Rotax lifters worn

[facthunter]

Ivan Tighe Cams. Nev

 

 

[Lyndon]

That's it correct

 

 

[facthunter]

Speedway background. They should know what they are doing. Nev

 

 

[JimG]

Thanks Lyndon, do you know if the had the camshaft re-nitrided ?

 

cheers

 

JimG

 

 

[facthunter]

If they are reground they have to be re nitrided. If you open up their website they go into it. Nev

 

 

[Lyndon]

I could not find any info on splitting the cases. Maybe you all know but case bolts studs etc is 25 nm. This seems to be secret. Cam timing is a breeze. Replace to two orings. Use three bond with a one not a two. Five dowels . Apart from that there is nothing else in the cases. Easiest thing you will ever do. Nitraded cam and hardened lifters. I don't think that works but I'm no expert. It was worn at 1740 hrs. So I'm guessing at 1000 hrs it would have been comprised. If Rotax got rid of the 1920s flat tappet cam I would not not have to do this.

 

Lyndon

 

 

[Lyndon]

I priced up genuine orings. Gee it would run at about 700 bucks. For one tenth I bought off the shelf jobbies. Almost 29 plus gst for a rocker cover o ring. Plus over 4 for the center bolt. There are no words to describe it.

 

Lyndon

 

 

[Downunder]

How about "Thieving B*stards"!

 

 

[Lyndon]

I think that is being polite. Why would anyone like Rotax buy an off the shelf oring for a dollar then sell it through their network at twenty dollars. Makes no sense. Just mark it up three hundred percent and sell it for three dollars. Then everyone is happy. The rings were outrageous but I didn't have much choice there.

 

 

[Lyndon]

Does anyone have a crankcase Dowell. I have lost one

 

Lyndon Wright

 

 

[Lyndon]

Update. I've been waiting for a crankcase Dowell. Anyway pulled the lifters apart and cleaned them. Absolutely perfect at 1740 hrs

 

 

 

[Lyndon]

Update. The main thru bolts are a torque to yield arrangement. Without checking 15 nm plus 180. I'm doing some research but in my industry torque to yield are one off use. I will get back to you. Ps I have to tool to remove the rear the engine if any one needs that. Also I'm about to do the gearbox service and preload. If anyone has thought of saving 600 bucks and doing it themselves.

 

Lyndon

 

 

[maulonir]

Preload for the friction torque or for the slipper clutch?

 

Rob

 

 

[Lyndon]

Is .039 tho or a mil unloaded. Depress then fit halves. Easy as

 

 

[Lyndon]

Shim as required

 

 

[Lyndon]

Ps always new halves

 

 

[Lyndon]

Before you disassemble. Scribe your splines with a 1 mm feeler. After cleaning and inspection, assembly with it all settled. Adjust your shims to the 1 mm Scribe. Perfect. Depress a bit over 1 mm install your new halves and it's done .

 

 

[Lyndon]

I have done my gearbox. All was good. A bit of fiddling with the three diaphragms to line them up. seems odd the middle one can't be centered and relies on the others to keep it in place. There is some offset wear because of this. But it clearly works as it's done 1740 hrs and is in very good Nick . Can't believe the new halves were 70 dollars. I still can't assemble my engine as I have issues with cam end play. This is taking a long time to sort but hopefully by the end of the week it can be sorted.

 

 

 

 

[dan3111]

I think some of the coolant pipe threads leak worse on some of the different coolants on the market . I have seen one 912 leak on all heads pipe bends witch was using Evans all its life .

 

 

[Lyndon]

I've been a bit quiet lately. You won't believe but 17 weeks to get my cam done. I've stopped my build till I sort the engine. I had allowed about five or six weeks all up. Apparently there is unemployed people in Australia. Well when I try to get something done it takes for ever and then it's not done correctly. It's been a comedy of errors. Anyway it's now sorted. New orings in the cases. New circlip and seal. Timing Mark aligned and gear in place before cam. All five dowels in place.

 

 

 

[Lyndon]

Seal and cirlclip

 

 

 

[Lyndon]

Timing Mark and gear

 

 

 

[Lyndon]

I've painted the cases in a nice Matt black. Came up really nice

 

 

 

[Lyndon]

Making some progress. I intend to prime the oil pump and fill the engine prior to fitting the top end. That way I won't wipe off all my cam lube. Then I should be able to fire it up with minimal engine turning.

 

Lyndon

 

 

 

[Downunder]

Don't forget the oil purge procedure before start up...... a "must do" for your engine.

 

http://docusearch.flyrotax.com/files/pdf/d05199.pdf