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Another Pro Crankcase Story


aussiechris
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Hey MagicMat, don't panic, I still think the 2011 and 2012 Ragas are the best bikes out there and I'll be keeping mine. From what I've read and been told: all the engine mounts must be kept fully tight including the swingarm pivot and the bash plate bolts, obviously the bash plate needs to be kept in the correct shape, and replace the bash plate rubbers regularly.

In my case the engine mounts where all tight except the swingarm pivot bolt (it was just finger tight). This is a problem because the hole in the frame on the right side is much larger than the bolt so relies on the bolt being super tight (I think the spec is 51 ft/lb) to securely locate every thing. My main fault was not replacing the rubbers in three years.

Thanks for the input Shyted. Turns out the Sydney dealer (I'm downunder) has all the bits I need and they should be here in a couple of days. It's taken me the past week to dismantle everything so I know what I need. While it's down, I'm throwing a set of rings in it (it's done a lot of hours) and I'm also springing a bit extra for a set of trick Xiu Engineering low friction main bearings. So with that and decoking the exhaust it should be better than new. I'll keep you posted but I imagine it will take me another two weeks to get it back together.

Chris

Brisbane Australia.

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Just an update - I’ve got my bike all back together and it’s running great. I can’t wait to get out for a practice on Saturday.

No major problems – these are a nice motor to work on. The cases I got are actually for a 2012 Raga which means they allow for a broken shift shaft to be replaced from the clutch side which is a nice feature. As mentioned earlier, I replaced the main bearings with the Xiu Engineering ones and also installed a new set of rings. My engine mounts and frame all line up perfectly. But I did use a press to put the right curve back into the bash plate. It’s obviously (now) important to ensure there is 8 to 10mm of space between the bash plate and the rear engine mount and that the rear rubber is in good order.

I can post some rebuild photos if anyone is interested.

I’d like to acknowledge the help and advice provided by the crew at the Sydney Gas Gas dealer (don’t want to break any rules by naming them but they are “Hell" of a good "Team"). Also, the videos by Jim Snell in the USA are invaluable.

Thanks for all your comments,

Chris.

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Hi MagicMat,

I'm sure your bike will be fine. I've given mine a hammering on big logs and rocks and, while I'm generally pretty diligent with maintenance, I had neglected to check and replace the bash plate rubbers. Metal to metal contact is not good.

Anyway, these photos might help you to check what shape yours is in.

This shows the original why my case broke - not enough clearance and the rubber broken in two...

post-16811-0-60946500-1423571787_thumb.jpg

This shows how it looks after repairing the cases and re-shaping the bashplate and installing new rubbers...

post-16811-0-11139000-1423571806_thumb.jpg

A bit wider shot of the bash plate clearance...

post-16811-0-16626900-1423571815_thumb.jpg

And the other side...

post-16811-0-79604700-1423571828_thumb.jpg

For reference, this is from the original factory pics showing the correct shape of the bashplate (mine was flat on the bottom...

post-16811-0-49780100-1423571838_thumb.jpg

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And just for your interest, here are some pics of my little repair job...

The sad sight of my beloved Gas Gas pulled apart...
post-16811-0-96577100-1423572314_thumb.jpg

The gearbox in pieces...

post-16811-0-11432200-1423572325_thumb.jpg

Crankshaft...

post-16811-0-08421200-1423572334_thumb.jpg

Crank and gears installed in the new right case...

post-16811-0-11027100-1423572346_thumb.jpg

New bearings installed in the new left case...

post-16811-0-44624700-1423572360_thumb.jpg

Cases put together (clutch on to check the gears are working)...

post-16811-0-58153100-1423572371_thumb.jpg

Right side with barrel installed...

post-16811-0-23459400-1423572384_thumb.jpg

Left side...

post-16811-0-65590300-1423572393_thumb.jpg

Measuring squish (head) clearance using a piece of soft solder...

post-16811-0-89062000-1423572408_thumb.jpg

Engine back in the frame...

post-16811-0-51187500-1423572419_thumb.jpg

Look, no more cracks!...

post-16811-0-97394300-1423572430_thumb.jpg

Finally, ready to ride...

post-16811-0-70378200-1423572441_thumb.jpg

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I have broken the frame on older ones in this area. The issue occurs when the skid pan stresses the frame too much. If you take your skid pan off and it is super compressed then you are playing with borrowed time. Re-arch your skid pan and make sure that its bolts are tight. If your skid pan bolts are loose then the only thing holding the two frame members together are the cases. The skid pan and the cases should work together here.

