6 spd. gear box could be installed but a wide ratio 5 spd from the BMW G450X could also go in. Either way the cost would be prohibitive though unless you find an engine being parted out which do come up on ebay time to time. I've seen complete used 5 spd G450X transmissions with all the shafts and related components go for as little as 350.00. Ask Tinken?
There is also an aftermarket company making a really wide 5 spd gear set for the Kymco 449 engine also.
These were 2 separate posts from another site. I don't know if the guy ever got it together or not but at the time earlier in the year. I did look at the website myself and the gear sets were listed.
See below.
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Nova Racing Transmissions Ltd. in the UK is building a wide ratio gear set for the G450X. The gear ratios are: 1st 13 - 33 2.538:1, 2nd 17 - 27 1.588:1, 3rd 20 - 22 1.100:1, 4th 19 - 23 0.826:1, 5th 18 - 26 0.692:1. The gears will use the original shafts. The first sets are scheduled to be manufactured in February, 2014. They can be contacted at
www.novaracing.co.uk.
I have two of the G450's. And I am buying three sets of gears at ~$1600 each. You will have to check with Nova for exact price. I took them one of my cases and transmission so that they could reverse engineer the gears and make sure that they would fit.
The first one I will put together with a 14 tooth countershaft and see how it feels. I do dual sport riding in Southern Cal, so I want a rock crawling first and still be able to run at 65-70 mph on the highway with out redlining the engine.
These gears may fit in the TC449 cases based on the fact that the gaskets are the same for both engines.
I did check on a six speed for this engine. According to Nova it is possible, but the cost would be ~$10000.
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