So Close!...
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@SpookDog I appreciate you are going for that OEM style, but I run a VHSA carb on my DT and it runs great. So it doesn't have to be the real deal for it to run well.
That said I had a similar issue when I bought my VHSA I didn't realise there were variants of it in a similar fashion and the one I was jetting to was different to the one I was interested in!
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I’m not for or against anything that works! I just don’t want other people to have to go through the same kinda shit I have. To be aware of the differences. Also Mikuni are good carbs but I’d rather run a Delorto 30mm flatslide if I was going to change to a ‘parallel’ carb
I used them before in ‘days gone by’ with nothing but a bellmouth on them and never had a problem, also old 30mm Amal carbs...I’ve never had so much trouble with a bike as I have with this Dtr. Then it just makes it more rewarding when you finally do suss out what was bitching with you in the end!
I’m @ 1300 miles and the head is still holding (& the cooling is great!)
Really does look like a good unblocked .25 pilot jet was all that was needed to stop it missing/knocking!@marcus
Was it marked near the choke? I read somewhere that it’s the place?... -
@Calum
I did not know that! I’ve been waiting for a realistic break in the nightmare so I can get a barrel done by PJME. I have a good condition (studs &threads!) 3mb that I’m gonna get a rebore done to. I’m also going to find out more about the o-ring conversion to the barrel. I really just want to know if it’s 1 o-ring (for the bore pressure only) or 2 (1 for the coolants outer as well). My current barrel is a bit worn & ‘slappy’ at low revs, which didn’t help my diagnosing at all!!
I’ve also got a couple of 4fu barrels. I wouldn’t mind getting one resleeved with a cast iron liner. It works out the same price as plating but with ‘future proofing’ rebore options
it’s just whether the FU porting makes it really financially worthwhile, HP wise? (If it doesn’t suit the Dtr I have a TZR (hw) chassis to put it in) I know the exhaust port is wider, ect, but don’t know how much difference it makes, Powerwise? Or if the inlet porting is different?... -
@SpookDog said in So Close!...:
I haven’t found a carb with any markings yet! I wish, it would of saved me a year of fucking around with the wrong jetting! I found out about my carb from the back of the Haynes manual. It says that 2004 onwards carbs have a unique plastic insert that sits over the main & pilot jets. That and a unique plastic throttle spring seat. That (my) particular carb has a 240 main & .25 pilot jet. At first I was trying to jet my carb according to the year! (1988, 210 main & 22.5 pilot) it had a 180 main jet in when I first got it! The manual even said it was a 26 mm carb to confuse things!
You live and learn!The main, important difference is that generic Mikuni carbs don’t have the 15-20degree slant that the Yamaha ordered Mikuni’s have. That allows the float bowl to be level...
There are carbs out there, but sheeple look at the asking price on fleabay like sites and copy unrealistic high prices. I’ve found reasonable people selling for £50 for a usable carb, but they are few and far between
...I wouldn't take too much notice of Haynes if I were you when it comes to DTR/TZR carbs, they've never quite got their heads around the difference between the TZR 2RK/'88 DTR VM26SS and the TM28SS fitted to the '89 onwards DTR. As far as I know all TM28SS carbs have the plastic insert which pushes into the pilot jet and fits around the main jet as my 1990 from my youth had it, and my '93 I bought in 2020. Likewise the plastic throttle spring seat; it's more of a retainer for the cable nipple in the slide really.
But regarding the angled venturi in the stock carb body, well admitting this isn't exactly going to make me look like a 2-stroke tuning guru but I didn't even notice it when I was on the site! Trying to imagine how that would affect the jetting; for a given float height it would have the effect of making the pilot jet and choke tubes more deeply submerged in the fuel but not sure it would affect the main jet too much as it's pretty much in the centre of the bowl.
Anyway I've asked the question on a couple of FB tuning pages so we'll see what everyone thinks:
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Yeah, the ‘VM26 flatslide’ proper confused the fuck out of me for quite a while (3mb00).
My carb is a 3rm02 1999 onwards model, not 2004 as I might of thought/said before? I’ll have to reread my thread, to check, my memory is FUBAR! It’s why I started documenting my nightmare here (I’ve lost too many notebooks)1512 miles and still running! Cooling is sublime and radiator is full. Also the bike is running it’s best ever! No knocking or misfires
I’m still riding conservatively, nothing over 80% throttle, or over 65-70mph...
