Carb Question

[FrankieJames7]

there seems to be a question no one knows the answer to. here's how it goes. i'm putting dynoport pipes on my ultra and rich told me .03" needs to be taken off of the slide cut away. the stock ultra sp slides are 2.0. that puts the cut away at 2.762mm.

the problem is rich was talking about round slides but i'm converting the sled to rack carbs. will a 2.762mm cut away on the flatslides provide the correct tuning settings for the new pipes?

 

[slededjr]

Flat slides would be different. Just phone Rich again.

 

[FrankieJames7]

Flat slides would be different. Just phone Rich again.

well ****. i don't think he has tuning info for flatslides either.

 

[FrankieJames7]

the next question. what is the flatslide cutaway equivalent to a 2.762mm round slide cutaway?

if that can't be found out i think the glorious egt and blow a few pistons tuning is going to have to happen. i will base jets off the xcr 800.

 

[slededjr]

the next question. what is the flatslide cutaway equivalent to a 2.762mm round slide cutaway?

if that can't be found out i think the glorious egt and blow a few pistons tuning is going to have to happen. i will base jets off the xcr 800.

will see what i can figure out for ya. I'm more of a DOO guy so i'll have to reach out to some of my contacts. Will get back to ya.

 

[FrankieJames7]

i have an idea. i also am getting a racepak avenger III with the probes and will cut the round slides to 2.762 and look at the egt's, then tune the rack's to those pre determined egt's. triple triple the only set up where you need to buy 6 needle jets at once lol

 

[FrankieJames7]

are flatslide and roundslide mikuni needles interchangeable?

 

[slededjr]

Yes. I sent you a link.
Also watch for detonation in mid range. Couple guys had to back timing off a degree or 2

 

[FrankieJames7]

i'm running spx cdi and slp powerdome heads but was still planning on taking about half a degree of timing out. i have egt's so i should be able to see if it detonates. don't the temps get cold for a brief second when you get some det?

 

[Clode]

you should consider a wideband to monitor the AFR, they react instantly and you dial each carb....you could buy 3 AEM widebands for the cost of a racepack

 

[FrankieJames7]

you should consider a wideband to monitor the AFR, they react instantly and you dial each carb....you could buy 3 AEM widebands for the cost of a racepack

i already bought a racepak avenger 3 with probes and wanted it for the other features as well.

the plan is to run the set up rich told me on my round slides, check piston wash and plugs, adjust jetting and then record the EGT's. when i put the flatslides on i will match the EGT's to what they were on the rounds.

plus idk what AFR the bottom end/mid range should be. i have the dynotech papers but they start at like 6500 rpm but do have AFR info. i don't need top end tuning it is the bottom end that i don't know about

 

[retiredpop]

What size of rack carbs are you using? I know the old SRX Viper Yamahas used TM33 carbs with triple pipes and they had a 1.5 slide.

 

[FrankieJames7]

What size of rack carbs are you using? I know the old SRX Viper Yamahas used TM33 carbs with triple pipes and they had a 1.5 slide.

38's.