Hawk is here, yay!

[hertz9753]

I was thinking about the Can-Am Bombardier 500cc 4 stroke motorcycle engine.

[pete]

Originally Posted by Megadan

Those are options, but I decided to go a slightly different route. I went ahead and setup an exchange on this adapter for the larger unit and I am going to bump up to the 32mm OKO. This will give me the spigot diameter to work with the Rotax carb boots I already have.

The 32mm carb has a 40mm OD out let... if I remember correctly...



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[Megadan]

Originally Posted by pete

The 32mm carb has a 40mm OD out let... if I remember correctly...



..

That is precisely what it has, but the flange adapter has a 34mm ID to work with carbs up to the 34.

[Megadan]

It's almost like these intakes were designed to drive you insane. Not one bolt pattern on either end of the intake manifold is centered. Carb side AND the head side are slightly offset, so neither adapter will work as is. This 34mm one could work, but obviously there is a drawback to it without port matching. It may be possible to drill a new pair of holes to center it up, but the casting won't allow them to sit as deep into the head.

So that leaves me with the second option, offset the port matching as seen in the second picture. It would allow a bit more wiggle room in reshaping the port for a taper this way to really kick up the velocity, and the offset moves the centerline of the intake port up a bit as well which would give a slightly more direct shot at the valve. This would split the port work into two main sections. The first half would be mainly focused on the upper left, and the second half would be on the lower right, which is where a lot of work is really needed around the valve radius and valve guide end to help open up the airflow some.

All of that said, short of making my own flange adapter at least, my only option is to either find something I don't think exists - a socket style intake for the CG250 that angles in the same direction as the Hawk/TT250 intake manifolds do - or write off the idea of a flat slide on a stock engine.

I am not opposed to making an adapter, but I was hoping to find a solution that didn't require fabrication. At least I know I can make it work with the ported head, so that's something. I was just kind of hoping to see if there would be any change in performance on an unmodified engine as well.

[pete]

is it possable to weld the bolt holes in the adaptor and re-dril them..



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[Megadan]

Originally Posted by pete

is it possable to weld the bolt holes in the adaptor and re-dril them..



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They are countersunk slots in each end, the flange is shaped exactly like the gasket in the picture. Sure, it's possible. That is a pretty big pair of holes to fill though. At that point it would likely be cheaper to simply make my own.

[pete]

yes i seen the pic of it....
realy it's pretty simple stuff...
anyone with a AC tig or even a mig
could do it.... because you are now drilling
the right spaceing they no longer need to be slots..


...

[Megadan]

I have an AC Mig and an aluminum welding setup, spool gun and all.

If I were going to go through that, I would rather just make my own flange and socket and call it a day. I may still do just that anyway, bt I am still playing with ideas at this point.

[pete]

Originally Posted by Megadan

I have an AC Mig and an aluminum welding setup, spool gun and all.

If you have the gear why wouldn't you do it...
it's the easyest fix....



.

[Megadan]

Originally Posted by pete

If you have the gear why wouldn't you do it...
it's the easyest fix....



.

The biggest issue is I don't have an argon tank at the moment. Just all of my welding gear, but it's not at my residence. I stopped welding regularly a few years ago and had to sell the tank in a rough spot between employment to help pay bills.

I actually decided to keep the smaller adapter, so I now have both along with both carbs. I went ahead and ordered another intake manifold from a TT250 through CSC as well as a couple other bits and bobs, and if everything shows up for this weekend I plan on doing a little experimenting to see what I can make work. My biggest fear with the 32mm is a potential loss of low RPM power or throttle response, so I will also see what the 30mm setup feels like if I can make it work.

[pete]

dose anyone sell desposable bottles of gas over there ?
we can get them in Co2 / Argon & Argon sheild "argon co2 mix"
not the cheapest way to buy gas.. but ok for those small jobs.
ours look like over size spray paint cans about 100mm round / 500mm high..

I use that crappy self sheilding wire in my mig... Have a 11 cubic metre bottle of
argon for the Tig , lets just say I aquired it.. don't know what I will
do when it runs out...


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[Megadan]

Originally Posted by pete

dose anyone sell desposable bottles of gas over there ?
we can get them in Co2 / Argon & Argon sheild "argon co2 mix"
not the cheapest way to buy gas.. but ok for those small jobs.
ours look like over size spray paint cans about 100mm round / 500mm high..

I use that crappy self sheilding wire in my mig... Have a 11 cubic metre bottle of
argon for the Tig , lets just say I aquired it.. don't know what I will
do when it runs out...


..

The closest I can get to disposable would be a rental, but even renting a small tank like a 20cu.ft. unit would end up costing around 40 bucks for a month. I have plans to get another tank here soon as I have a few winter projects I want to work on in both aluminum and stainless.

I wish I had my own tig setup... I would get into too much trouble lol. Thankfully, I am quite handy with a spool gun, and most of my welding experience is with aluminum. At one time in my life I used to weld frames for box trucks, semi trailers, and the like, which are usually 3 to 6mm thick box and L tubing. Lots of people find it weired that I am better with aluminum than steel, but it's just what I have the most experience with.

[pete]

trucks.... bloody shitty things..
been there done that....
I built the booms for Grant Dolton's maxi ketch that won
the Whitbread round the world race in 1990... took 5 of us 4 months to build
the masts / booms....
everything is carbon fiber now...


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[Megadan]

So, since I had a stock tube fail, I decided to go ahead and upgrade to a different type of tire. I decided on a compromise, although I am sure to change my mind later, and bought the Shinko 705's for now, since the bike mainly sees the road. I had to order them in through my local shop, but they were nice enough to toss in some 3.5mm heavy duty tubes for half off since they had no tubes I needed in stock, and I get free mounting as well. Not complaining! I will see how they do and go from there. They are cheap enough that if I end up wanting something else I won't feel too bad about swapping them out, and I can probably sell them easily enough to recover some money.

I also decided to do a little upgrading to the bearings while I am at it. I managed to get my hands on some German made SKF bearings through my work at wholesale price (job perks lol) for the front and rear wheels. I do also have a steering stem bearing set to convert to tapered roller bearings, but we will see if I am up for doing that now or as a winter project.

Also, I can confirm that the intake manifold for the TT250 is a dead on match to the unit on the Hawk, with the only change being a brass nipple for a vacuum line that needs to be capped.

[pete]

on dry / firm ground you maybe surprised where the 705s will take yer....



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