1977 400F2 first restore project

[McCabe-Thiele (Ted)]

Thanks for the advice guys I'll look for a replacement. No rush as I'm now taking the engine apart to find out what else might be knackered. Got the engine out today, front left lower engine mounting bolt was sheared, it was "glued" in. The remaining bolt is I suspect going to be difficult to fish out. Feels like the work really starts here.

https://photos.app.goo.gl/bZUXdfnkSrRnsyKRA

That's bad luck to find an engine mounting bolt glued in  - I am very lucky that mine are all OK. I have been told here not to mix up the left & right front bolts as they are different in length - putting one in on the wrong side can puncture the casing so beware

[Laverda Dave]

There should be a captive type nut set into the engine casting on the lower front left and right. It will likely be siezed into the casting due to road salt corrosion. The bolt doesn't screw into the engine casting as such, it screws into the thin captive steel nut. If the bolt has snapped off you will have to drill the remainder out to free the captive nut. Be very careful when doing this as the engine oil gallery is the other side of the captive nut and the casting is thin. A lot of people including me in the 80’s refitted the bolt after removing aftermarket crash bars and not realising the bolt is longer than standard. The result, a punctured oil gallery and a scrap engine!

[smoothoperator]

Thanks Ted and Dave. I've been researching this and see it's a common problem. The bolt on the other side came out fine, I can't recall if the nut came out even though it was only yesterday. The offending bolt has sheared where the threads start. I was thinking of grinding out the nut with a dremel or drilling out the remaining bolt first. I think it might be tough going drilling this out however it's not like there are any threads to preserve as the nut will have to come out whatever. I'm worried that if I grind the nut out first then the remaining bolt will be difficult to drill as it might spin and it's not like you can get behind it to push it out. After a bit of a Christmas rest I'll give it a clean and re-assess. Also it might be easier to tackle once I've split the crank cases. I also think I might need to invest in some good drill bits. Maybe it will come out easy after a few whiskies.

[smoothoperator]

Drilled out the engine mounting bolt which was mostly something like body filler until well down to just above the nut. Drilling the actual bolt wasn't too bad as I used a new 11 mm HSS Cobalt bit. 10 mm bit wasn't long enough to give clearance between the drill chuck and the crankcase. I drilled away a good part of the nut also. Anyhow it was all going fine until the bolt was relieved when the end of the nut was reached. I could see cracks open up slowly in front of my eyes, almost in slow motion. Bummer. The end of the bolt was pressed up hard against the crankcase which must have been causing stress. The pictures tell it better than words. First image shows most of the bolt removed before any cracks. 3rd image shows the indentation in the crankcase made by the end of the bolt. Anyhow this leaves me needing replacement crankcases or possibly a welding job? I haven't split them yet as I'm waiting on a clutch nut tool at the moment. Can't wait to see what's inside!

https://photos.app.goo.gl/sHrq2Xko7tHU2FuE7

[Nurse Julie]

Oh poo ☹️☹️☹️

[McCabe-Thiele (Ted)]

Drilled out the engine mounting bolt which was mostly something like body filler until well down to just above the nut. Drilling the actual bolt wasn't too bad as I used a new 11 mm HSS Cobalt bit. 10 mm bit wasn't long enough to give clearance between the drill chuck and the crankcase. I drilled away a good part of the nut also. Anyhow it was all going fine until the bolt was relieved when the end of the nut was reached. I could see cracks open up slowly in front of my eyes, almost in slow motion. Bummer. The end of the bolt was pressed up hard against the crankcase which must have been causing stress. The pictures tell it better than words. First image shows most of the bolt removed before any cracks. 3rd image shows the indentation in the crankcase made by the end of the bolt. Anyhow this leaves me needing replacement crankcases or possibly a welding job? I haven't split them yet as I'm waiting on a clutch nut tool at the moment. Can't wait to see what's inside!

https://photos.app.goo.gl/sHrq2Xko7tHU2FuE7

That's horrific - hope a good alloy welder can sort it - it looks doable.
Are you sure you made the cracks & they weren't done by the person who broke the bolt ?

