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    1. Member Jettaboy1884's Avatar
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      10-06-2017 09:13 PM #2026
      Quote Originally Posted by dougkehl View Post
      I approve of this decision
      Thanks! I'll be posting up some pics soon. I picked up the carbs today. They're Mikuni 40mm's and the bowls are notably sloped compared to the carb bore. The guy I got them from was just sitting on them for years and thought they came off a Yamaha R1. A quick Google Search seems to confirm that.

      I've been ripping off all the CIS parts, and I cut off the raintray ('87 Cabriolet). So much more room behind the motor without the raintray!

      Can I remove ALL the CIS related wiring, including the Lambda ECU under the dash, etc?

      Is the Distributor and it's related wiring completely independent of the CIS system? I plan to run the stock vacuum advance distributor for the time-being.

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      10-06-2017 09:18 PM #2027
      Quote Originally Posted by Jettaboy1884 View Post
      Thanks! I'll be posting up some pics soon. I picked up the carbs today. They're Mikuni 40mm's and the bowls are notably sloped compared to the carb bore. The guy I got them from was just sitting on them for years and thought they came off a Yamaha R1. A quick Google Search seems to confirm that.

      I've been ripping off all the CIS parts, and I cut off the raintray ('87 Cabriolet). So much more room behind the motor without the raintray!

      Can I remove ALL the CIS related wiring, including the Lambda ECU under the dash, etc?

      Is the Distributor and it's related wiring completely independent of the CIS system? I plan to run the stock vacuum advance distributor for the time-being.
      Yes, you can remove all of the CIS wiring and the Lambda control module. The ignition is it's own harness and system and can be retained with no issues. You may need to incorporate the open/closed throttle switches for the ignition somehow, it's been quite a few years since I started my setup. I'm also using a knock-box setup from a 16V.

      Sent from my SAMSUNG-SM-G930A using Tapatalk

    4. Member Jettaboy1884's Avatar
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      10-06-2017 09:41 PM #2028
      Good point on the throttle position switch. I'll keep those parts, and will figure out a way to integrate it into the linkage.

      I'm going to make a pile of all the CIS related parts, compared to the carbs. I think it will be a good motivating factor for others to take the plunge!

    5. Member Jettaboy1884's Avatar
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      10-08-2017 11:31 PM #2029
      Some pics of the carbs as promised. If anyone can confirm these are from an R1 and has any model # info for ordering parts, that would be much appreciated! So far I've been looking at a website "Bike Bandit" for Mikuni parts.

      These seem pretty complete, but a previous owner filled in the vents on the front. I'm planning to do a partial disassembly to clean and further inspect them.





      I'm curious if this is normal for there to be the gap in the bore here? It looks like it's supposed to be this way, but doesn't exactly seem friendly to airflow...

      Last edited by Jettaboy1884; 10-08-2017 at 11:34 PM.

    6. Member Jettaboy1884's Avatar
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      09-06-2018 03:59 PM #2030
      ^ Replying to myself as I found a few answers. Hopefully people are still following this.

      I found a great site with diagrams of the carbs and reasonably priced (I think) parts: https://www.bikebandit.com/oem-parts...5829#sch521742

      I also learned that the barrels in the front are not supposed to be all hacked up as mine are. It seems the Previous Owner modified them by plugging up the vents in the front with JB Weld then cut out the barrels to return that functionality (possibly the main air idle jet under there...)

      Since the R1 carbs were a bit rough I scooped up a set of recently rebuilt carbs from a ~ 1998 Ninja 900. They're in much better shape and very similar in size at about 36.5mm bore. The R1 carbs are 40mm IIRC. The smaller bore will be fine for my relatively stock 8v.

      And on to my question: I have a spare in-tank transfer pump from a parted '87 Cabriolet. Does anyone know if the flow rate would be good for carbs? My plan is to keep the in-tank transfer, then put an in-line filter and the second transfer pump in place of the high-pressure CIS pump. I'll run a return-style adjustable fuel pressure regulator in the bay if needed.



      Last edited by Jettaboy1884; 09-06-2018 at 04:18 PM.

    7. Member yeayeayea's Avatar
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      09-08-2018 06:58 AM #2031
      Quote Originally Posted by Jettaboy1884 View Post

      I'm curious if this is normal for there to be the gap in the bore here? It looks like it's supposed to be this way, but doesn't exactly seem friendly to airflow...

