Mr Keith Krause Please help!!

[TheCafeKid]

Im looking for a jet kit for my 77 750, with pods and 4into1...Dyno doesnt seem to list one...Know where i can find one?? Thanks!!



TCK

 

[KEITH KRAUSE]

Im looking for a jet kit for my 77 750, with pods and 4into1...Dyno doesnt seem to list one...Know where i can find one?? Thanks!!

TCK

As far as I know, no one makes a kit for your specific model anymore.
However, you may get lucky if you do some searching and calling.
Find out what your stock jet needle is and you can then compare that to the 78/79 1000 that uses your carbs. If the needles are identical, then you can use the jet kit that Dynojet uses for the 78/79 1000.
In your case, with the DJ kit, you should be able to run the stock 15 pilot jet too.
Only thing that leaves is the correct main jet. In most cases, depending on what pipe and pods you have, a '77 750 would require a main jet in the 125 to 132.5 range (Mikuni brand jets). The 138 main jet used in the DJ 1000 kit is approx' the same size as a 130 Mikuni main jet. So the kit may work for you. If not, it shouldn't be too hard to get the main right within a couple tries buy testing and buying separate main jets.
What you want is that DJ jet needle if it is the same for your 750.
Like I said, check for the info here or make a new topic asking for the jet needle info. I know someone here has the correct answer. DJ may be able to help too if you call them. Depends if they keep any records. They used to make a 750 kit, so did K&N and Factory I believe.
If no luck, I can help you re-jet if you want to try the stock needles.
Many times the stock needles won't work well enough due to leanness. But if your pods are the cheaper types you may be able to get the stock needles to work well by placing the jet needle e-clip in the bottom (richest) position. From my past experience, the bottom position is the only chance the stock needles have but it also depends on your stock/factory jet needle position. I'm pretty sure your specific year had the needles at the middle (3rd) position but something makes me think they may have been at the second position (?), which if so, would help you even more with the additional range of richness you could set them (3 full positions richer).
If you can use the stock needles, I'd most likely recommend 17.5 pilot jets too but you can also test the stockers first and see if they can work along with richer pilot fuel screw settings.
Whatever you decide, be positive the bike is ready for the re-jet or you're wasting time. Good compression, valve clearances, good spark/timing/connections, clean/synched carbs, etc, before any re-jet.
Let me know if you need further help.

 

[TheCafeKid]

Thanks Keith! While its sort of disconcerting to know that they dont make a kit for my bike, Im not entirely sure that i need it. I guess i should have posted with more detail my problem...

with the pods and 4into1 im actually having a RICH problem rather than lean..and it seems to be more in the slowspeed/idle circut. (Stumbly idle, wanting to drown at lights, very rich smelling exahust) Valve adjustment is done as well as a synch. Also while doing this Steve and i notice that the air screws were all over the place as far as how many times out they'd been turned (not by me, havent touched em aside from this since ive owned it ) So we adjusted them all to 1 1/2 turns out, and really it didnt seem to do much as far as idle went, except maybe slightly smooth it, so im assuming the PO went fat too far on the fuel screws too. Now im still learning carbs so these are complete assumtions and i could be way off so keep that in mind..hehe...I dont seem to have a problem at throttle she hauls a$$ in that department, and when you get going or get on it a bit there is no smoke (as best as i can tell in the mirrors with lights behind me) Should i pull em off and tinker with the fuel screw adjustment? Whats a near stock setting? (They're VM26SS) Any other suggestions??

I appreciate it!!

TCK

 

[KEITH KRAUSE]

It would help if you told me the current jetting set up.
What brand pipe?
What brand pods?
What size mains?
What position are the jet needles at?
Is the pilot jet stock?
A ballpark setting for the pilot fuel screws underneath (with your mods) would be approx' 1 1/2 turns out from lightly seated.
The side air screws should be set for best idle. If the bike isn't co-operating, just set the air screws to 1 3/4 for now.
Also, remove the 2 floatbowl vent lines and leave the ports open.
I would raise the stock jet needles 2 full positions from stock. The carbs must be re-synched after disturbing the needles. If you have no idea where the needles are now, then do a 1/3 throttle position test and read the plugs.
Do a full throttle test and read the plugs to see how the mains are mixing.
Minimal throttle test at a steady cruise around 35/40 in 4th gear will tell you how the pilot circuit is mixing.

