Refitting carb hacks
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Getting the carb off your DT is a bit of a pain in the ass isn’t it?
However it’s light work compared to when it comes to putting it back in. Refitting as you know is a bitch.
So this poses the question what’s the easiest way to put it back in?
I’ve had my carb in out so many times recently and can’t seem to find the knack for getting it in as easily as it came out. I’d really appreciate a good hack as it appears my air boot now has a habit of coming off anytime I attempt to put the carb back in
A friend of mine had said whilst working on his DT age used to take the air boot and air filter out install the carb as normal then pull the air boot through onto the carb.
@Stevie-Wonder Use the three tags on the air boot at the carb end to pull it onto the carb body; if these have decided to get out and walk (many do) just use a flat bladed screwdriver to get the air boot back on to the carb. Do this carefully so you don't gouge the carb body or slide or put a hole in the boot.
From your post, of greater concern to me would be the fact that the air boot pops out of the airbox so easily; this is downstream of the filter meaning your engine can suck dirt if it doesn't have a good airtight seal. I used a product called Seal-All (a petrol- and oil-resistant glue) to bond mine into the airbox, to do the job properly you really need to remove the airbox completely and clean everything up with brake cleaner etc., then rough up the airbox surface where it will be applied.
Also a good time to take a look at the filter holder inside the airbox as these often get neglected and the foam on the back rots out (this costs £40 for a piece of plastic). This allows dust to enter the engine as well. Clean it up, get some 5mm air filter foam off eBay and bond it to the holder with more Seal-All. Also good to dribble a little foam filter oil on here whenever it's disturbed for filter cleaning etc.
Lastly stay away from Twin-Air filters; I bought one and it was too small to fit the air filter frame (annoying). Yambits ones are more than adequate. half the price of stock and tolerate being washed with petrol before you re-oil them. Oil up 2 or 3 at a time, put them in a plastic bag and swap them after you've been out greenlaning etc.
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Yes mate a major pain refitting a carb on a Dt125r, gave it some thought and ended up removing the whole air box and remodelling the cover that the filter lid sits in so that most of the access screws are now at the front, got massive hands so this gives me more room to lever the rubber boot over the carb mouth after warming the boot on a radiator.
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@Stevie-Wonder Use the three tags on the air boot at the carb end to pull it onto the carb body; if these have decided to get out and walk (many do) just use a flat bladed screwdriver to get the air boot back on to the carb. Do this carefully so you don't gouge the carb body or slide or put a hole in the boot.
From your post, of greater concern to me would be the fact that the air boot pops out of the airbox so easily; this is downstream of the filter meaning your engine can suck dirt if it doesn't have a good airtight seal. I used a product called Seal-All (a petrol- and oil-resistant glue) to bond mine into the airbox, to do the job properly you really need to remove the airbox completely and clean everything up with brake cleaner etc., then rough up the airbox surface where it will be applied.
Also a good time to take a look at the filter holder inside the airbox as these often get neglected and the foam on the back rots out (this costs £40 for a piece of plastic). This allows dust to enter the engine as well. Clean it up, get some 5mm air filter foam off eBay and bond it to the holder with more Seal-All. Also good to dribble a little foam filter oil on here whenever it's disturbed for filter cleaning etc.
Lastly stay away from Twin-Air filters; I bought one and it was too small to fit the air filter frame (annoying). Yambits ones are more than adequate. half the price of stock and tolerate being washed with petrol before you re-oil them. Oil up 2 or 3 at a time, put them in a plastic bag and swap them after you've been out greenlaning etc.
Seal-all ordered. I think I was going to have to take the air box etc out anyway to refit the air boot as there’s a giant red spring that gets in the way
I’ll check the foam at the back of the filter cage.
Also I’ve had good luck with piper cross filters for the DT, they’re good quality, dual density and come pre-oiled if I remember. Another bonus is a lot of ebay sellers will sell you one with a couple of cans of air filter lube + cleaner for the same price as most people do the filter alone.
Lastly they also fit. -
Seal-all ordered. I think I was going to have to take the air box etc out anyway to refit the air boot as there’s a giant red spring that gets in the way
I’ll check the foam at the back of the filter cage.
Also I’ve had good luck with piper cross filters for the DT, they’re good quality, dual density and come pre-oiled if I remember. Another bonus is a lot of ebay sellers will sell you one with a couple of cans of air filter lube + cleaner for the same price as most people do the filter alone.
Lastly they also fit.@Stevie-Wonder
If it's winter I use a hair dryer to soften the rubbers first...
Put a bit of 2 stroke oil on the carb in & outlets. Loosen the airbox mounting bolts and push back as far as possible. (Without the slide and carb top fitted) Fit carb to inlet first. I then slide the airbox side rubber over the carb.If its a bitch i use a medium flathead screwdriver (that i have smoothed the edges off of) I then fit the jubilee type clip to the airbox/inlet side of the carb, because it gets in the way if left on the rubber. Fit the slide and carb top. Tighten up inlet clip and airbox bolts and enjoy!!...It's one of my least favourite jobs cause I've done it so fekin often!...
