just got a "85"DT175 engine used it has a YZ top end on it? anybody have info

[steptoe1111]

hey guys just wondering if someone can tell me a little about this engine i picked up for my dt?

i have a 1978 dt175e it is the mk1 7wire cdi type with the rounded section swing arm with mono shock

now i was having trouble with miy high speed coil on the stator and was getting a week spark it was bogging out above 2500rpm

so i started looking for replacement stator plates only to find people want $160 pluss for them!

the local bike shop had a flywheel and stator off a mx100 but he wanted $175 i ended up telling him to leave it

last week i got a complete used engine of ebay for $150 localy

i ran engine numbers to find out its 1985 model it has a mk11 flywheel with the 4 slots in it and i was able to fit it to the 78 dt175e

(i got the cdi aswell its a 6 wire type)

after alot of playin around to get the timing right its going pretty well it took a bit of playing around to find the right timing as there were no marking indicating TDC ad the mk11 flyheel and stator both have ther keyways about 90degrees off compared to the mk1 so i ruffly mesure 1.8mm BTDC and started there

but all thats good and were running better than i thought anyway after noticeing the almost 2mm top ring end gap

i had the engine apart and dident even bother to use the feelers becaus it obviously waaaay too big

but surprising still runs

now i had both engines apart this morning i was hoping to fit the later 85 model top end to my 77 lower end because the 85 topend is almost emaculate condition but i ran into some problems doing that

i relised that the topend that is on this later model dt is actualy from a YZ175

i reasembled both motors and got my old going again

but i would love to try this new one out but im going to have to swap the complete engines over

the truoble i ran into was the transfure ports are larger and overlap the flange on the earlyer dt case so they are not compatible

but what can i expect from this other engine?

ive already looked at the inside and it has much larger transfure ports than the early dt's, larger intake ,bigger reeds, and a boost bottle and apart from almost perfect compresion and a emaculate bore and piston "wich im sure i will notice"

whats the main benifit of the haveing the YZ topend on the dt botom?

was it a performance mod back in the day?

or has somone just done it caus it fits and the had the bits already?

ive added some photos of the engine the last one is the dt175e the older model

[url=http://s647.photobucket.com/user/steptoe1111/media/IMG_20141009_112223_zpscf607986.jpg.html]

[steptoe1111]

ive been doing a little more reading ...

have I got a complete yz175 engine here?

the guy advertised it as dt175 "78" model engine but said he pulled it from a dt125 frame

wich made me think it dt lower end with yz top end but im not completely sure

im not sure if this bloke realy new much about the engine either!

I checked the engine no wich is 1EJ-009201

according to this here

http://dropbears.com/y/yamaha/modelcodes.htm

the bottom end is definatly a dt175n "85" model

[Airhead]

it's a DT175U shaun

[blackhat250]

I didn't think ther was a YZ175 . you get The IT175, YZs" were 125/250 400/465 Which were all pre-mix , [ no oil pump,]

See where it bolts to bottom end, - and DT Uses long bolts,

[dt502001]

When it comes to the dt175 I leave it to the guys here who know everything about them ,but non of them motors are yz as the yz never had a tack drive or came in a 175 that would be a IT but again they didnt have tack drives ,so you must have some mix mash or as Airhead said it just a u model?

[Airhead]

heres one

http://i440.photobucket.com/albums/qq121/1783iana/DT175Pics016.jpg

[blackhat250]

Ah , well according to the Yz register, they made a YZ175 [ eng no- 1L8] in 1976 ... discontinued tho ,as dosnt appear in any other year,

There was no YZ425 either , but a IT425 ,,

[steptoe1111]

thanks for the replys guys

I was fairly certain its a dt bottom end

but in the photo above you can see the letters YZ stamped on the bottom of the cylinder that's what made me think its a yz175 cylinder

I knew from doing a little reading that they only made the yz175 for a year or two back in "76"

but it had me curious as to why someone would put a "1976" barrel on a "85" model bottom end

I heard about people putting it175 top ends on DT bottom ends as a performance mod

because the porting on the IT cylinder is meant to be heaps better

I thought someone has done something along those lines with this

on the LH intake side there is some more casting numbers that read 18L00

does that help confirm what type of cylinder it is genuine DT or YZ?

if it is a YZ top end I was thinking I may have something special that someone in the past had spent a lot of time on to make something that would leave almost every other DT for dead

but if it isn't well the then I still got a wicked motor anyhow in much better condition than my 175E

and its an MX too :) (im pretty excited anyway to see what the diference is hopefully more power and some 2nd and 3rd gear wheelies would be cool to

cheers to paul I wouldent have known it was a DT175U model that will come in handy when I order the crank seals im going to replace just to be on the safe side

[steptoe1111]

you might be right again paul that casting that I said sais YZ stamped on the cylinder may actualy be Y-2

so if its all factory DT175U

then well im still glad its an MX

wich will still be a decent upgrade on the plain jane DT175e I have at the moment anyway

[Airhead]

Yeah I'm fairly sure 18L is a DT175 number mate

theres an aussie forum shaun, might be useful for you?

http://www.yamahait.com.au/forum/index.php/board,25.0.html

[steptoe1111]

cheers airhead ill put em in my favourate list in IE

off topic ... do you or any other people here have any experience with "or have done ther own" rewinding of the source or high speed coils on the stator plate ???

Id like to repair my old stator and prepaired to rewind it myself or give it a go anyway,

ill make a new post on the subject anyhow,

may take me a couple of weeks but

ill let you all know how this later model engine goes to ... im hopeing it hammers

thanks a lot guys

[Airhead]

no mate i've never had to rewind coils, always bought new ones if I needed one, you should take care to wind in the same direction as the original though.

I recentl;y bought a used stator from ebay, I'll check out the high speed coil and if it's good you can have it if you want it?

[steptoe1111]

ill pm ya mate

[dt502001]

heres one

http://i440.photobucket.com/albums/qq121/1783iana/DT175Pics016.jpgWe

We never got them the case was formed for them but not drilled,, always learning something new