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1909 miles and still copacetic!! Cooling still good. No popping, missing or knocking since cleaning out the pilot jet with notched wire, rather than air blown through...
Fitted Brembo carbon~ceramic pads tonight. Was a total PITA! Had to loosen the bleed nipple to retract the piston enough to fit over the pads. Is there a one way valve in the master cylinder?!...
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@SpookDog You shouldn't need to do that to push the piston back although it might be necessary to remove the reservoir cap to back-bleed the brake like that as there's a membrane under the cap which is designed to expand and occupy more space inside as the pads wear.
Also well worth attacking the underside of the reservoir cap (if it's the front brake) with a brass wire brush as there's two little channels which allow the membrane to do this by letting air in above it during this process (and if these are blocked that could be why you couldn't push the piston back). Still at least you know the bleed nipple moves!
Failing that the Yambits master cylinder repair kits are ace and a lot cheaper than OEM!
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The top was off of the reservoir when I tried. Piston movement isn’t not stiff or binding. Have no idea why I couldn’t retract it without cracking off the bleed nipple 🧐
First impression of the Brembo CC pads is very positive, especially considering they’re not bedded in at all!
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I’m @ 1964 miles now and it’s running so sweet it’s unreal compared to my previous escapades!
60something miles on the Brembo’s and I’m well surprised @ how positive they are! It’s hard to judge brakes on a bike with such a bad front end. Just touching the front brakes makes the forks dive (what feels like) 2~3 inches, then firm braking takes it the rest (like I said, it’s hard to judge). But I’m convinced these carbon-ceramic Brembo’s are in a totally different league than the red EBC pads I was using (NOT ‘Red Stuff’ which I couldn’t find a vendor for). If your front brake leaves you feeling insecure then these are worth the £24 for the confidence they inspire IMHO
I’m gonna get a pair for the rear as soon as I’m flush...I can’t wait for the 40 days for my progressive springs to get here to pass! I’m hoping to have the full ticket of a front end that doesn’t get down right scary over 55mph!
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2170 miles since the rebuild and all is well. Zips up to & cruises @ 60mph (@6000rpm) so smooth and quick if there’s no headwinds!
Gonna try the Exol synthetic and see how it stands up to castrol1 and silcolene comp2...
Ordered the Brembo carbon ceramic pads for the rear and am gonna fit them with the front calliper with the new bigger diameter master cylinder...
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2320 miles with no head blown! I’m officially calling it FIXED!! All caused by a too small pilot jet, un~fucking believable
Now I can get a rebore & new piston (that I trust completely) and get on with other jobs needing doing, like forks, paint, exhaust, new 6 foot friendly seat, new loom, ect -
Jacking it would only make it worse for me. It’s the slipping down & forwards that stretches out my butt & boys. I need a higher, better padded/supported front to my seat. My but fits onto the spot where the soft thicker front foam levels out onto the thinner padded rear. There’s a ridge there I think...
Don’t RE’s have different tank, seat, config than the Dtr? I’m guessing they improved it...
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@SpookDog the forward most lowest part of the seat is where you should be sitting with you inside leg squeezing the tank for ultimate control/stability. But sounds to me like this part is too low for you? The dt125r seat height is 840mm/33inches, and the dt125re is 915mm/36inches so considerably taller. You can swap the seats as I've seen it done but you'd need to also swap the tank and all panels. A bit extreme though for a classic bike. Alternatively remove the seat cover and pack it up with a bit of memory foam or similar. Probably then best to fit a new seat cover.
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If I sit there my knees are too far forward. My elbows stick out like chicken wings. Also my ankles won’t let my feet bend up enough to operate the gearshift. I just can’t fold myself up enough, imagine like a clown on a mini bike! But squatting for a dump
Cheers for the RE info. I didn’t realise the tank, seat & panels could be fitted to a dtr I thought the exhaust was different as well?...
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@SpookDog slight difference in the exhaust, mainly the bracket near the radiator which can be easily adapted with a little spacer but there would be no need to change the exhaust. Have you considered wider bars with risers and rotate the gear lever forward on the teeth by 15-20 degrees?
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