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Another thing that makes DTR carb maintenance a lot easier (as long as you don't live in a really cold climate) is ditching (not completely) the carb warmer hoses.
I prefer to keep the banjos on the head/thermostat housing and just run a short hose from one to the other as it makes bleeding the cooling system a lot easier, but cutting the carb out of the circuit altogether makes it a lot more approachable for jetting changes etc.
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Another thing that makes DTR carb maintenance a lot easier (as long as you don't live in a really cold climate) is ditching (not completely) the carb warmer hoses.
I prefer to keep the banjos on the head/thermostat housing and just run a short hose from one to the other as it makes bleeding the cooling system a lot easier, but cutting the carb out of the circuit altogether makes it a lot more approachable for jetting changes etc.
@HOTSHOT-III bleeding the cooling system? Pardon my ignorance but anytime I’ve done it all I’ve done is I’ve pulled both hoses off them off (one has a bit of coloured electrical tape to differentiate the two) stuck a clean bit of m10 thread into the hose then use the clamps that where already in place to leaks. Not had any issues and I’ve been doing it that way and using the bike for years now
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@Stevie-Wonder
If it's winter I use a hair dryer to soften the rubbers first...
Put a bit of 2 stroke oil on the carb in & outlets. Loosen the airbox mounting bolts and push back as far as possible. (Without the slide and carb top fitted) Fit carb to inlet first. I then slide the airbox side rubber over the carb.If its a bitch i use a medium flathead screwdriver (that i have smoothed the edges off of) I then fit the jubilee type clip to the airbox/inlet side of the carb, because it gets in the way if left on the rubber. Fit the slide and carb top. Tighten up inlet clip and airbox bolts and enjoy!!...It's one of my least favourite jobs cause I've done it so fekin often!...
@biohazard13 said in Refitting carb hacks:
@Stevie-Wonder
If it's winter I use a hair dryer to soften the rubbers first...
Put a bit of 2 stroke oil on the carb in & outlets. Loosen the airbox mounting bolts and push back as far as possible. (Without the slide and carb top fitted) Fit carb to inlet first. I then slide the airbox side rubber over the carb.If its a bitch i use a medium flathead screwdriver (that i have smoothed the edges off of) I then fit the jubilee type clip to the airbox/inlet side of the carb, because it gets in the way if left on the rubber. Fit the slide and carb top. Tighten up inlet clip and airbox bolts and enjoy!!...It's one of my least favourite jobs cause I've done it so fekin often!...
In the past despite what the Haynes manual says I’ve had more success going inlet first, it’s also worth noticing despite what Haynes manual says I 100% agree anytime I’ve taken off both jubilee’s lifes been easier.
You just have to be very careful not to lose/drop the later spacers that go in-between them.
Anytime I’ve done it I’ve pulled the carb out tilted it 180 degrees out away from the engine and took the the slide out that way, rotating the carb 180 degree’s each time to get to the screws. With a short stubby JIA screwdriver it’s not that awkward and you don’t have to remove anything
Also cheers for writing that, glad somebody else knows the pain
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@biohazard13 said in Refitting carb hacks:
@Stevie-Wonder
If it's winter I use a hair dryer to soften the rubbers first...
Put a bit of 2 stroke oil on the carb in & outlets. Loosen the airbox mounting bolts and push back as far as possible. (Without the slide and carb top fitted) Fit carb to inlet first. I then slide the airbox side rubber over the carb.If its a bitch i use a medium flathead screwdriver (that i have smoothed the edges off of) I then fit the jubilee type clip to the airbox/inlet side of the carb, because it gets in the way if left on the rubber. Fit the slide and carb top. Tighten up inlet clip and airbox bolts and enjoy!!...It's one of my least favourite jobs cause I've done it so fekin often!...
In the past despite what the Haynes manual says I’ve had more success going inlet first, it’s also worth noticing despite what Haynes manual says I 100% agree anytime I’ve taken off both jubilee’s lifes been easier.
You just have to be very careful not to lose/drop the later spacers that go in-between them.
Anytime I’ve done it I’ve pulled the carb out tilted it 180 degrees out away from the engine and took the the slide out that way, rotating the carb 180 degree’s each time to get to the screws. With a short stubby JIA screwdriver it’s not that awkward and you don’t have to remove anything
Also cheers for writing that, glad somebody else knows the pain
@Stevie-Wonder
It's easy to get the carb into the inlet with the clip on though. More hassle fitting it after IMO. It's the airbox side that's the bitch!...
My only real tip would be fitting the carb top with alen bolts. Makes life easier not having to tilt the carb to fit or remove. Means you can fit or remove it any time even with carb fitted tight in place...Oh yeah! If youre gonna. Just blank the coolant outs at the head with allen bolts and copper washers. Less to fail...
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@Stevie-Wonder
It's easy to get the carb into the inlet with the clip on though. More hassle fitting it after IMO. It's the airbox side that's the bitch!...
