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Posted

Just finnished restoring my DT and cant get it running right. Took it into the shop and had it back twice and its still poo. He said it was too rich as when he took the air filter panel and filter off it run much better. Then lowered the jet to 90. It wont rev out or idle for long. 40mph tops. Think i will have to sell as is if i cant get it sorted asap as going through divorce and may need the cash. Cost me £100 in the shop and it aint got me anywhere.

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  • Moderator
Posted

Hi Clive, makes me wonder if you have a carb from a later bike marked 3U500 fitted to an early bike with access to the air filter on the right of the bike ??? That would do it!

People advetise carbs on ebay ***DT175MX CARB***

what they often fail to say, probably because they dont know...is the id number on the carb. The two carbs are jetted differently and more importantly have different throttle slides. This was because of a revised air filter box on the later bikes, notably the ones with a square sect swing arm.

Posted

Hi Clive, makes me wonder if you have a carb from a later bike marked 3U500 fitted to an early bike with access to the air filter on the right of the bike ??? That would do it!

People advetise carbs on ebay ***DT175MX CARB***

what they often fail to say, probably because they dont know...is the id number on the carb. The two carbs are jetted differently and more importantly have different throttle slides. This was because of a revised air filter box on the later bikes, notably the ones with a square sect swing arm.

What should mine be then m8y. Was going to purchase a replacement carb of ebay for a dt175mx but as you have pointed out it may be wrong model 2H500 - Made by RT. Mines a round tube rear swing arm. At work at the moment so cant look but i dont recall seeing the number very clearly as it was vapour blasted. Will look later. Do you know the correct model for my bike?

  • Moderator
Posted

What should mine be then m8y. Was going to purchase a replacement carb of ebay for a dt175mx but as you have pointed out it may be wrong model 2H500 - Made by RT. Mines a round tube rear swing arm. At work at the moment so cant look but i dont recall seeing the number very clearly as it was vapour blasted. Will look later. Do you know the correct model for my bike?

Yours should be 2H500 Clive, if it has a 3U500 fitted that's your problem. You are seriously risking major damage with large throttle openings and only a 90 jet fitted!

I would prefer to buy a used carb Mikuni rather than a copy RT?? will be much cheaper too £30 - £40 I would say

This is what you need

Copyof100_0652.jpg

These are the spec's your carb should have

Mikuni VM24SS, Number 2H500

Standard Set up with factory porting, standard exhaust and air filter

Throttle Slide cutaway, 2.0

Needle, 4j13 Clip position 3 from top

Needle Jet, 249 0-2

Main Jet, 130

Pilot Jet, 25

Reed side diameter, 35mm

Filter side diameter, 43mm

Length, 85mm

Float Height, 21mm

Posted

Yours should be 2H500 Clive, if it has a 3U500 fitted that's your problem. You are seriously risking major damage with large throttle openings and only a 90 jet fitted!

I would prefer to buy a used carb Mikuni rather than a copy RT?? will be much cheaper too £30 - £40 I would say

This is what you need

Copyof100_0652.jpg

These are the spec's your carb should have

Mikuni VM24SS, Number 2H500

Standard Set up with factory porting, standard exhaust and air filter

Throttle Slide cutaway, 2.0

Needle, 4j13 Clip position 3 from top

Needle Jet, 249 0-2

Main Jet, 130

Pilot Jet, 25

Reed side diameter, 35mm

Filter side diameter, 43mm

Length, 85mm

Float Height, 21mm

Cheers m8y. Will let you know later. Apart from this problem the bike looks great. will take a few pics later. That said i still think i will have to part with it. Nightmare!! Hopefully i will get a decent price.

Posted

Sorry to hear that Clive :(

Will try and hold onto it but if you have been through divorce you know what i mean!!! :angry:

Posted

Will try and hold onto it but if you have been through divorce you know what i mean!!! :angry:

Ok so i have the correct carb. Wish it wasnt to be honest so i could try and sort?

  • Moderator
Posted

Ok so i have the correct carb. Wish it wasnt to be honest so i could try and sort?

OK Clive you should have a good look at the components or the carb then, make sure they match the spec I listed...everything...including the slide cutaway

Posted

OK Clive you should have a good look at the components or the carb then, make sure they match the spec I listed...everything...including the slide cutaway

Will check in sat morning m8y as at work.

Posted

DSC02586.jpg Just need to get the beuty running right

Still not runing right, new carb fitted all standard. It starts but smokes alot and stinks of fuel. Havent managed to get it ticking over yeat. Just seams gutless when you rev it. Spluttery not crisp.

  • 2 weeks later...
Posted

Still not runing right, new carb fitted all standard. It starts but smokes alot and stinks of fuel. Havent managed to get it ticking over yeat. Just seams gutless when you rev it. Spluttery not crisp.

Anyone local to me who knows what there doing and can sort this for me and earn a few quid?

  • Moderator
Posted

Anyone local to me who knows what there doing and can sort this for me and earn a few quid?

Clive it would help if you fill in your profile, It's no use asking if anyone is local and not saying where you are!

If it comes to it...I could post you yet another carb to try. or we could take it through the forum and you examine your carb and see if all the components and settings are as they should be. I already posted the details of this earlier

Posted

Clive it would help if you fill in your profile, It's no use asking if anyone is local and not saying where you are!

If it comes to it...I could post you yet another carb to try. or we could take it through the forum and you examine your carb and see if all the components and settings are as they should be. I already posted the details of this earlier

The carb is totally new so all standard. Stressed at mo Bloody divoce crap!!

Posted

Totally new but a genuine one or re-produced?

no not genuine. reproduced m8. Think its just the stting up of the bike if im honest and i dont have a clue regarding that. If it aint that it has to be crank seals?

Paid once to get it sorted in the shop but they were crap so not paying them anymore. but will pay to get sorted by someone who knows what thee doing.

  • Moderator
Posted

no not genuine. reproduced m8. Think its just the stting up of the bike if im honest and i dont have a clue regarding that. If it aint that it has to be crank seals?

Theres a quick and easy test for crank seals ;)

I wouldnt have trusted the repro carb though

Left crankseal would be prone to suck air and run lean and hard to start, right seal would be prone to burn transmission oil and be rough running and smoky

Posted

Looking at the crank on the clutch side, does anyone know the size of the o-ring between the bearing and gear spacer?

Posted

Still not runing right, new carb fitted all standard. It starts but smokes alot and stinks of fuel. Havent managed to get it ticking over yeat. Just seams gutless when you rev it. Spluttery not crisp.

Clive: Try to install a #25 pilot jet and #150 main jet. This solved my exact same problem m8. ;)

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