Jump to content
crenninger

What is the stock jetting/needle, which needle do I have?

Recommended Posts

Hi everyone, 

I got an estate sale VFR750 '91. So unfortunately I can't know much of history on the bike.

 

I took the carbs out, I got a 40 and 132 jets and the needle pictured below

 

My questions, 

1- what is the stock jetting, I under either 38 or 40 and 128 or 130 , which one ?

2- is the needle below the stock? (I doubt it) and if not, what is the reference for a stock needle?

 

I do not care about performance, I only care about getting the bike back to an easy to ride bike, I don't need the last bit of horsepower.

the bike has a K&N filter and a twin brother full exhaust (collector and left side carbon exit)

 

thank you

 

unnamed.jpg

Share this post


Link to post
Share on other sites

38/130 is stock. Those look like Dynojet needles but the main jet would be a DJ120 or 124. Assuming the needles are correct the clip should be on the third groove from the top. Are there brass shrouds visible in the carb throat?

http://www.dynojet.com/pdf/1139.pdf

 

Share this post


Link to post
Share on other sites

Not sure on main and needle, even though 38 idle jet is stock as on VF750 as well, they are sometimes changed out to the 40 because it corrects an issue of slow return to idle(too lean). Return others to stock if that's your intention, but I would be leaving the 40 idle's....JMHO.

Sent from my HTC_PN071 using Tapatalk

Share this post


Link to post
Share on other sites

Sounds like someone bumped the jets up to the next size because of the K&N air filter and Two Brothers exhaust. The exhaust on it's own wouldn't require rejetting since the collector is still used, but maybe it felt better. It also sounds like mixed parts with OEM jets and Dynojet needles. That's weird.

 

You indicated it might not be easy to ride at the moment. Tell us about that. The jetting might not be the cause (or only cause) and maybe a proper carb cleaning will sort it out.

 

Cheers,

Glenn

 

 

Share this post


Link to post
Share on other sites

SO the previous owner was known to muck around and taking the carbs appart as the weather changed....

so.... I got the bike last weekend, I haven't ridden it.  It has been sitting in the garage for about 6 years.

i am going over it before anything.

i did put fresh gas and it started, so that was my green light to dig further.  I hope it makes sense.

 

the neighbors said he had to let it warm up like 10-15 minutes before each ride, I found a totally open air box, and this weird combination of needle and jets... so I'll start from scratch.

 

exhaust is a full (header/silencer) twin brother left side exit.... yeeeaaaa....

 

does anyone has a picture of a stock needle? I see some on eBay I'd like to make sure they are the correct ones.

 

also, does the stock needle needs any washer/spacers?

 

 

regarding the dynojet needle, it's in the 5th groove from the top!?,!  A carb tinker he was... Rest In Peace Steve :-)

Share this post


Link to post
Share on other sites

OK, you got the FULL Two Bros left exit system. That's AWESOME - like the Holy Grail of exhaust systems! In that case, the 40/132 combo is good. I would do a proper cleaning INCLUDING using an ultrasonic cleaner and put them back together with the components you have. I would set the needle clips in the 3rd groove to start with. I suspect you'll end up with them in the 4th groove.

 

Cheers,

Glenn

Share this post


Link to post
Share on other sites

So I am adding the K&N filter to replace the open air box, and you are suggesting i go with 132 main even it should be the dynojet main which I don't have?

 

I don't mind messing around with the needle which are easy to get to, but once I have the carb back in, I'd rather not mess with the main..

Share this post


Link to post
Share on other sites

Yes. The jetting should be correct for the exhaust. The K&N by itself wouldn't need a jetting change, but sometimes people do it. Try what you have. If you want to change the needles after, not a big deal.

 

Be sure to do a bench synch before you put them back in. Did you count the turns on the pilots before you took them out? If not, set them by the manual initially.

 

Cheers,

Glenn

Share this post


Link to post
Share on other sites

I haven't taken the pilot yet. Will count. 

 

Bench sync, I'll check how to do that. I have a carb tune vacuum tool but always used it with the bike running. 

