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Pol Tarrés to Yamaha for 2021

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1 hour ago, Tepco said:

Really? If you can buy a kit to put a 2t in a 4t at your house. I would imagine some frame mount changes and air box boot change. And to make it perfect, fork and shock re valve,  I would certainly hope that would be "minor adjustments" for a factory..

Remember this is already done by private companies pretty regularly with good success.

Your definition of “good success” is vastly different than a factories definition.

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10 minutes ago, MANIAC998 said:

Your definition of “good success” is vastly different than a factories definition.

Agreed, but I will say there is quite a difference between good success and great success..

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6 minutes ago, Tepco said:

Agreed, but I will say there is quite a difference between good success and great success..

The companies that did the conversions right added to the 4 stroke chassis. Meaning they weren't just swapping a 2 stroke into a stock 4 stroke chassis. Basically reengineering the chassis to accept something it wasn't meant too. The right way to do it is to just engineer it for the motor from the get go... which is why yamaha has kept 2 separate chassis'. 1 for 2 and 1 for 4 strokes.

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On 1/9/2021 at 8:51 AM, Tepco said:

I've never done one but you would imagine the factory could make the minor changes needed to make it work. 

I thought service Honda was doing a good job but I've never ridden one.

I've done the conversion.  First off the 2T engines that exist are not designed as a stressed member while on the 4T they are.  That has a huge effect on the motor mounts and gusseting.  The downtube configuration between the two because of the exhaust outlet has a big effect on stiffness thus handling of the bike.  In my case once I'd done all that, the bike was horrible.  I had to modify the fork valves and change the shims, change the rear suspension linkage, change the triple clamps, and change the rear shock valving.  The radiators, exhaust, and throttle changed too.  What didn't change was the subframe, airbox, handlebars, and brakes and even then things were a compromise.

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3 hours ago, Tepco said:

Really? If you can buy a kit to put a 2t in a 4t at your house. I would imagine some frame mount changes and air box boot change. And to make it perfect, fork and shock re valve,  I would certainly hope that would be "minor adjustments" for a factory..

Remember this is already done by private companies pretty regularly with good success.

A picture is worth a thousand words. Nothing sexy or modern here. The photo shows a 1977 Suzuki RM125 frame that I have modified to fit an 1976 XL250 Honda 4 stroke engine.

Basically the frame rails below the swing arm pivot have been dropped 100 mm and remade, all the engine mounts revised, the front down tube replaced and re-angled forward and numerous other alterations made.

Sure, I could probably bracket it to take the original engine but the little 2 stroke would look like a cock in a sock. The same logic applies for high end manufacturers: dedicated designs and optimisation.

 

001.JPG

Edited by Momus
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