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DT 175 mx Modding


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I have an early 80s DT175mx (2K4). I tend to just use it for off-road fun in the fields. I have neglected it for a while since moving home. A few years ago I swapped the rear Swing arms from a tubular type to a box-section type with great success. I am looking to MOD it a bit further and am looking to do away with the Magneto and points for a modern electronic ignition. Are there any modules that would suit this type of upgrade or should I just persevere with what I have got? I did find something on the Net about using the module from a honda C90? I have great plans for the Bike and one day I may get it road ready. I'm just tired of having to take a dozen or so kicks when I first try and start it after its sat a while!

I'd like to also put a larger set of sprockets and chain combination but I can't remember from what larger DT model parts I can use?

Any tips to Modding a DT175mx would be gladly appreciated too

I'd just like to add that YAMBITS and Ebay have been a great help for parts already aqcuired.

Cheers

Rob

(I have even thought about putting the DT175mx engine etc in an off-road buggy as designed by a Haynes Manual.)

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  • Moderator

I have an early 80s DT175mx (2K4). I tend to just use it for off-road fun in the fields. I have neglected it for a while since moving home. A few years ago I swapped the rear Swing arms from a tubular type to a box-section type with great success. I am looking to MOD it a bit further and am looking to do away with the Magneto and points for a modern electronic ignition. Are there any modules that would suit this type of upgrade or should I just persevere with what I have got? I did find something on the Net about using the module from a honda C90? I have great plans for the Bike and one day I may get it road ready. I'm just tired of having to take a dozen or so kicks when I first try and start it after its sat a while!

I'd like to also put a larger set of sprockets and chain combination but I can't remember from what larger DT model parts I can use?

Any tips to Modding a DT175mx would be gladly appreciated too

I'd just like to add that YAMBITS and Ebay have been a great help for parts already aqcuired.

Cheers

Rob

(I have even thought about putting the DT175mx engine etc in an off-road buggy as designed by a Haynes Manual.)

Sorry to pop your bubble but your bike should have CDi anyway if its a 2k4 (monoshock) only the 125's had points. Also if mine has sat for a few days that needs a couple of slow kicks to get her going.

Chain and sprockets are also limited, i think there are smaller rear sprockets but you will have to hunt them down, i sometimes think mine could do with some higher gearing but i think it would spoil the way the bike rides for a tiny top speed increase.

Before you ask on tyres you havent the clearance for anything more aggressive than a road legal open block.

It is relatively easy to fit an entire DTR front end, been there done it and was so impressed i put the standard stuff back on :( . The forks foul the tank and the lock is crap, the front of the bike is far to high and shags the handling, and the real shocker. So long as you don't get it hot that drum is a better brake in everything but water.

You could fit a jack up kit, that lifts the bike about 30mm without affecting the handling or suspention. Other than keeping it sweet there really isn't all that much to mod.

And as to putting the engine in a buggy, heathen :angry: , thats where a lot of the old 175's have gone already.

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Thanks very much for your reply, Cynic.

I hadn't delved into the guts of the engine and with its age I assumed it was points and not a CDI. I got a Haynes manual through the door just minutes after sending my post and it too explained the CDI unit. (A Senior Blond moment).

I crashed the original bike a few years ago and damaged mainly cosmetic items. The frame was totally mangled at the back.Steering was buckled and the throttle cable jammed. Also the exhaust silencer was hanging loose.

(The throttle jammed on and at a T junction in a forest track, I was going to fast to take the corner or stop. My instinct told me to disembark off the rear of the bike and I ended up with terrible gravel rash).(holding the clutch in never helped either!)My friends that were out riding with me blamed the performance racing reeds as I could not make it up a Peaty boggy hill, I think it was just my inexperience on the saddle. My previous bikes were a DT50mx, I had at 16. A Kawasaki ke125 I had at about 20! and it ended up in 500 pieces. then this DT175mx that I've had since 2007 (27ish) And YES I haven't got my bike licence for the road! I'm just a big kid and prefer the off-roaders buzz!

I swapped the engine across to a spare frame I had. It had a box section rear monoshock swing arm and the old one was tubular. The coil has been replaced and I made a rear fender out of a cattle feed bucket. I fitted a neutral light and a kill switch (so I don't crash it again, hopefully?)

