Engines

[bogieboy]

pat of me would love to put an old yammy wr500 smoker in my Roketa....hehehe dimensionally its actually smaller than the stock 200.....

[ChipToothy]

Originally Posted by bogieboy

thats exactly the type of positivity i have found trying to buy a DR engine...LOL!!!!

Only prob is the Hawks can’t survive the trip

[ChipToothy]

Originally Posted by bogieboy

about the only thing that has ke[pt me from doing so is the radiators.... plenty of room for the motor, but the rads make it a pain.... i have considered trying to find a dr600 motor or something similar to shoehorn in, but havent found one cheap yet....LOL

What about using a smaller raid or 2 small ones stashed away like oil coolers?

[bogieboy]

Originally Posted by ChipToothy

What about using a smaller raid or 2 small ones stashed away like oil coolers?

plausible.... in my opinion, its not enough of an increase in power to justify the loss of bottom end... hence looking at a bigger smoker... just imagine how a china bike would scoot with a 40+hp 2smoker....

[Megadan]

I would personally stick with air cooled. I had given this same idea a bunch of thought and in the end concluded that I could buy the whole bike the engine came from for the same price as doing the conversion.

Now, if this is an exercise in "why not" then many of the XR engines could fit and work in the Hawk frame. The real question would be if the chassis could hold up under the extra power.

Personally, if I were going to go for a shoehorn engine fit into a Hawk frame, I would go for broke and try to stuff an XR650L engine in there. Nice low revving super torquey air cooled single with 35-40hp and 40-47lb-ft. It won't have the top end of a 2 smoke, but you could tractor up and over just about any obstacle. It's no taller or longer than the 400, and only a tiny bit wider at the engine case. The cylinder is much wider, but there is room to spare for that dimension.

Again, this is the "why not" approach. A good 650L engine is going to run around 1200 bucks or so. You can buy a complete older XR650L in good shape for $2500-3000, and you get all of the great hardware that comes with it. Thus is the reason swaps are rarely ever done.

Here is a XR600 and XR400 side by side for your entertainment.

[ChipToothy]

Originally Posted by Megadan

I would personally stick with air cooled. I had given this same idea a bunch of thought and in the end concluded that I could buy the whole bike the engine came from for the same price as doing the conversion.

Now, if this is an exercise in "why not" then many of the XR engines could fit and work in the Hawk frame. The real question would be if the chassis could hold up under the extra power.

Personally, if I were going to go for a shoehorn engine fit into a Hawk frame, I would go for broke and try to stuff an XR650L engine in there. Nice low revving super torquey air cooled single with 35-40hp and 40-47lb-ft. It won't have the top end of a 2 smoke, but you could tractor up and over just about any obstacle. It's no taller or longer than the 400, and only a tiny bit wider at the engine case. The cylinder is much wider, but there is room to spare for that dimension.

Again, this is the "why not" approach. A good 650L engine is going to run around 1200 bucks or so. You can buy a complete older XR650L in good shape for $2500-3000, and you get all of the great hardware that comes with it. Thus is the reason swaps are rarely ever done.

Here is a XR600 and XR400 side by side for your entertainment.

That price range will not even get a well used Honda 250. $3,500 for a 250L is the cheapest I can find local.

[ChipToothy]

The Hawk is $2,495 at the powersports dealerships down here.. college town.

[Megadan]

Originally Posted by ChipToothy

That price range will not even get a well used Honda 250. $3,500 for a 250L is the cheapest I can find local.

That's also a point, market does matter. As a whole though, the XR650L isn't very high on the desirable scale for many riders, especially the younger crowd. Low revving, somewhat heavy, and very tall. It isn't a sexy looking bike either. It isn't unusual to find a really nice low mile XR650L for the same price or cheaper than the newer 250's and 450's.

Perfect example about an hour away from me. https://lincoln.craigslist.org/mcy/d...774369783.html

Now, the XR650R on the other hand, those are desirable, and usually sell for $5k or more in good shape.

[ChipToothy]

Originally Posted by Megadan

That's also a point, market does matter. As a whole though, the XR650L isn't very high on the desirable scale for many riders, especially the younger crowd. Low revving, somewhat heavy, and very tall. It isn't a sexy looking bike either. It isn't unusual to find a really nice low mile XR650L for the same price or cheaper than the newer 250's and 450's.

