Carb Mod Question

[84xj1100]

Just completed the carb mod to increase gas mileage on my 86 Venture. The mod from this site (with pics I may add) says to remove the white fiber/plastic spacer and replace with x2 m4 washers.

 

Here's the lead in to the question.....when I removed the "slider"..the needle itself had some "play" to it...you could push it in a little and feel the tension of the spring.

 

After the mod....that movement/free play is pretty much gone.

 

Is this normal???

[skydoc_17]

Hey Ed,

I don't know if you have put your Carbs. Back together or not but the reason the needle "springs in and out is so the the needle doesn't destroy the seat of the main jet. Could it be that you have the washers on the wrong side of the lock washer? The object of the shim mod is to move the needle closer to the main jet seat so the shims should be thinner than the nylon washer, thus there should be slightly More spring in the needle. I have attached some pics of this mod and I now machine a nylon washer to replace the stock Yamaha Spacer that is in the slider. If you are interested in the replacement nylon spacers, PM me.

Earl

[Venturous Randy]

No, it is not normal. Given you should have reduced the thickness from about .120 to about .070 using only two washers, you should have even more play in the needle spring movement. I also suspect if the #4 washers you are using are about .032 in thickness, you will probably need one more washer for the bike to run right. Can you measure the washer thickness? And, you did use flat washers?

RandyA

[84xj1100]

Thanks for the info folks.......I don't have the ability to measure the thickness of the washers however the two of them put together (eyeballed) are about half the thickness of the OEM washer.

 

I also feel a little (lot) dumb :bang head: in that after I put everything back together I took a peek at the mod (pics) again and realized that my needles (86 Std) are adjustable (they have multiple settings). I am therefore going to remove the washers, replace the OEM washer and simply adjust the circlip setting up a notch. What a dope

[bald josh]

so i was going to do the needle/shim mod @ a year ago and ran into the same prob as 84xj, i just put it back together stock and forgot about it. yesterday i thought id try again and went and got the washers from ace and same problem, the needles had no play in and out, a little side to side but none in and out. i remembered this post and searched for it. my needles do not have any adjustment?!? so looked a little closer and discovered the prob/solution. not all washers will have the exact OD measurement and sure enough the ones from my local ace are too big. i think the area inside the slider that the needle/ clip/ washers fit into is tapered and so it all seems to fit fine at first but when you start to tighten it down there is not enough room for the washers to seat proper. I could feel it when tightening, but was unsure why. i went back and found nylon washers 1 the same thickness as two stainless washers but with an OD just a bit smaller and all works perfect. now there is free play in and out like stock.

I did try and slide the slides into the carbs with the stainless washers and i could feel the needles rubbing in and out. dont want to cause alarm but if you dont know if there was free play with the needles id check. and i bet Eds washers are spot on so the carb mod kit he sells would be worth it.

attached pic is of a stainless washer STUCK inside the slide.

im gonna go for a ride this weekend and enjoy checking the fuel mileage.

[jasonm.]

what size washers are recommended to start? #4 or #6? Does #4 fit over the needle? #6 stainless and nylon are easy to find. But #4 not so... AND how much is a good start to drop it? The factory washer is 2.5mm thick. I can get nylon #6 washers in 1.7mm. Is this a good start? Please reply.

[Grisolm1]

FYI

 

My stock? nylon spacers (with the little nub) measured 0.100". Replaced them with 0.75" worth of washers of correct dimensions and had spring action going on. Mileage didn't improve measurably, still ~37 and the bike had a definite lean condition so I took them out.

[jasonm.]

this is why I may need this mod.Look at my last post on this thread ... http://www.venturerider.org/forum/showthread.php?t=49478&highlight=shim&page=2

[mrich12000]

Princess Auto has digital snap and vernier to do this job you really need it.

[jasonm.]

Thank you, I have both a digital caliper and old school "C"style caliper to measure shim thickness. If the weather stays good here. Any changes I make will be in small steps. To start at .100" = to "no nubb" on the stock shim , using shims I purchase. I hope have this sorted out by Saturday.