Wednesday, November 23, 2011

Mikunis

hi all,
 
just a little update to those who are interested.
I have been in the process of putting triple mikuni hsr 42's on the red motor in the J&S Hunter.
These are often found on harley davidson's and are meant to be a good carby's in that area, so I thought I would give it a go.
As seen from the photo's they fit very neatly into the engine bay. Took a bit of mucking about to get linkages and the manifold sorted but am pleased with the result.
I initially had a bit of hassles with getting it to idle but ended up being an air leak. I upgraded the pilot jet and tonight took it for a run. Am very impressed with the instant and light throttle response and a definite improvement on the 465 holley- also better than the triple su's and the webers (i feel the overall performance will be equal if not better than the webers and if the bike fraternity forums are to be noted- better fuel economy- they flow 30% better than su's), and that is without going on the dyno to get the fuel ratio and jets exactly right- I think the main may need adjusting as a very small flat spot at 3/4 throttle. Have had to get my head around different tuning methods these carbs have. Quite simple and effective in reality. The way these are working out I am seriously thinking of putting these on the grey motor and the Mk4.
Will let you know when I get to the dyno in Byford to do a little bit of fine tuning.
 
stacey-pres with a smile!

5 comments:

David said...

I like this thinking.
My son is currently working at bike wreckers to get through uni.
He keeps talking about getting six big bike carbs and putting them on a triple Weber manifold for the new 179HP race motor we have in the shed.
You've inspired me to give it a go.

Anonymous said...

if you want to put 6 on, really not benificial unless you have a 12port head, then I would go HSR40- remember these flow 30% better than su's. would be awson tho and am thinking along the 12 port head idea with 6 for a bit of fun one day.
stacey

Anonymous said...

Stacey
Much , much, better looking than that humongous Holley you used to have on there. Now all you need is a twin cam head.
peter m

Seacraft said...

I've got a Seacraft TS ski boat with a freshly built 186 with 3 of the HSR45's shipped in from the US. It has a stage 3 equivalent 9 port head, wade 140 grind cam, solid lifters and roller rockers. I'm at the stage of setting up the jets. I'm interested to know what you changed out apart from the needle valve assembly to accommodate the use of a fuel pump(4.2 to 2.3 for pressure feed). I am still looking for a place to run in the motor and tune the carbs in Victoria. I would really like to do it properly with a wideband lambda sensor, but may have to resort to old school plug checking and feel. How did you get your setup running in the first instance? Cheers.

Anonymous said...

I am interested in the manifold. Did you start with a SU style manifold and modify it to fit or can you purchase this type of manifold. thanks