      That slide is vacuum actuated. Under the black cap is a diaphragm. At idle that slide closes down to keep airflow directed near the main jet to help fuel atomization. The black slide has a needle valve that controls fuel flow as well. At WOT that slide moves completely out of the airstream, and also opens the needle valve below it. If your slides are not moving freely, you may need to clean your carbs or possibly could have a damaged diaphragm.

    8. Junior Member Shikeira's Avatar
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      09-25-2018 10:13 PM #2032
      I love the inspo on here.

      I was wondering if anyone has run CBR 900RR carbs on a 16v before. I just want something to get rid of the Jetronic injection currently in my Scirocco.

      I would assume they are similar to the R1 carbs , and I've seen them much cheaper than R1 carbs on eBay ATM.

      -J
      RUN-16V

    9. Member
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      09-25-2018 10:39 PM #2033
      Quote Originally Posted by Shikeira View Post
      I love the inspo on here.

      I was wondering if anyone has run CBR 900RR carbs on a 16v before. I just want something to get rid of the Jetronic injection currently in my Scirocco.

      I would assume they are similar to the R1 carbs , and I've seen them much cheaper than R1 carbs on eBay ATM.

      -J
      It all comes down to bore, flow rate, and the ability of the carbs to flow enough air to support the engine. Yes, it is only a 100cc difference in the original engine, so you should be ok. It's just good to ask.

      How much cheaper? Granted, its prob been 10 years, and as they have gotten older I can't imagine they've gone up in price that much. I paid around $125 shipped for my R1 carbs. Peanuts when compared to the rest of what it takes to get them running, or especially to refurbish a CIS system.

      Sent from my SAMSUNG-SM-G930A using Tapatalk

    10. 09-26-2018 08:00 PM #2034
      Quote Originally Posted by YJSAABMAN View Post
      Quote Originally Posted by Shikeira View Post
      I love the inspo on here.

      I was wondering if anyone has run CBR 900RR carbs on a 16v before. I just want something to get rid of the Jetronic injection currently in my Scirocco.

      I would assume they are similar to the R1 carbs <img src="https://www.vwvortex.com/Anthony/Smilies/confused.gif" border="0" alt="" title="Confused" class="inlineimg" />, and I've seen them much cheaper than R1 carbs on eBay ATM.

      -J
      It all comes down to bore, flow rate, and the ability of the carbs to flow enough air to support the engine. Yes, it is only a 100cc difference in the original engine, so you should be ok. It's just good to ask.

      How much cheaper? Granted, its prob been 10 years, and as they have gotten older I can't imagine they've gone up in price that much. I paid around $125 shipped for my R1 carbs. Peanuts when compared to the rest of what it takes to get them running, or especially to refurbish a CIS system.

      Sent from my SAMSUNG-SM-G930A using Tapatalk
      I've seen most R1 carbs around the $215-$250 mark and most CBR carbs around the $150 mark. I'm still in school and flipping burgers for a extra cash ATM, so every cent counts :lol

    11. Member Jettaboy1884's Avatar
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      09-26-2018 08:53 PM #2035
      Deals can be had if you search around and wait for the right opportunity.

      I picked up the R1 Carbs above for ~ $100 off Craigslist, and the Keihin CVK (Think they're from a Ninja) were from a friend of the family at a whopping $50.

    12. 09-26-2018 11:29 PM #2036
      Also, I've been getting super confused on what I need to get a carb setup running. I know I (obviously) need:

      -Carbs
      -Jets (not sure what size)
      -fuel pump (heard things from using a Carter one to a bike pump to using the OEM one with a regulator, not sure which one to use &#x1f914;
      -fuel line (specific to the carbs, but if I use the bike fuel pump, do I need to re-do my fuel lines?)
      -manifold (using a template from a gasket with specific diameter tubing. Should I bend the tubing to make the intake ports?)
      - air filters
      -some sort of ignition (MSD? SAAB distributor? Hotel? Trivago)
      -throttle cable (modified bike brake cable I saw here)

      This is all I think I need. I heard a lot about moving the alternator down and angling the radiator to make room. I appreciate any information you can provide &#x1f600;

      -J

    13. Member yeayeayea's Avatar
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      09-27-2018 02:09 PM #2037
      Quote Originally Posted by Shikeira View Post
      I love the inspo on here.

      I was wondering if anyone has run CBR 900RR carbs on a 16v before. I just want something to get rid of the Jetronic injection currently in my Scirocco.

