Early Drum Brake RD250/350/R5 Front End
- Thread starter 1sttimer
- Start date
Interesting. What are you planning on building?
That's not a bad front end but more than is needed on a small bike and not really enough for anything a whole lot faster. I always used CB77 or CB450 drums but they are not so great either on a middleweight machine. GT750/550 4LS is not a bad brake but it weighs as much as a mid sized boat anchor even after a lot of machining. I have had a few of those and my preference for a 2LS is XS1 Yamaha.
Fontana or Oldani or replica RC181 would be nice but above my pay grade.
That's not a bad front end but more than is needed on a small bike and not really enough for anything a whole lot faster. I always used CB77 or CB450 drums but they are not so great either on a middleweight machine. GT750/550 4LS is not a bad brake but it weighs as much as a mid sized boat anchor even after a lot of machining. I have had a few of those and my preference for a 2LS is XS1 Yamaha.
Fontana or Oldani or replica RC181 would be nice but above my pay grade.
1sttimer
Over 1,000 Posts
Yamaha CT2! I’ve owned this bike for a while and really enjoy it but I’ve always toyed with building it into a track bike. I decided to go for it and learn along the way. The RD250 front end comes pretty close to bolting on from what I hear and seems to be a solid upgrade. You might be right being more than needed but I think it is used fairly often on the CT platform for racing. You coming at it from a weight perspective or stopping power?
I live about 1.5 hours from Carolina Motorsports Park and there’s an AHRMA event in about 3 weeks down there. I connected with a guy who helps build them and I believe he’s going to be there so my plan is to take the family for the weekend and soak up the sights and smells and ask a ton of annoying newby questions.
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yes... both. A light bike doesn't need a whole lot of brakes and big brakes weigh too much, so just enough is what you need. That's a 72 reed valve motor if I googled it right, so what class does that fit into? F250 perhaps? Stock OEM front hub is a little samll though, so your plan makes sense. Are you sure you wouldn't prefer a nice Oldani or Fontana replica in magnesium alloy? Tell the family that it's small and light so it must have been cheap......
Yes to your plan to go to a race weekend and ask lots of questions. Soak up the knowledge and take lots of pictures.
1sttimer
Over 1,000 Posts
yes... both. A light bike doesn't need a whole lot of brakes and big brakes weigh too much, so just enough is what you need. That's a 72 reed valve motor if I googled it right, so what class does that fit into? F250 perhaps? Stock OEM front hub is a little samll though, so your plan makes sense. Are you sure you wouldn't prefer a nice Oldani or Fontana replica in magnesium alloy? Tell the family that it's small and light so it must have been cheap......
Yes to your plan to go to a race weekend and ask lots of questions. Soak up the knowledge and take lots of pictures.
Yeah the 72 is reed valve, so new tech. I can get into Formula 125 with the reed valve but it’s excluded from 200 GP. I think what I will end up doing is using a CT1 top end which is piston port and try for both classes.
My pockets aren’t deep enough for special alloys
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There are some fast CT1 based race bikes out there. It seems to be a good starting point and apparently makes a lot more power than our CB160 based racers.
Exotic alloys are designed for us mere mortals to dream about. There always has to be something better, lighter more powerful to lust after.
Exotic alloys are designed for us mere mortals to dream about. There always has to be something better, lighter more powerful to lust after.
