The All Elusive DR 125 SE (94-96)

Sorry that I haven't been back here, I expected to receive emails for any updates to the thread.

Check your carb, and replace all the jets.

The air fuel thing in front of the bowl, I have mine set at about 2, kientech recommends no turns past 2, but at 1 1/8 my bike won't idle properly unless i raise the "ticker."

If you removed the airbox lid and drilled out your exhaust with a 1 1/2" hole saw, and welded in a 4" piece of 1 1/2" metal conduit, then bump up the main jet to 120 or 125, I'm running 125 right now, but tonight I'm replacing it with the 120 to see if it removes the high rpm bog.

Good luck with checking the valves, I had a hell of a time just checking the rear one, and I couldn't even manipulate the feeler gauge to check the front, I hope theyre ok.

I would not go big bore kit, too expensive. I'd just buy a dr200 engine and throw it in there, but first I'm going to buy a stage 1 or 2 cam for a drz 125 and see how that works.

Also, shim your jet needle, like a 1/16" or so, just a little, and make the point sharper, that's what comes with kientech's kit.

I looked, but I couldnt find any reeds on my bike. I've had that fricken carb off and on probably 20 times this last week.

Remember the race grind cam is made to use a PVL ignition,so the mid is a better choice for a stock motor.I have a PVL in a klx,single best mod for the bike.Not going to work on a street bike if you still need lights as it wont charge a battery and is bump start only.

I will swap out the carb to a 26mm mikuni, the one i have from powroll.This thing runs outstanding on a stock KLX.

four strokes dont have reeds

four strokes dont have reeds

Early 80's xr500 did have a reed valve though I don't know of any other models that had that technology.

Well then, a pvl is definitely out of the question, I've heard that adding a cam was the single best investment one could make powerwise in the lowly 125 motor. I have to have lights, though, as this is my local commuter. I've been switching back and forth between the 120 and 125 main, and I noticed that 125 does have quite of bit of high rpm bog. The 120 is going to be the way to go for me.

Edited by Cav1er

Most four strokes dont have reeds, but a rare few do, and this is one of them, btw, the reeds are located in the cylinder head. Boyesen makes them and their called "602 Power Reeds" theyre supposed to help abolish or minimize "spit back". which in normal case scenario, thats what valves are for. ive yet to see mine, but its coming soon lol heres a link to the reeds on amazon http://www.amazon.com/Boyesen-1982-1988-1994-1996-1978-1981-1979-1981/dp/B000GU36U0

Edited by Bad_Billy_Robinson_3

I just received my LT 230 E cam, and upon install, My bottom end torque shot up. The bike lost traction when I goosed it in my driveway, and I brought up the front end quite quickly at a stop sign. The downfall, and the main reason for switching back to stock cam, is my loss of top end. With the lt230 I was unable to top 60mph, and with my stock cam I am able to top out at about 65mph with no wind.

Another thing I purchased was an lt185 cylinder, and I'm thinking that I'm going to research a Dr200 Top end and piston to see if I can bump my displacement up- since what I've heard is that the dr200 is just a 185 with a longer stroke. Fingers crossed!

Upon further research, I found that the Dr200 piston has a bore of 66mm, while the 185 is only 63.

I went and purchased the matching piston for the 185, but I've read that compression is too low when using the 185 cylinder and piston with a 125 head.

One person used an lt 160 head, but I would rather bore the cylinder out to 66mm and find a domed piston to bump up compression.

If anyone has done any swappage with the cylinders and heads, feel free to post results and tips!

Otherwise, Be on the lookout for my post in the next couple weeks when I attempt this build.

Upon further research, I found that the Dr200 piston has a bore of 66mm, while the 185 is only 63.

I went and purchased the matching piston for the 185, but I've read that compression is too low when using the 185 cylinder and piston with a 125 head.

One person used an lt 160 head, but I would rather bore the cylinder out to 66mm and find a domed piston to bump up compression.

If anyone has done any swappage with the cylinders and heads, feel free to post results and tips!

Otherwise, Be on the lookout for my post in the next couple weeks when I attempt this build.

awesome effort, im definately waiting for your test results, keep the info coming, btw, have you found your reeds yet?

Just got the entire bike dissassembled- with the exception of the instrument cluster (handlebars) and engine/transmission, in about 4 1/2 hours!

Planning on stripping and painting this week- I forgot to take stock pictures, but It was bone stock, and pretty clean for being 18 years old.

When I had the cylinder head cover off, I did not see any place for reeds, and I cannot find anyplace where it mentions reeds in the service manual.

When I have the cylinder head off this week, I'll take some pictures and post them to clear up whether this thing has reeds or not.

I found a piston at akunar.com that I hope is going to work, I just need to measure pin to deck height on my piston to make sure it clears, They have 2 options for the bore I want to go (65.5mm) one has a height of 13mm, the other 13.5. Pretty cheap too- like $34. But since they're shipping from thailand, shipping costs more than the item. Still cheaper than any wiseco piston I've seen

IMG_0438.jpgIMG_0436.jpgIMG_0435.jpgIMG_0434.jpgIMG_0433.jpg

Edited by Cav1er

Just a little preview...