      I would assume they are similar to the R1 carbs , and I've seen them much cheaper than R1 carbs on eBay ATM.

      -J

      Yup.


      https://forums.vwvortex.com/showthre...gh-compression

    14. 09-28-2018 10:48 AM #2038
      What size jets would you recommend for a bone stock 16v? I was thinking around 170.

    15. Member yeayeayea's Avatar
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      09-28-2018 02:57 PM #2039
      1.8 or 2.0 16v?

      A bone stock CBR 900 rr makes 125hp at 10000 rpms

      So while these carbs will flow enough fuel to make 125+hp in stock form, our motors won't rev to 10k. Which means there will be more time between intake strokes since there will be less per minute, which is when the car actually pulls the fuel in from the carb. So to make 125hp with less rpms, each combustion must make more power to average out to 125hp since there are less of them.

      I'd start with a stage one jet, or get a drill index if you are comfortable drilling out your main jets yourself. slowly increase main jet size until you hit your desired A/F ratios.

    16. Junior Member Shikeira's Avatar
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      10-09-2018 02:14 PM #2040
      Its a 1.8 16v. I read from some other threads that around 165~170 is a good jet size for 1.8. Im still getting a parts list together and Im pretty sure I have everything minus the manifold and water neck, which i plan to order from Bogg Bros.
      RUN-16V

    17. Member Jettaboy1884's Avatar
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      06-16-2019 11:17 PM #2041
      Probably time I post an update on my carb conversion, and I also need some help...

      From pics above, I was in the middle of swapping these onto an '87 Cabriolet but ended up getting a Mk2 Golf with a gunked up CIS system (easy decision).

      Carbs are Keihin CVK, likely from a '96-'03 Ninja ZX7-R. After chasing down a couple of vacuum leaks, and hooking up the distributor advance, I am at the point where I can get them to fire up and idle. They'll only run with the choke (really a fuel enrichment circuit) engaged... I have a couple of issues I could use help with, here's what's happening:

      • Starting when cold takes a few attempts before sputtering to life.
      • As soon as I disengage the choke circuit it will die, regardless of how long it's been running.
      • I am using an AEM wideband O2 gauge.
      • I have the pilot mixture screws (fuel side) about 4-4.5 turns out, which concerns me as they loose "snugness" around 5 turns out so I know I'm pushing it.
      • Once warmed up with choke circuit still on and throttle 100% closed, AFR is around 12:1 - 13:1. If I blip the throttle off idle it bogs and dies.
      • If I crack the throttle plates using the thumb screw, it is my understanding that the plates uncover more (up to three) pilot holes. However, turning in the screw (opening plates) lowers RPM quickly and AFR progressively goes off the gauge (~ 17:1) and will die.
      • When warmed up, if I give an aggressive throttle pull it will bog a second then rev up. The AFR goes lean off the gauge though...


      I don't have air filters yet (ordering tomorrow). I noticed if I cover a bellmouth or two with my hand, it revs up a bit easier and healthier-sounding, but still lean off the gauge.

      All the above is leading me to understand I'm way too lean all around... So I removed the carbs, opened the bowls (not too bad inside) pulled the pilot mix screws and started cleaning. See pics below.

      My main jets are 148, and pilot jets are 38. It's a stock low-compression 1.8L 8v, so any recommendations on either jets?

      Some Pics:

      Carbs with throttle linkage. Carb faces (with bellmouth) not installed yet here.



      Bowls a little gunky, but otherwise decent:



      For fuel I am using the stock CIS in-tank "lift" pump with new 5/16" hoses to the front and CIS stuff removed. I did try an under-car low-pressure pump but it wasn't moving any fuel, so I bypassed it.
      In the bay I have a transparent filter, then another filter that has a second 1/4" outlet functioning as a return. This setup puts 3 PSI to the carbs.
      I had tried using the Holley adjustable FPR (laying on strut tower) in a return arrangement, and it functioned the same as this setup...




      Super-tight clearance to the firewall with carb bellmouths on:

      Last edited by Jettaboy1884; 06-16-2019 at 11:22 PM.

    18. Member
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      06-17-2019 06:22 AM #2042
      What does your fuel pressure do when you open the throttle? Does it hold or does it drop off?

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    19. Member Jettaboy1884's Avatar
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      06-17-2019 07:09 AM #2043
      ^ Good question, I was always watching AFR, but never paying attention to the FP gauge...

