Attn 42 Mikuni's Team ( John-Mike-Jeff-etc-etc)

[Phil-1100]

Well I have to agree and disagree with Carlos, I have never had any trouble starting my bike with the 39's fitted. I went though a English winter with snow on the ground still no problems. Twist the thottle 3-4 times bike fired up easy pease.
39's are a a lot harder to tune than the Mikuni's.
I have handled a few,
Mikuni
Amal
Keihin
SU
Weber
Dell'orto
Bendix
Zenith
To name a few

 

[ThruxTonUp]

Can you explain the rod ratio thing to me? Fred did once over the phone, but I think it either went in one ear and out the other, or flew right over my head...

the 103-84hp happened with the D&D street pipes, right?

What kind of numbers is Fred getting from Speed Triples?

Right on the pipes, Rod ratio only affects the guys with stroker motors, and has to do with how much side pressure the rods and pistons are putting on the sides of the cylinder wall. In other words when you build a stroker bike and leave the rods the stock length the rod ratio is low on the bonnie's - can't remember exact numbers but like 1.6 and some change, Nascar runs their rod ratios in the 2.0 and more. Fred has got two sets of custom made rods for a bonnie one is a 1/4 inch longer the other 1/2 inch these when combined with a proper spacer/gasket set under the barrells increase the rod ratio to more acceptable levels - though the 1/4 inch is still not quite optimal I don't believe, if I'm remembering right. Scott's motor the first round when it started smoking at 12-13,000 miles was due to a poor rod ratio - the top of the piston - the area above the ring lands was actually hitting the barrels the pistons were rocking so much in the bores due to the low rod ratio, this caused the pistons to deform and flatten down causing the rings to then stick in the grooves due to the side/edge of the pistons being "hammered" down , when they stuck - oil control/cylinder pressure was affected and smoke out the pipes resulted.

Check on his web-site down in the vendor area - seems he is getting 123 RWHP from them with just porting and a cam change if I remember right. We where going to dyno them last night but the dyno truck was a no show, at the dealership we where going to. The thing is they are 995 or 1050's and getting those kinda numbers on a counter balanced crank, SO why not a 1100 bonnie - what is the hold up to keep you from getting 120 plus RWHP - Fred thinks its very doable, so we will see. He has explained his whole plan for a 120 plus bonnie - but I'm sworn to keep the secret. The more he learns about the motors, the more things change - even on porting, engine size, carbs, etc.

 

[ThruxTonUp]

I disagree with you and Mike as well John!
Tune the carbs properly and you will not have starting problems at all!

Come tune my carbs Carlos, then will tear up some twisty mountain roads and go Duc hunting. :fight:

 

[1087]

Come tune my carbs Carlos, then will tear up some twisty mountain roads and go Duc hunting. :fight:

Nah... is worthless John!
You have way better carbs than those little ones.
Keep and going pulling the choke, in the meantime until you swap carbs, be sure to leave the bike inside, that will facilitate cold start in the morning or late night

 

[Fast Freddy]

thanks John, freddy

 

[mikenva]

I disagree with you and Mike as well John!
Tune the carbs properly and you will not have starting problems at all!

well atlest we can all agree and disagree and still talk and be nice.
See i leraned something new about 39mm carbs (put bike inside when its cold lol.If you cant get them tuned call 1-800 carlos for free house calls for tuneing .lol damn thats a deal I better order some soon .CARLOS DO YOU BRING THE BEER TO?

 

[1087]

well atlest we can all agree and disagree and still talk and be nice.
See i leraned something new about 39mm carbs (put bike inside when its cold lol.If you cant get them tuned call 1-800 carlos for free house calls for tuneing .lol damn thats a deal I better order some soon .CARLOS DO YOU BRING THE BEER TO?

That's a very good one Mike!:cheer:
Wish we can get together one day and have a great time!
beers on me of course!
1-800 Carlos LOL!

