crenninger Posted June 18, 2017 Share Posted June 18, 2017 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 Link to comment Share on other sites More sharing options...
rhubarb Posted June 18, 2017 Share Posted June 18, 2017 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 Link to comment Share on other sites More sharing options...
Member Contributer Forbes Posted June 18, 2017 Member Contributer Share Posted June 18, 2017 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 Link to comment Share on other sites More sharing options...
slovcan Posted June 18, 2017 Share Posted June 18, 2017 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 Link to comment Share on other sites More sharing options...
crenninger Posted June 18, 2017 Author Share Posted June 18, 2017 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 :-) Link to comment Share on other sites More sharing options...
slovcan Posted June 18, 2017 Share Posted June 18, 2017 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 Link to comment Share on other sites More sharing options...
crenninger Posted June 18, 2017 Author Share Posted June 18, 2017 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.. Link to comment Share on other sites More sharing options...
slovcan Posted June 18, 2017 Share Posted June 18, 2017 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 Link to comment Share on other sites More sharing options...
crenninger Posted June 18, 2017 Author Share Posted June 18, 2017 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!! Link to comment Share on other sites More sharing options...
slovcan Posted June 18, 2017 Share Posted June 18, 2017 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 Link to comment Share on other sites More sharing options...
crenninger Posted June 18, 2017 Author Share Posted June 18, 2017 pilot screw: 2 turns out Bowl - 10mm should I change any of that? Link to comment Share on other sites More sharing options...
slovcan Posted June 19, 2017 Share Posted June 19, 2017 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 Link to comment Share on other sites More sharing options...
squirrelman Posted June 19, 2017 Share Posted June 19, 2017 If you need any hands-on tuning help contact Derek Capito at MotoLab near you. He's amazing! Link to comment Share on other sites More sharing options...
crenninger Posted June 19, 2017 Author Share Posted June 19, 2017 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.... Link to comment Share on other sites More sharing options...
crenninger Posted June 19, 2017 Author Share Posted June 19, 2017 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. Link to comment Share on other sites More sharing options...
Member Contributer Terry Posted June 19, 2017 Member Contributer Share Posted June 19, 2017 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. Link to comment Share on other sites More sharing options...
crenninger Posted June 19, 2017 Author Share Posted June 19, 2017 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. Link to comment Share on other sites More sharing options...
crenninger Posted June 19, 2017 Author Share Posted June 19, 2017 One question. What are these 2 tubes which are out in the open? Shouldn't they have at least a small breather filter? Link to comment Share on other sites More sharing options...
crenninger Posted June 23, 2017 Author Share Posted June 23, 2017 Anyone on the open port / breather that may need a filter? Link to comment Share on other sites More sharing options...
rhubarb Posted June 25, 2017 Share Posted June 25, 2017 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. Link to comment Share on other sites More sharing options...
crenninger Posted July 23, 2017 Author Share Posted July 23, 2017 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. Link to comment Share on other sites More sharing options...
Member Contributer JZH Posted July 23, 2017 Member Contributer Share Posted July 23, 2017 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, Link to comment Share on other sites More sharing options...
crenninger Posted August 6, 2017 Author Share Posted August 6, 2017 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 Link to comment Share on other sites More sharing options...
slovcan Posted August 6, 2017 Share Posted August 6, 2017 Try the needle clips in the 4th groove and see what that does. Link to comment Share on other sites More sharing options...
crenninger Posted August 8, 2017 Author Share Posted August 8, 2017 4th groove from the top I assume correct? I'll try this weekend. Link to comment Share on other sites More sharing options...
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