vacuum slides

[DrtRydr23]

I've got a question for all you jetting guys out there.  I've got a 97 GS and have been trying to do a successful rejet off and on for some time now.  I've got a K&N pod type filter (RU-2970) and a Cobra F1R slip on cannister.  I started off with a Dynojet kit and tried to jet it to stage 3, but I have not been able to get the bike to run right since.  Now I'm thinking of scrapping the Dynojet kit and doing the DIYS way by buying jets and shims.  I've got the Jetting matrix bookmarked so I don't need to know what jets/shims to buy, however I do have a question about the slides.

In the dynojet kit they have you drill out the slide lift holes and install nylon correctors.  One corrector closes off a hole, while the other narrows the diameter of the second hole.  How much does altering the diameter of these holes effect the jetting?  Am I going to need to buy new slides, or can I do the DIYS rejet using my "drilled and corrected" slides?

Any input would be greatly appreciated.

Thanks,

John

[The Buddha]

IMHO - no exact proof since I haven't done a DJ job start to finish ... have done some fixing on some ... but not nearly enough to say wihtout a doubt ... The slide correctors in DJ are needed to correct the lift rate of the slide (nothing to do wiht jetting at all) because DJ needles have that drastic taper ... that makes the sensitivity pretty high to needle. So if your slide comes up too fast you will over rich it for a few instants as your revs climb ... making for a bike that falls on its face. Hence you need it "corrected" Stock needles taper more gradually, and the main jets are larger to compensate. So while we add in almost the same measure of fuel at each throttle position, we do it with a less sensitive alternative. DJ developed their kits to be a drop in ... so the stage 1 on the thing uses 122 mains, so simply put you can open the top and swap needles out ... no need to take off carbs. Yea except to drill out the brass plugs on the air screws - morons. You can go to the stock needles if you have 1 of the correctors. If you ahve installed both you can drill out the one with the hole ... and make it larger. You need to have it at ~ 2mm. I will sell ya a set of stock slides for $10  :mrgreen:  if you want ... and you can run that and see. But drilling out one will work just fine I think ... if not you can get the slide from me ... The rest of the stock stuff will be all fine. 150/40/3/1.
Cool.
Srinath.

[vfrocket]

what is your exact problem?

I had some issues with my DJ kit but it was completely my fault. I forgot to transfer the small white plastic spacers that are on the stock needles to the new needles. One I figured out where I had gone wrong, I transfered the spacers, and it ran like a top.

[DrtRydr23]

Thanks for the info srinath, though I thought it was 2 spacers?

what is your exact problem?

I had some issues with my DJ kit but it was completely my fault. I forgot to transfer the small white plastic spacers that are on the stock needles to the new needles. One I figured out where I had gone wrong, I transfered the spacers, and it ran like a top.

vfrocket - As for my exact problem......generally i've got a little dead spot in my acceleration between 5500 and about 8000 rpm when I'm at 3/4 to full throttle.  Until I get up to 4th and 5th gear, then it won't accelerate over 6000 rpm at all unless I run it up to over 8000 in a lower gear and then upshift (keeping the rpms over 8000).  I've tried both stage 3 mains with the needles set on the 1st, 2nd, and 3rd notches, and I can't get rid of that dead spot between 6 and 8 grand.  It really bogs down at 6000 and then picks back up after 8000.

I'm real tired of messing with it and if I tear down the carbs again I want to try something that I know has got a decent chance of working.  If you've got any other suggestions, I'm more than willing to hear them.

Thanks,

John

[vfrocket]

I am at a loss, however there may be somthing else going on with the carbs reguardless of the re-jet. What that is I dont know, since I got mine to work great.

I did note in the DJ instructions that it said for faster acceleration to remove one of the slide compesators...?

[vfrocket]

perhaps one of your diaprhams has a hole in it? or maybe the little o-ring up by the diaphrams is missings???

just shots in the dark.

[ktrim]

my 89 is doing the same thing.  no kit just a diy rejett .  cant figure it out so let me know if you do so I can fix mine

[DrtRydr23]

perhaps one of your diaprhams has a hole in it? or maybe the little o-ring up by the diaphrams is missings???

just shots in the dark.

As far as I can tell, my diaphragms are good, and I know both the o-rings are there because I saw them today.  It was not doing it before the rejet so I figure its got to have something to do with the rejet.  I keep thinking that drilling the slides screwed something up, but since I don't know jack about carbs, i'm really not sure.  I'm thinking about buying srinath's slides just to eliminate any possible problems with the slides or diaphragms.