 

[TheCafeKid]

Ok, Im going to tell you that ive not pulled these carbs apart at all, Ive only owned it for a little over a month..so as far as the needle setting and jet sizes, I've no idea. Yeah thats prolly not good, but i had hoped to just get er running decent untill winter, when i plan to do a full on break down, as im considering an 844 kit for her. Either way, she's getting tore down this winter for a general going over, cleaning and gasket replacement...

After talking to you, here's what ive done...

I pulled the carbs off, and lo and behold the fuel screws were all over the place, not nearly as bad as the air screws but bad enough...i turned them all in to light seat, then tried a 3/4 turn out..and for some reason, this seemed to make it worse, more smoke, higher, and crappier idle. Confusing to say the least. SOO i pulled em off again, and re-sat and turned them all out 2...much smoother, lower idle, and seemingly very little smoke. I also pulled off the vent lines as you suggested and that also seemed to help. Dunno if thats just wishfull optimism interfering with judgement, but it seemed to anyway. Here are some pics of plug chop tests, general 30 mphish in 4th...tell me what you think (anyone for that matter)

Plug 4

Plug 3

Plug 2

Plug 1

Sorry they're a little blurry, camera didnt want to focus on that point that close for some reason...
Any imput would be appreciated!!

Thanks Guys!

 

[TheCafeKid]

Ok after consulting my manual these are the stock jet sizes/settings...

main jet>>>>100
Air Jet>>>>>0.7
Needle Jet>>O-6
Jet Needle>>5F21-3
Pilot Jet>>>>15
Pilot Air Jet>>1.6
Cutaway>> 1.5
Air screw >> 1 Turn Back

Dont know if thats whats in it as i said, but thats the stock stuff..

 

[TheCafeKid]

It would help if you told me the current jetting set up.
What brand pipe?
What brand pods?
What size mains?
What position are the jet needles at?
Is the pilot jet stock?
A ballpark setting for the pilot fuel screws underneath (with your mods) would be approx' 1 1/2 turns out from lightly seated.
The side air screws should be set for best idle. If the bike isn't co-operating, just set the air screws to 1 3/4 for now.
Also, remove the 2 floatbowl vent lines and leave the ports open.
I would raise the stock jet needles 2 full positions from stock. The carbs must be re-synched after disturbing the needles. If you have no idea where the needles are now, then do a 1/3 throttle position test and read the plugs.
Do a full throttle test and read the plugs to see how the mains are mixing.
Minimal throttle test at a steady cruise around 35/40 in 4th gear will tell you how the pilot circuit is mixing.

Pipe type is V&H 4into1
Pods appear to be cheapies..heavy but not stamped with any indications
As for jet size i can only assume they are stock as they dont appear to be different or ever had been removed..


Ugh..heh it seems to be running more smoothly now, since ive adjusted the pilot fuel screws, but im still baffled as to why more turns out made it run better, still will blow a little smoke if you let it sit idling for a bit, but much better than it was...and yeah im pretty sure its not oil smoke. smells like gas and has a white whispy rather than blue/black and heavy look to it..

 

[KEITH KRAUSE]

Sorry for late reply. Busy as heck.
If you've read any of my past replies, you know I preach how the bike must be completely tuned first before jetting. I know you want to wait to rebuild the carbs, etc, and just get it running better for now, but that's not the way to do this. Dirty carbs, poor spark/ignition timing, etc, can cause your problems too. You also have no idea as to the condition of the carbs inside. The float levels could be off and that too could cause your problem. Makes no sense to jet under these conditions. For example, if the floats are off, adjusting the air/pilot fuel screws may not have the effect you intend. You really do have to do the basics first. If you don't, how can you assume any problem is purely jetting related? You'll just get in deeper.
You did provide some plug shots but they're poor quality. Actually, we've seen that plug pics are pretty hard to determine. It's probably best if you judge for yourself if you have basic knowledge of plug reading. Many websites will display color charts from lean to rich that will help you compare easily. After that, you just need to know how to test. The pilot circuit should be tested at something close to minimal throttle position. The jet needle at 1/3 throttle and the mains at full throttle. In all cases, chop off and read.
Your plug reads, blurry as they are, seem to look a little lean on the insulator, yet dark/sooty on the rim. Mixed results like this could be from poor/retarded timing, just to name one possibility. Of course, this is only after a low speed run so we're looking primarily at the pilot circuit mixture here. I'd like to know how 1/3 and full throttle effect the plugs and performance too.
I want to help but you're going about this contrary to how I do things, and my advice is based on how I do this kind of work. With so many unknowns, what do I advise you to do first? I gave some "ballpark" air and fuel screw settings and the 2 floatbowl vent lines should ALWAYS be removed with pods. Your current screw settings make sense to me though they seem to confuse you.
Sorry if I'm not much help but there's just too many things that can cause your exact problems and you have to do basic tuning and maintanance first before trying to jet it correctly.