The gear linkage is now spring loaded so it will fold up if I drop the bike.

The bike had been wired to start off the kick-start as the battery is no longer there (done by a previous owner). And the two stroke oil tank has been removed also not by me.

I did have a Blond moment in the swap! For days I cleaned the chain, 1 link at a time. I was looking for the join and could not find it. I decided to split it at a random link. To then fit it across along with the engine and other salvageable items. I bought a replacement joining link only to find the one I had been looking for on the chain, 3 links from the split. D'OH! New chain and links required and sprockets as they are badly worn. That's why I'm looking to change the ratio?

The wiring loom is a mess but I was lucky in finding a feed for the neutral light and killswitch, without a manual. I replaced the headlight (1 with a flap down cover) and fitted an on/off switch but that was damaged in the crash, so back to the drawingboard with that?

I have a lot of work to do to put it right with as many uprated tweaks. Any upgrades or advise is appreciated, if it means I don't have to kick it over a dozen or more times to get it going.

I have decided that it should stay as 2 wheels and putting it into an off-road buggy is no longer an option for my DT.

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Sounds like what you ment was not moding in the sense we normally get on here. I'm afraid i may have been guilty of an assumption that you wanted a billion horspower etc etc, not actually making it better for your specific use of the bike which is entirely reasonable.

First off, and you will be pleased about this, the engine electrics are superbly reliable and entirely self contained, it could be a separate loom. The battery has nothing to do with it. You will find a black wire with a white tracer coming from the CDI, if you earth that engine stops. Put the switch or lanyard wherever you like just link it to the black and white.

If you are on dirt a lot then another suggestion would be to keep an eye on the exhaust studs every once in a while crack em on and off so they don't corrode into place and snap they also take a lot of stick from vibration and when the exhaust hits the floor/ trunks/ rocks etc so being able to change them easy will be a bonus. The IT175 has bigger studs for this very reason.

Also keep the rear suspention greased especially the sw arm spindle bush or it WILL sieze, same with the top bush on the sw arm.

As far as performance there isn't much, you have the pipe, carb should be ok as is. Maybe go up 10 points on the main if you are wide open a lot as they do get hot at high rpm.

Tyres, anything will fit the front, limited by size and mud clearance on the rear. There are some all surface knobblies that fit and work ok but i found a knobbly on the front and an open block road tyre (mitchelin used to do a good one) on the rear was better off road as you can handle the rear sliding around and the bike seems to run better on the dirt with the rear spinning up.

Other than that keep the engine electrics drenched in WD or similar and if you havent already fit an early airbox and filter. With that it will nick a tiny bit of power from the top end but you can run in water up to around 3ft (1m) deep, or up to your knees when on the pegs if you prefer a more accurate measure (still cold though as that was over my boots :angry: ).

I have had a lot of fun on mine off road, used to ride with a couple of big Kwaks and a Honda all with knobblies etc, aside from needing fuel more often than they did i was always with them, may have had to work a little harder sometimes and took a few knocks for my trouble but i still think i had the most fun. Plus the little DT is a bloody site easier to pick up that a 600 thumper ;) .

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Cheers for even more advise Cynic.

Yeah, I maybe should have used another word than Modding. My bike just looks tatty, like it should be on a scrapheap. I just want my bike back to the way it should run and be ran. I was thinking bigger Carb, bigger sprockets and chain, better exhaust system and before I had my blond moment thought of the electrical upgrades. (not that I need that now after your heads up). It has a performance foam air filter as the original housing wasn't there when I bought the bike. A little extra horses would be nice, but not too many. The Racing Reeds did help I think! Why buy a 1.1 corsa and do it up when you can buy the VXR model? so to speak! Slight power gains I'm looking for, I need to see how many times its been Bored out. Maybe I can improve there!

Its physical appearance I need to concentrate on more, once the running is sorted out. Rear suspension jack ups seems like an option. I could do with a new seat and rear fender. Clocks would also be a bonus, even if I'm just going across fields and dirt tracks.