Hear that srinath???

Later,

John

['04gs500f]

(RU-2970) i just ordered that for my 04, i thought that was the lunchbox part #?

['04gs500f]

(RU-2970) i just ordered that for my 04, i thought that was the lunchbox part #?

http://www.knfilters.com/search/applications.aspx?Prod=RU-2970

RU-2970 Product Specifications
Product Style: Dual Flange Oval Universal Air Filter
Flange Center to Center: 4.188 in (106 mm)
Flange Inside Diameter: 2.375 in (60 mm)
Flange Length: 0.625 in (16 mm)
Flange Type: Centered
Height: 3 in (76 mm)
Outside Length: 7.375 in (187 mm)
Outside Width: 3.625 in (92 mm)
Top Style: Rubber
Top Material/Finish: None
Base Outside Length: 7.375 in (187 mm)
Base Outside Width: 3.625 in (92 mm)
Filter Re-Oiling Amount: 0.55 oz (16 ml)
Flanges: 2
Inner Wire: No
Top Outside Length: 7.375 in (187 mm)
Top Outside Width: 3.625 in (92 mm)
Weight: 1 lb (0.5 kg)
Product Box Length: 4.5 in (114 mm)
Product Box Width: 5.5 in (140 mm)
Product Box Height: 9.13 in (232 mm)

[DrtRydr23]

(RU-2970) i just ordered that for my 04, i thought that was the lunchbox part #?

I'm not sure what "lunchbox" means, though I guess it does kind of look like a lunchbox.  Anyway, judging by the specs on your last post I'd say it is the same one.  It's like a double flange pod filter, instead of the normal single pod for each carb.  It gives you a lot more air flow, and it makes a HUGE sound difference.  My bike is easily twice as loud as it was before I changed filters.  Now if I could just jet the bastard......

John

['04gs500f]

yeah when you said pod i was thining of the two pods...

[The Buddha]

OK Ktrim - you have my carb bodies ... did I put in diaphragms in it ... or did you use yours I dont remember ... Send me details ... I'll think it over and tell you.
Drtryder - You're talking about the blockers for the holes in the bottom of the slides ... not the spacers on and under the needle ... VFRocket was refering to spacers under and over the needle. Rip in diaphragm - you're not going to make 8K in 5th or top gear no matter what ... The slide holes make the slides go up, more holes they go quicker. Shutting off 1 is a good way of getting them to go slower so the motor spins up at about the same speed and that causes rise in venturi velocity and makes the slide rise. Your 8K wall ... might be slides going up so slow ... motor struggles and as the slide goes up too slowly ... in reality the rising rpm will cause an increase in the venturi velocity, thereby sucking more fuel ... and the slide isn't rising fast enough to let in enough air ... so its going too rich and starts choking on its own fuel ... and the self sustaining cycle of sucking/velocity/rise/air/gas is slowed to a crawl ... and you feel like its hit a wall ...
Now buying my slides wont help you if you're trying to avoid the real problem of fixing the carbs ... my slides only let you avoid drilling the insert out ... Yes its easy, but the plastic plug needed slides to be drilled, tapped and installed, and well Its a bad idea ... cos a 4-40 nylon screw will fit in the stock hole ... and can be drilled/pulled out with no ill effects. Anyway ... send me your carbs ... may be better than buying slides ... BTW ... fitting your diaphragms on the slides I send you ... will give you fits and shakes ... not too hard, but the diaphragm is a bit fragile, the first couple I did nearly had my heart thumping out out out ...
I dunno, instinctively I get carbs ... the XS(mikuni), the Nitehawk(Keihein CV's), The eli's (Keihein CVK's), the virago (mikuni), the maxim (hitachi), all seem like ... "well this is easy" ... but OK I should say maybe I am wired that way ... In engg school I would look and go flu mech is easy ... while everuone else was having fits ... empirical crap, iterative calculations, assume a value and cycle through and converge on the right value ... whatever ... just worked into my brain easy. So i'd just say ... send it over, I'll figure it out. I have seen people do stupid stuff, and mechanics are real bad ... takes patience and a delicate touch ... most mechs are ham fisted and impatient ... As usual basic trouble shooting is free with rejet, else $20 for disassemble and check everything.
Cool.
Srinath.

