Home Forums Shifter Karts CR80/85 Tech Talk

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    • #9964
      Derek Lodato
      Participant

      All former or current 80cc/85cc Shifter Drivers, Mechanics and Tuners. This topic is for us to discuss tuning, maintenance and performance of strictly the 80cc\85 class.

      I’m new to shifters and chose a New CR85 package from Alden Engines so I welcome advice on tuning, tech tips, performance modifications and maintenance on the 80cc/85cc packages.

      Any and all advice on best place to buy parts to fine tuning these incredible machines would be welcome

      Let’s get these 80’s back out on the track

      Thanks!

    • #9989
      Gary Smith
      Participant

      Congratulations on your motor package purchase!

      Just a few questions :

      What type of racing?  Sprint, Road Racing or Dirt?

      Where are you located?  Altitude for jetting

      Running an airbox or open filter? again for jetting

      I run sprint tracks with 700- 850 feet straights, I find that a 17 tooth countershaft sprocket and a 27 tooth axle sprocket work best for me. I run a K&N style air filter at about 800 feet above sea level, and my jetting is 37.5 on pilot jet and 195 on main jet.

      I order a lot of my parts online, I find that  fastech-racing.com, and sharkshifter.com have most of the parts I need. Every once in a while I stop by my local Honda motorcycle shop to gets parts as well.

      I hope you enjoy this motor package!

      Gary

      Honda CR80 #55

    • #10015
      Derek Lodato
      Participant

      @ Gary. Thanks for your input. I’m located in Florida and will be running a CR85 package for Sprint only.

      I plan on running a K&N style air filter. I believe the straights are about 600 ft at my main track.

      My engine is modified by Alden Engines. When I change the top end would I need a special heavy duty top end kit or could I simply replace it with a top end kit from Honda OEM?

      Thanks Gary

    • #10091
      Gary Smith
      Participant

      Derek, before you order any parts make sure you know if it is a CR80 or a CR85, the only difference is the piston and ring size. Both Fastech-Racing and Sharkshifter carry top end kits for both CR80 & CR85. The kits come with a heavy duty wrist pin bearing.

      Gary

      Honda CR80 #55

    • #10093
      Derek Lodato
      Participant

      Thanks Gary… I appreciate your input

    • #12600
      shaun s noll
      Participant

      i’ve heard the cr85 pistons last longer for some reason.  i have two cr80s that i run, one swedetech setup from years ago and then have a woltjer ported cylinder that has ports WAY bigger than the swedetech or my other project X ported cylinder.  I always run the upgraded wrist pin bearing and woltjer pistons from Fastech (jon is the man and always helped me out, highly recommend ordering from him)

      always been curious how many hours you guys run your pistons before rebuilding them?

    • #12607
      Gary Smith
      Participant

      Shaun, I put about 12 hours on my top end when I replace the piston, ring, wrist pin and bearing. I’ve had one wrist pin bearing cage fracture, stayed together and caused no damage, dodged a bullet there!

      Gary

      Honda CR80 #55

    • #12926
      shaun s noll
      Participant

      WOW!  is that a cr80 or cr85 Gary?  I had been told 3.5-4 hours on a piston was the lifespan for these built shifter kart cr80s so if you are getting >10 then I am wasting tons of money and time on pistons!

    • #12929
      Derek Lodato
      Participant

      @ Shaun – This is a great question. I purchased a New Alden CR85 Engine with only break in time on it. I attempted to get a hold of Harry Alden but I heard he isn’t easy to get a hold of these days. My question to him was going to be “How often do I need to change out the Top End and Bottom End?

      I have heard many opinions on this. The engine I bought is said to put out 29hp so my guess is I will have to change out top end quite often but the seller said I should be able to get 8-10 hours on it. I have heard as low as 3-4. Still I am not certain. Anyone out there experienced with 80/85cc want to shed some light on this question for me?

      Is there a sudden drop in power as a early warning sign or should I just remove the head to look for signs there after 3-4 hours of run time?

      It would be MUCH appreciated. Also, any good builders out there you recommend to perform the engine work?

      I have been told that I could learn to do the top end myself – is it super difficult?