I would love to spend the time and money making it outrun my mates bikes in an off-road capacity. Too keep up with the big boys! My mates all removed their headlights to lose that unneeded bit of weight. I'm of a belief that if I fit a headlight, I will be able to stay out later in the Evening. Unfortunately, I now live in a first floor flat. My bike lives an hours drive away in a farm shed. Did I mention I'm 30 with a 7 month old daughter that takes up a lot of time!

I think the rebuild progress has been successful so far and once complete will be a proud day. I might even strip the bike again and get things shot-blasted and tidied up.

You have given me a lot of good advise and things to consider.

I'll need to get pictures up of it. I have a few pre-crash( the day of the incident!). Not sure if I have any of the rebuild, but if I decide to strip it again then I could take pics of the new rebuild process.

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Cheers for even more advise Cynic.

............. I need to see how many times its been Bored out. Maybe I can improve there!

.........

Banish all thoughts of boring for borings sake Rob, for one you will not gain any noticeable power increase and for another you will be removing precious life from what is fast becoming gold dust,... DT175 barrels ;)

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I have been chatting with a previous owner of the bike today, getting a brief history of the bike and he seems to think it was maybe Bored to the max at the point he had it(possibly room for 1 final Bore?). I think I'll leave that for now (emergency only!).He did go a bit OTT with silicone and instant gasket around the head. (That reminds me, I did notice a broken Stud in the Head when I moved the engine across - Forgot to fix that!) Should have spares in my spare engine. The younger guy I bought it off just ragged it to oblivion, always having to stall stop it!

Its done a few more hours running since and taken a hammering from me so I'm hoping the engine is solid enough not to go down that route anyway.

The guy I spoke to today says I need to get rid of the Performance Reeds for a starter?

I'm having to think about a complete engine rebuild anyway now I think about it. The engine casing is corroding (I think from the heavy Scottish Winter Salt over its years?) and cracking, lucky I've got the spares.

Engine numbers are different but they both start 2K4. They should marry up as I don't think there is that much difference?

Just hope I don't damage this one too much and I'm glad that spares are available. Thats how my kawasaki ke125 has ended up in pieces and many boxes.

It gives me lots to think of now. My old man does shot blasting and metal polishing and his pal does custom spray painting. Maybe have to buy them a few beers to help me out?

Cheers guys

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  • 2 years later...

Having unfortunately neglected my DT175MX for 3.5 years, I'm back in the mindset of getting it going again PROPERLY this time! I am still curious to know what I can achieve from the ideas I had all of those years ago now.

Today I bought an Iridium NGK Spark Plug yet to be fitted and last week I fitted a new Rear sprocket and chain. An Upgrade with a 525 (actually they sent me a 530) chain. A new front sprocket will be fitted in the coming weeks.

Small improvements and a big grin on my face as it fired up last week after multiple kicks (into double figures and more!) and some tinkering with the fuel/ carb system.

It wanted to pop the front wheel in every gear, when I finally gave it a deserved blast in the pouring rain.

This time I intend to take pictures and upload them onto here!!!!!

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Talk About blast from the past.. :spin2: check the pitch of chain fits new sprocket,,, :yeah:

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It wanted to pop the front wheel in every gear, when I finally gave it a deserved blast in the pouring rain.

This time I intend to take pictures and upload them onto here!!!!!

I can't believe it wanted to pop up! I give mine full throttle in 1st and it starts dying at 6k while rattling its guts out...Maybe I need to take it to the shop for a good tune.

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I checked before I fitted it but I trusted the Ebay seller's description and communications that was selling the upgraded set-up. It did fit and I was mega chuffed too.

I remember an old 1985 film (yes I'm that old!) Called the Dirt Bike Kid. He believed in the bike and it came to life. Plus I'm sure it might have been a Yamaha too! DT's are very forgiving, I should know, I've crashed mine off-road enough times!

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If its running.out.of puff at 6k it may be down to a dodgy high speed coil if you have the older type of cdi.

My blue one pulls very nicely, and wheelies too easily even with ridiculous high gearing.

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Having bought an Aug 1982 The Biker magazine a while ago because of its Project DT Enduro article, I finally purchased the June 1982 edition the other day off eBay. It arrived this morning and now with both DT enduro articles, I can now consider the small tweeks and things to make my DT175 worthy of my vision again.

Its amazing that these 31 year old magazines are talking about just the type of things I have and am considering doing to my DT!

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