 

[KEITH KRAUSE]

Oh, one other thought.
White, wispy smoke as you describe is most likely oil burning. White smoke lingers longer if you think it could be condensation.
Any jetting/mixture/weak spark problem would only result in a dark/heavy exhaust due to poor combustion, not anything white.

 

[walt]

You said you were using cheap pods. I will try to post two pics. In the first photo the filter on the left is a K&N, on the left is a Emgo. The second pic shows how the Emgo mounting ring interferes with the air passages at the carb mouth. I found this on another site.

 

[walt]

I did that wrong...here is the second photo.

 

[TheCafeKid]

Sorry for late reply. Busy as heck.
If you've read any of my past replies, you know I preach how the bike must be completely tuned first before jetting. I know you want to wait to rebuild the carbs, etc, and just get it running better for now, but that's not the way to do this. Dirty carbs, poor spark/ignition timing, etc, can cause your problems too. You also have no idea as to the condition of the carbs inside. The float levels could be off and that too could cause your problem. Makes no sense to jet under these conditions. For example, if the floats are off, adjusting the air/pilot fuel screws may not have the effect you intend. You really do have to do the basics first. If you don't, how can you assume any problem is purely jetting related? You'll just get in deeper.
You did provide some plug shots but they're poor quality. Actually, we've seen that plug pics are pretty hard to determine. It's probably best if you judge for yourself if you have basic knowledge of plug reading. Many websites will display color charts from lean to rich that will help you compare easily. After that, you just need to know how to test. The pilot circuit should be tested at something close to minimal throttle position. The jet needle at 1/3 throttle and the mains at full throttle. In all cases, chop off and read.
Your plug reads, blurry as they are, seem to look a little lean on the insulator, yet dark/sooty on the rim. Mixed results like this could be from poor/retarded timing, just to name one possibility. Of course, this is only after a low speed run so we're looking primarily at the pilot circuit mixture here. I'd like to know how 1/3 and full throttle effect the plugs and performance too.
I want to help but you're going about this contrary to how I do things, and my advice is based on how I do this kind of work. With so many unknowns, what do I advise you to do first? I gave some "ballpark" air and fuel screw settings and the 2 floatbowl vent lines should ALWAYS be removed with pods. Your current screw settings make sense to me though they seem to confuse you.
Sorry if I'm not much help but there's just too many things that can cause your exact problems and you have to do basic tuning and maintanance first before trying to jet it correctly.

Ok well i do appreciate what help and pointers you've given me..i know its tough and as i said im no carb guy..break something in a motor and generally i can fix it, but tuning carbs, especially 4 of them, has elluded me quite a bit. At any rate, as far as doing the other things, the valve clearance has been adjusted, we also synched the carbs and checked the timing, Manual says 17 degrees, i had 18 degrees on 2-3 and 15 degrees on 1-4..didnt know what the timing was to be set at at the time of checking it, now i do, i will adjust and see how that helps..Also, please excuse my ignorance, but if you would, please explain to me how adjusting the fuel screws OUT made it better considering i seem to be running rich, at least down low? Wouldnt IN restrict the fuel flow, or am i completely wrong?? The manual i do have does very very little to explain more than Steve has gone over with me on the carbs..Bottom line seems to be i will have to resign the fact that they are going to come of the bike and get torn down. I'll use the examples that are here in the Garage portion, as they seem pretty thorough, but is there anything i need to know about the VM's vs the BS's that could get me in a bind?? Appreciate it again Keith, sorry to be a pain..

TCK

 

[TheCafeKid]

Ok so ive started breaking the carbs down. One at a time so i always have one complete to reference. The jets and needles appear to be stock as per the manual. 511 on the main, bleeder is 17.5, and the needle clip is placed in the third slot. I'll have to order some Orings and gaskets, and while they weren't filthy, they did have some sediment in the bowls. One thing i did notice on the first one ive broken down is the plate/washer from the slide asbly is missing...did it not have one? If so will i need to replace it?? Good lord id hate to think of attempting that. Once i start to put these back together do you have any suggestions for me as far as moving the needle up or down? I'd like to set it up for my set up as close as possible and then figure out from there whether or not im going to need to change jets. Thanks again for your assistance!

