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oldaz

247 bash plate

22 posts in this topic

The manual doesn't show a bash plate for the 247, so wondering if anyone ever made one for the Cota 247 and if so, any pictures?

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This small one was on mine when I got it - it protects the case covers but leaves the frame exposed as it is fitted above the frame. I have broken the frame on rocks so I got a guy to cut out a sheet of aluminium plate and I bent it into shape.  Problem engine sat lower without original and  when I measured it up for new one  I forgot to allow for the cases and so I ended up with both.  Sorry I don't have a recent shot with both.

bashplate.jpg

crankcase.jpg

schmick.jpg

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On 10/01/2018 at 5:01 PM, oldaz said:

The manual doesn't show a bash plate for the 247, so wondering if anyone ever made one for the Cota 247 and if so, any pictures?

Bloody good question Oldaz, I've been thinking about the same thing for a while for when I finally extract my finger and restore my '74 black frame 247(clutch lever under).

My thoughts were to weld some home made triangular metal brackets(around 3mm thick) up front either side of the downtube and something similar out back all hidden but flush with the mesh plate with 8 mm nuts welded to these metal brackets. Idea being to make any of these alterations hidden up behind the existing mesh floor of the Cota and then bolt up a 5 or 6mm alloy plate that any half decent fabricator should be able to form for me. The whole setup should only rob me of 5 or 6mm of ground clearance(thickness of alloy plate) which matters little to me as it's only going to be an occasional ride on sections suitable for a near 45 year old bike. 

It's all irrelevant now, but the late great Chris Leighfield did offer alloy bash plates back in the day, cannot find any close up pics that show how they were attached unfortunately.

 

Last Cota 247 6.jpg

Edited by fourex
forgot how old the bike is.

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Hi Fourex, I don't think you need to go so far as to weld bits in. My plan is to cut to size, then bend up the aluminium plate similar to what's in Keychange's last picture, except to make it a little longer so it goes to the cross-member at the rear of the existing perforated piece. I'll use 2 half clamps over the cross-member at the back and one each side at the front held by countersunk hex screws (sketch below) - simple but effective.

Thanks for posting the article - I already made the aluminium chain guard, didn't think I would need an extra rim lock (unless I get way more serious), Aluminium bash plate in progress and steering lock puts the inside fork tube at right angles to the head stock on full lock - if that makes sense.

MontBashPlate.jpg

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Thanks for the pictures Keychange, there's enough detail to allow me to make one. It will go under the frame like the one in the last picture.

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I had considered saddle type attachments like you have suggested but they really are a pain in the a*** when compared to some permanent type fixtures.

That photo attachment is of the last Cota 247 from an Australian magazine in 1979, Cota 247 C i believe.

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The 247c had tubular loops welded to the front area of the frame to protect the cases, no bash plate as such.

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My 247 came with a Renthal plate that bolted below the engine on top of the lower rails.  Let me see if I can post a pic with the phone, since Photobucket is holding all my old pics hostage.  Of course there is the super sano plate/frame mods on Wobbler's 247. 

 

post-1071-0-98037900-1408019214.jpg

 

 

post-1071-0-00804800-1408018887.jpg

Edited by brewtus
Wobblers cool 247 mods
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Thanks Brewtus, but the 247C obviously uses a different lower frame. The bash plate in your pictures takes the place of the lower frame rails in the earlier frames. Those lower rails and plate on my frame are badly scored from rock damage, so I'll fit a similar shaped plate under the frame rails.

Fourex says the saddle type clamps are a pain, but at the moment I don't envisage taking the plate off very often - if it turns out the plate has to come off regularly I'll no doubt do something to make it easy.

Thanks for all the input on this, now I know which way to go.

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14 hours ago, cleanorbust said:

The 247c had tubular loops welded to the front area of the frame to protect the cases, no bash plate as such.

The third model 348 (1978?) also has those tubular loops for case protection

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14 hours ago, oldaz said:

Thanks Brewtus, but the 247C obviously uses a different lower frame. The bash plate in your pictures takes the place of the lower frame rails in the earlier frames. Those lower rails and plate on my frame are badly scored from rock damage, so I'll fit a similar shaped plate under the frame rails.

I was under the impression that the frame had been modified for the plate.  I scabbed the pics to get a guide on the footpeg mod.  Wobbler doesn't seem to post anymore, and has not responded to my PM last October inquiring about the bike.  Heck, one of my teammates (heavily) modified a TY80 frame to accept a DT100 engine, and did a similar mod to the lower frame for his bashplate.  B)

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8 hours ago, brewtus said:

I was under the impression that the frame had been modified for the plate.  I scabbed the pics to get a guide on the footpeg mod.  Wobbler doesn't seem to post anymore, and has not responded to my PM last October inquiring about the bike.  Heck, one of my teammates (heavily) modified a TY80 frame to accept a DT100 engine, and did a similar mod to the lower frame for his bashplate.  B)

That's certainly possible, although I'm not sure why you would go to that much trouble on what many regard as a "weak" frame. Removing the bottom rails wouldn't do much to stop the head piece cracking so many of these end up with. I noticed some of the later bikes use a similar system, but the plate is mounted a lot more securely - don't know if they suffer the same frame cracking.

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5 hours ago, oldaz said:

That's certainly possible, although I'm not sure why you would go to that much trouble on what many regard as a "weak" frame. Removing the bottom rails wouldn't do much to stop the head piece cracking so many of these end up with. I noticed some of the later bikes use a similar system, but the plate is mounted a lot more securely - don't know if they suffer the same frame cracking.

There are two reasons why people remove the bottom rails and fit a structural bashplate on Montesas (and Bultacos).

One is that the original tubes become so badly damaged from impacts that fitting a structural bashplate is cheaper and easier than replicating the original design.

The other is the improvement in ground clearance without raising the C of G.

Montesa and Bultaco eventually moved to using the structural bashplate design in the late 1970s (Cota 349 and Sherpa T 198/199A). From what I've seen in old photos, it is a concept that appeared in about 1968 or 1969, initially on the Sammy Miller Highboy Bultaco frame.

I reckon if you did it to a Cota 247 or an early Bultaco, you would have to be very careful with the design to avoid reducing frame integrity, which is marginal already on those bikes.

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As threatened, pics of the Renthal plate -

 

IMG_7221.JPG

IMG_7222.JPG

 

The bottom rails on my 247 show lots of rock scarring as well (big shock).

 

IMG_7223.JPG

 

I'll most likely just run this period-correct plate on the bike, unless I really get jazzed up about modding it.  For now, footpeg mods and having the frame re-nickled are the starting points to reassembly. 

Edited by brewtus
Added text
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8 hours ago, brewtus said:

As threatened, pics of the Renthal plate -

 

IMG_7221.JPG

IMG_7222.JPG

 

The bottom rails on my 247 show lots of rock scarring as well (big shock).

 

IMG_7223.JPG

 

I'll most likely just run this period-correct plate on the bike, unless I really get jazzed up about modding it.  For now, footpeg mods and having the frame re-nickled are the starting points to reassembly. 

Bottom scarring on mine is as bad or worse, so while the engine is out I will form up the 5mm aluminium plate that's going underneath - I figure a loss of 5mm ground clearance isn't going to affect much for me. I've already panel beaten the bottom as good as I can get it even though there's still some bends and scarps that aren't supposed to be there.

I wasn't aware of any of these frames being "nickled" from the factory.

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