      It's going to be about a week before I get the carbs back on. I am cleaning them and ordering up filters which will need some trimming for fitment.

      What would the fuel pressure indicate? I'd assume at idle the 3 PSI reflects closed fuel ports, and at open throttle it should drop a tick as the floats drop and let more into the bowls?

    20. Member
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      06-17-2019 12:44 PM #2044
      Yes, it should drop a little bit, but not a lot. If it drops too much you may want to try losing the return line and just running a dead headed system.

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    21. Member Jettaboy1884's Avatar
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      06-26-2019 08:16 AM #2045
      Finally some success, cleaning the carbs was the key!

      I was told they had been cleaned before I bought them so I didn't think to open them up and check... I did a light disassembly on them, pulling the pilot (idle) screws, pilot jet and main jets. It's amazing how tiny the pilot jet holes are, and easily gummed up... I sprayed nearly a can worth of carb cleaner forward and reverse (where possible) through the pilot and main circuits.

      I have the pilot screws about 2-1/4 to 2-1/2 turns out which is much more appropriate. The throttle plate thumb adjuster works exactly as expected now, raising and lowering the idle speed properly. The starter circuit (choke) works much better, and I can close it off after it warms up for a couple of minutes.

      Once warmed up with choke off, I've got the AFR fluctuating around 13-15 with idle RPM around 1,000. If I blip the throttle I am still getting an bit of hesitation before revving, and an occasional backfire out of #4 cylinder. It seems to get better the longer I run it though.

      Fuel pressure at idle is pretty steady, mostly at 3 PSI but randomly dipping to 2.5 PSI and back up. I added a 1-way valve after the return port, which I know is functionally pointless but helps put a little bit of resistance in the line.

      For idle AFR, should I open the fuel screws a bit more and run it richer? That might help with the throttle blips off idle going lean?

      And I assume my next step is trying to drive it and put some load on the engine? No real way to ascertain how the Main & Needle are functioning by just revving it without load...
      Last edited by Jettaboy1884; 06-26-2019 at 08:28 PM.

    22. Member Jettaboy1884's Avatar
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      06-26-2019 08:27 AM #2046
      I also had a scary incident and have to revise my throttle linkage...

      I was standing in the drivers door revving it up with the pedal and the cable snagged on one of the bolt heads (two small bolts with blue locktite) and held the throttle open about 50%. It revved up to redline for what felt like an eternity (probably 5 seconds) while I fumbled around and shut it off... I'm not sure if the ignition system was cutting spark or I was floating valves...


    23. Member yeayeayea's Avatar
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      06-26-2019 04:23 PM #2047
      I know on my 89 16v, there was no rev limiter. The valve float was the only thing that limited your revving, and that happened north of 8000rpm. The Rev limiter in a CIS car is built into the fuel injection i think, not the ignition (Fuel cut)

    24. Member Jettaboy1884's Avatar
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      06-26-2019 08:39 PM #2048
      I believe you are correct on that, being that CIS is so sensitive to fuel pressure. Also explains why the fuel pump relays are so particular...

      This is a bone stock, low compression, small valve 8v with hydro lifters so it wouldn't surprise me if it were floating valves around 6500...

    25. Member yeayeayea's Avatar
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      06-26-2019 11:19 PM #2049
      Quote Originally Posted by Jettaboy1884 View Post
      I believe you are correct on that, being that CIS is so sensitive to fuel pressure. Also explains why the fuel pump relays are so particular...

      This is a bone stock, low compression, small valve 8v with hydro lifters so it wouldn't surprise me if it were floating valves around 6500...
      If that is a single valve spring motor then that is probably the case. I believe the 16v was dual valve spring from the factory but my memory is foggy. I had autotech cams and valve float hit right after 8k and made a funny sound.

    26. Member Jettaboy1884's Avatar
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      06-29-2019 08:42 AM #2050
      I finally drove the car for the first time (ever) yesterday. I've got the idle A/F ratio pretty good between 12-14. Now I need to move the AFR gauge into the dash so that I can see what's going on under load.

      The car is pretty soft all-around, and the carbs definitely need some tuning, but I am so happy to finally have driven it!

      I did a quick revision on the throttle linkage to eliminate the cable snag issue. I need to tweak the cable clamp setup, but this works for now.



      And here's a video of it running. Hopefully I can embed this correctly:

      Last edited by Jettaboy1884; 06-29-2019 at 08:46 AM.

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