swapping vintage carburettors for modern ones, will it make more horsepower.

[PE MAN]

was just wondering how a old 2 stroke will go with a modern day carb. carbys have come along way in 30 years when it come with cars. do 2 stroke act the same or would you have to get the ports matched to suit. or is that only if you intend to go bigger

[GD66]

May not make any more absolute horsepower, but will without doubt start more easily, and run up through the rev range better. You can go bigger, but then you will have to port to suit. Depending on the bike in question, you may just enjoy the improvement by itself and leave it as is : the same, but BETTER !

[Slakewell]

IMO Bings make the best HP.
There a cruel mistress needing much work to get perfect. Sometimes it just dosen't work out because you cant find beg steal or buy the right needles but when it dose thou the seamless perfect horsepower is worth it. 

[Lozza]

More depends on the engine it's bolted to, a fully optimised engine responds to a better carb, a stocker won't know the difference. I saw a dyno graph of the same engine with 28mm PWK and a 28mm VM runs. VM made less at peak but was a mile ahead on the run up to peak power. The flatslides have better throttle response especialy the cresent shaped slides.

[Tim754]

GD66 you have answered that perfectly! I agree 100% that there is bugger all HP improvement with out other items matched to the carby, but things... may.... operate more friendly allowing you to concentrate on riding better = more speed and less strain. Cheers Tim754

[Captain Bilko]

Gee. It's amazing that the factories ever sold any bikes considering how much needs to be done to them to get them to (apparently) run properly.
They musta been just slappin' 'em together any old way.....

[Mike52]

Gee. It's amazing that the factories ever sold any bikes considering how much needs to be done to them to get them to (apparently) run properly.
They musta been just slappin' 'em together any old way.....

The more money you spend on them the faster you go.
This principal is open ended.
Light speed has been a barrier but could be overcome with a little bit more money and  flashy new riding gear of course.
Gav McLeod won the 250 class at one 4day on a bog standard XR200.  He also rode a XL500 to Wiepa , stripped the road gear off and won his class.
I,ve owned a few bikes with BINGS fitted and never had a problem or complaint.

[PE MAN]

the motor is stock pe400 besides a GMC pipe that will be here shortly... dont want to muck around with the cylinder just yet. when it comes time for a rebuild then might.

[GD66]

Well, unless the stock carb has been caned mercilessly for a huge mileage by a ham-fisted ruffian, or it's gunked-up beyond redemption, it'll probably be ok to use with a thorough cleanup : maybe just jet it up a size or two depending on Geoff's suggestions with the use of his new pipe.

[frostype400]

I found that my pe400t went better with Geoff's pipe on stock carb setup I am going to get a pe400 motor hotted up soon for my project that will have a disc front end I am going to use a mikuni 38mm flatslide with powerjet on that.

[PE MAN]

mmm sounds good frosty... i got a spare motor in the shed as well. minus piston & flywheel. sometimes i imagine of making it some ridiculous monster an try an think exactly what it will go like... lol

[frostype400]

Yeah cool buy a couple of sprockets would be my advice for your stocker watch out though to big and the chain will rub the case if you go one tooth down on stock sprocket you'd be amased at the difference front wheel is alot quicker to jump up in the air.

[wmc83]

I changed from a mikuni tm38 to a keihin pwk a/s on my bike as I wanted it to idle.   it was straight forward to do but the problem is finding a jetting benchmark for older bikes I was lucky as it's a common mod for my bike so there was a ton of info available.

[PE MAN]

yea had a 49 tooth on it before, went back to a 46 thought id like a little more speed.

[frostype400]

I go 48 rear try 13 or 14 front.