Author Topic: Indian 741 from England, engine rebuild.  (Read 10138 times)

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Offline desperate

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Indian 741 from England, engine rebuild.
« on: February 25, 2011, 09:56:21 AM »
It's been a while since I posted on here, last October in fact, which was when I decided to pull the engine out of the Indian. I've owned it over 20 years and never really done much to it apart from a top-end job with Royal Enfield pistons and huge valves. It ran OK but I could hear a rumble from the bottom end on tickover. Stay tuned for a catalogue of disasters & how to fix them with no money. Some people would build thier engine first, then build the bike, but I needed the bike done to give me the inspiration to tackle the engine. I've put a picture of it below to remind you what it looks like, I'm hoping to get to Bonneville in 2012, so starting to build it in 2010 turned out to be a good move.

The first thing I found was a large crack in the driveside bearing housing, right round a left hand thread!
« Last Edit: February 25, 2011, 09:58:24 AM by desperate »
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Offline desperate

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Re: Indian 741 from England, engine rebuild.
« Reply #1 on: February 25, 2011, 10:14:09 AM »
A repair section is available, but I couldn't afford it. Everyone said it was impossible to fix it, but I laid in bed thinking about it one night and the solution came to me, weld it and sleeve it, but the crack was right round the left hand thread, would welding destroy it? The solution was pretty simple. I vee'd out the crack down to the thread, screwed the big nut in fully, and put a clamp around it (the crack had opened up). My mate ally-welded it, and while it was still hot, I unscrewed the nut. I had my doubts if it would unscrew, but it did, and a big bonus, it had protected the thread just as I'd hoped.
The next job was to make a mandrel that would be a good fit through the main bearing. With this bolted up I could hold the casing in my three jaw chuck, and it would run true. After sawing a 2" section off the shelf behind my lathe (so I could get the swing) I could machine 2mm off the damaged section where it had been welded. I had already machined a 2mm thick ring from some old tube, and it was a hard press-fit over the freshly machined bearing housing. Once I'd pressed it on I finish-machined the ring to size.
The reasoning behind this repair is that aluminium expands more than steel when it gets hot, so the hotter the engine gets, the tighter the repair gets. Total cost was zero, so that made me grin.
Next job, the crank, oh dear!
« Last Edit: February 25, 2011, 10:18:30 AM by desperate »
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Offline Beairsto Racing

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Re: Indian 741 from England, engine rebuild.
« Reply #2 on: February 25, 2011, 11:28:02 AM »
Very cool Indian racer!!  :cheers:
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Offline 38flattie

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Re: Indian 741 from England, engine rebuild.
« Reply #3 on: February 25, 2011, 11:31:47 AM »
Sweet!

Very nice repair,  great thinking! :cheers:
With sufficient thrust, pigs fly just fine. However, this is not necessarily a good idea. It is hard to be sure where they are going to land, and it could be dangerous sitting under them as they fly overhead. -- RFC 1925

You can't make a race horse out of a pig. But if you work hard enough at it you can make a mighty fast pig. - Bob Akin

