Dellorto or Mikuni TM?

[koko64]

While I have been working on Mikuni BDST 38 CV carbs, I have also been interested in both Dellorto and Mikuni TM flatslide carbs on short manifolds. I have dealt with the Mikunis before but not the Dellorts.
Price wise the Mikunis are available for $179 each.
Those of you with experience with either of these carbs are welcome to share your thoughts. Pros znd cons of each carb?

[randtcastell]

I am certain the Dellortos are Italian, so there is only one best choice. Your Paso will love the 'strumenti Italiani' because they speak a common language.

[Maico88]

I have a 750 Sport with 36mm dellortos. It runs well at at throttle openings, so the dellortos will work very well. However, I also have an RD400 with flatslide mikuni carbs and a 100/7 BMW with flatslide mikuni carbs. The flatslides made a dramatic improvement in the way that both run. That said, I don't have dyno results for any of my bikes, so my opinion is only subjective.

[koko64]

I have a 750 Sport with 36mm dellortos. It runs well at at throttle openings, so the dellortos will work very well. However, I also have an RD400 with flatslide mikuni carbs and a 100/7 BMW with flatslide mikuni carbs. The flatslides made a dramatic improvement in the way that both run. That said, I don't have dyno results for any of my bikes, so my opinion is only subjective.

Thanks

The TM carbs are an economical option for flatslides
Guessing a jetting baseline is the hard part. The Mikuni CV carbs may not have the same jetting scale as the TM carbs as a reference point.

On the other hand there is a wealth of experience here tuning the Dellortos.

[koko64]

A difference in air jet circuitry between various Mikuni TM flatslide carbs came to my attention. It means that some have a closer relationship to jetting patterns in common with Mikuni CV38 and Keihin FCR39/41 carbs, and some were light years away.

As I was pondering this, a forum member pmed me with a great offer on a set of TM40 flatslides. They had the circuitry that I could relate to in regards to making reasonable guesses for baseline jetting.
Some TM carbs will make sense to your past experiences of tuning more than others it seems. A quick look at SUDCOs site showed at least three types of TM carbs, and that's not counting the 2 stroke versions.

I also got three Dellorto tunning guides today. Great reading. Noticed Dellorto make a flatslide carb that looks like an elegant European styled FCR. Check out dellortodirect.com and the VHSG carb at $2400 - $2600 each! Only the Italians can make a flatslide carburetor look beautiful.

[88WhitePaso750]

A bit late to the party, but...

My 88 750 has Mikuni TMs and they rock. The only issue is the delicate mounting angle to bring the bowl closer to level. These carbs with the NCR header make this bike sound mean. The Mikuni's are easy to tune.

I am looking for a throttle cable for this setup, mine is getting rough. Any sources?

[koko64]

Powerbarn.com.

They sell cables and even make them to your specs if they dont have a kit.

Excellent service.

[koko64]

Powerbarn identified the TMs I have as TM38s (TM38/85 model). Interestingly, they are 39.7mm at the bore through to the spigot with a 62mm bellmouth. Thats alot of carb and effectively 40mm. The BDST CV are about 37.5mmish by comparison. The nice fellow at Powerbarn sas very helpful, he said the actual size of the carb does vary, and may do so depending on the carb being an aftermarket race model or supplied oem model.

Therefore model designation doesnt always directly reflect actual bore size. I spose BDST38 sounds better than BDST 37.5! Just something to keep in mind.

Regarding Dellortos I dont know, but someone on here will.

[Andrew2]

Hey Koko,
I ran 40mm Dellortos on my Paso when I had it and it ran great.I think they would be overkill on say the milder tuned engine of a 750F1 but with the bigger valves of the Paso I had no trouble.The difference between them and the Weber was amazing.

Cheers
Andrew

[randtcastell]

I must agree and chime in with Andrew, I have 40mm Dels on my Paso, and it runs great as well. Never an issue.

[Skins]

My 750 Paso purrs like a kitten and bolts like a scared cat with 36mm DelOrtos. Starts first turn every time, even when cold, also.