      Thanks again,

      Derek

    • #12955
      William Martin
      Participant

      Top end rebuild is straightforward…not necessarily “easy”, as it takes some care to get it right. You will want a flat plate with a slot in it to slide under the piston so you can pull it down to the plate, helping you not twist the connecting rod while you extract the wrist pin. You really need a pin puller, but it can be removed by heating the top of the piston with a propane torch until the pin can be pushed out with “very little” side force on the piston. Never force it…that’s how rods get bent. When you have the old piston removed, use it to push your new ring into the bore about a half inch down the bore. Measure the end gap of the ring (feeler gauge), make sure it is within the specs that should be on the paper that comes with your replacement piston/ring/pin kit. If it’s too tight you might have a ring “stick” when it gets hot. If you don’t have a tool to insert the new clips in the piston pin bore grooves, be really careful not to nick up the piston or shoot the clips off into space…it is tricky. Pay attention to the markings on the piston top so as to get the new one in pointing in the right direction. Put some of that gooey pre-lube oil on the wrist pin bearing prior to reassembly, as well as on the piston skirt. Keep everything very clean, including your fingers while you do this work! Put a non-fuzzy towel over the open top of the engine crankcase, no extra stuff wants to be falling in there. That’s all that comes to mind…if you already knew all this, apologies for boring you…if I left out anything important, someone should feel free to chime in here and add information.

      Good Luck,

      Bill

    • #12999
      Derek Lodato
      Participant

      @ Bill … Thanks…That is the most descriptive response I have heard to date! I greatly appreciate it

      I definitely want to work on this but most likely I’ll shadow someone during my first round

      Check your inbox

      Thanks again Bill

    • #13029
      Gary Smith
      Participant

      Shaun, I have 4 motors, 2 are stock, 1 is a 105cc big bore and the other is a modded cr80. I currently have 3.5 hours on the modded motor, and still running strong. The Honda  service manual says the piston and ring should be replaced at 7.5 hours with the piston pin and bearing being replaced at 22.5 hours. I figure the piston and ring can go a little a little longer than the recommended  time rather than the small end bearing. I have been running these CR80’s for 6 years and doing top ends every 11-12 hours with no problems with piston or rings. The ring gap after 12 hours is at the max of the service limit, which I feel is taking the parts to the limit. The only failure I had was at 11.5 hours,the small end bearing cage broke into 3pcs, but remained intact, no damage to anything. The motor was running fine, I only found out about the bearing doing my routine top end rebuild.

      Gary

      #55 Honda CR80.

    • #13391
      Carlos Perez
      Participant

      Hi guys! I am new to shifter racing. I should’ve got into shifters before, I love it! It was a big jump from a clone to a shifter! LOL.

      I have a 101 question that I have no idea: What makes a “modded” engine? What do I need to look for when I open the engine? I haven’t done it yet.

      The reason I am asking is because I was practicing at my local track and one of the guys there asked me if it was modded because it sounded louder and different than others. My local track rule book states that I should run stock 80/85 cc’s.

      Any pointers are appreciated!!

       

    • #13394
      Matt Dixon
      Participant

      My guess is the silencer needs to be repacked, very simple to do.

      As for want to look for when opening the top end is any scratches on barrel wall, blow by on the piston , not sure if you can with an 80 but look at lower rod bearing.

      94y

    • #13454
      Gary Smith
      Participant

      Carlos,

      I think your question is ” How do I tell if I have a modded engine?”  correct?

      Check your bore size, CR80 1986-2002 47.00 mm, CR85 2003-2007 47.50mm, any other bore size is not stock. You mentioned 101, check you bore, if it measures 52.00mm, it is an aftermarket 101 big bore kit. Check your rules, might still be legal. Another thing to look for is enlarged transfer ports, these are the 2 little holes in the reed cavity in the cylinder you see when you remove the reed cage. In stock form they are rather small, look like a reverse capital “D”, 7mm dia rod fits snug, quite frequently they are enlarged. Also if your head has “O” rings rather than a gasket, it has been modified. Check your rules as what is termed “stock”.

      Gary

      #55 Honda CR80

    • #13574
      Carlos Perez
      Participant

      Thanks Gary! That’s exactly what I was looking for.

      Cheers.

       

      Carlos

    • #19222
      shaun s noll
      Participant

      i’ve got a bunch of extra stuff laying around like mounts, pipes, etc, PM me your phone number and I’ll make you a good deal

    • #19248
      Curt Smock
      Participant

      PM’d you my # Shaun. Thanks. I hope to hear soon. I need to get this stuff ordered

       

    • #19771
      john Dillon
      Participant

      Derek. Have you had it out and running yet?

    • #22928
      Rod Balding
      Participant

      Need a starting place for jetting a Mikuni TM-28.

      Stock CR-80 with K&N
      Older RLV K-4 pipe and 12 x 3 M-4 silencer
      VP-110 / Burris Castor @ 6oz. to gal
      Altitude – 750′ Above Sea Level
      Ave temp 85*
      Ave hum 80%

      Thanks for any help .

