Curvy tuning - what bits will go best?
 

I thought i'd ask the org to see what experience other folks might have had tweaking their bikes up.

I'm going to be doing the pointy intake cam swap sometime soon, and at the same time will be getting a dynojet kit fitted and getting it set up properly. But should I try a Stage 1 or 3 jet kit? The bike is currently fitted with a road legal remus grand prix can. I think I know the answer to this one, but to get any decent gains off the cam swap it'd be worth putting on a less restrictive can wouldn't it? And of the three main filter brands which one would people recommend most? I've currently got in a K&N, but was considering a change to either a BMC 205/10 RACE or a Pipercross MPX044.

The target is anything up to but not more than 80bhp at the rear end (junior powerbike class limit). If there's any room for improvement after the mod's above then the next bit to add was a factory pro ignition advance kit.

cheers for any advice you have :-)

Re: Curvy tuning - what bits will go best?
 

I've got a curvy with much the same mods as you are thinking of (full system, cam swap, dynojet kit, BMC filter).

The most logical way of doing things is to sort out the exhaust system first to get the bike breathing better, i.e. full system and filter which will obviously require some change to the fuelling. Once this is done then think about doing the cam swap. If you do the cam swap without the exhaust first then I don't think you will get the full benefit of the hotter cams.

Whether you go for dynojet needles or stick with mikuni is up to you. Many people have reported good results with mikunis and they are obviously much cheaper (just the cost of the jets - no new needles required). I'm happy with my dynojet kit though.

If you do go for dynojets my advice would be to not worry about different 'stages' - the kits don't seem to come with realistic jet sizes anyway. I ended up buying specific jets from PDQ as they are only a couple of quid for a pair.

If you want performance then stay away from the K+N filter as its not much more free flowing than stock. Again I'm happy with my BMC race rs (i think) filter.

In case it helps later on I have a WRP full titanium system, BMC race RS, pointy cams, dynojet needles and am using 180 dynojet mains front and rear. No idea what clip the needles are on without looking though (and I don't plan on doing that until the weather warms up again). No idea what power it makes now (its never been on a dyno - all set up with my backside) but I'm way more happy with it than I was when it was stock.

Re: Curvy tuning - what bits will go best?
 

Cheers for the advice spoon. I might see if I can do the whole shooting match in one go and have it dyno'd when everything is fitted. Just thinking that if I get it set up for a particular exhaust system and filter, then go and tinker with the cams surely it'd need another run to get the fuelling spot on again?

Re: Curvy tuning - what bits will go best?
 

To be honest if the fuelling is OK I don't think the cam swap normally requires any further changes to be made (mine certainly didn't). If the fuelling is out before the cams though I think the cams will make it more obvious.

Re: Curvy tuning - what bits will go best?
 

Ive done a cam swap on a 2001 650, before and after dynos showed a useful gain of 6 hp and the air fuel was fine,10,000miles on it with no hassle.
If you fit a free er flowing system/ endcan then you may benefit from carb tweaks but the cam alone doesnt need it. The dyno guy reckoned a +5 Main jet might be a slight benefit, and an emptier can would be good for another 2 HP.

Re: Curvy tuning - what bits will go best?
 

Those gains are much bigger than I thought they would be, good luck charlie let us know how you get on.

Re: Curvy tuning - what bits will go best?
 

The cam swap gives a healthy extra shot of top end and doesn't usually need any fuelling changes. You might as well wait until it's all on though and you can see the top end power. My tuner (PDQ) used a Dynojet kit but they might have been able to get it close enough without - it's a collection of bits and bobs, not some magic bandage that fits anything and cures all.

Re: Curvy tuning - what bits will go best?
 

Dave
I take the 6hp gain with a wee pinch of salt , the before ( hot sunny day) and after ( WET AND COLD) dyno runs were on different dynos , different weather and 3 years apart.
My seat of the pants dyno notices a healthier pickup just before 7,000 rpm with a stronger pull right to the red line. These readings are from a cagiva raptor 650 which has a free er exhaust system ( 2 into 2 with link pipe) than a stock curvy .
Cheers

Re: Curvy tuning - what bits will go best?
 

Cam swap and full leo system, how much do you want to spend?

Re: Curvy tuning - what bits will go best?
 

To get upto the 80bhp for the junior powerbike class measured SAE you will need to have some head work too. Pointy cams will really only add 2-3bhp at the most from every one that we have done and back to backed dyno runs.

Generally as a starting point with a full system make between 68-71bhp dependant on fueling and system. Cams and open air filter with appropriate jetting will see about 74bhp if its healthy. The rest is down to actual machining work top and bottom end and pistons etc.

Bear in mind my readings are from our Dynapro dyno which reads about 5-7bhp different to a dynojet.