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The TTR250 FAQ web pages -> TTR250 -> Repair and maintenance "stickies" -> Bottom end engine rebuild
Post Info TOPIC: Bottom end engine rebuild
TTRfan


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Date:
Bottom end engine rebuild
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With the current interest in big bore kits that require the crankcases to be stripped for boring to take oversize sleeves I thought this would be a good time to create a pictorial guide to include a full strip down and rebuild.

I am hopeful that the 350cc big bore kit will prove successful and, if it is, the engine I used for the photos will be rebuilt as a 350cc for my brother Trev. I have another engine ready to use for my own kit wink

So, the guide only takes you as far as two empty cases. That said, they still have their bearings fitted and they all seem quite good, all run smoothly, so I am loathe to knock them out at this stage as new bearings would add a lot to the cost of the rebuild and, to be honest, it is rare for a bearing in the TTR crankcases to go bad. That said, I am tempted to replace the main bearings although the TTR ones are big enough to use in a tractor engine so that is probably unnecessary...... Decisions, decisions disbelief

See here

As usual feedback appreciated!

Brian



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mossproof


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Posts: 1433
Date:
Bottom end engine rebuild - part 1 - taking it all apart!
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Great work Brian. Photo's so much better than the diagrams in the manual.
Just awaiting part 2 - putting my 350 test mule motor back together and I'm not sure I've got the gearbox right - only seem to have 2 gears + neutral at the moment but I've run out of patience for the day and will attack it again tomorrow and see whether I've got to crack it open again...
Appreciate the huge effort you go to on these how-to threads, thank you.
Simon.

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robs


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Date:
Bottom end engine rebuild
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Man I love this site! The how to guides and knowledge sharing here is amazing (thanks everyone). I'm also wildly looking forward to reading about more of the 350 big bore stuff that is going on.

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TTRfan


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I have taken advantage of Paul Olesen's recent article on removing and replacing crankcase bearings to update my guide - see the updated version here

I would really appreciate anyone who has done a bottom end rebuild having a look through and let me know of any errors or omissions plus, of course, anything that can be added to make the guidance more helpful biggrinbiggrin

Brian



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