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Post by rctaudio on Feb 3, 2011 0:23:41 GMT -6
Hello all, So a while back I drilled out the baffles on my 90 454. After that I ordered new pod filters off the inter-webs and rebuilt my carbs. It didn't exactly like the combo and wouldn't even run... My "temporary" fix was to wrap 2 shop towels around each filter and zip tie them on so they wouldn't fall off.. I know, Classy right? Well My "Temp" fix is really starting to piss me off since it looks UGLY and it has a slight overheating problem/ not much power/maybe bogging down at high RPM's. I looked into a couple of local shops that wanted $200+ parts to Re-jet and I feel more then confident to take on the task. I've been scouring the Inter-webs the past few months for info on re-jetting and I just wanted to get some straight answers. I believe the carbs are Keihin CVK34, and the stock jets are 125 for the main and 35 for the pilot. what specifically do i need to buy in order to have everything I need and WHERE should I get it from? I'm not sure how many sizes i need to go up and I understand there is a little bit of Trial and error. Also do I need to buy new pilot jets? what about new needles? and the spacers for the needles? my heads just spinning and I'm "psyching" myself out. I just need some mental support! Thanks in advance for all your help  The days have been starting to get real pretty and I told myself I would complete this before having another "ghetto" ridding season |
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Post by Blaine on Feb 3, 2011 6:42:05 GMT -6
I recently re jetted and added pod filters.I went from a 125 main jet to a 130. I never had to change the pilot jets.The needle jets on my carbs are non adjustable unless you shim them.The only thing I changed on my carbs were the main jets and installed new carb kits.I got the main jets and kits from a local dealer.I took pieces of aluminum (pop cans) and cut them to fit inside the filter and block off about half of the filter surface,keeping the aluminum facing to the outside to block wind.I hope this helps.  |
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Post by rctaudio on Feb 3, 2011 12:53:33 GMT -6
Blaine, Do you also have the baffles removed from your bike? Also, are you saying you restricted the airflow with an aluminum can or am I missunderstanding? Also do you know of any online sites that sell the jets cheap? I found some a while back but have since lost the links. The local shops i've called around here want $20 a jet... EACH
Thanks for your help!!!
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Post by Blaine on Feb 3, 2011 15:07:24 GMT -6
Blaine, Do you also have the baffles removed from your bike? Also, are you saying you restricted the airflow with an aluminum can or am I missunderstanding? Also do you know of any online sites that sell the jets cheap? I found some a while back but have since lost the links. The local shops i've called around here want $20 a jet... EACH Thanks for your help!!! I have Harley mufflers on my bike that are a straight thru design.They were on the bike before I changed to pod filters and the bike ran fine.I cut the can open and wrapped it around the outside of the filter to get the basic shape I wanted, than trimmed to fit inside the filter.You can experiment with the size you need to block off more or less air.I bought my jets from a after market dealer in my area for $2.50 a piece.That is about what they are worth.I bought my carb kits for about $15.00 a carb.$20.00 for a main jet,what a rip!!!This is my bike below with the Harley mufflers installed. |
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Post by Blaine on Feb 3, 2011 15:22:29 GMT -6
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Post by rctaudio on Feb 3, 2011 16:34:26 GMT -6
NICE!, super clean! so you're still restricting the airflow on your pods... I dont really want to do that to mine so I should order the 130 and 135 size jet to be safe? and you're saying that I shouldnt have to order a pilot yet or a new needle with shims or any of that. I should just be able to get away with just ordering the larger main jets and then going from there? I dont mind having to go back and order more stuff later I just want to try and have everything I need so i can kock it out in a weekend and then fine tune it over time. What about new seals for the carbs? I partially rebuilt them about a year and a half ago, will the seals be able to go back on or will I have to order new ones?