--Biff

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I would have advised to helicoil the cylinder studs since you had everything apart !

hope they hold up for you(mine pulled the threads out since mag is soft so was advised to helicoil all four)

also run the float drain on rhe carb downwards so it can drain when needed otherwise it will die at steep angles!

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Hi Nicos, thanks for the tip about helicoiling the barrel studs. I had never heard of any pulling out of the cases. So that's something else I need to keep an eye on. I machined those studs and dowels myself from stainless steel because I hate how the original zinc plated ones go rusty. Same goes for all the screws and engine mount bolts. Any bolt you want to continually check for tightness ends up going rusty and then bike looks old before it's time. And I like shiny things!

I totally agree with you about the fuel overflow hose on the Keihin carb. RIght from day one I wondered what was the point of running it uphill but I thought I'd try it in the standard position and found that the bike runs perfectly at any angle. We've got some very steep stuff where we practice including the mega hill climb "Behemoth" and the bike runs spot on going up or down it. It also starts first kick hot or cold. So after three years I just ended up leaving that way. But I know plenty of others on this forum have found otherwise like your good self.

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I was chasing a lean condition on my bike for ages when it was only a couple of weeks old and thats when I discovered the front right stud was loose in the cases causing an air leak!

Nick at trials uk told me it was common on the ragas with the mag cases and advised me to helicoil all four!

regarding the carb bowl vent,the way it is routed from the factory is straight down behind the shifter and onto the skid plate.

I also re routed it with the rest of the carb vents to keep the area under the engine cleaner but it would bog and run rough if stopped at an angle especially pointing down for a while so put it back the way it was!

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How did them special main bearings fit?, were there any problems? Did they deliver quickly?

I'm thinking about getting some as I have to do my mains anyway and they work out £22 cheaper than the standard ones from Gas Gas, so even with the shipping they might still work out good value and be a good upgrade.

I wonder how much the electric waterpump kit is? I'm quite tempted as the 300's run too hot for my liking.

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Hi Nicos, I beg to differ on the factory routing of the carb overflow hose. The photo below is of a brand new bike and you'll see how the hose is routed upwards. There's even a factory plastic clip that holds that hose to the transmission breather. I checked an old copy of a prominent trials publication at the time (issue 28 August 2011) and the test article shows the same routing. Having said that, I do agree with you that it probably should be re-routed to allow the fuel to escape and many, if not most, people do just that - but mine works fine like it is. Unlike the Del-orto, the Keihin PWK28 has only one bowl vent hose (in addition to the overflow) on the off side and it is about 40mm long pointing down.

post-16811-0-23873900-1423737241_thumb.jpg

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Hi Steve,

No problems fitting the Xiu main bearings. My dealer had them in stock in Australia. They appear to be made to the same fit as the originals. Best to heat the cases to 120°C and freeze the bearings and they will drop straight in with just a stiff push to get the external o-ring to go into the case. The bearings come with internal and external o-rings but I note the internal one is just black rather than the orange viton o-ring that the genuine ones have. Also, there is no arrow marking (like the genuine ones) on the edge of the bearing to align the oil drain hole so you need to mark it yourself with a felt tip pen.

To remove the right side main bearing from the crank will require a bearing spreader that can lock into the external o-ring groove and a puller or press to finish the job. Installing is no problem, again heat the bearing to 100°C and freeze the crank and it drops straight on. Again a further push is required the get the internal o-ring onto the shaft.

You’re getting a good deal if the Xiu bearings are cheaper than the genuine ones. I had to pay AU$72.00 each (compared to $52.00 for genuine).

I’ve only ridden the bike briefly (can't wait till the weekend) and can’t say I notice any difference but on the bench the Xiu bearings are definitely easier to turn than the originals. And I can’t comment on their longevity.

Chris.

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Hi, Thanks for the info, The XIU bearings are 35 euros each (about £25.92). The dealers in the U.K want £37.42 for the genuine ones.

I figured they are worth a try due to the price and that the genuine ones don't last 5 mins anyway.

I didn't want to find out they were slightly tighter than the genuine ones as I have Magnesium cases and wouldn't want to tempt fate.

I've got an adapted puller that I made for doing the pro mains, works really well on the crank, and a large press.

Thanks Chris, I'm gonna email them to get some shipping info and ask about the electric waterpump too.

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