 

[ThruxTonUp]

Nah... is worthless John!
You have way better carbs than those little ones.
Keep and going pulling the choke, in the meantime until you swap carbs, be sure to leave the bike inside, that will facilitate cold start in the morning or late night

If we were all really smart we would be ditching the carbs and going to state of the art fuel injection set-ups, which brings up the busa point again and not the reason I bought a bonnie to begin with. Love the simplicity.

 

[mikenva]

hey who said we are smart lol.I been thinking about busa and kaw 14 might get one next spring.Wont ride it much but if someone kicks my bonnies ass i can say let me go get my other bike lol.If it wont bad enough fred had to get me looking at honda 1000s.Damn will i ever grow up ,I hope not lol.

 

[1087]

If we were all really smart we would be ditching the carbs and going to state of the art fuel injection set-ups, which brings up the busa point again and not the reason I bought a bonnie to begin with. Love the simplicity.

That will happen. We already are in the Busa leagues dollarwise, at least many of us, not including you , because you got the bike with the parts on it.
Still love the carburetors for my Bonneville.
Bottom line:

Mikuni's: Better

But up to this day you have the most powerful street motor, with the wrong rod ratio and with carbs that you are no to fond to it( 39' Keihin's), and my 1087 in this early stage(39 Keihin's) is way more torquey and powerful than the big mouth from the Ace Cafe Forum, with the Wiseco 1100 , no counter balancers, Jorgen module( 8900 RPM's 3+), micropolish gears,,etc,etc.
So The Proof is on the Pudding.
I will anxiously wait.

 

[mikenva]

carlos looks like you got that boy beat so far but I dont think you want any parts of bills 1200 yet .Theres alot more for all of us to learn.One thing I learned years ago is theres allways something faster out there,so you got to keep learning and keep a open mind.

 

[agro]

That's why I will do my own back to back comparo.
I will finish the mods with the 39's on it.
Then I will swap to 42's.
Then I will swap to 45's.
The winner will stay in the bike for good.
Why?
Because is my personal bike, and I stay with whatever gives me the best.
And in my whole entire life I always been looking for the best.
But up to this point I'm giving a run for their money to anybody with 42's.
Then I will tell you the...:shh:

Hey Carlos, how ya doin man? All good I hope.

Got a couple of questions, besides 3mm extra diameter and choke of the Mik 42's what are the difference in adjusability between the Mik 42's and Keihin 39's?

Also are you going test with 41mm Keihins? And is TPUSA going to offer 41 Keihins in a kit?

Waiting on someone to offer 41mmm Keihins with TPS as a kit, afterall the 39mm Keihin Sudco kit for our bikes has TPS, might ask Sudco if they could substitute 41's with TPS instead of the 39's in their kit.
Don't care what anyone says, I wanna run the TPS on my carbs.
Just fitted my Pieman modified igniter onto my Thruxton and it rocks! 790 ignition maps with 9000 rpm limit. Better idle quality, throttle response and stronger midrange, have '03 790 cams but have only fitted the 790 exhaust cam, advanced 1 tooth. This setup has 9 degrees overlap, total, with 16 degrees extra duration over the Thrux exhaust cam.

 

[mikenva]

Why do you think you need the tps?Have you done any testing with out it hooked up?
I have and cant see where it helps with flat slide carbs.If you have the right wot map with some added advance you wont even know the tps is not hooked up.Once you get these bikes making good hp and tuned right they just run good at any throttle opening.
As far as the tune on the 39s and the 42s I think what hurts most people who cant get the 39s right is there are more things to change then are needed (more things to get wrong).
One thing the 42s have that is needed is you can adj where the pumps start and stop working,thats a must.I think alot of people dont understand what the pumps should do.What they need to do is supply fuel when needed to get around low vac that happens when you open the throttle fast and the carbs cant supply gas at the low vac to keep up.(thats why you get the bog if the pumps are not right.)But you have to have the right amout of pump at the right time to much to soon will cause it to flood and cause the bog to.)

 

[Texas94fs]

:thread:Wow some of this is like chinese to me. . . I just cant wait till i have enough money for more go fast parts!

 

[1087]

Hey Carlos, how ya doin man? All good I hope.

