Carb Upgrade.

[croatiancowboy]

Hello folks. My name is Paul, I'm also the Croatian Cowboy. I ride '97 VN1500D2 Classic that I've recently converted to what I call a knuckledragger Bagger.

I have every Thunder MFG option they make on this bike. I have just finished porting an polishing the heads, and new 1600 Meanstreak valve seats and valves installed, all titanium springs and retainers, custom MLS headgaskets, Manual Cam Chain Tensioners, Duo Clutch, Barnett Steels and Carbon Friction Plates, I have a custom cut 6mm tube in between the two circlips that ride on the shifter in the stator housing keeping them permanently spread. I have a Memphis Shades batwing with custom stereo mount, Power Acoustik headunit and 2x Sony Xplod 5.25" Vance&Hines Long Shots, I've a 500 MicroFarad Capacitor helping keep everything stable. Dynatek Coils, and a dynatek 3000 for a 2000 vn1500 Carb with TPS sensor input.

Now here is where the fun begins, I have recently scored a 44mm Keihin CVK Screaming Eagle Carb from a Harley obviously, but I acquired for changing the cam chain tensioner to the upgraded twincam 88 model on his ultra classic.

This is my problem, I don't have a baseline to where to start from here, because its a 44mm, does that mean the amount of flow of air will be increased that much? Or can I start at a baseline number where the cvk40 left off, with thunderslide stage 7, 190 main, 50 pilot ? Then start from those same numbers and slowly move up where I feel the need ?

Has anyone done this ? Besides drilling out the cable holders on the Carb and currently waiting for a thunder cvk Carb adapter from Carb mount to Type A pattern BAK, I haven't done anything else. I'm just looking to pull numbers in the quarter (last season pulled 13.5@98mph).

Just want to send out RacinRay a shout out for working magical powers and waving wands and chanting hokus pokus and making my Four speed gearbox come alive again!

Thanks in advance.

Croat Cowboy.

[cnc]

Sounds like an interesting bike, got any pic's for us?
I am more familiar with playing around with Mukuni's than CV's but assuming that your carb boot and intake port do not limit the potential increase in air volume using a 44mm carb and the Cv40 is dialed in correctly with the present jet #'s then I would suspect you will be running lean using those same jets.

Disregarding any other limiting factors, here is a rough calculation of the circle area difference between a 40 mm and a 44mm diameter circle.
RADIUS = 20
DIAMETER = 40
CIRCUMFERENCE = 125.66370614359172
CIRCLE AREA = 1256.6370614359173

RADIUS = 22
DIAMETER = 44
CIRCUMFERENCE = 138.23007675795088
CIRCLE AREA = 1520.53084433746

Not sure how much this helps and you might also google jetting charts for a 44cv carb.

[croatiancowboy]

It'll only let me post 5 at a time, I still have a couple that may be of interest to many that just pass by and take a look, or want to know more. Thanks for the info provided. I'm going to up the main to 220, start plug reading with the 1/4, 1/2, 3/4, WOT tape around the grip trick and coast with kill switch to a stop, pull plug. Clean and retry until I get paperbag brown. I'm still waiting for a ThunderMFG 44mm Harley adapter type A bolt pattern adapter. So the best I can do for now is pics I have, but I am most greatful for the forumla u provided. I should've spent more time in school instead of drinking, and hitching rides to the dragstrip when in my younger days.

Cheers brother, this Heineken and shot of Tokilkya is for ya! :cool:

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[croatiancowboy]

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[croatiancowboy]

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[mick56]

Originally Posted by croatiancowboy

It'll only let me post 5 at a time, I still have a couple that may be of interest to many that just pass by and take a look, or want to know more. Thanks for the info provided. I'm going to up the main to 220, start plug reading with the 1/4, 1/2, 3/4, WOT tape around the grip trick and coast with kill switch to a stop, pull plug. Clean and retry until I get paperbag brown. I'm still waiting for a ThunderMFG 44mm Harley adapter type A bolt pattern adapter. So the best I can do for now is pics I have, but I am most greatful for the forumla u provided. I should've spent more time in school instead of drinking, and hitching rides to the dragstrip when in my younger days.

Cheers brother, this Heineken and shot of Tokilkya is for ya! :cool:

Attachment 9647Attachment 9648Attachment 9649Attachment 9650Attachment 9651

Mate,as you dont mention any change,can i assume that they are standard piston's.

[croatiancowboy]

Originally Posted by mick56

Mate,as you dont mention any change,can i assume that they are standard piston's.

They are thunder 95" overbore. The heads are ported and polished and cut to accept 1600 meanstreak seats and valves were installed.

Every option that thundermfg sells for the bike performance wise, was done. But with extras such as kwibble high lift springs titanium retainers. Nothing has been to the Carb besides the thundermfg light wieght slide and adjustable needle, and I have thrown a 220 main jet and 48 pilot into it, shorter spring for slide. Also the accelerator pump is probably going to be swapped over for either the boyesen model I may just go twinshot.