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Post by Blaine on Feb 3, 2011 18:29:55 GMT -6
NICE!, super clean! so you're still restricting the airflow on your pods... I dont really want to do that to mine so I should order the 130 and 135 size jet to be safe? and you're saying that I shouldnt have to order a pilot yet or a new needle with shims or any of that. I should just be able to get away with just ordering the larger main jets and then going from there? I dont mind having to go back and order more stuff later I just want to try and have everything I need so i can kock it out in a weekend and then fine tune it over time. What about new seals for the carbs? I partially rebuilt them about a year and a half ago, will the seals be able to go back on or will I have to order new ones? If you rebuilt them a year and a half ago they should be fine.You should only need the larger jets.Some people on here didn't need to re jet at all.The restricting of the pod filters is for more vacuum for the needle jet to work properly.The needle jet needs a certain amount of vacuum to open properly.If the needle jet doesn't open properly,the bike will have a bog every time you crack the throttle.This is the main reason the air box has restrictions in it's design.This is exactaly what you are doing when you wrap the filters with rags.  |
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Post by rctaudio on Feb 3, 2011 19:11:44 GMT -6
yeah got that one. so my bike wont even idle if it doesnt have the rags on them.... do yout hink i'll need to order a new needle thats adjustable too? or should I just replace the jet and then go from there?
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Post by Blaine on Feb 3, 2011 19:24:06 GMT -6
yeah got that one. so my bike wont even idle if it doesnt have the rags on them.... do yout hink i'll need to order a new needle thats adjustable too? or should I just replace the jet and then go from there? I would replace the main jet and work from there.Only change one thing at a time.That way you will know if you are on the right track.Your needle jet controls throttle between 1/4 and 3/4 opening.By shimming the needle you are raising the needle and getting a richer mixture.I checked e-bay,you can get a adjustable needle for $7.95 each if you end up needing them. |
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Post by rctaudio on Feb 3, 2011 21:40:53 GMT -6
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Post by Blaine on Feb 3, 2011 22:11:41 GMT -6
You are right on the money.Good luck.Keep us posted with your results. |
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Post by eaglerider on Feb 4, 2011 15:11:23 GMT -6
You might have to even go larger on the jets, depending on your altitude, etc. I am using late model (larger CFM) Ninja carbs with (if I remember right) 150 jets. 'Course, I have a EX 500 engine with competition cams in my "454".   |
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Post by rctaudio on Feb 11, 2011 1:40:11 GMT -6
Sorry in advance for the long post.... couple of questions too... So, My order came in today. I got 130,132,135,138, and 140. I may have gotten a little over zealous ...Didn't have much time to work on it but I really wanted to believe that it would be a simple fix so I pulled out the carbs and took out the stock (125) and put the 140's in. It does not appear that much has changed... I didn't let it warm up fully, but I warmed it up enough to not stall and it still didn't like WOT. I'm not sure much has changed, so I might need either bigger jets or one of those adjustable needle kits. but I think my idle may not be ideal. Let me better explain the state of the bike, maybe I'm going at this wrong... It was running just fine before I decided to: I drilled out the baffles to make it louder. I removed the stock air-box and added 2 cone filters which flow A LOT moar My "temp fix was restricting airflow by zip tieing a shop-towel around each cone filter it then road "better", still bogging down slightly at medium/wot, and running a little hotter then I cared for, but it was ride able.... If you can call it that ;D I removed the rags in hopes of rejeting it myself properly and... Now it idles a little less them smooth, and at a higher RPM if I throttle about 1/4 it starts to rev up (not very smooth) and gets to about 4-5 grand and that's about as far as it goes. If i roll the throttle any more it will just bog down tremendously..until I release and It goes back to idle. I'm not sure if it will kill it as I haven't WOT long enough to find out. but If i put my hand over the carbs it will then rev happily again. I know its definitely running lean Question 1 Can