TCK

 

[KEITH KRAUSE]

OK. First of all, you're not a pain. So if my reply sounded "blunt" or something, disregard that.
It's just me trying to say you must do the basics first. Clean and INSPECTED carbs are one of those basics. You really do have to pay close attention to truly get the carbs cleaned. I use at least 100 psi to blow out all passages after cleaning with cleaner.
If richening the fuel screws underneath helps at a certain throttle position, then it means you're lean at that throttle position, even if you think otherwise.
Also, be sure to install new manifold o-rings. They're cheap and are critical to performance. Inspect the manifolds too for hardening/cracking.
Now as for your last post, you said "the plate and washer are missing from the slide assembly". If you mean the thin brass plate that goes under the throttle arm base and the washer you mention is one of the two jet needle plastic washers, then yes, you have to replace those for the carbs to operate correctly. There are actually two plastic spacers/washers used with the VM carbs jet needles. The thicker spacer, actually called a ring, goes directly on top the jet needle e-clip and the thinner spacer goes directly under the clip. Without the top ring, the bike will run much richer than intended at anything above approx' 1/6 throttle position.
If those, or other parts are missing, these carbs have been subjected to poor maintanance and that's even more reason to inspect everything closely and get them back to good shape so you don't drive yourself nuts trying to tune/jet them.
For one thing, inspect/set the float levels. I believe your carbs should be between .90 and .98". I always set then right in the middle....94".
As for jetting, you said you have a "511" main. That's obviously a typo.
See my previous suggestions for jetting. If you found the jet needle with the e-clip in the 3rd position from the top, that would be the factory set position and I assure you that's way too lean considering your mods. If those pods and pipe flow as they should, then my past experience says to lower the e-clip to the 5th (bottom) position. Any decent pipe and even the cheaper pods should require at least "1 1/2" positions richer at the jet needles. A 1/2 position is achieved by use of a .022" jetting spacer. Since it's always best to jet rich and work your way back if necessary, and because I doubt you have those jetting spacers, I suggest trying the 5th position first. If it is a bit rich, then it depends on the plugs and performance if you should go to position 4 1/2 or ?? Who knows, you may even find that the bottom position isn't rich enough. If that happens, we'll discuss what to do later. I'm betting two full positions richer will work, as long as the other basic tuning is done and you have good compression, etc.
Remember, every time the jet needles are moved, the VM carbs must be re-vacuum synched. You can't accurately judge performance or trust uneven plug reads because the carbs aren't synched well and drawing uneven vacuum.

 

[KEITH KRAUSE]

Also, the VM carb series article here will help you. It takes a little finger dexterity to work with the slide asembly but you can do it.
Just don't be in a hurry with carb work and use GOOD fitting tools for all hardware to avoid trouble. Read some past posts. Lots of info here to save you from a problem. For one, always seat the sharp tipped pilot fuel screws LIGHTLY when determining their settings. Seating them too hard can break off the tips in the carb body and the carb won't perform well. Inspect the screws for sharp tips.
Another basic, keep all parts with the carb they came out of. Don't mix float valves and float valve seats, etc.
Anything you need to know about these carbs, just ask before doing something wrong or assuming something. I'll try to come around often enough to help.

 

[TheCafeKid]