Got a couple of questions, besides 3mm extra diameter and choke of the Mik 42's what are the difference in adjusability between the Mik 42's and Keihin 39's?

Also are you going test with 41mm Keihins? And is TPUSA going to offer 41 Keihins in a kit?

Waiting on someone to offer 41mmm Keihins with TPS as a kit, afterall the 39mm Keihin Sudco kit for our bikes has TPS, might ask Sudco if they could substitute 41's with TPS instead of the 39's in their kit.
Don't care what anyone says, I wanna run the TPS on my carbs.
Just fitted my Pieman modified igniter onto my Thruxton and it rocks! 790 ignition maps with 9000 rpm limit. Better idle quality, throttle response and stronger midrange, have '03 790 cams but have only fitted the 790 exhaust cam, advanced 1 tooth. This setup has 9 degrees overlap, total, with 16 degrees extra duration over the Thrux exhaust cam.

Hello Michael;
I'm doing fine, what about you?
About the 42 and 45's I can't say anything yet until I start to play with adjustments and tuning, you know it's so easy to make bragging claims, but I'm not into that.
As soon as I have my own conclusions I will let you know.
We have no decision yet about the 41 Keihin's, if it worth to make the kit or not, there is not much flow difference compare to the 39's.
I'm glad that you are happy with your modified ignition box.
Did you do before and after dyno runs?
Please let me know.

 

[agro]

Hello Michael;
I'm doing fine, what about you?
About the 42 and 45's I can't say anything yet until I start to play with adjustments and tuning, you know it's so easy to make bragging claims, but I'm not into that.
As soon as I have my own conclusions I will let you know.
We have no decision yet about the 41 Keihin's, if it worth to make the kit or not, there is not much flow difference compare to the 39's.
I'm glad that you are happy with your modified ignition box.
Did you do before and after dyno runs?
Please let me know.

Doing fine mate.
No dyno runs, saving my money for a big block kit and carbs, still undesided which way to go on these, BP or TPUSA

Carlos, what is the difference in adjustability between the Keihin and Mikuni??

Also you said in one of your posts you are using the stock Thruxton igniter with 7800 rev limit, I thought Thruxton igniters went to 8000?
I know mine used to come on @ 8200 rpm indicated on the tacho, but these tachs are not that accurate.

What happened to your 790 igniter module. Is it fried? Maybe you coould send it to Pieman, he might be able to sort it out and upgrade it?

 

[Phil-1100]

Ignition Module - Pieman, Jorgen they both do the same mod. 3° advance over 3000rpm, to a 790 box. I have had mine changed two years ago, works brilliant.

Phil

 

[mikenva]

OK lets see what we have learned here.
#1 If you have stock or poor flowing heads the 39s are just as good.But they wont start in cold weather unless Carlos tunes them for you.lol
#2 42s are better if you have a good head and they will start in cold weather and you can tune them yourself.
#3 jojje or pie man boxes work good
#4 We dont know shit yet lol
#5 I love giveing my friend carlos shit lol
#6 Ridetillurot bike is so fast people dont want to talk about it lol

 

[sweatmachine]

OK lets see what we have learned here.
#1 If you have stock or poor flowing heads the 39s are just as good.But they wont start in cold weather unless Carlos tunes them for you.lol
#2 42s are better if you have a good head and they will start in cold weather and you can tune them yourself.
#3 jojje or pie man boxes work good
#4 We dont know shit yet lol
#5 I love giveing my friend carlos shit lol
#6 Ridetillurot bike is so fast people dont want to talk about it lol

that's a pretty good list!

I agree on all counts, and I'm still curious about #6.

 

[Ridetillurot]

OK lets see what we have learned here.
#1 If you have stock or poor flowing heads the 39s are just as good.But they wont start in cold weather unless Carlos tunes them for you.lol
#2 42s are better if you have a good head and they will start in cold weather and you can tune them yourself.
#3 jojje or pie man boxes work good
#4 We dont know shit yet lol
#5 I love giveing my friend carlos shit lol
#6 Ridetillurot bike is so fast people dont want to talk about it lol

They aren't allowed