someone explain to me the difference between surging or stumbling and even bogging down? I think I understand but maybe I'm misinterpreting them and going about this all wrong  I thought it idled OK but in retrospect the idle/ 1/4 throttle could be a little smoother, its not "jerky" but its not that smooth either.... I will but the stock 125's back in on Saturday and try and achieve a smooth idle/ 1/4 throttle. Probably should have done that before I ordered the jets but I "thought" the idle was "good 'nuff". Hopefully I can get a smooth idle or I'll have to make another order. Question 2 I what range should the idle be, RPM wise? I believe prior to the exhaust and intake it was idleing below 1000 and now I had it pegged to somewhere around 1000-1200 <- that seems a little high for me, but then again I'm used to cars idling around 7-800. Question 3 Once I drill out the little cover that covers the slow jet screw, do i have to recover it with something, or is that there so it doesn't come undone? I've noticed on some other carbs that its not always hiding, so I'm not sure if they hide it to keep you from messing with the stock mixture or if it keeps dirt/whatever form penetrating the carb. Thanks for spending the past 3 hours reading this  and of course for your wisdom!  |
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Post by rctaudio on Feb 11, 2011 1:42:13 GMT -6
You might have to even go larger on the jets, depending on your altitude, etc. I am using late model (larger CFM) Ninja carbs with (if I remember right) 150 jets. 'Course, I have a EX 500 engine with competition cams in my "454". oh and to answer your statement, I'm in Cali, near SF to be exact, so Altitudes not an issue, do you think with my set up I need to jump above 140's? oh and Shes real pretty! |
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Post by Blaine on Feb 11, 2011 7:36:20 GMT -6
The idle should be around 1200 r.p.m.The mixture screws need to be adjusted to get a smooth idle as they affect idle to1/4 throttle.You don't need to reinstall the caps once you make your adjustments.It sounds like you need to shim or adjust your needles to get a richer mixture,as main jet only effects 3/4 to wide open throttle.Also if you have no restriction on the filters you will not get enough vacuum to open the slides(needles) properly.When you put your hand over the carb,you are creating more vacuum.making the slides work properly.Surging is normally when the bike wants to keep jumping ahead,and bogging or stumbling is a hesitation when you "crank" the throttle. |
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Post by rctaudio on Feb 11, 2011 13:12:34 GMT -6
The idle should be around 1200 r.p.m.The mixture screws need to be adjusted to get a smooth idle as they affect idle to1/4 throttle.You don't need to reinstall the caps once you make your adjustments.It sounds like you need to shim or adjust your needles to get a richer mixture,as main jet only effects 3/4 to wide open throttle.Also if you have no restriction on the filters you will not get enough vacuum to open the slides(needles) properly.When you put your hand over the carb,you are creating more vacuum.making the slides work properly.Surging is normally when the bike wants to keep jumping ahead,and bogging or stumbling is a hesitation when you "crank" the throttle. Also I forgot that I removed most of the "smog" stuff when I removed the stock airbox. so dont know if that throws anything in the mix ok so basically I wont be able to get the bike to run properly with the air filters I have because they are TOO unrestrictive to produce enough vacuum? So i need to try maybe that soda can trick to reduce the vacuum inside the air filter? Blaine, could you post a picture of the can set up, if its not too much trouble. I'm just having a hard time visualizing it Thank so much! |
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Post by Blaine on Feb 11, 2011 14:10:03 GMT -6
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Post by Bearded Biker on Feb 12, 2011 7:40:57 GMT -6
do you know when the last time your valves been adjusted and where is your idle mixture screws set at? this could be some of your problems. gayland
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Post by rctaudio on Feb 12, 2011 14:07:37 GMT -6
do you know when the last time your valves been adjusted and where is your idle mixture screws set at? this could be some of your problems. gayland dont know on the valves, its probally ben a long time. as far as the idle mixture screw... thats the one that needs to be drilled out right? I just emptied the carbs and drilled out the block for the pilot screw adjustment thingie. I backed them all the way in and will start opening them up 1/4 turn at a time until i reach the proper mixture. Now I just have to wait until the bowls fill with fuel.... about 30 minutes or so? |
