|
Carbs
Apr 11, 2021 10:21:34 GMT 1
Post by jon on Apr 11, 2021 10:21:34 GMT 1
Hi all,
I’m having a nightmare trying to decide what type and size of carbs I should get for my 385.
I don’t want to over carb it, and have had advice to go for 28s or 30s.
28s could be either Mikuni flat slides or PWK? I’ve heard a few stories of PWK being difficult to jet?
30mm TMX looks good, but I’m not so sure on the powerjet? Has anyone blanked this and upjetted?
Also really I want to keep the airbox. So billet manifolds may make connecting carbs to it a headache.
I’m running the oil pump so need to either find a boss on the carb, or if using a billet manifold I’ll tap that.
Jon
|
|
|
Carbs
Apr 11, 2021 10:47:51 GMT 1
Post by stusco on Apr 11, 2021 10:47:51 GMT 1
Bare will tell you PWK are easy and very forgiving to jet, i have them i went with the advice on here and when muts dyno’d it he only changed a pilot one size pwk has a spigot you can use for the oil pipe
|
|
|
Carbs
Apr 11, 2021 11:22:57 GMT 1
Post by jon on Apr 11, 2021 11:22:57 GMT 1
I hear what your saying, and it seems hit and miss with PWKs. You either lucky or not.
Norbo states in his shop about the flat slide Mikuni’s he has for sale ‘ simpler to set up then the PWK’.
Jon
|
|
|
Carbs
Apr 11, 2021 11:42:23 GMT 1
via mobile
Post by midlifecrisisrd on Apr 11, 2021 11:42:23 GMT 1
I found the pwk's really easy to set up
Standard 38/135 jetting ain't a million miles off
JJH needles with airbox
Enough people with them to advise on jetting
I'm now running 35/140 on my 385
Airbox fitted, snorkels out, standard filter, drilled lid
28's work with standard cable with a little mod
Not sure how the 30's work with the extra 4mm travel and how it affects the oil pump set up
Also pwk's are about 5mm shorter inlet to airbox so help with fitment
I'm not using a billet manifold but got v4 reed and 10mm spacers so a good 15mm further back
Steve
|
|
|
Carbs
Apr 11, 2021 12:43:51 GMT 1
Post by jessy03 on Apr 11, 2021 12:43:51 GMT 1
Jetting can be hit and miss, I’m on 45/138 with a gutted/drilled airbox, I’m building one at the minute and hoping to use some TM32 with airbox, it will be a tight fit,might be doable. Jess
|
|
|
Carbs
Apr 11, 2021 12:52:39 GMT 1
Post by Tobyjugs on Apr 11, 2021 12:52:39 GMT 1
I believe its more to do with the experience you have with jetting the carbs. A standard carb for our bikes has more bits you can alter or adjust compared to a PWK. I would go with the carb you feel more at home with, unless you want a specific trait which one carb displays more than others you can choose from.
|
|
|
Carbs
Apr 11, 2021 12:55:40 GMT 1
Post by dusty350 on Apr 11, 2021 12:55:40 GMT 1
Got my Pwk 28's from Mutts, who drilled and fitted the oil line spigots for me and also sorted a base line jetting to start off with - may need tweaking for the 400 engine, but no 2 bikes are the same anyway. He said the Pwk's are good for mid 70's bhp. Go too big and you could have driveability issues. Billet intakes may mean lining carbs up with the airbox could be difficult. Whenever I've used billet intakes, I've used pod filters, by choice rather than necessity, but they do seem to sit the carbs at a different angle to stock. My intakes were also drilled and spigots fitted - I've blanked off the carbs and the oil pipes run to the intakes so you wont need to upset them if the carbs come off for jetting changes. I had to trim the outer cable cover to allow the inner cables on the throttle to work properly with the Pwk's - simple enough to do Dusty
|
|
|
Carbs
Apr 11, 2021 12:56:03 GMT 1
Post by Tobyjugs on Apr 11, 2021 12:56:03 GMT 1
If i can remember correctly Yazza had big problems trying to jet his TMX carbs together with Mutts. They then made a quick swap over to the PWK's and they found it much easier to jet and gave more constant results.
|
|
|
Carbs
Apr 11, 2021 12:57:19 GMT 1
Post by tony2stroke on Apr 11, 2021 12:57:19 GMT 1
I have put some knock off 30mm PWK powerjet carbs on my standard porting 250LC with RAMAIR filters, initial results are good, starts and runs nice up down back lane, ticks over great too, early days to say for sure yet, most likely need to re-visit the jetting, I have heard of a few people now using them, just with the knock off you need to do your own quality control, also put gen Keihin jets in.
Had to cut down the angled cable guide and tap the end to screw in to carb top, but no problem really.
|
|
|
Carbs
Apr 11, 2021 13:54:09 GMT 1
via mobile
Post by midlifecrisisrd on Apr 11, 2021 13:54:09 GMT 1
2 simple ways to sort the cable when using 45 degree elbows
Way I did it was to grind the cable adjuster lock nut down to half thickness
Other way is to take an m6 x 0.75 die (Think that's the m6 fine) and cut the adjuster thread down a little more
Steve
|
|
|
Carbs
Apr 12, 2021 16:41:45 GMT 1
Post by bare on Apr 12, 2021 16:41:45 GMT 1
Or remove the metal angled bits entirely ? As I found My cables (albeit Bespoke DIY ones from good grade Bicycle bits) Did the bend into the carb top, far more smoothly / less friction than the metal bits allowed.
|
|
|
Post by JonW on May 6, 2021 5:02:58 GMT 1
2 simple ways to sort the cable when using 45 degree elbows Way I did it was to grind the cable adjuster lock nut down to half thickness Other way is to take an m6 x 0.75 die (Think that's the m6 fine) and cut the adjuster thread down a little more Steve I do these things too. doesnt take long and means you can use an OEM cable.
|
|
|
Post by jessy03 on May 6, 2021 10:47:01 GMT 1
You could just fit the angle tops off your std carbs, fitted perfect.
|
|