OK. First of all, you're not a pain. So if my reply sounded "blunt" or something, disregard that.
It's just me trying to say you must do the basics first. Clean and INSPECTED carbs are one of those basics. You really do have to pay close attention to truly get the carbs cleaned. I use at least 100 psi to blow out all passages after cleaning with cleaner.
If richening the fuel screws underneath helps at a certain throttle position, then it means you're lean at that throttle position, even if you think otherwise.
Also, be sure to install new manifold o-rings. They're cheap and are critical to performance. Inspect the manifolds too for hardening/cracking.
Now as for your last post, you said "the plate and washer are missing from the slide assembly". If you mean the thin brass plate that goes under the throttle arm base and the washer you mention is one of the two jet needle plastic washers, then yes, you have to replace those for the carbs to operate correctly. There are actually two plastic spacers/washers used with the VM carbs jet needles. The thicker spacer, actually called a ring, goes directly on top the jet needle e-clip and the thinner spacer goes directly under the clip. Without the top ring, the bike will run much richer than intended at anything above approx' 1/6 throttle position.
If those, or other parts are missing, these carbs have been subjected to poor maintanance and that's even more reason to inspect everything closely and get them back to good shape so you don't drive yourself nuts trying to tune/jet them.
For one thing, inspect/set the float levels. I believe your carbs should be between .90 and .98". I always set then right in the middle....94".
As for jetting, you said you have a "511" main. That's obviously a typo.
See my previous suggestions for jetting. If you found the jet needle with the e-clip in the 3rd position from the top, that would be the factory set position and I assure you that's way too lean considering your mods. If those pods and pipe flow as they should, then my past experience says to lower the e-clip to the 5th (bottom) position. Any decent pipe and even the cheaper pods should require at least "1 1/2" positions richer at the jet needles. A 1/2 position is achieved by use of a .022" jetting spacer. Since it's always best to jet rich and work your way back if necessary, and because I doubt you have those jetting spacers, I suggest trying the 5th position first. If it is a bit rich, then it depends on the plugs and performance if you should go to position 4 1/2 or ?? Who knows, you may even find that the bottom position isn't rich enough. If that happens, we'll discuss what to do later. I'm betting two full positions richer will work, as long as the other basic tuning is done and you have good compression, etc.
Remember, every time the jet needles are moved, the VM carbs must be re-vacuum synched. You can't accurately judge performance or trust uneven plug reads because the carbs aren't synched well and drawing uneven vacuum.

Thanks again for your responces

Bad news is that i can possitively say that the two plastic spacers and the metal plate in each slide asmbly are no longer there...you said this would make the bike run rich...so i think that would be contributing to my confusing problem. My guess is the PO removed them in his way to avoid rejetting for the pods and pipe?? The tough part is; Where the heck am i going to find replacements?? This could very well be no good at all In the event that i can find no replacements is there something i can use in their place? Now im very frustrated. Id hate to think im going to have to find new carbs altogether over this, but i get the feeling that may be the case...

Thanks again

TCK

 

[KEITH KRAUSE]

Thanks again for your responces

Bad news is that i can possitively say that the two plastic spacers and the metal plate in each slide asmbly are no longer there...you said this would make the bike run rich...so i think that would be contributing to my confusing problem. My guess is the PO removed them in his way to avoid rejetting for the pods and pipe?? The tough part is; Where the heck am i going to find replacements?? This could very well be no good at all In the event that i can find no replacements is there something i can use in their place? Now im very frustrated. Id hate to think im going to have to find new carbs altogether over this, but i get the feeling that may be the case...
TCK

That's too bad. The thin brass plate with the dimple is needed to allow the jet needle to be in a "fixed" position and not allow it to rotate and slowly damage itself. That must be replaced.
As for the plastic ring and thinner plastic spacer, they are necessary too for good carb operation and obviously the jetting is effected greatly.
It's possible to replace them with similar pieces, possibly found at a hardware store, but since you need the brass plates, it's best to get some cheap "parts" carbs. As long as the needed parts are there, it shouldn't matter what condition the carbs are in. The parts you need are rarely damaged.
You can also make a new post in the parts wanted section. Many members have extra parts I'm sure. Just be sure to ask questions to be sure you get the identical parts.

 

[KEITH KRAUSE]

And another thought, I hope the jet needles still have their spring.

 

[TheCafeKid]

That's too bad. The thin brass plate with the dimple is needed to allow the jet needle to be in a "fixed" position and not allow it to rotate and slowly damage itself. That must be replaced.
As for the plastic ring and thinner plastic spacer, they are necessary too for good carb operation and obviously the jetting is effected greatly.
It's possible to replace them with similar pieces, possibly found at a hardware store, but since you need the brass plates, it's best to get some cheap "parts" carbs. As long as the needed parts are there, it shouldn't matter what condition the carbs are in. The parts you need are rarely damaged.
You can also make a new post in the parts wanted section. Many members have extra parts I'm sure. Just be sure to ask questions to be sure you get the identical parts.

Ugh thats what i was afraid youd say...well..ill put the post out there, and then start scouring ebay...worst comes to worst i guess i could always reaplace them with a set of tuned Keihin carbs..but thats 700 bucks...rough. Thanks again Keith for your help, and i'll probably hit you up for more info should i find this stuff...:-D

 

[TheCafeKid]

And another thought, I hope the jet needles still have their spring.

I cant remember if i pulled one off of there or not when i took em apart..ill have to go look...i know there were lots of springs heh. The one bonus i did think of is that these carbs were also on quite a few Kaw models too, so i should be able to find some donors somewhere...Always a silver lining...heh