I bet YouTube can help

 

thank you!!

Share this post


Link to post
Share on other sites

Great. Look for the "paper method" for bench synching. You can vacuum synch after. The bench synch will get you close for starting/driving after carb install. Curious to know what Steve had the pilots set at vs stock.

 

Cheers,

Glenn

Share this post


Link to post
Share on other sites
7 hours ago, crenninger said:

pilot screw: 2 turns out

 

Bowl - 10mm

 

should I change any of that?

 

Pilot screw initial setting should be 1-1/2 turns for the 49 state bike or 2-1/2 turns for a California bike.

 

Bowl - 10mm? Is that the float height? I don't think it is supposed to be adjustable on ours. That's not to say it CANNOT be adjusted. I just don't know. I can't find a spec for float height in the manual. Most of the V65's are 7-1/2 mm (just for reference, may well be 10mm). Let's wait until someone else jumps in with float info.

 

BTW, idle speed for the California bike is 1200 - the 49 state is, I think, 1000 or 1100.

 

Cheers,

Glenn

Share this post


Link to post
Share on other sites

If you need any hands-on tuning help contact Derek Capito at MotoLab near you.  He's amazing!

Share this post


Link to post
Share on other sites

Thx, I know Derek. I've done plenty with him regarding the 640 carb and fcr...

i had promised myself to buy injection only going forward....

Share this post


Link to post
Share on other sites

Alright, carbs are back in. 

3rd clip on the needle, 2.5 turn (ca bike) 132 main, 40 idle. 

 

The bike started great, idles ok, 

for now the issue feels like the bike is struggling to get off idle, once past 3/4000 rpm she goes up ok. 

This is on the rear stand, not riding. 

 

I haven't checked for an air leak yet I'll have limited time in the next 10 days. 

 

Share this post


Link to post
Share on other sites

Sorry for the dumb question...did you clean out the low speed jet circuit as part of the rebuild? Because that sounds like where your poor running is coming from. 

Share this post


Link to post
Share on other sites

Yes, took all the jets out and cleaned. 

Also spray carb cleaner throughout and waited to see it coming out before putting the jets back it. 

Share this post


Link to post
Share on other sites

One question. What are these 2 tubes which are out in the open? Shouldn't they have at least a small breather filter?

 

 

IMG_4817.JPG

IMG_4818.JPG

Share this post


Link to post
Share on other sites

http://www.hondapartsplus.com/oemparts/a/hon/506ca725f870023420a3fbba/air-cleaner

 

6, 7, 8, 9 and 12 (2) for the large tube.

 

http://www.hondapartsplus.com/oemparts/a/hon/50540f9cf870021c54bedc7c/carburetor-assy

 

39 and 26 (2) for the smaller. This may only apply to the 1990.

2017-06-25-015745.jpg

Share this post


Link to post
Share on other sites

Sorry everyone for the late reply, I finally got around to cleaning the carb for a 2nd time and now it's working as expected! Goes through RPM fine.

 

 

Share this post


Link to post
Share on other sites

Is it a CA-spec bike?  VIN would have "RC361" in it.  The opening pointing to the rear of the bike would have gone to the rear cam cover (for the PCV, I think).  The angled one on the left should be left open or connected to the airbox if CA-spec emissions equipment has been deleted.

 

I wonder whose bike it was.  Might have been a member...

 

Ciao,

Share this post


Link to post
Share on other sites

Hi, yes it's a CA bike. It wasn't a bike from a member.

So I took a 55 miles ride today, the bike runs great after 4k RPM, but still hesitate under 4k and/or while on small throttle openings like 1/8 1/4  then the bike really runs well.

 

I've got the stock needles now but not installed, the FP are still there.  I look on Honda parts and the Stock needles needs a washer which I don't have and Honda doesn't sell anymore.

 

Does anyone knows the thickness for these? or better yet have a set of washers laying around?  I am thinking to go back to fully stock and go from there.

 

thank you 

Share this post


Link to post
Share on other sites

Try the needle clips in the 4th groove and see what that does.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×