[mick56]

Originally Posted by croatiancowboy

They are thunder 95" overbore. The heads are ported and polished and cut to accept 1600 meanstreak seats and valves were installed.

Every option that thundermfg sells for the bike performance wise, was done. But with extras such as kwibble high lift springs titanium retainers. Nothing has been to the Carb besides the thundermfg light wieght slide and adjustable needle, and I have thrown a 220 main jet and 48 pilot into it, shorter spring for slide. Also the accelerator pump is probably going to be swapped over for either the boyesen model I may just go twinshot.

The reason i asked was those valve cut out's,i have wondered how close the standard piston's get to the valve's. What sort of bhp/torque figure's are you getting out of that motor,and what do you reckon it's cost you.

[blowndodge]

Lot of money to put into that bike.

[cnc]

Originally Posted by croatiancowboy

It'll only let me post 5 at a time, I still have a couple that may be of interest to many that just pass by and take a look, or want to know more. Thanks for the info provided. I'm going to up the main to 220, start plug reading with the 1/4, 1/2, 3/4, WOT tape around the grip trick and coast with kill switch to a stop, pull plug. Clean and retry until I get paperbag brown. I'm still waiting for a ThunderMFG 44mm Harley adapter type A bolt pattern adapter. So the best I can do for now is pics I have, but I am most greatful for the forumla u provided. I should've spent more time in school instead of drinking, and hitching rides to the dragstrip when in my younger days.

Cheers brother, this Heineken and shot of Tokilkya is for ya! :cool:

Nice, what's with the red bottle with mdf on it ? Not nitrous is it ?
That's how we always read plugs when jetting snowmobiles around here, although in our case the lower rpm up to almost 1/2 throttle the main jets and needle position did not really come into play more the low speed jets. Since you could burn up pistons in about 5 minutes running too lean with a 2 cycle. We were more concerned with wot readings.

[croatiancowboy]

Originally Posted by mick56

The reason i asked was those valve cut out's,i have wondered how close the standard piston's get to the valve's. What sort of bhp/torque figure's are you getting out of that motor,and what do you reckon it's cost you.

The standard I don't know. But the throw on these Ross pistons, from thundermfg, is about a solid half inch below the head. I have a solid 1/2 oil mark between the mating surface of the head and the jug, in the jug. But I also have custom MLS headgaskets that I can't remember but about 0.30 thousands thicker and allow me to torque the ARP bolts to just over 76ftlbs. rather than stock at 60 something, I was worried once I shoot giggle gas into her she might unravel. I did my research, here. Lol.

I did have dyno numbers and pics to show, before the headwork and 44mm Carb, she was just over 79hp and 87ftlbs of toque just over 4400rpm. But that was also before the spring upgrade also, and missing 6 inner valve springs. In the quarter my best was 13.5 and my reaction time was well on point with a hawk. But now with the farther upgrades before I broke my cvk40 I outran my friends twincam 88 and he pulled a 12.54 in a quarter. I would say I was well over 2 full car lengths ahead of him. Mind u his bike is fully stripped aswell, mines got a fairing stereo, and hardbags. Plus his swing arm is stretched and rigid.

I will post dyno numbers as well as time slips. We don't do 1/8th up here in Ontario. Only quarters. So those will be my times. But thats only if this thunder plate makes delivery before the season is done. Poppa needs to make some money I spent on the damn thing. I have no problems dropping a grand at a time on the table when a Harley owner wants to flap his gums. I got no problem taking my money home along with his. :cool:

[croatiancowboy]

Originally Posted by blowndodge

Lot of money to put into that bike.

Thanks brother. I'm glad people noticed. Its not cheap thats for sure. I got the bike for just over 3 large Canadian paceos. Put probably twice that into her. But the smile on my face when I shame a Harley owner who's well into the 15k mark just in upgrades, not including the price of the bike, the smile on my face is ear to ear baby.

[croatiancowboy]

Originally Posted by cnc

Nice, what's with the red bottle with mdf on it ? Not nitrous is it ?
That's how we always read plugs when jetting snowmobiles around here, although in our case the lower rpm up to almost 1/2 throttle the main jets and needle position did not really come into play more the low speed jets. Since you could burn up pistons in about 5 minutes running too lean with a 2 cycle. We were more concerned with wot readings.

Thats an msr tank, auxiliary fuel. Just so I don't get stranded leaving the province. the 4.2 gal tank or 16 liters barely clears the last gas station in Ontario to manitoba. There isn't any hiway men in blue along the stretch so I tend hit it a little and have some fun with her. But I'm all about keeping her safe and not giving bikers a bad name by doing stupid things on public roads. I track it when I want to race, I wont lie. I'm no angle, I have showed some what I am made of. But for the most part track only.

No the giggle gas isn't coming until next year. I have to warrant a license to transport it now. No one will sell it to anyone here now, license and safety course is a must or huge fines, at least with bikes. Cars I don't know about.