paxo Posted February 19, 2013 Report Share Posted February 19, 2013 Is it common practice i.e. ok to remove the frame tubes under the engine and replace them with a heavy bolted in alloy bash plate to provide better clearance etc ? I'm asking as I'm restoring a Bultaco 350t (159) and the tubes under the engine are quite dented and flattened. Cheers Paxo, Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 19, 2013 Report Share Posted February 19, 2013 Yes Quote Link to comment Share on other sites More sharing options...
mrb505 Posted February 20, 2013 Report Share Posted February 20, 2013 There is not much gain in ground clearance if any I've just done a 183 frame and the rear of the plate is the same height as before, at the front the plate is higher but I had to grind off,weld,drill and tap a new gearbox sump hole or the plug would have been lower than the plate, luckily I had the cases split at the time. I'm sure you could lift the engine, alter the swingarm pivot,exhaust etc etc and gain an inch but its a lot of work. I think with my 183 I should have belted the tubes back down bolted a ali bash plate over them and went riding. 1 Quote Link to comment Share on other sites More sharing options...
mrb505 Posted February 20, 2013 Report Share Posted February 20, 2013 Here is a before picture Quote Link to comment Share on other sites More sharing options...
mrb505 Posted February 20, 2013 Report Share Posted February 20, 2013 And a after photo, Red line is where I'll put a rubber pad Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 20, 2013 Report Share Posted February 20, 2013 Very nice job. I especially like the rubber slipper for the lower chain run Quote Link to comment Share on other sites More sharing options...
brt650 Posted February 20, 2013 Report Share Posted February 20, 2013 Gosh mrb505, I can't believe you have cut the bottom frame tubes off. Why can't people leave there bikes alone. Next thing you'll be fitting a flat slide carb. Cheers brt650 Quote Link to comment Share on other sites More sharing options...
2stroke4stroke Posted February 20, 2013 Report Share Posted February 20, 2013 Surely cutting the tubes out was a fairly common period mod? Quote Link to comment Share on other sites More sharing options...
woody Posted February 20, 2013 Report Share Posted February 20, 2013 Not really, you never saw that many done. They do look much neater with the bashplate though. Quote Link to comment Share on other sites More sharing options...
mrb505 Posted February 20, 2013 Report Share Posted February 20, 2013 Yes it is or was brt650 is just taking the p*** He's just trying to cover up his creation the Hontaco or commonly known as the Frankentaco Quote Link to comment Share on other sites More sharing options...
paxo Posted February 20, 2013 Author Report Share Posted February 20, 2013 Thanks for that folks......I think I will leave them as they are for the time being, at least I know I've got the option of removing them once I've flattened them a bit more :-) Are there kits available for the brackets/bash plate or is it a DIY only option ? Cheers Quote Link to comment Share on other sites More sharing options...
sherpa325 Posted February 21, 2013 Report Share Posted February 21, 2013 Hi , this is a DIY project and I have not seen any kits for the conversion. I have done about a dozen of these over the years. I started doing them in 1974 on the model 125, the previous model 92 etc had mild steel frames with thicker walled tube and were less prone to flattening, the 125 on the other hand was chrome moly and thin walled and flattened easily. The tubes will eventually hit the engine and force both the magneto and primary cases upwards causing them both to leak, which is a real pain. All the ones I did in the 70's were to fix that problem and to gain some ground clearance. To gain ground clearance you need to remove the rear round tube that runs under the back of the frame and replace it with a flat piece that is mounted higher [like the Sammy Miller frames]. The problem doing it this way is that you have to raise the pegs 15-20mm otherwise they will be lower than the bashplate. If you remove the lower tube remember to have the swinging arm installed when welding the new piece in, and to have the motor installed when making your bashplate as the frames tend to spring slightly when cut, also most install rubber between the plate and the engine - when making the rubber cut it the same width as the engine without the cases on - so if the basplate gets pushed up on the outside it will not push the cases up causing them to leak Cheers Greg Quote Link to comment Share on other sites More sharing options...
sherpa325 Posted February 21, 2013 Report Share Posted February 21, 2013 (edited) These are the best photos I have from back in the day. You can buy the bashplate to suit the 199 series through 'Inmotion UK', also maybe worth putting late model footpeg mounts on as well, as they really make the bike feel more stable, also available from Inmotion Cheers Greg Edited February 21, 2013 by sherpa325 Quote Link to comment Share on other sites More sharing options...
brt650 Posted February 21, 2013 Report Share Posted February 21, 2013 Did you get that bike in 1879? It's just I have photo's of my great grand parents and the photo looks the same. The bottom photo that is. It's just that I thought i could see Ned Kelly in the back ground. Cheers Brian I still can't believe you people have to modify stuff. Quote Link to comment Share on other sites More sharing options...
feetupfun Posted February 21, 2013 Report Share Posted February 21, 2013 I'd like to use Greg's top picture to show people what normal 1970s handlebars look like when they tell me that mine look like ape hangers Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.