1978 yamaha dt 250 monoshock rebuild/ rear end lift

Hey guys I'm kind of new to dirt bikes(vintage or newer) and I have a 1978 yamaha dt 250. I was wondering if it's possible to get a little more height out of the rear end, maybe a aftermarket shock or something?



are you looking for more overall travel?  raise the rear to quicken steering?  


an IT250 rear shock is longer than the DT's... don't recall how just how much longer, though.

i've got one from a '77 IT250 and another from a '78 YZ250 i can measure if ya want.


keep in mind the countershaft sprocket is pretty far from the swingarm pivot on the DT... the chain tension can vary quite a bit between topped out and bottomed out.  the chain may even rest upon the swingarm pivot (it almost does on my IT at sag with me on it)

More travel it bottoms out quite often and it sits fairly low for me. Would just rebuilding it do the trick?

I Think the 78 dt 250 is 5 inches of travel any more would be great

the '77 and '78 IT250 has just shy of 8" rear travel

i've got about 11" out of my '77 IT250 with a longer/modified YZ shock & YZ400 swingarm, but also have longer forks (from a late model YZ).  putting just the rear end up that much would make it pretty unstable at speed.


your shock is probably shot, given the age of the bike.  Race Tech, Works Performance and a few others rebuild and modify them. Race Tech does a great job with their gold valve... but it can get pricey.  I had them do the rear of my last monoshock bike... transformed it from harsh and horrible to livable.  

Would it be hard/impossible to rebuild?

Will almost all yz forks fit?

i've rebuilt a couple monoshocks myself, but it's a serious PITA and each time i swear i'll never do it again.  


i think the DT is a sealed unit (ie. no schrader valve). it'd need to be drilled to release pressure & tapped for a valve. the actual parts like the o-rings & clips are cheap enough (maybe $15), but the shocks are a pain to get apart and back together.  then it should be recharged with nitrogen (compressed air works, though not quite as well). it's around 200psi.


sending it out for a basic rebuild & recharge is ~$150 last time i checked.  i'd just go that route.


YZ forks: dunno. the last DT i had i left prettymuch stock.  i put 2008 YZ450f forks on my IT, but it wasn't a straight swap... took some machining of the fork stem.   prior to these forks, i had a set of early 80s YZ250 forks that were completely drop in with no mods at all.  Not sure if the DT and IT are similar enough as far as the neck goes, for forks.

Edited by dhallilama

I've been thinking about dropping new forks in the front but I just want to find ones that drop in without much/any conversion because I'm pretty new to off-road bikes

easiest/cheapest would be just to rebuild the stock forks... new seals, bushings if needed & oil don't cost that much and will make a tremendous difference vs worn out suspenders.


if it were me, i'd thow as little $ at it as possible. rebuild the forks, *maybe* rebuild the rear shock, ride it and have fun. eventually you'll either grow to seriously dig the bike and end up throwing more money at it than it's worth or move on to something more modern/faster/ etc.

Oh I already seriously like the bike I've liked the look of older ds/mx bikes. I would just like the whole bike to be higher because (hopping logs) I've already cracked the exhaust right where it bends a u after it comes out of the engine and I feel like I'll keep doing that just because it's so low and the exhaust comes down just infront of the skid plate.

Edited by Trailride802

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