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Offline desperate

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Re: Indian 741 from England, engine rebuild.
« Reply #4 on: February 27, 2011, 07:07:11 AM »
Splitting the crankcases revealed a can of worms. One main bearing thrust washer had disintegrated, allowing the crank to run against the timing side main bearing, scoring the flywheel & rubbing away the end of the main bearing outer. Amazingly all the bearings (drive & timing sides) were perfect, and the casings were undamaged, all the wear being limited to the timing side flywheel & main bearing, so it wasn't too bad......until I split the flywheels. There are four caged roller bearings in the big end, or at least there are in most Indians. Mine had three, plus a few hexagonal rollers and no sign of the fourth cage. Once again, amazingly, there was virtually no damage to the rods apart from a little scuffing, and there was superficial damage to one flywheel. The big end pin, however, was kaput.
I soon found the cause of all this, the oil feed through the big end pin was blocked solid with carbon deposits.
Now, I'm a great believer in fixing things rather than replacing, mainly because I have little money, so it's time for some serious hours on the lathe to repair the flywheels. Spinning a flywheel in a lathe that's not bolted to the floor is interesting, the bob-weights make it rock. The centre of the wheel was turned down until all the damage had disappeared, then an insert was made. This was screwed to the flywheel with 4 tiny 3mm screws. Holes were drilled through the insert into the flywheel for two 3/32" pins, which stop the shims rotating. The two countersinks you see are to aid removing the shims when setting up end float.
The repair was so successful on the timing side flywheel that whilst all the machines were set up, I did the other side too. The rods were posted to Moen at Indian Parts Europe to be checked out. The inside of the flywheel where the big end had scuffed it didn't need machining, but the shim pins were damaged, so they were replaced.
Blimey, I just made it sound real easy. In fact, that took me 4 attempts and nearly a week to do!
On a different subject, can anyone tell me how to post full size pictures on here?
« Last Edit: February 27, 2011, 07:12:49 AM by desperate »
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Offline thefrenchowl

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Re: Indian 741 from England, engine rebuild.
« Reply #5 on: February 27, 2011, 07:27:57 AM »
Hi, Desparate,

I'm sure you'll iron out all these niggles, it just takes time and as you say, little money outlay...

I've noticed this site is a bit weird about full size photos.

I did notice, if you right click on photo and check "properties", it comes up with a sort of reducing pixel factor similar to what's displayed on your earlier ones: 47.87 KB, 640x427

You can adjust it yourself to make your photo bigger or smaller...

In general, anything smaller than 100kbits should come up unaltered...

Keep on the good work,

Patrick
Flat Head Forever

...What exactly are we trying to do here?...

Offline Unkl Ian

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Re: Indian 741 from England, engine rebuild.
« Reply #6 on: March 09, 2011, 11:13:14 PM »
Should be able to host pics on Photobucket etc, and hot link to them full size.

Nice work on the repairs.
I guess the answer is "a Secret" .

Offline desperate

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Re: Indian 741 from England, engine rebuild.
« Reply #7 on: August 24, 2011, 10:02:14 AM »
I bet you thought I'd given up. The engine is now fully rebuilt & started first kick. What was originally going to be an "only fix what's broken" job turned into a "fix everything possible" mammoth rebuild. Rebuilding an old Indian over in the UK aint easy and I got badly messed about by people who reckoned they could rebuild my crank. During the months it was going from one rubbish company to the next I foolishly decided to polish all the aluminium, the old fashioned way, with assorted grades of wet & dry paper. I know it'll end up getting ruined, but it kept me busy until my parts came back.
I helicoiled all the casings to Metric....UNF & UNC are almost impossible to find over here, & ALL the bolts etc. are stainless where possible.
It fired first kick & ran nice, but there's still a lot to do before I bring it over in 2012.
Special thanks go to Moen at Indian Parts Europe, I'd have never got it finished if it were not for him, this was not an easy rebuild. I've written a build diary on my website, "Brit Chopper" so if you've got a few hours to spare it's waiting to be read.
Here's the link   http://www.britchopper.co.uk/forum/viewtopic.php?f=72&t=28166
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Offline Peter Jack

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Re: Indian 741 from England, engine rebuild.
« Reply #8 on: August 24, 2011, 10:46:38 AM »
When you double click on the thumbnails you've posted they come up to a decent size.
You've done some really nice work.

Pete

Offline peterdallan

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Re: Indian 741 from England, engine rebuild.
« Reply #9 on: August 24, 2011, 11:38:37 AM »
Nice digger style!!

Offline strathbran steve

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Re: Indian 741 from England, engine rebuild.
« Reply #10 on: September 11, 2011, 05:05:20 PM »
just read the build thread on BC Chris, great work  8-) cant wait to see how you get on on the salt.

I'd love to take my stroker scout to Bonneville some day!

best o luck, Steve
« Last Edit: September 11, 2011, 05:36:46 PM by strathbran steve »