a drill fractionally larger than the thread major diameter and go very carefully. There should be plenty of thread exposed to remove the remains with pliers or a Mini Mole Grip once the rocker cover is off.

If you have one, a left hand drill bit (yes, I'm serious, they do exist) using the drill in reverse can be useful - the vibration and heat often loosens the fastener while you're drilling the head off...

Edited By Martin Harris on 31/01/2019 10:32:22

Bob Cotsford31/01/2019 10:22:31
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8637 forum posts
483 photos

Find a torx or similar star drive bit that is just a smidgeon too big to fit in the rounded out hole. GENTLY tap it into the screwhead using the smallest hammer you can find. If you are lucky the bit will bite enough to get the screw out. If it feels likely to spin try heating the screwhead using a soldering iron then try again.

Denis Watkins31/01/2019 10:35:49
4536 forum posts
123 photos

Last resort Manish, slot the head with a dremel

Very carefully, with motor secured

Mask off the head area with a shim of Coke Can, hole punched, with a paper or leather punch

Secure the shim

Cut a slot for a flat head screwdriver

ken anderson.31/01/2019 10:40:38
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8712 forum posts
808 photos

happened to me with my OS 91 4/st....the rocker cover.i took one allen bolt out and the other wouldn't have it...I drilled the head off and this left the stump in...I lifted off the cover and got a hold of the stump with some pliers …. no damage or mess ..

ken anderson...ne..1...stump dept....

Former Member31/01/2019 10:52:33
724 forum posts

[This posting has been removed]

Manish Chandrayan31/01/2019 10:54:58
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645 forum posts
73 photos

Thank you all, Will try the Torx first and heat the area some before applying the Torx driver. If that does not will see if I can use the pin punch and shock it (gently) into submission.

That Screwgrab! Might as well order one to try out

Tim Flyer31/01/2019 10:56:05
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1296 forum posts
236 photos

If the bolt was tightened too much into the rocker cover, spraying a bit of “plus gas” or other super fine release agent and leaving it over night before trying to undo the bolt might also help. Bolts do bind a bit to aluminium if over tightened.

Edited By Tim Flyer on 31/01/2019 10:56:28

Jon - Laser Engines31/01/2019 13:39:46
5560 forum posts
270 photos

You can also dive the a screw a few whacks with a small hammer. This will flatten the head off a bit and close up the hole. Then take an allen key or driver with a nice sharp end on it and tap that down the middle. It works like a broach and can re form the socket.

If that fails then just drill it out with a 2.5mm drill

Manish Chandrayan11/02/2019 12:49:00
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645 forum posts
73 photos

Update on the stubborn screw. First method employed was to use a Torx bit. That did not work out. Next was to whack the head with small hammer in the hope that deformed head will grab the key. Head did deform a bit, the key did grab but as soon as force was applied it slipped. All these were tried with the head heated all around with a heat gun.

Next up was to carefully cut a notch in the head and use a flat screwdriver. The entire engine was covered with masking tape, including area around the stubborn screw. And using an almost worn out cut off disc on Dremel carefully cut a slot on the screw head. The worn out disc (very small dia) ensured that there was no damage to adjacent material. With the slot cut, attempt was made to dislodge the screw using heat and a flat screw driver. But it was seen that the head was deforming and the screw had not yet budged.

Finally decided to drill out the screw. Drilling was commenced using a 2.4 mm bit and some oil to keep things cool. While drilling it was noticed that the slot had moved a bit (clockwise). That was an indication that the bond was broken. Drilling was stopped, the area cleaned (used a magnet to ensure all steel filings etc are picked up) and used the flat screw driver as a chisel at an angle. Few thwacks with a rubber mallet and the screw moved. Process was continued carefully to move the head about a full rotation. Post this a flat screwdriver did the job.

Now that it is off, what size is the replacement screw please?

Jon - Laser Engines11/02/2019 12:57:22
5560 forum posts
270 photos
Posted by Manish Chandrayan on 11/02/2019 12:49:00:

Now that it is off, what size is the replacement screw please?

Was it a rocker cover screw? If so its M3x25

Manish Chandrayan11/02/2019 13:26:44
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645 forum posts
73 photos

Yes Jon, it was indeed the rocker cover screw! 3mm should not be problem locally. On the good one, metric allen keys do not fit so I assumed them to be non metric

Jon - Laser Engines11/02/2019 13:33:46
5560 forum posts
270 photos

They are metric. 2.5mm key should be the one

Martin Harris11/02/2019 17:21:13
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9409 forum posts
255 photos

Could this be an early 150 and use Imperial fasteners, Jon? There is a 7/64" size which is not included in every "set" and would be approximately 2.8mm AF...

Edited By Martin Harris on 11/02/2019 17:38:19

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