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Post by rctaudio on Feb 12, 2011 15:25:42 GMT -6
OK so I here's what I've got figured out. idle is good = correct size pilot jet? 1/4 throttle good = correct size pilot jet? 1/2 to 3/4 throttle BAD = need to shim my needle to get it to sit higher? WOT = good I think. I took out the 140 and put in the 130, seems to be good, but kinda hard to tell with all the crapness the mid-range is having so I think once I shim the needle I'll have to readjust the idle and wot, but cause that will increase fuel flow through out the spectrum... right?, or does it mainly only affect 1/2 to 3/4 throttle? Thanks for all your useful insight!!! |
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Post by Blaine on Feb 12, 2011 16:32:56 GMT -6
OK so I here's what I've got figured out. idle is good = correct size pilot jet? 1/4 throttle good = correct size pilot jet? 1/2 to 3/4 throttle BAD = need to shim my needle to get it to sit higher? WOT = good I think. I took out the 140 and put in the 130, seems to be good, but kinda hard to tell with all the crapness the mid-range is having so I think once I shim the needle I'll have to readjust the idle and wot, but cause that will increase fuel flow through out the spectrum... right?, or does it mainly only affect 1/2 to 3/4 throttle? Thanks for all your useful insight!!! Yes, you need to raise your needle,or block some air flow.Hard to know your wot till you get the mid range right.Your pilot jet is fine.you might need to fine tune your idle mixture after. |
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Post by rctaudio on Feb 12, 2011 18:33:27 GMT -6
OK I did both, I tried this soda pop method to block some air and I put 4 small washers to raise up the needles( I'd guesstimate its about 1/8 inch).... its better but not quite there. there is a hesitation (by hesitation i mean it will NOT accelerate for a second or so and starts loosing RPMs quickly, then it catches WOT and takes off... yeah its a little scary) around medium throttle but I'm not sure if I'm backfiring now.... when I rev it high and then let off it pops while coming down the RPMs.. its not super loud but I do hear it pop every 1000 rpm or so. Really wish I left the stock air box on right about now.. the only reason I went to these air filters was because I didn't want the pain of removing the stock air box everytime I needed to mess with the carbs. Question Is the mixture screw different from the pilot screw? Question2 What are my next steps? question3 What other ways can I restrict airflow from this thing without it looking tacky? Also... I've noticed that when I give slight throttle... and I mean SLIGHT throttle it will work its way up to like 4 grand.... but its been that way for a while I think. I never "noticed" it before, i just always thought it was annoying when I couldn't maintain slower speeds without constantly getting off the throttle. So I think I've made some progress, but I'm also made a lot of discouragement as well.. I really want to get on it and go, but I've dumped a whole day into this and haven't gotten it to a point that I think would be safe to ride. I know there is a severe learning curve, this being my first time jumping through these hoops but SO much frustration! no wonder people take these in and pay 300 ish to get them done. I'm really thinking I could undo everything I've done, wrap the shop towels back on and zip tie them. then start this process again and start from a more stable platform. <-- this set up did not have any hesitation, it would just bog down, but at least still accelerate. |
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Post by Blaine on Feb 12, 2011 19:07:31 GMT -6
The pilot screw & mixture screw are the same.If you raised the needles 1/8" that is way to much.one washer is probably plenty.With the aluminum in the filter,you can make it as big as you need,to block off as much air as you want.As was stated,you need a good valve adjustment. |
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Post by eaglerider on Feb 15, 2011 8:42:27 GMT -6
I think u still have a valve adjustment problem. For years, GWK and I tried to tell our members that these engines are very sensitive and "love" a good vaslve adjustment. They are very different from other engines. Most have now come to realize it is true....a good valve adjustment effects a number of things on these engines. Before any modifications, the engine should be running the best possible...that include all adjustments.