I couldn't find the decals that I wanted online so I masked, cut, and painted my own!IMG_0453.jpg

Also, I got the lt 185 piston and cylinder installed, and did a test-she runs!

I don't see no reeds.IMG_0450.jpg

And a comparison of the 125 and 185 pistons.IMG_0449.jpg

So, I've decided to go a similar way as dougtrip, but I've caught a little snag.

Doug took his 125 motor, stroked the crank with a 7mm pin, put in a Lt 160 Con Rod, and had the jug sleeved to fit a 65.5mm akunar piston, with a top of pin to deck length of 13mm, and a pin of 14mm.

I've measured the stock 125 piston, and it's 16.8mm from the top of pin to deck, and has a 14mm wristpin.

Refering to the chart from 500XC

Rods.jpg

I've tried to find the length between the center of the crank pin and the deck height.

Based on stock lengths, center to center of the stock rod is 106.4 + 7mm ( center of small end to top of pin) + 16.8mm (top of pin to deck) = 130.2mm

Now I relate that to Dougs build- Center to center of the lt 160 rod 101.4 + 7mm (center of small end to top of pin) + 13mm(top of pin to deck) + 7mm stoker pin=

128.4mm

He said that upon installation, the piston was only .033 in the hole, so my question is, Where did the 2mm go? (2mm=.0787")

What I want to do is use the stock rod with the akunar piston to get 106.4mm + 7mm+ 13mm= 126.4, and then install a 4mm stoker pin, and maintain my head and base gaskets to make up for the extra .2mm.

Anybody have some insight on my math? Somewhere, something is wrong, and I'd prefer to find out now than wait until I've installed a stroker pin and have the piston bash my head.

Akunar.com

Just a little update, Got everything on the street today, The addition of the stock lt185 cylinder and piston is a game changer! The base gasket at the back of the motor is leaking like a son of a b!tch, but that's a minor problem. 70+mph.

I am sooo stoked, i finally got to ride the DR, ive been putting in quite a bit of seat time out in the woods and it handles like a dream, even with the minor issues i still have to iron out. and Cav1, its awesome to see the progress youve made and im saving this thread to my comp as i type so i have all the info when i do my upgrades, hey btw, u never found the power reed cage? hmmm

Cav1, Dude, all i can say is, Epic job well done, thank you for all the knowledge and info youve given on this topic. it would be great to get out and catch a ride with ya someday. cheers bud

I'm glad you got out.

I was able to get my 185 cylinder bored out to 65.5mm, and bought a akunar piston and 3mm stroker pin. Got everything together and running with a vm26 carb- wheelies in 2nd, and able to top out at 75 with stock gearing.

I'm about to buy a megacycle cam, 393-00, and some new tires. This thing is going to rock.

IMAG0842.jpg

IMAG0846.jpg

Future oil cooler- not plummed yet, waiting on banjos...

If you're ever in southern illinois, shoot me a message and we can go ride!

Definitely no reeds though, I've had the head completely apart, and ported the intake.

Guys, I'm new here - but I find this very inspiring :)

I'm in Ireland and I'm buying a 2004 DR125 at the weekend - and I was looking for any info regarding the DR - as I found many websites and forums for all sorts of bikes, but not much on the DR - until this one :D

I had a GN125 few years ago as a second bike, and I sold it as it was rusting away...now I have a 650GS single which is good for long distance travel, but for town I needed something smaller, and the little DR seems enough for what I need.

I plan to add few mods as well, so I'll keep you posted.

Anyone knows where I could find a service manual online? I had the Haynes 'GN, GS and DR 125' manual but I thought a soft copy of the oriinal Suzuki would do as well .

Thanks again for the details posted here.

Octo

Cav1er,

I have a 1994 DR125se. And a Madass 125. How much of a power increase was increased by doing the exhaust mod? How much louder was it?

How much power was lost by installing that universal air filter?

Also, I installed the 125 main jet and have the kientech kit with uni filter and the air box cover removed. I get the same high load and ow RPM bog when at WOT. I noticed you said you switch back an forth between 120 and 125 main jet. I am curious to What was the

Disadvantage of the 120 main jet?

The power to noise ratio for the stock exhaust was about equal- gained maybe 5 decibels- tops. It made it have a much deeper sound though.

The power gained was noticable- a little snappier and a couple mph's at top speed- but you're only going to get a little by sticking with the stock exhaust.

I honestly don't think I lost any hp with the addition of the filter, if anything it helped get rid of the bog- more air to compensate with the increase in fuel. But the filter, in my mind, is crucial if you're going to be tuning the carb or engine- you don't have to remove the seat to get to the carb.

Now, jet changes for me are literally- turn off and drain fuel from carb, loosen spigot clamp, rotate carb, and remove the bowl screws.

The disadvantage to the 120 main jet is that it doesn't push as much fuel as the 125, but the 125 was pushing too much so I stuck with the 120. I hated getting up to speed and have my front end dive because the engine bogged due to a rich main.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now