Here i go again ..

[Suzukidave]

Looking really good Dave! Did you use an offset sprocket to get your chain aligned correctly? If yes, where did you get it?

Getting the sprockets lined up is a combination of the engine block being centered in the frame putting the rest of the engine off to the left side a bit and the GS750 transmission that has a longer output shaft .

[water cooled]

Dave...anything new on the project...

[Suzukidave]

Still picking up parts needed to complete the cooling system like hoses and over flow bottle . I purchased a top hose for the TL1000 and it fit up to the connections pretty good but the thermostat outlet was the wrong size to fit the hose so back to ebay to purchase a outlet off the TL1000 but it doesnt fit my adapter plate so now i need to fab a new plate . Its all these nit pick items and then there's the carb jetting

[Suzukidave]

Replacement adapter plate for thermostat outlet ( still have to drill mounting holes )

[Suzukidave]

Holes drilled and the one tapped , gets the TL1000 outlet mounted and pointing in the right direction

[tz375]

Is that second sensor just a filler or does it act as a thermo switch to turn on the fan?

[Suzukidave]

It was a sensor for the FI system

[Suzukidave]

and then there's the carb jetting

I did as much net searching as i could think of but didnt find too much info on tuning these AC Sno Pro 440 ~ 34mm carbs . Along with TZ375's suggestions i went with what i hope is middle of the road jetting .. 27.5 pilots , 300 main jets and 6FM4-60 needles .. the needle jets are pressed in and not changeable so i have to tune around them . The Sno Pro engines for a 440cc twin crank out a very nice 100 hp so on my engine this jetting very well could be pretty fat .. but better that then lean

[Suzukidave]

Also picked up a radiator over flow bottle so the list of little things is getting a bit shorter

[tz375]

Dave,

Did you jet it for above 10,000 feet and temps around -20F? Jetting charts for sleds are interesting and typically only one setting on the chart is close to our conditions. Your approach is sound. Until it runs, it's really hard to predict what it will end up needing, but safe is always better than sorry.

As a single data point for reference, XCR800 Polaris has main jets vary from 280 for 40F at 12,000' up to 460 for 0-3,000' below 20F. On that chart, 0-3,000' at over 40F is a 390 main jet. That's on a Reed valve 800 triple with TM38 carbs. 34 flats will need smaller mains.

440 Polaris runs from 170 to 310 mains with the carbs on your bike and above 50F and below 2,000' they recommend 260 mains.

I think your 300/27.5 is as good a guess as any to start with. Get the idle and off idle right first and take it from there.

[Suzukidave]

Thanx Richard for the tuning input out of the 5 carbs i have i got a variety of jetting including 3 smaller 17.5 pilots and 2 ~ 230 main jets . The site i ordered from has a good assortment of parts http://www.arcticcatpartshouse.com/oemp ... carburetor" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false; .. there prices are good but the shipping cost ( handling ) is a bit steep

[Suzukidave]

Did a search for Jet chart and found this .. still shows i may be rich

[tz375]

Or not.....


Zero feet above sea level at 20-40 degrees is #280 and you are at 300 on a smaller cylinder which will probably provide a lower signal (pressure differential) resulting from the lower air velocity through the carb. Reality is that we won't know until you run it.

Just as a sole data point, my bike was chronically lean on the dyno when I first ran it (18:1). And that was stock carbs, larger mains, and stock exhaust but with oiled UNI filters. With JEMCO's it was less lean than with stock pipes and with 3 into 1 it was almost perfect through most of the range and all those runs were with 117.5 mains IIRC. Of course after that I changed everything and have no idea what the jetting is like now and I have to run different jungle juice this year and that should require jetting changes.

As I said earlier, get idle right first and then take it for a gentle run and get a sense of what it's like and then strap it to a dyno and run it through the rev range to see what the numbers look like. Make sure that teh exhaust sniffer fits far enough up inside your pipes. On stock pipes the sniffer can't get past the first baffle restriction and the numbers are probably artificially low. Exhaust suck in way more air from the outlet than one might imagine and at the rear end of the exhaust it will read way leaner than it really is.

[water cooled]

I see you have the head inserts...Looks great Dave! Getting very close...

[Suzukidave]

I see you have the head inserts

Yeah .. many years ago a list member offered up a service to send him your stock head and he would cut out the stock head chambers and add back in replaceable inserts . Even all those years ago Richard was a guiding hand and CC'ed the inserts finding them a bit to tight for street pump gas use so i sent them off to Scott Clough (sp) racing where he machined in a new profile .