640 Intake

QuinnO · 01-02-2010, 12:37 AM

Are the 640cc & 770cc intake manifolds interchangeable?
Look the same in photos, (bolt arangement on reed block).

I want to use 2 SBN's with a stock 95 Daytona 640 intake.
Or, if it fits in any way a setup off a 770?

Who's selling a dual carb set up for a 640? Theres one on ebay, $349....
I got my whole Tiger for that. Greed need not apply.

Thanks all ! W A N T E D

jetski9010 · 01-02-2010, 09:13 PM

I think the 770 ones are different. My 770 intake manifold are two seperate manifold's and not connected like that one in the picture.

QuinnO · 01-05-2010, 01:15 AM

But , Is the bolt pattern the sam? The 640 & 770 take the same reeds. That tells me I can bolt on a 770 set of carbs & intakes. I would prefer 2 single plenum runners with no cross over. Like tunnel rams. I can make linkage with heim joints.

lownrangr · 01-05-2010, 02:06 AM

i'd bet the bolt pattern is the same.

ryanr · 01-05-2010, 02:23 AM

i have a set with mani from a 95 daytona 640 that i am willing to sell cheap. too bad they are in my snow covered shed at the moment.i'm sure that they could use a cleaning and /or possible rebuild. i took them off a running mtr. late this past fall. let me know

dank · 01-05-2010, 09:25 PM

Bolt pattern is the same but the spacing apart is not. I will look for a dual carb setup for a 640.

QuinnO · 01-07-2010, 03:30 PM

Dig em out when you can and there sold. I need the cfm of 2 carbs. There BN 38's right. do you have everything on them? linkage & flame arresters? I may use 2 BN 44's on that intake with parts from the 38x2 set up. Let me know what you have to sell when you get them in youre hand.

Dank if you find a set up give me a shout. I'll post it, if I buy any.
Thanks folks!

GustoGuy · 01-13-2010, 03:44 AM

I have a 1999 TS 640 that I made a few modifications to. My first mod was to get rid of the stock air attenuator and put in a Prok multifit with an aluminum adapter and rejeted the carb by putting in a 137.5 jet. I then found it was running too rich and would bog so I modified my stock 135 jet with 6mm fuzzy pipe cleaner and polishing compound and a cordless drill. It took about 5 times of doing this until I had it running just right. I then took out the choke plate and put in a mukuni primer kit. I noticed that It had a lot more get up and go after this and would seem to cavitate quite a bit with the stock artco impeller. I wanted to find a good impeller for getting off the start as well as top speed so I contacted Dave at Impros and I ordered a reconditioned 146mm Polaris Skat Trak 12-17 slimline and that really helped the bottom end. It now has a much better jump out of the hole when you nail the throttle and it really got rid of the cavitation hesistation when you hit the throttle hard. Since you have a 640 you should check out Group K's article on performance mods for the Tigershark 650. Group K even does a lightening of the stock flywheel where they remove 0.7 lbs and since its on the outer perimiter it offers a noticible improvement in throttle response and acceleration. Since the 640 only makes good power after the rpm exceeds 3800 the flywheel lightening helps the engine to get into the power band sooner and that helps it get up to plane faster. I am going to pull my flywheel this spring before the season starts and send it to Group K to be lightened. I 'll let everyone know what kind of results I get. Regarding dual carbs on the 640 Group K found that a 44mm SBN single carb out preformed a dual 38mm in every catagory so it is possible to get good acceleration and power from a single carb setup. Good luck

QuinnO · 01-13-2010, 06:06 AM

Wow the fuzzy pipe cleaner thing, I never thought of that! Slick! Thats a good reply, best yet I think.
I did read Group K's article and all that testing helps. I am going to lighten the fly wheel as well. I ported a new 644cc jug to have the exhaust port at 85* and the transfers at 116*. High RPM. I designed dual 2 stage diffuser expansion dry pipes to hit hard at 4200 RPM & max out at 7100 RPM. (2 Stroke Wizzard Tuned Pipe v.1.0) Having them fabricated right now.Im going to run the MSD inhancer, I was thinking a new "Nice" impeller with a stock pitch. I was also planning on a wet NOS kit with a 50 HP shot for fun.
The SBN is a Yamaha BN 44 right? I have a BN44 stock on a 95 Motego 640. I just cant see a ski built to scream being ok on a 44mm. My exhaust ports are almost that size each, so I can move way more air than a 44 can. Now 2 - 38's = 76mm. How much head & Jug work was done on Group K's 640? Im going to have to look.

lownrangr · 01-13-2010, 03:26 PM

Quote:

Originally Posted by QuinnO

Wow the fuzzy pipe cleaner thing, I never thought of that! Slick! Thats a good reply, best yet I think.
I did read Group K's article and all that testing helps. I am going to lighten the fly wheel as well. I ported a new 644cc jug to have the exhaust port at 85* and the transfers at 116*. High RPM. I designed dual 2 stage diffuser expansion dry pipes to hit hard at 4200 RPM & max out at 7100 RPM. (2 Stroke Wizzard Tuned Pipe v.1.0) Having them fabricated right now.Im going to run the MSD inhancer, I was thinking a new "Nice" impeller with a stock pitch. I was also planning on a wet NOS kit with a 50 HP shot for fun.
The SBN is a Yamaha BN 44 right? I have a BN44 stock on a 95 Motego 640. I just cant see a ski built to scream being ok on a 44mm. My exhaust ports are almost that size each, so I can move way more air than a 44 can. Now 2 - 38's = 76mm. How much head & Jug work was done on Group K's 640? Im going to have to look.

i for sure would not go stock pitch.