Vintage Dirt Bike Q & A

Hello everyone. I am new to the site and I am looking for a recommendation on my 79 CR125R. I am putting a 21 inch front wheel on to replace the 23 inch circus wheel. What will this do to the handling, steering etc..? I have also heard of modifying the frame to change the steering angle. I feel is this might be too much work? The final thing I heard was putting a slightly shorter shocks on the bike i.e. 17 inch -vs- 17.5 inch will help even out the 21 inch wheel. Please let me know of any recommendations you guys might have. Long live the Elsinores!! Mike

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1981 Maico 490
1996 Gas Gas 270
1974 Honda XL412 Powroll Rocket
1979 Honda CR125R
1978 Honda XR75

Hi Mike,

I'm trying both mods to my 79 CR125. I've ordered 17" shocks and plan to have a spare frame cut next month. I wish I had answers for you right now, but I won't test the shocks for a few weeks. I planned to ride the bike with the 23" one last time, then with the 21" and finally with the 21" and shorter shocks.

J

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#829 The "Factory Novice"

1988 Honda CR250RJ
1983 Honda CR480
1981 Can-Am 250 MX6-B
1979 Honda CR250RZ
1979 Kawasaki KX250 A5
1978 Husky 250CR
1978 Honda CR250R
1977 Yamaha YZ400D
1977 Suzuki RM125B

J,

Thanks for the information on your 79 CR125. I am sure the extensive testing of all your combinations will pay off in the end. I look forward to hearing your results. What kind of 17 inch rear shocks are you buying? My CR is in the restoration stage and I am looking for a pair of shocks. Progressive and Works Performance seem to be priced the best? Have you done anything to your engine to increase the output? Do you recommend anything trick? I know this little 125 will never compete with my Maico 490 but I still think it will work well on tight tracks. I ride the 40+ Am class and just ride for fun.

Regards,

Mike

_________________
1981 Maico 490
1996 Gas Gas 270
1974 Honda XL412 Powroll Rocket
1979 Honda CR125R
1978 Honda XR75

Mike,

I think Works Performance are your best bet for performance/$. I bought a Pro Form pipe, a Mikuni carb and Boyesen reeds. I haven't been able to get out and test the setup yet (swamped at work).

As can happen I've gone overboard with this project ($$$), but I love the way it will look when I finish soon.

J

_________________
#829 The "Factory Novice"

1988 Honda CR250RJ
1983 Honda CR480
1981 Can-Am 250 MX6-B
1979 Honda CR250RZ
1979 Kawasaki KX250 A5
1978 Husky 250CR
1978 Honda CR250R
1977 Yamaha YZ400D
1977 Suzuki RM125B

ive owned and raced a 79 cr125 for 2 years now-
i installed a CR480 21 inch front wheel w/brake so the thing would have a decent front brake and it handles a lot better with NO frame mods-the key to making it work is to stiffen the weak stock front spring rate to make the fork ride higher in its stroke-also consider rear shock "sag" -this applies to old bikes just like modern bikes-with correct spring preload and stiffer fork springs the rake of your front end can be set to where you need it in most cases-mine works great-i have works performance rear shocks and i threw away the "upper" short light fork springs and replaced them with a set of the "bottom" cut to the same length and the ends recurled giving the fork much better balance to the rear of the bike.You can get these cheap of an old parts bike.I also installed air caps but dont run air and added thicker fork oil to "slow" the compression and rebound dampening-you must go to a heavier oil or the fork will "pogo" on rebound stroke with the heavier straight spring rate.
Also get a Proform pipe and silencer-its much easier to ride with added midrange over the stock exhaust-its worth it
all this made my bike a LOT better

Hello,

I have a collection of Ì79 CR125RÌs in which two of them have FMF frames (that I currently building into Mugen kit bikes); the FMF frame gives the bike better tracking in the turns and eliminates most of that wonderful tank slapping the stock frame gives when backing off the throttle. My main race bike for the past 6 years has been a stock framed bike with 12Ó Simons, 21Ó front wheel and 17Ó Fox AirÌs; the bike turning is fair, but nothing like a FMF frame Ì79 or an Ì80 CR125RA÷thatÌs just the fact and will always be. However, mounting a 21Ó on the front ÏandÓ changing or setting up the forks with more travel/little sag (as described above) will make life on the Ì79 CR125R much easier.

Good luck,
Robert D. Hawes Jr.
Mesa, AZ.

Thanks for all the replys. This gives me a lot of information about possible changes I can make to my 79 CR125. It sounds like changing from the 23 inch wheel to a 21 could make the bike handle very poorly if not done right. The only 23 inch tire I have found is a Cheng Shin. Not the best tire in the world but it will work. The 23 inch might be the option until I find a 1980 CR125R. Besides, I bought the bike to have fun on and it is much easier to start than my Maico 490. Where would one get a FMF modified frame that will work with a 21 inch wheel? I am sure the cost of a FMF frame would make this an expensive modification? Are there modification specifications out there for this change? Thanks Again Mike.

