Intake rubbers

[caya]

Hi,

 at first, sorry if this was already discussed somewhere else, but I really tried to find it with no results.

So the thing is, I decided to refurbish carburetor on my Honda and since I really don't like being under pressure I just got another carburetor from friend and put it in order and learned how that thing works. Till this weekend I thought there won't be any catch but as I unmounted old carburetor I found that both intake rubbers (those between carburetors and engine's body) have some sort of restrictor (not that kind to lower power output to 25kW or whichever value is common in UK, I am not from there so I really don't know).

www.dropbox.com/s/nhxqfr394borbox/NTV650_p%C5%99%C3%ADruby.jpg

The restrictor is part of the rubber and on the collar of rubber is embossed value "37kW". It was little surprise, but I was suspecting there was something wrong with my Honda, since friend who I occasionally travel with has same model, just little younger and little more vital with better mpg. The rubbers are old, very likely original so ordering new ones is prolly best idea. First hand shop for ordering parts for me is wemoto but their rubbers - or at least descriptive picture - has larger inside diameter. Wemoto guy wasn't able to tell me what's inside diameter of these rubbers, he just claimed that manufacturer makes what was originaly used by Honda, alright... but the picture(and not only wemoto, but also various ebay sellers)shows rubbers with much larger diameter. That's actually good for me because jets in "new" carburetor are larger than jets in "old" one and more air flowing into cylinders will be appreciated.

Now why I am writing all this: does anyone know what's proper inside diameter of these rubbers or has any experience with this? Thanks

PS: excuse my english, I am not native speaker


 

[slug]

hi caya, not expert but will try to help you.. yes by photo you have
a restrictor fitted,, as you say on yours it is fixed in place, in the uk
they can be removed and same inlet intake rubbers used... the Honda ntv 650
inlet rubbers should be the same on all years,, the Honda 600 ntv carbs
are a different size can not be used on the 650 ,,or the 600 inlet rubbers are
different.. if you order the rubbers the correct year and model for your model
you should get correct part,, measure your original carb it will be the extrernal diameter
of carb outlet and engine inlet,, should be the same.. you can get on ebay uk there are a set
for 17 pounds new on there.. ask in questions for supplier to check inside dia of rubbers,,
with restrictor removed you will find a large increases in power, also you say you may need larger jets..
your English is very good .. we love to help fellow ntvrs,,

[De Graaf van Salland]

For your information:
Set of second-hand intake rubbers from Otterparts : 22,50 euro



GvS

[caya]

slug

I've been browsing internets today and found two different inside diameters for these rubbers. New parts(mostly from ebay UK/DE) have usually full open diameter as those on wemoto. Though I found at least one used set on german ebay with exact same reduction. It's almost like new sets are sold in only - big - size.

I asked the guy in wemoto and he said he doesn't know and can't find this information in any catalogue. I really don't feel to visit local Honda dealership, last time I was there I was leaving quite disappointed, their own database seems to be quite poor.

@de Graaf van Salland

Those rubbers I was expecting to find on my bike and those I want to fit in. The refurbished carburetor I plan to mount has 140/135 (front/rear) jets while the old one has 132/128. I believe that with new setup bike shouldn't be dead above 5500 rev/min. as it used to be.

It's though just deduction rather than proven fact hence I was asking whether someone knows a bit about it.

Thank you guys

[slug]

yes the bigger jets should be better if you fit pipe without restrictor fitted, lots more power.
just check spark plug colour after running for a few days. should be brown in colour,, also while you
are checking carbs, check very fine filters above float needle, they need good clean very fine mesh,
any more questions please ask we are here to help..