4-stroke 450 in a 125/250 chassis > Advice needed.

The wife has shown interest in racing next year. There is a racer in our club that has a couple Honda 125GP bikes that he has put 450 4-stroke Honda motors in. My wife really likes the bike and feels a lot more comfortable on that size chassis versus the 998 or SV she usually rides on the track. Confidence is everything to her and if she wants it...I'd like to help her as she has been by biggest supporter over the years at the track.

As I said, we'd like to tackle a similar project. Are there any good resources? Any frame/engine combos that might be easier than the other (less fabrication work)? I have dreams of the new KTM 450 EXC-R motor in a RS250 chassis....mmmm

Cheers,
Keith

 

I dont have any info, but heres something similar that you might be interested in.

http://www.450moto.com/

or seach for 450 moto on google.

good luck

 

Cedric Smith from the PNW did it. From what I heard, it took a lot of fabrication to make the 450 fit into the 125 frame. There we even some frame cutting and welding to make it work. There's a cool picture of him holding it up. I'd love to have something like that but it's way beyond my mechanical know how. The 450 in a 250 chassis has been done numerous times and seems to be way easier. Won't get you the ridiculous power to weight ratio but should still be fun. I've got a couple 125's in my garage now and if one blows up and I find an awesome fabricator, I might have to offer one up to the cause.

 

Cedric's bikes are the ones she likes. I am completely open to a 250 chassis. She weighs 105lbs so I'm not worried about weight.

We saw Roland's supersingles at MotoGP. Although they are indeed smaller than most I believe they are still larger than even a 250 frame.

 

GP Racer

:tut: Please don't destroy a perfectly good and collectable GP bike to build a "special". All of the development work will never pay off off when you go to sell it!

Your wife will learn alot more by riding a real RS125 or TZ125 GP bike than by riding a "frankenbike" that isn't supported by any manufacturer or group of like minded racers. Join the USGPRU site and pick up a decent RS or TZ to start off with. If you have the money and still want a four stroke...buy one of the new bikes being built Moriwake + Honda have a bike that will be available shortly. There are several other companies that will be making one. Check out Road Racing World for info.

parillaguy

 

^^^ I was waiting for that.

 

Yeah, I saw that one coming also. I'm not one for chopping up a perfectly good 125 but...if I happen to destroy one and it becomes too costly to repair, then maybe, just maybe it will be turned into a frankenbike.

I did talk to a friend of mine who was thinking of tig welding a custom frame and using RS125 components to fill in the gaps but again, it comes to cost and experience. The Tigcraft frame looks awesome and appears to work well in Europe but cost a butt load just for the frame. How much money do you want to invest in such a venture? Personally, if I built something, I'd feel pretty damn proud. Even if I had to sacrifice a 125 in the process.

On a side note, I got one of my 125's running this weekend and now the wife has claimed it as her own. She's also on the petite side and maybe one day will be on it. Has your wife considered a NSR50 to get her confidence up on the track? If my wife get's more serious, I might look into one and take her down to the kart track in OR.

 

The wife has done several track days. She started on a Monster and then migrated to a 998. She had 8 track days scheduled for this year and in all actuality she does pretty well. The 998 is not really a competitive bike in the class it would run in and it is definately not the class for her to start out racing in. I think she could do well in the lightweight superbike class and it's in the laptime's she would be comfortable with. I think she could excell more on a smaller and lighter bike. Hope that sums up the confidence end....

 

Sounds like 125's will be a great place to start. If you're going to be going to any of the trackdays at Pacific (5/22 is my next one), let me know and she can try out one of my 125's for a session to see how she likes it. And then when she falls in love with it, you can help me build a 450 .

 

Thanks!