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Help With Ty Mono Carb


ar22
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I have a Delorto PHBH26 carb which I have had from new

basicaly I am thinking of off loading it and do not want to mislead any one so am looking for some advice as to how good my memory is (and if the carb is of any use)

I owned a 1984 250 mono (first ones out)

For some reason at this time it was the thing to do to change the carb to make the bike run better

I used it for a year then sold the bike but kept the carb

Is my memory correct and is this a thing anyone else remembers. I can't even remember if it was significantly any better than standard

any views ??

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I have a Delorto PHBH26 carb which I have had from new

basicaly I am thinking of off loading it and do not want to mislead any one so am looking for some advice as to how good my memory is (and if the carb is of any use)

I owned a 1984 250 mono (first ones out)

For some reason at this time it was the thing to do to change the carb to make the bike run better

I used it for a year then sold the bike but kept the carb

Is my memory correct and is this a thing anyone else remembers. I can't even remember if it was significantly any better than standard

any views ??

The PHBH26 (probably a "CS" model) is the "large body" Dellorto used on the 1996 JTR370 GasGas Trials and some Fantic models for a few years that I'm aware of. It's a little "cranky" to tune correctly but, if your Mono came with a Tekei, like my 85' Mono came with, probably a step up (I have a Mikuni on mine now). I also had a 96' JTR370 and changed to a 28 Keihin. The carb has a fairly wide spigot so it might stretch some manifolds, resulting in cracks in some cases, and it's the reason why the 96' 370 manifold is often used in GG Keihin conversions as the spigot diameter is essentially the same as the 28 Keihin.

The Fantic guys always need parts and could probably use it (I just gave my old PHBH to a Fantic owner) so it does have value.

Hope this helps.

Jon

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yes it is all coming back to me

you could use the carb i have or as some did, put the left carb from a 350LC on the ty (it had choke) I think they were Mikuni

from memory my bike ran perfect jetting was sorted,

although it may be taller and sits a bit funny. (I think)

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yes it is all coming back to me

you could use the carb i have or as some did, put the left carb from a 350LC on the ty (it had choke) I think they were Mikuni

from memory my bike ran perfect jetting was sorted,

although it may be taller and sits a bit funny. (I think)

I think the LC's came with VM26's, which would be good for most upper displacement Trials bikes. I've got one on my TY350 and it's been bulletproof and not antsy to tune, and once set, it takes a big change in atmospheric conditions to throw it off (like going from sea level to 8200 ft.).

Jon

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  • 8 months later...
I have a Delorto PHBH26 carb which I have had from new

basicaly I am thinking of off loading it and do not want to mislead any one so am looking for some advice as to how good my memory is (and if the carb is of any use)

I owned a 1984 250 mono (first ones out)

For some reason at this time it was the thing to do to change the carb to make the bike run better

I used it for a year then sold the bike but kept the carb

Is my memory correct and is this a thing anyone else remembers. I can't even remember if it was significantly any better than standard

any views ??

JSE,

I have a 1984 TY 250 mono. Mine has the TK carb.

Were you running the PHBH26 on your 84 mono? Was it a direct fit? Any clearance issues with the frame etc......I see that it's a tight fit under the frame where the carb sits.

I may be interested in it........

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JSE,

I have a 1984 TY 250 mono. Mine has the TK carb.

Were you running the PHBH26 on your 84 mono? Was it a direct fit? Any clearance issues with the frame etc......I see that it's a tight fit under the frame where the carb sits.

I may be interested in it........

I have a Mikuni VM26 on the 85' TY350 now, never ran a PHBL but I would imagine it would work well. The VM fits right up with no problems and is often used on the older bikes, like the Bultaco Sherpa-T. The "choke" lever and fuel spigot is on the left side, but it's easy to run the line to the tank and by bending the lever down a little bit, it's easy to use. They are fairly easy to obtain and give better response and are easy to tune as parts are easy to come by. I've also got a Mikuni flatslide 26mm that I've modified for a spigot mount and may try that just for fun.

I've got a bad case of the "Hmmm, I wonder if that would work" disease and often try things to satisfy my mechanical curosity, which up to this point has been insatiable, but then again, it's also been productive and fun.

Jon

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The TK on my 84 mono ty has the throttle cable going into the top of the carb at an angle, to allow for frame clearance. Does the VM fit in this regard? Not sure if the older ty's have this same frame clearance issues.

I have a Keihin 28 PWK. Don't think it would fit due to above reason.......may just have to put it on the Cota 348.

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The TK on my 84 mono ty has the throttle cable going into the top of the carb at an angle, to allow for frame clearance. Does the VM fit in this regard? Not sure if the older ty's have this same frame clearance issues.

I have a Keihin 28 PWK. Don't think it would fit due to above reason.......may just have to put it on the Cota 348.

The PWK Keihin-28 may have a slightly shorter body (bell to spigot end) and a taller slide housing so there might be clearance problems, but here's a photo of the VM Mikuni-26 on the TY Mono (the cable comes straight up from the slide cap, without an angled fitting, and works fine) and a photo of the modified Mikuni 26mm flatslide I'm going to try:

Jon

Edited by JSE
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The TK on my 84 mono ty has the throttle cable going into the top of the carb at an angle, to allow for frame clearance. Does the VM fit in this regard? Not sure if the older ty's have this same frame clearance issues.

I have a Keihin 28 PWK. Don't think it would fit due to above reason.......may just have to put it on the Cota 348.

Here's some photos I took for an article for Trials Comp News comparing the Keihin to a PHBL (which is closer in size to the VM and TK carbs):

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Neat, Pat!

Looks like you got the "modified" PWK for one of the modern bikes with the controls on the left side?

The PWK off the KX80 has the adjustments on the right side, which would be perfect for the TY.

What size jets did you end up with and how is the performance, compared to the TK?

Jon

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Hi Jon,

Apologize for being a stranger..will shape up :rolleyes:

The performance from Keihin/GG-07, twinair togther with your reedcage and BJ head mod is great, she runs like a modern.. with ~15kg backpack, the piston is worn though... The carb offers a more adequate mixture, you can explain it much better than I :thumbup: , better responce, perfect idle (clean down to rpm like a 4-s if you like, I dont, using ~700rpm), mid, top (did truend the crank down to 0.05mm couple years ago)

The jetting is now 50 and 130, 1.5t out, middle clip pos, GG std needle, first time Ive seen middle brown spark on this bike...light with 45 and 127....

Have not messaured the tot airvol, but vol airbox incl boot must be larger than GG, because those jets are big..Have not messaure the floater hight.

Performance with TK 42 and 125 was as Yam, but sparks dark brown to black..

Did found spare flyw, now red weight and will probably test a DEP this season, would have liked to test if a GG middle box fits and red the lenght of the pipe, but I guess there is not room enough either way.

Have not rised the ext port yet..

Cheers

Patrik, as I remember, is from Gothenburg, Sweden, and has been doing a lot of different and interesting things to the TY Mono.

Pat, ar22 first asked this question as he had, as I remember, a PHBH from an earlier bike and thought about using it. My experience with the PHBH is that it's difficult to get it to work right. I had one on my JTR370 and soon swapped it for a PWK28. Have you had any experience with the PHBH? (it's the "large body" Dellorto with the oval bore and was used on a lot of the Fantic bikes).

Jon

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