Vintage Dirt Bike Q & A

Hi all,

I'm new to the forum.
I was 15 when I raced a 74 Elsinore from 1975 through the early 80's.
Had many,many fond memories on that bike. I've been looking for a few years and finally found a 75 CR125 to restore and ride about a month ago.
Grew up in Northern Indiana and did most of my racing at Red Bud in Michigan, K&R Raceway near Hobart, and Shady Hill near Kouts.

The bike is mostly complete (will post some "before" pics when I get a chance).
I'll be going through it completely (engine, frame, paint, etc.). I'm a skilled mechanic and all the mechanical work will be done myself. I actually still have my old OEM Honda shop manual for it.
I'll leave the painting to someone who knows what they're doing.

Looking to do a stock type restoration. The bike will be ridden, not displayed.

My plans are to do it up in the silver & green 73/74 colors.

Have a few initial questions.

Besides the obvious color difference, can someone tell me the differences between the 73/74 model from the 75? The only thing I remember was the shorter pipe without silencer.

The carb that is on the bike now doesn't look correct to me. I'm not at home now so I can't post a make/model. I do know that it's not he flip lever choke Keihin that I remember.
Can someone let me know what the correct carb is? Were the 74 and 75 carbs the same?

I haven't started the project yet but at a quick look, I'll need a front number plate (with attachment hardware) and possibly one side panel (one has a crack).
Besides a crummy paint job, the tank and fenders are in good shape.
Again, I'm pretty sure the carb is not stock and it will also need all the air filter components from the boot back.
Will be looking for another stock (preferred) or DG type pipe.
Will also need new handlebars, on/off switch and I'm sure some miscellaneous hardware.

Thanks all.. Glad I found the forum..

Ken
Northern Kentucky

_________________
Do it once.. Do it Right..
75 CR125, 89 CR 250, 61 Harley Pan/Shovel, 70 Triumph 650, 74 Honda CB750, 74 Kawasaki H2, Suzuki Z400 & Z250 quads and a few CT70 and QA50 min trails...

hey i currently use this pipe (DG reproduction)
http://dirtoverstock.com/detail.aspx?ID=140
on my 75 cr125
it is AMAZING it will really wake the bike up
if you know how to ride it youll pull a good 4 - 5 extra horsepower out of it
just thought id help out
-sam

Thanks Sam.. 4 to 5 Hp increase, wow. That would be really significant. As I recall, stock hp was 17.

Just to let anyone else that might want to add to the thread regarding the 73/74 to 75 differences...

I did learn from reading an earlier post that the 75 has an extra transfer port in the cylinder.

Any other know differences would be appreciated..

Ken

_________________
Do it once.. Do it Right..
75 CR125, 89 CR 250, 61 Harley Pan/Shovel, 70 Triumph 650, 74 Honda CB750, 74 Kawasaki H2, Suzuki Z400 & Z250 quads and a few CT70 and QA50 min trails...

Ken,

As far as I know, the changes from the '74 to '75 were mainly detail/cosmetic changes, except for the boost-port cylinder and pipe you mentioned, and possibly thicker-wall front fork tubes? It also appears the '75 has a unique air cleaner setup.

Below is a link to an eBay auction with fairly good photos of the stock carb. The same carb (with minor changes) was used on the '74-'75 CR125, MR175 and MT250, and possibly the FL250 as well.

http://cgi.ebay.com/ebaymotors/HONDA-MT ... ccessories

It sounds like you'd prefer to keep it stock, but one change I would suggest is to use an MT125 composite head gasket, which will not leak like the copper CR gasket. The head will have to be milled .030" to keep the compression the same; perhaps an eBay head could be used.

Ray

_________________
'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric

Some of the changes I remember are:
Kick starter shape
footpeg mounts reinforced to the frame
rear shock shaft diameter
carb cap different
fork tube caps different
kill switch\ button
rear sprocket size
sprocket stud size increased
seat foam thickness
side plate mounting bands
and somewhere in the evolution the DID rims changed slightly
cylinder head stud thread pitch
and there are probably others

Yup I love my dg pipe iv built my cr to an evo racer
you can find some old articles on vintage factory about the old dg cr racers
but it's not a beginners pipe either
you gotta keep it revin pretty good
but it's an awesome pipe for a great price

Oh and I read that the original test showed 19 horsepower but the bike was actually a little lean they said that after they got it dialed in it was showin 22 horses which was pretty good
so I hope this helps y'all
-Sam