Different dynos will give different #'s!!!! JMO.

 

wildchild i think they must be talking at the crank.

 

No thats rear wheel HP. Ive read tons of theads on 686s and their HP #'s and none were around 48. They were all around 60. I dont think the dyno was working right or something. Are you sure you lose 20 hp from the crank to the rear wheels. Im almost positive its 10 HP you lose and that would make you at 58 hp (the norm). I think thats the problem.

 

There is about a 20% loss from crank to rear end.

 

Rear wheel / crank is NOT the issue.

Different Dyno's are the issue.

I GUARANTEE you would have about 55HP on the Trinity Dyno.

I think 48 sounds a little low for a mild 686 but, only a couple HP low.

There can also be a big difference between one 686 set-up and another. A mild 686 (11:1 compression, stage 1 cams, stock valve springs) vs. an aggressive 686 (12:1 or higher compression, stage 2 cams, heavy duty valve springs, port work, larger valves, different carbs, etc.)

Also, if you have done a 686 and haven't done a clutch kit you may be seeing some clutch slipping but, I think your HP # is pretty much right on.

Go see if you can find a 55 HP Trinity Raptor to race (I know you will beat it.)

(Not trying to dog just Trinity, I think there are a number of shops that have dynos that consistantly put out higher numbers than others do. I call this the fat chick in the size 6 Tommy Boy Jeans Dyno. The cloths companys have been doing it to the ladies for years. . . they all want to be a size 6 so, the cloths companys just keep making the size 6 bigger and bigger. Can't tell me you would rather have a 50HP quad than a 60HP quad. Everyone wants the higher HP engine but, is the number real or inflated for your ego? Heck, if we were alive 100 years from now a "D" cup will probably be a training bra[img]i/expressions/face-icon-small-shocked.gif[/img])

 

Dynoguy - I stand corrected. Sorry about the misunderstanding. Have fun

 

Thanks Duneme, your right on. When I was building stockcar engines for a living our 600hp engines were dominating the hutter and others 660-680hp and our 700hp engines were doing the same to their 750hp engines. Point is, just as you said, some people like to publish higher numbers and racing Dyno's is a waste of time.
We are talking about a trail machine here as well, raced on weekends.
It has the stock carbs, 10.18:1 compression ratio and LOTs of bottom end.
The truth is, you advertise HP but you drive torque!!
Happy roosting.

 

why would you buy a 102mm piston with stock compression?

 

LOL, as we just talked about, all is not as advertised!!
The piston is a J.E., I'll have to check at the shop for sure but I believe it was advertised as a 12:1 piston. I did have to grind a bit from the combustion chamber to unshroud the valves, but only a few CC's
This piston with the deck height and chamber volume before grinding would
have been about 10:5:1