Hi, i am looking for a bit of extra power, i was looking at the mikuni 42 to replace my stock carby on my 99 model dyna twincam 88 cube, Looking at mikuni website - http://www.mikuni.com/fs-products_guides.html
they say there is approx 25% or approx 10 to 20hp difference, does anyone know how true this could be?, whats everyones thoughts on this? will it be worth the money? or should i just go new headwork, cams, pistons? any other suggestions for increase of bottom end power?
I fitted an HSR42 to my TC88B and fuck - has it livened it up ! I bought the carb ex US for $380 Australian and seriously doubt whether you would get better bang for your buck improvement. Was running SE breather kit in stock air cleaner (now have a MoFlo fitted) and Samson upswept fishies - not exactly performance pipes but the carb has delivered more "seat of the pants" power throughout the rev range and it is very crisp in the mid to upper rev range. Go for it.
Philthy
in the kit filthy, does it come with different size jets? did you fit it and tune yourself? i will be looking at fitting the carb myself and take it to get dyno tuned later on if needed
Not sure if you get additional jets in the kit, I would suspect not. You wont have to Dyno it, the instructions for tuning are very good just take it out on the raoad using a bigger jet each time until it hits a brick wall. I have found they are a little sensitive in the Southern OZ weather conditions including temp and humidity and barometric pressure, but easy to dial out with air adjuster while at a set of lights.
oh yeah, and they are a good carby.
Great carby. Not as easy to tune as some think though. I've got pretty close in the past by seat of the pants, following the book and LOTS of stuffing around, but it's hard to get it spot on without a dyno or afr meter (for me anyway!). It has several adjustable circuits, so it's not as simple as just adjusting the main jet. The main jet really only matters at WOT, although surprisingly your main jet CAN affect your idle mixture! Idle and off idle: (pilot jet, pump nozzle, pump adjustment, idle mixture) Quarter Throttle: Needle diameter 3 quarter throttle to Main Jet transition: Needle clip position Full Throttle: Main Jet They do work pretty well out of the box, but I recommend a proper dyno tune to get it spot on - you won't regret it.
Try this.
$372 US delivered. Bought a bit of stuff from USMOTOMAN.
tinyurl.com/2exjbd8
Well in the end you said you want more go, but if your got a CV 40 the HSR42 does not flow any more air, & as nado has said they are complex to tune. but from what i have seen a carb on its own not going to make a lot of difference.
99dyna, i'm thinking, if you want more low end go, changing your primary ratio to 3.37 will give you more low end go than changing from a CV40 to a mikuni42, as you will be on the power quicker. also reason i'm saying change primary ratio is it won't efect your speedo like a secondary ratio change would.
Just read the OP again. If you want bottom end (low end torque), why not just keep the CV, make sure you've got a decent air cleaner and mufflers, and bolt in an Andrews TW21? That would wake it up. It would run out of puff by 5 grand or so, but pull like a steam train right of idle. Besides, the CV will probably work better in the lower ranges anyway.
There are a few tweaks you can do to them as well.
www.nightrider.com/biketech/hd_cv_mods.htm
I reckon the above combo would give you the best bang for buck, assuming you're not going for top end peak horsepower. Think about where you do 90% of your riding - I reckon you'd love this setup.
Then if you take it to the next level, just bore the barrels, SE Flat Tops, .030 cometic head gasket and you'd really be cooking. Should be able to do this for under a grand. The extre cubes make a big difference low down.
Just a few suggestions....