My only real tip would be fitting the carb top with alen bolts. Makes life easier not having to tilt the carb to fit or remove. Means you can fit or remove it any time even with carb fitted tight in place...Oh yeah! If youre gonna. Just blank the coolant outs at the head with allen bolts and copper washers. Less to fail...
@biohazard13 that really is a first class tip. Makes perfect sense.
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@HOTSHOT-III bleeding the cooling system? Pardon my ignorance but anytime I’ve done it all I’ve done is I’ve pulled both hoses off them off (one has a bit of coloured electrical tape to differentiate the two) stuck a clean bit of m10 thread into the hose then use the clamps that where already in place to leaks. Not had any issues and I’ve been doing it that way and using the bike for years now
@Stevie-Wonder said in Refitting carb hacks:
@HOTSHOT-III bleeding the cooling system? Pardon my ignorance but anytime I’ve done it all I’ve done is I’ve pulled both hoses off them off (one has a bit of coloured electrical tape to differentiate the two) stuck a clean bit of m10 thread into the hose then use the clamps that where already in place to leaks. Not had any issues and I’ve been doing it that way and using the bike for years now
TBH Your reply got me thinking because I never used to bleed the cooling system after taking off the carb back when I was running the carb warmer circuit, I just used to open the radiator cap and top it up when I'd finished (and it wouldn't need much if I was quick blocking off the carb warmer hoses).
The carb warmer circuit actually serves as a cooling system bleed when it's been completely drained for an engine rebuild etc. as when refilling, it allows any trapped air bubbles to be expelled from the very top of the cylinder head, round the carb warmer circuit and out above the thermostat. Which is why the DTR cooling system doesn't need any bleed screws unlike a lot of MX bikes, the 350YPVS etc.
The Yamaha manual tells you to remove the carb warmer hose from the thermostat housing when refilling and refit when fresh coolant with no bubbles emerges but in practice if you fill the system slowly, you don't need to.
IMO unless you live somewhere really cold like Scandinavia you don't need the carb warmer circuit so the best compromise is to just run a short hose between the two banjos to ensure the cooling system remains self-bleeding and then you can have easier access to the carb. Not difficult to pop the hoses off and plug them as you say but imagine if you got really into tuning and were trying to jet/set up the carb, after the umpteenth time letting it cool down to put a dribble of coolant into the rad you'd get a bit fed up with it!
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@Stevie-Wonder said in Refitting carb hacks:
@HOTSHOT-III bleeding the cooling system? Pardon my ignorance but anytime I’ve done it all I’ve done is I’ve pulled both hoses off them off (one has a bit of coloured electrical tape to differentiate the two) stuck a clean bit of m10 thread into the hose then use the clamps that where already in place to leaks. Not had any issues and I’ve been doing it that way and using the bike for years now
TBH Your reply got me thinking because I never used to bleed the cooling system after taking off the carb back when I was running the carb warmer circuit, I just used to open the radiator cap and top it up when I'd finished (and it wouldn't need much if I was quick blocking off the carb warmer hoses).
The carb warmer circuit actually serves as a cooling system bleed when it's been completely drained for an engine rebuild etc. as when refilling, it allows any trapped air bubbles to be expelled from the very top of the cylinder head, round the carb warmer circuit and out above the thermostat. Which is why the DTR cooling system doesn't need any bleed screws unlike a lot of MX bikes, the 350YPVS etc.
The Yamaha manual tells you to remove the carb warmer hose from the thermostat housing when refilling and refit when fresh coolant with no bubbles emerges but in practice if you fill the system slowly, you don't need to.
IMO unless you live somewhere really cold like Scandinavia you don't need the carb warmer circuit so the best compromise is to just run a short hose between the two banjos to ensure the cooling system remains self-bleeding and then you can have easier access to the carb. Not difficult to pop the hoses off and plug them as you say but imagine if you got really into tuning and were trying to jet/set up the carb, after the umpteenth time letting it cool down to put a dribble of coolant into the rad you'd get a bit fed up with it!
@HOTSHOT-III said
“imagine if you got really into tuning and were trying to jet/set up the carb, after the umpteenth time letting it cool down to put a dribble of coolant into the rad you'd get a bit fed up with it!”
Which is exactly why I blocked off the hoses with Allen bolts and copper washers!
It’s bad enough faffing about with the airbox
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H HOTSHOT III referenced this topic on
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Okay so I think I’ve solved it, if you cut away the tab/loophole that the coolant line at the rear feeds that’s attached to your air box (don’t worry everything still follows it’s original route and looks clean) you can then take off your battery tray and unbolt your air box and remove the whole system air boot included with absolutely 0 effort at all. To refit you simply the procedure in reverse, to fit it it all in you have to approach from the exhaust side and twist
All that’s required is you remove your rear exhaust/silencer, rear quarter panels and seat
I shit you not, what is usually a 45 minute job with lots of profanity is now a piece of piss
