Ready to Rumble....Blue Collar VS Dax!


Dec 26, 2007
Scottsville, VA
Hi All,

Just wanted to do an informal comparison between the Dax 70's that I have normally gotten and Blue Collars bike engine kit (I got the lower priced of the two versions he sells....I didn't want to wait until he got a new batch of his "better" engine kits (only $10 more than his lower priced kits) because I had somebody that wanted to buy a bike from me "right now"....So....I had to make one ASAP and get it shipped out....

In all fairness, the engine kits I got from Dax are from awhile back so things may have changed since then...

As far as delivery speed, other than Blue not having the more expensive kit in stock (which I wanted BUT when things sell well that's good huh?), Blue wins....

In opening the boxes I gave the edge in factory packing to Blue Collar.....Inside the boxes, many of the pieces were separately boxed inside as well.....some even bubble wrapped Dax's kits ship to me well also just not boxed inside a biggie either way so long as stuff isn't broken when you get it right?....Just my first impression....

After opening the pieces in Blue Collars kit, I noticed the carb already had the throttle cable installed.....nice....No fighting to have to install the throttle cable....Dax's kits required assembly of the carb / throttle cable but that may be good force one to learn how to do things (such as if you have to adjust the needle up and down with the eclip)...On the other hand hard to argue with convenience.....

Instructions - Blue Collar By Far!!

Gas tanks, CDI - Same either way

Sprockets....Dax gets the nod here since his kit runs with the HD 9 hole mounts (8MM bolts) chromed and weighs less too (17.9 oz)....Blue Collar had a "raw" cast looking finish and weighed in at a somewhat massive 24.7 ounces... Both sprockets have the same tooth count.... Of course had I gotten the Upgraded kit from Blue Collar I would have gotten chrome too....I don't know if Blue's upgraded kit has 6 MM bolts or 8 MM bolts either case you won't be breaking the bolts and will probably want to upgrade sprockets in either case so this category may ultimately be a moot point.....

Chains - about the same

Mufflers - same but Dax's has the "round" bottom where the exhaust opening ends and Blue has flat bottom at the exhaust opening...No tuned pipes here so has to say if one is better than another.

Clutch Lever - Both had lockout pins to hold the clutch out but I have to give the nod to Dax for being just a little nicer here on the area where your fingers pull the clutch in....less "taper" so my fingers fit better on the Dax Clutch lever....Blue's lever did have an extra screw to hold "adjust" the clutch lever tho....

Throttle / Kill switch - On my older Dax kits I got the separate red kill button and rubberized throttle twist grip.....Blue gets you a throttle assembly that looks nicer, has a built in kill switch, but has a plastic feeling grip area....Tough choice here...If Blue had a rubber grip it would be Blue all the way but since not, I prefer the rubber feel of Dax....Besides I choke my engine out ;-)

Chain Guard - Same

Hardware - Same

Idler pulley - Same

Spark Plugs - About the same....The Factory removed the "tip" on Blue's kit
kit so you don't have to unscrew it yourself...Not a biggie....but one more thing you don't have to do

NOW the meat of the matter....The engine itself.....

A quick glance, shows the finish on Blue Collar's engine is shinier than Dax's flat cast look....Maybe the factory used clear finish?....Blue's is probably easier to wipe clean because it is "smoother" but will this hurt heat dissipation?....Maybe a little but not enough to matter probably....

Dax's engine uses a longer clutch pull lever....that is a plus....leverage makes working the clutch a tad the nicer clutch lever mentioned earlier to boot...

Dax has a chromed intake BUT more importantly it measures nearly 16 MM ID vs Blue's 13.5 MM ID....Hands down Dax Inhales better (I did NOT take the intake off tho to see the actual size of the cylinder port opening tho).

Not readily seen in the pics BUT Blue's head gasket looks to me to be
about 3 to 4 times the thickness of Dax's head gasket.....Can you say easy compression increase by simply thinning the gasket ?!?!?....Hmmmm....uncork the torque!...Of course I didn't measure compression so hard to say what the result of thinning the gasket would be....(instructions say stock compression is 6 to 1).

Cylinder - Dax has the top three fins that are a little larger than the others....Blue's cylinder doesn't ....Although the additional sq. inches of cooling fins may be nominal it theoretically can give a little better cooling due to additional surface area....Not a lot maybe but possible that every little bit counts....But then again it is probably so nominally different as to be inconsequential....

Exhaust port - Blue wins Hands down here....Huge area for the spent gases to exit...Much larger than Dax.....Nicer gasket too BUT the gasket is NOT perfectly matched to the port opening and since it is metal covered it will have to ultimately be tossed if one is to match the port to the opening of the gasket.....Of course ALL this is a moot with the stock exhaust since the flange on the exhaust is smaller than the exhaust port of the cylinder.....Can you say "Dremel time"....

Front Mounts - The Front Mount on Blues engine will accommodate a larger frame tube than Dax's (Blue has a larger opening radius)....that can be a PLUS or MINUS...Plus in that it will already accommodate a big tube BUT if the down tube is small there will be a gap....You can always File a Dax to fit....Although a little more work is possibly involved Dax get's the nod here at least for the smaller down tube equipped bikes...

Heads - Externally Blue gets the nod here for the larger reinforcing ribs on the "dome" by the spark plug (see pics)

Beef of block - Looks about the same But I like the Dax here because of the
extra metal around the clutch lever opening, and the extra metal where the bolt goes through to hold the engine halves together (under the exhaust port)....Probably not of any real significance but it is a detail.

So what about performance?

In all, it may be easier to hop up Blue's engine...Simple bolt on performance...
Bolt on the better intake from Dax, use a thinner head gasket to up the compression (I think the Dax head gasket would work BUT I did not open the engine up to verify)....

To Hop Up Dax's engine essentially the same way you would have to remove the cylinder head to open up the exhaust port with a dremel, and you would have to mill the head.....a little more labor intensive BUT at least it's free... just a little time.

As far as inside the engine....I didn't open it up...

As far as real world performance....I had to ship the completed bike to its new owner....since I had to ship it out as "new" I couldn't run gas through it to see how well it ran.....A tragedy I know....BUT I will order another engine from Blue Collar just to see his upgraded kit!!....The T shirt and stickers were nice too!

In all, The Dax 70's I run have been great....I'll look forward to getting Blue Collar's other engine and doing actual motorbiking with it just to she how it does in comparison.....

Hope this helps....



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minor bike philosopher
Jan 15, 2008
north carolina
thanks for the information it says a lot about the engines truly not all coming off the same line, but I wonder just how much real world difference there would be to a buyer of either engine.

They seem to all be the same BASIC design. A little different finishes and maybe the qc is better one place than another but unless I saw it being done I might be inclined to call that hype by the factory.

But then heck, I build weedeater bikes what do I know.

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
up north now
I think the shiny-er finish is paint. I have one engine of unknown seller that has a nice silver finish.

Nice to know the intakes are that much different. I have both, but never really paid any attention to them. In fact I thought the cast one looked better...


New Member
Mar 5, 2008
Looks to me like the drive sprocket on the Dax sits out a little further from the mount.If so it would be a good thing in the case of wide tires.Ron