Vintage Dirt Bike Q & A

hi dave

i'm loving this build! i've got a 1980 dt175 myself i've been looking at trying to hop up a little. i have been thinking the blaster 200 has almost the same bottom end. i was thinking maybe the clutch basket might swap to get a stronger clutch? i'm pretty sure the plates are wider on the blaster than the dt, and i think theres more of them too. i also have a blaster (ported with a fmf on it--that thing will fly!) and i've been thinking about trying to swap some other parts. i know the reed cage is bigger, but i wonder if it can be made to fit. pretty sure the blaster has a 28mm carb too. do you have any pictures of what you had to do to get the yz reeds to fit?

i had bought a newer bike, but riding it is just not the same as my old dt! again great build and looking forward to seeing it finished!

a fridnd of mine took a die grinder and ground out the walls of the reed cage assembly area on the cylinder and reinforced it with epoxy,between the fins and all and he did a very good job.

i plan to add a YZ80 26 mm carb and a reworked stock DT175 pipe soon,with those in place it should really sing then!

with the RT180 pipe and 24 mm carb it hits the power band at around 3700 to 7000 rpm and in the lower gears it pulls to 7500 to 8500 and if in 1st or 2nd it will pull to 9500 rpm but that is not where the peak is so it has a decent amount of over rev and it is forgiving with a decent amount of torque.

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(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!

a friend of mine took a die grinder and ground out the walls of the reed cage assembly area on the cylinder and reinforced it with epoxy,between the fins and all and he did a very good job.

_________________
(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!

Tere is another way, I looked at daves mod but decided i didnt want to do the extensive grinding to fit v force reed cage, so this is what I did to mine
Cheap as chips

are those different from the boyesen reeds? I did think about trying a set of those. Did they make a big difference in the power? Most of the reason I was looking at changing the reed cage was so I could get a bigger carb on it without the cage turning into a bottleneck. With a decent port job and some exhaust modification it should flow enough to make the bigger carb do some good shouldn't it? That was my thought anyway. I may be way off, I haven't seen any of these modified at all until now

they are fantastic bikes to hop up and it is possible you can give mild big bore bikes,some 250's and even some competition 175 Enduros or dual purpose 175 Enduros a real hard time.

here is a video of one of my later rides on the 78 DT175,it was made in late April or early May and it was cold then so no top end runs.i let it wind out in first and second gear and did this by rolling on the throttle.i also did some roll ons later in the video to show how well it pulls.

top end i suspect would be around 70-75 MPH.the 24 mm carb and stock RT180 pipe is likely holding it back so there is still a lot of untapped potential in the engine.


i also went cow trailing and paused to take a picture of a very scenic area.


both the video in the first image and the image below it has a FMF Turbine core 2 universal 1 1/8" silencer installed.

click the first image to see the video,it can now wind to 9500 due to going a bit leaner on the jetting,mainly the main jet.

_________________
(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!

this is the reed cage i am using,it is a Moto Tassinari Vforce 3 reed assembly for a YZ85.it makes the stock reed cage look silly in comparison.it has 4 petals and is said to help out the bottom end power a bit.the bike is very tractable at low RPM but it shines after 4000 RPM.i am basically posting this as a refresher.






the reed cage walls needed a lot of material removed before it could fit.

_________________
(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!

i got a correct 1978 seat sometime back,there was both steel seat pans and plastic ones in the 1978 model year on the 175.

i suspect this bike due to it's 3-77 build date had originally a steel pan but i got a plastic seat pan style seat.the metal ones are prone to cracking and the plastic ones held up very well.




this is the 78 seat being contrasted with the 1979 seat.the 78 seat is a bit longer than the 79-81 seat is so it is a one year only seat on these.

_________________
(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!

i got a Rider's seat cover on Ebay and installed it.it has a great fit and is identical to the Yamaha seat cover.

the covers are stapled on the plastic seat pans.

_________________
(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!

i got a new Motobatt battery as the Rocket-Fuze battery failed in just over a year.i hope this one holds up better.


i also scored a very nice set of side panels,these are hard to find in this condition.


here they are installed.








all that is left to do is getting a nice tank and the front fender for the rest of the cosemetic stuff and of course installing the 26 mm carb and addressing the pipe,perhaps a little more on the cosmetics by addressing the handlebar controls and other stuff and it will be a nice looking and running rider grade bike.

_________________
(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!

i got this new headlight assembly that includes the Headlight bucket,the bracket for the headlight and a repica headlight rock guard that was used on the TT500 back in the day.this setup will also fit the 77-79 DT250 and the 77-78 DT400 and possibly he XT series from that era.it will also fit the 78-81 DT125 as well as the 78-81 DT175.


this came from Yuni parts in the UK.the wiring colors are a little different but they plug in place of the original harness without alteration. the headlight globe is assembled upside down as the pilot bulb faces downward on the bike once assembled.assembled this way the high and low beams are reversed.i just reclocked the glass with the reflector and this solved this problem.


it looks pretty cool to me and i tested it later that night,it functions well.the bulb itself in the headlight is replaceable.

_________________
(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!

hi thought i would join to show you my dt ,its mint,i ve have had this dt since 1991 and paid a wopping £125 for it ,i ve had 7 in total and they have all but one, that i own ,which is for restoration at a later date ,have looked like this ,i have come as far as possible with it after many years of modding dt,s ,
350 ypvs carb,
ledar nozzle kit
mikuni power jet kit
origanal fresco front pipe ,way better than the newer big one system
12volts, this is a must
professionally ported,
acerbis nost mudgards,cemoto headlight ,aftermarket side panels made in france
dtr125 front end
trailteck instrument cluster with digital speedo,
standard air box with 3 holes,these bikes do not like K&N,s
bigger sprokets to get over chain chewing swin arm up,
brand new rear wheel £90
dt 175 twin shock kick start,they just dont break
ty tank decals ,
4 inches added to stand
just had the engine reconed as the oil pump cable was slack and it damaged the barrel and big end bearing,very cheap to do,had a small amount of change out of £150 ,

that is a really cool bike,what year is that one?

_________________
(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!

its 1981

that is cool! i thought the 1981 models had a round tube swing arm. is that a stock swing arm?

_________________
(2) 1968 DT1 1970 RT1M,1970 DT1C 1971 RT1B Enduro 1974 MT250 1974 DT250A (2) 1975 DT400B 1974 DT100,1978 DT175
1975 CR250M1 1979 CR250R 1979 Kawasaki KZ400H1 Jesus is Lord!!