_________________
1981 Maico 490
1996 Gas Gas 270
1974 Honda XL412 Powroll Rocket
1979 Honda CR125R
1978 Honda XR75

Hello,

Currently, buying a Î79 FMF modified CR125RZ frame depends on finding someone whoÌs willing to sell one÷the only one that I know of who was will to do this was Horvet in OH.; and the last time I talked to him about it, he wanted more then what I was willing to pay÷that was over 4 years ago, so IÌve no idea if Rick still has the frame (or is willing to sell it). Since then, IÌve found two frames for myself. However, IÌve had plans too have some stock frames modified down the road since I have 8 of these bikes and have access to the original FMF jig used to modify the frames (I also have a ÏreliableÓ fabricator locally to do the work). Unfortunately, it takes me (what seems like) ÏforeverÓ to get anything done, just about every part of these bikes is a side project of its own; Mugen decals, Fox Forx, Fox axles, Fox triples, Simons stems, Mugen radiators, Mugen pipes, Fox Piggy Backs, Fox Twin-clickerÌs, CR250RZ cranks, fiberglass number plates, Mugen air boxes, FMF frames and the list goes on and on. My free time available to this hobby is devoted towards finishing the things I need at the current time for my current projects; so itÌs very likely that I will not make this happen for about a year or so÷IÌm not sure what your time frame is? As for the Ì80, a real good bike, but it just doesnÌt have the Ïcool lookÓ of a Ì79 (in my opinion). The Ì80 CR125RA can have its frame problems too, it is ÏveryÓ common to find the rear tube section (under the seat) broken, bent and glob welded. The stock shocks were way too soft and would let the rear tire pound the heck out of the rear frame section, rear fender and silencer when bottoming. I had enough parts to build five Ì80 CR125RÌs, but had to cut it down to TWO because three of the frame were junk with the amount of damage to the rear frame section...be sure that you ask or check. The Ì81 CR125RB frame has the same issue. I know, this is probably ÏwayÓ more information about nothing then what you needed÷sorry.

Take care,
Robert

Robert,

Actually I was hoping for more info. We can never get too much good information. It helped me because I've been looking for a 1980 CR125, but maybe I should just buy the lower end and forget about the rest of the bike. LOL Like you I have a fondness for the 1979 CR125's. My favorite bike of all time is Johhny O's 79 Mugen 125.

I know you must have too many irons in the fire, but I always go to the website hoping to see more pics of the Mugen projects. When are you gonna finish those darn things?

J

_________________
#829 The "Factory Novice"

1988 Honda CR250RJ
1983 Honda CR480
1981 Can-Am 250 MX6-B
1979 Honda CR250RZ
1979 Kawasaki KX250 A5
1978 Husky 250CR
1978 Honda CR250R
1977 Yamaha YZ400D
1977 Suzuki RM125B

J,

I know...when am I? I keep asking myself that question...telling myself to "just finish something." The '79 ME125 kit bike which is close to 70% finished and sitting in my kitchen for about the last 2 year is starting to feel just a little neglected...as is the '81 ME125 kit bike in the bed room. What to do man, what to do?

Sad about the mugencross...neglected as well.

Robert

I found a very reputable motorcycle frame shop that will do my 79 CR125 frame mod. The cost will be the only prohibitive factor. (Isn't it always?)

I will keep you all updated on the progress

J

_________________
#829 The "Factory Novice"

1988 Honda CR250RJ
1983 Honda CR480
1981 Can-Am 250 MX6-B
1979 Honda CR250RZ
1979 Kawasaki KX250 A5
1978 Husky 250CR
1978 Honda CR250R
1977 Yamaha YZ400D
1977 Suzuki RM125B

If you are looking for mods for your 125's or 250's I ave a CD I have made that has all the articles on the 125 and 250 CR's 78-80 from MXA and DB. It has the frame modification that Al Baker did to the 79 125, step by step with pictures, doesn't look to be to hard of a project, this has articles on DG, Fox, Mugen, LOP, FMF, Baker,and tons of other useful info, 1980 Fox Catalog included on the CD and a parts microfiche for the 78-80 250. 12.00 includes shipping to US
mailto:jesse@brmemc.net

Hey OldMXer,

I have one of your CD's and let me tell everyone it is well worth the $12! When I look back on all the money I spent to get most of those articles in magazine form I kick myself.

If you want great old articles get his CD instead of shopping for them on eBay.

J

_________________
#829 The "Factory Novice"

1988 Honda CR250RJ
1983 Honda CR480
1981 Can-Am 250 MX6-B
1979 Honda CR250RZ
1979 Kawasaki KX250 A5
1978 Husky 250CR
1978 Honda CR250R
1977 Yamaha YZ400D
1977 Suzuki RM125B

Hey Old MXer,

I appreciate your input for the 79 CR125. I do believe I will purchase one of your CD's also so I can make my CR125 rip. What is your address and what kind of payment do you require i.e. paypal, money order etc..?
Has anyone tried the basic carb, pipe/silencer combination and had a real increase in usable power? Anyone interested in a cherry 1981 Maico 490? Mike

_________________
1981 Maico 490
1996 Gas Gas 270
1974 Honda XL412 Powroll Rocket
1979 Honda CR125R
1978 Honda XR75