Perfect example about an hour away from me. https://lincoln.craigslist.org/mcy/d...774369783.html

Now, the XR650R on the other hand, those are desirable, and usually sell for $5k or more in good shape.

Yeah I would love that 650L



I'm trying to buy this, if it's not already sold this will solve my road needs.


https://fayar.craigslist.org/mpo/d/8...767951181.html

[timcosby]

Originally Posted by bogieboy

about the only thing that has ke[pt me from doing so is the radiators.... plenty of room for the motor, but the rads make it a pain.... i have considered trying to find a dr600 motor or something similar to shoehorn in, but havent found one cheap yet....LOL

take a look at the engine guards in the 2013 wr(world record) post earlier. im thinking radiators or oil cooler would fit right in that outside opening on each side!

[pete]

Yamaha XT660....Bolt straight in...


..

[DualSport]

Originally Posted by JerryHawk250

That's what they make welding machines and torches for. Get ur done!

Have fun using even flux-core MIG on a Taiwanese "junk metal" frame..

I've seen both the RPS frame and engine block turn to powder with very little force using only a cheap short wrench and finger tips.. I've worked on RPS bikes more than anyone on these forums at this point from rebuilding the engines to tapping new threads on vibration-worn bolts and repairing vibration-worn harnesses..

I should of posted a pic of the entire engine block in what looked like metal bread crumbs when a rocker hit the wall just by me pushing down on it with a rod.. You can break a RPS engine block with a bare hand and the frame is basically pewter-stock..

[Megadan]

Originally Posted by DualSport

Have fun using even flux-core MIG on a Taiwanese "junk metal" frame..

I've seen both the RPS frame and engine block turn to powder with very little force using only a cheap short wrench and finger tips.. I've worked on RPS bikes more than anyone on these forums at this point from rebuilding the engines to tapping new threads on vibration-worn bolts and repairing vibration-worn harnesses..

I should of posted a pic of the entire engine block in what looked like metal bread crumbs when a rocker hit the wall just by me pushing down on it with a rod.. You can break a RPS engine block with a bare hand and the frame is basically pewter-stock..

Using flux core mig would be just about the worst setup to use on any tube frame bike, regardless of how good or bad the metal quality is. That just screams blown holes and turd weld beads. The effective wire diameter is .023 on most flux core, which gives way too much of a narrow hot spot for thinner gauge steel. You would have to be a damn good welder to pull off a good weld on even high grade tubing without screwing up.

Considering there is more than one example of people that have successfully welded to the stock Hawk frame, it's not impossible. A .035 Forney 42276 wire with a 75/25 Ar/CO2 blend would be my personal combination of choice if I were going to go the MIG route. Might make for a wider weld, but it will distribute the heat better (limits relative penetration "focus") and lay a flatter smoother weld.

To each his own though.

[DualSport]

Originally Posted by Megadan

Using flux core mig would be just about the worst setup to use on any tube frame bike, regardless of how good or bad the metal quality is. That just screams blown holes and turd weld beads. The effective wire diameter is .023 on most flux core, which gives way too much of a narrow hot spot for thinner gauge steel. You would have to be a damn good welder to pull off a good weld on even high grade tubing without screwing up.

Considering there is more than one example of people that have successfully welded to the stock Hawk frame, it's not impossible. A .035 Forney 42276 wire with a 75/25 Ar/CO2 blend would be my personal combination of choice if I were going to go the MIG route. Might make for a wider weld, but it will distribute the heat better (limits relative penetration "focus") and lay a flatter smoother weld.

To each his own though.

I've seen people weld them too.. on peg brackets and the top engine mount. I've also seen the frames crack nowhere near a joint on bikes that were only ever taken on paved roads.. Changing the steel around the engine or suspension by welding new joints would be interesting to see..

I agree on solid core and gas. I just use flux-core cause it makes reliable welds in the field much easier..

[jimwildman]

I picked up an old ('70's) XL350 engine with these thoughts in mind.

I can verify that this is doable, and if I fit the xl500s in there the 350 should be no big deal.




This an older xl350 engine? I hear the 350s was hard on cams. A buddy of mine had an old xl350 2 valve.. that thing ran soo smooth, and had a great exhaust note with the underswept pipe.