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Post by rctaudio on Feb 15, 2011 21:09:45 GMT -6
I think u still have a valve adjustment problem. For years, GWK and I tried to tell our members that these engines are very sensitive and "love" a good vaslve adjustment. They are very different from other engines. Most have now come to realize it is true....a good valve adjustment effects a number of things on these engines. Before any modifications, the engine should be running the best possible...that include all adjustments. Yeah, I'll take your wisdom on the situation. I ran out of time this weekend but will be taking it apart this week/weekend to adjust the valves. I'll let you guys know how it runs afterwards |
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Post by eaglerider on Feb 16, 2011 7:17:37 GMT -6
Just take your time, and re-check the adjustment when done....use the higher values listed, for better results. Don't worry about the valve noise when proper adjustment is done...these engines are kinda "noisey".
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Post by Blaine on Mar 4, 2011 8:41:39 GMT -6
rctaudio hows things going? Did you make any headway? |
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Post by malochai on Mar 19, 2011 19:28:09 GMT -6
Sorry if this is a dead post but thought I'd share...First off Thank you all so very much for putting me onto the solution to my *very* similar problem....
Comes down to Carb theory 101...losing power not so much at 5K rpm but at 25%-60%-ish throttle...simple answer...Needle jet....further explaination....vacuum as stated previously....the pod filter are just too open...
...TY Capt. Redundant you may be saying...I know....BUT...I thought I'd share my solution....
I was alittle put off by the idea of putting loose metal inside the pod filter....plus my first attempt just didn't fit right...so I used a bundle of spline from a screen project on my home...the little ribbed rubber tubing that you use to seat window screens in the frame.
By stuffing .125 diameter spline in between each ridge of the pod filter I was able to limit the airflow and provide the vacuum needed...And it looks awesome to boot...adds a alittle contrast to the purple pod material just like it belongs there.
I figure it's great cause it looks great, isn't destructive to the pod (thought about siliconing up the pod), and is fully adjustable...just remove a few strips if needed. Not to mention it actually improves filtration since the only place air gets through the mesh is sorta doubled up.
So hopefully this will aid others in the quest to remove that pain in the a$$ air box....TY all for the inspiration that achieved success.
Now if I can just figure out why my 454 wants to idle at 3k without any choke no matter what I do LoL....but at least I can ride now.
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Post by eaglerider on Mar 19, 2011 19:43:08 GMT -6
Throttle cable adjustment too tight?  |
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Post by Blaine on Mar 19, 2011 19:47:19 GMT -6
Sorry if this is a dead post but thought I'd share...First off Thank you all so very much for putting me onto the solution to my *very* similar problem.... Comes down to Carb theory 101...losing power not so much at 5K rpm but at 25%-60%-ish throttle...simple answer...Needle jet....further explaination....vacuum as stated previously....the pod filter are just too open... ...TY Capt. Redundant you may be saying...I know....BUT...I thought I'd share my solution.... I was alittle put off by the idea of putting loose metal inside the pod filter....plus my first attempt just didn't fit right...so I used a bundle of spline from a screen project on my home...the little ribbed rubber tubing that you use to seat window screens in the frame. By stuffing .125 diameter spline in between each ridge of the pod filter I was able to limit the airflow and provide the vacuum needed...And it looks awesome to boot...adds a alittle contrast to the purple pod material just like it belongs there. I figure it's great cause it looks great, isn't destructive to the pod (thought about siliconing up the pod), and is fully adjustable...just remove a few strips if needed. So hopefully this will aid others in the quest to remove that pain in the a$$ air box....TY all for the inspiration that achieved success. Now if I can just figure out why my 454 wants to idle at 3k without any choke no matter what I do LoL....but at least I can ride now. I like your solution of the splines in the ribs.Just to clarify,if cut to the proper size,the aluminium can't move around inside the pod.You need to check your cables for signs of binding.If you do not have any free play in the cables,the bike won't idle.If your idle increases when you turn the bars side to side,your cables are routed wrong.Hopes this helps.Thanks for posting your pod tip. |
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The days have been starting to get real pretty and I told myself I would complete this before having another "ghetto" ridding season
and of course for your wisdom! 