[smoothoperator]

I think the crankcase was doomed from the point someone sheared the bolt, this must have happened when it bottomed out. I have managed to track down the previous owner and he has been kind enough to give me a pretty full history, certainly at some point the bike had crash bars fitted, then removed...I noticed the cracks appear whilst the dirt was still on the casing, so in the first image, the cracks weren't there. I should have taken another image to show how they looked before I cleaned off the dirt to show how they revealed themselves. I'm looking at replacements rather than welding, depending on what comes up. However open to all options at the moment.

[Rozabikes Tim]

I think the crankcase was doomed from the point someone sheared the bolt, this must have happened when it bottomed out. I have managed to track down the previous owner and he has been kind enough to give me a pretty full history, certainly at some point the bike had crash bars fitted, then removed...I noticed the cracks appear whilst the dirt was still on the casing, so in the first image, the cracks weren't there. I should have taken another image to show how they looked before I cleaned off the dirt to show how they revealed themselves. I'm looking at replacements rather than welding, depending on what comes up. However open to all options at the moment.

If you are going down the replacement route I do have a set of cases stashed away under the bench. No crank. Think they have had the usual camchain bolt issue from memory... PM me if of interest. I wont want silly money.

[McCabe-Thiele (Ted)]

I think the crankcase was doomed from the point someone sheared the bolt, this must have happened when it bottomed out. I have managed to track down the previous owner and he has been kind enough to give me a pretty full history, certainly at some point the bike had crash bars fitted, then removed...I noticed the cracks appear whilst the dirt was still on the casing, so in the first image, the cracks weren't there. I should have taken another image to show how they looked before I cleaned off the dirt to show how they revealed themselves. I'm looking at replacements rather than welding, depending on what comes up. However open to all options at the moment.

If you are going down the replacement route I do have a set of cases stashed away under the bench. No crank. Think they have had the usual camchain bolt issue from memory... PM me if of interest. I wont want silly money.

This sounds like a life saver or should I say engine saver.

[Skoti]

Wouldn't cost you much to try and repair it with metallic repair paste such as JB weld.

Groove the cracks out with a dremmel, clean out with thinners and then apply the metal paste.

If it's not successful then you've not lost much....


Good luck

Skoti

[Bryanj]

If you are stripping the engine anyway why not have it welded internaly

[taysidedragon]

If you can't fix it I've got a spare set of cases with matching crankshaft.
I need to make some room in the garage!

[Laverda Dave]

Bummer . That's exactly what happened to my first 400/4. I bought it with crash bars fitted, took them off because they were rusty and replaced the bolts. When I stared the bike I quickly had a pool of oil under the engine from the crack. I bought a replacement engine for £50 from Frank but that was in 1979!

[smoothoperator]

Thanks so much for the help guys, Tim has me sorted with a matching crank and cases which is fantastic.

[sprinta]

Drilled out the engine mounting bolt which was mostly something like body filler until well down to just above the nut. Drilling the actual bolt wasn't too bad as I used a new 11 mm HSS Cobalt bit. 10 mm bit wasn't long enough to give clearance between the drill chuck and the crankcase. I drilled away a good part of the nut also. Anyhow it was all going fine until the bolt was relieved when the end of the nut was reached. I could see cracks open up slowly in front of my eyes, almost in slow motion. Bummer. The end of the bolt was pressed up hard against the crankcase which must have been causing stress. The pictures tell it better than words. First image shows most of the bolt removed before any cracks. 3rd image shows the indentation in the crankcase made by the end of the bolt. Anyhow this leaves me needing replacement crankcases or possibly a welding job? I haven't split them yet as I'm waiting on a clutch nut tool at the moment. Can't wait to see what's inside!

https://photos.app.goo.gl/sHrq2Xko7tHU2FuE7

Are you sure they are cracks and not just casting flaws as they all seem to have slightly raised ridges? Pity you did not clean the cases in the area first as if they were they present before drilling you would have seen them?