[DrtRydr23]

srinath,

When I said that I thought it was two spacers, I was referring to the spacers on the needles.  Your message said that the rejet for my setup would be 150/40/3/1.  I assumed that meant 150 mains/40 pilots/3 turns on the mixture screw/1 washer on each needle.  I was saying that I thought it was two washers on each needle.  Another thing about those washers.  I looked for #4 washers at Home Depot and they only had fiber ones, no metal.  I bought the fiber ones because they seemed pretty sturdy.  Although I'm thinking I might still try to work with the dynojet kit for now.

It's kind of funny because I took the nylon corrector with the hole in it out of the slides and now the bike will pull through 8000rpm in all gears at 1/2 throttle, but closer to full the bike still bogs down.  Especially in 5th & 6th gear where giving it full throttle completely bogs the bike down (maybe even a little in 4th too).  I tried to put tape over about 1/3 of the air filter to see if I'm running lean or rich, but the tape blew off before I could get up to speed.  I'm gonna have to try again tomorrow as I'm tired pf messing with it today.  I'm assuming I'm running lean because I've got the 128 main in, and I've got a K&N lunchbox filter.  The only bigger main in the DJ kit is a 134, which I guess I'll try to put in tomorrow.  Maybe that'll help.

Maybe.

John

[vfrocket]

If I remeber correctly, the only difference in the stage 3 setup and the stage 1&2 was the size of the mains. I used stage 3 (134).

[DrtRydr23]

If I remeber correctly, the only difference in the stage 3 setup and the stage 1&2 was the size of the mains. I used stage 3 (134).

According to the kit there are two mains for stage 3.  The 128 is for stock exhaust with the lunchbox filter.  The 134 is for perfomance exhaust or a "slip on with a high flowing baffle."  I started out with the 134 and had some problems, so I switched to the 128.  This did not solve my problem.  I'm not really sure which main to use because I've got a Cobra F1R slip-on, and I have no idea how much of an increase in airflow it gives me over stock.

I also can't figure out if I'm lean or rich in the middle.  Over 8K the bike pulls good at full throttle, but btw 5.5k and 8k it bogs down.  It picks up good after 8k if I can get it there.  If I'm in 5th or 6th then I can't even get to 8K at full throttle (but I can at 1/2 throttle) unless I drop to 4th and run it up to 10k or so and then upshift to 8k in 5th.  Then run 5th up to 10K and then shift up to 8k in 6th.  I can run it up from there until I chicken out and back off.  I'm sure I've wrote all this before, but I figure if I write it again someone will come up with something ( I hope).

The way I see it I've got to be either lean or rich in that 5.5 to 8k area.  Even if I figured it out though, I'm not sure how to fix it.  Either raise or lower the needle, or enlarge/narrow the holes in the slides to increase/decrease the vacuum.  Not real sure though.

John

[vfrocket]

man thoes are some interesting symptoms.... Mine kinda did the same thing, it would bog a 5k and die. Then I figured out that I did not install the plastic spacer fromt he stock needle to the the new DJ needle. Once it put in on, all was good.

[DrtRydr23]

man thoes are some interesting symptoms.... Mine kinda did the same thing, it would bog a 5k and die. Then I figured out that I did not install the plastic spacer fromt he stock needle to the the new DJ needle. Once it put in on, all was good.

Yeah, I checked that after you posted it before and they're still there.  I think I need to mess around with the clip position on the needle, and maybe my main jet.

What kind of set up are you running?  I mean like exhaust, clip position on the DJ needle, and all that stuff (I know you're running the 134 mains).  Also, did you put the little nylon correctors in your slide when you did the DJ rejet?

[vfrocket]

yeah, I am using the stage 3 kit. so 134, e clip on second grove, and the compensators. I also have srinath flange, with Wileyco pipe, and K&N lunchbox filter. Other than the mistakes I made by not putting on the spacers, it ran perfect after the install.

so I am a little perplexed by yours not working properly since mine runs like a top with the DJ kit.

I have heard that the diaprhams can have udectable pinholes in them that cause such symptoms, or the little o-rings missing can cause this as well. I wonder if it is a fuel starvation issue or a vaccume leak???

I am at a loss.

[vfrocket]

also did you put the little white plastic washer on top of the needle??? it holds the spring against the needle. I made a mistake when I put them together after a carb clean, and accidentally istalled the platic washer like spacer through the needle instead of on top.

the result was an exteremely rich condition.