    • #22929
      shaun s noll
      Participant

      I’m not claiming to be an expert but the way I would do it is set the clip in the middle and probably start at 195 main jet and go from there with air screw 1 turn out or so.  Then adjust the clip to get the mid throttle you want and tune the main jet by running the motor at full throttle then immediately shutting it down and looking at the plug.  That’s the easy way to do it imo and once you get more comfortable with how they are supposed to run you can do it more by feel.

      I always have ran redline oil at 25:1 for what its worth

      if you google around there is a mikuni manual on how to tune these carbs, if you stay on the rich side they are pretty damn tough motors.

      good luck!

      • #35903
        Broch Evans
        Participant

        Shaun, I saw your comment above saying that you usually get 3-4 hours of piston life, I can get at least 1 or 2 solid seasons (50+ hours) out of a cr85 piston, with minimum to moderate over-rev. How long is your track and your races, and if you know, what is your water temp during races/practice?

    • #23034
      Rod Balding
      Participant

      Thanks Shaun , I haven’t ran them yet , but I’m close to your suggestion with 200 main to be on the safe side and you are correct , they are tuff little motors.

    • #23067
      Dave Holstein
      Participant

      Does anyone know how to obtain the IKF specs/rules for 80cc?

      I have looked at the IKF site so long my eyes burn…

      • #23142
        David McDowell
        Participant

        Dave, They are contained in the standard IKF rule book. As far as I know you do not need a special book for shifter karts. You can order the rule book right from their web site.

    • #23335
      Derek Lodato
      Participant

      I posted this on the WTB classifieds but since you are my 80/85cc guys I figured I’d ask. I need a 32mm x 90mm engine mount for my CR85.

      I have a 2011 GP10 32mm Shifter Chassis.

      If you have an extra one to sell please PM me…. Thanks

    • #23354
      shaun s noll
      Participant

      did your other mount not fit?  I have several mounts that will work for you but you were going to check to see if the mount you have fit first.

    • #23406
      Derek Lodato
      Participant

      @ Shaun .. No it did not fit. I need specifically a 32mm x 90mm mount with a matching 32mm bottom clamp

      I cannot deviate from this. Let me know if you have that EXACT size for a CR80/85 Engine.

      Thanks Shaun

    • #23415
      shaun s noll
      Participant

      I definitely have one as 2 of my 80 shifter chassis are 32/32

    • #26483
      Kyle Riedel
      Participant

      heres a tech question. does the trans use the same gears in all year models? im looking at the 3rd gear set on shark shifter, but found it cheaper on another site. theres only one set on SS, but the other site’s saing it wont work in my 2001. they have it listed or 1982-1999 year models. ive only been in the class for a year now and i seem to remember when doing research last year, the gears are the same from ?’96 on?.

      17 years of karting
      2009 NTK Yamaha heavy champion
      Yamaha
      Tag St.
      80cc shifter

      • #26636
        Gary Smith
        Participant

        According to my service manual 1995-2007 CR80R/RB, the only difference is 5th and 6th gears in 2005- 2007 models.

        I believe you are looking for the billet heavy duty 3rd gear, it should be the same in all years, make sure it is a 28 tooth gear and you should be O.K.

        Gary

        #55 Honda CR80

    • #26668
      Gary Smith
      Participant

      Kyle,

      Call John at Fastech Racing, he should be able to help you out.

      831-384-5278

      Gary

      #55 Honda CR80

    • #27268
      Dave Holstein
      Participant

      Also, where can one get the upgraded third gear for the CR80?

    • #27269
      Kyle Riedel
      Participant

      Its gonna be hard now. You may have to figure it out and find a machine shop. A local racer told me about a month ago that the guy who made them passed away. I’m not sure how true this is, but it explains why sharkshifter is out of them.

      17 years of karting
      2009 NTK Yamaha heavy champion
      Yamaha
      Tag St.
      80cc shifter

    • #29348
      Fred Robertson
      Participant

      Can anyone recommend a good gear/clutch fluid?  I got my 80 out for the first time over the weekend, but am experiencing some severe clutch slip in 4/5/6 gear when the motor hits the powerband of the pipe.  It holds fine in the lower gears.  It is properly adjusted with the cable being as loose as possible without the button coming out of the lever on the transmission when fully released.  There is about 1″ of freeplay in the lever on the wheel.  I am using Redline motorcycle gear lube currently which says it is wet clutch and Honda transmission compatible.  Could the fluid be causing the slip?

      • #29350
        Kyle Riedel
        Participant

        No the fluid should not be causing that. Not if its made for tranny. I believe I have like a standard 5/10w in mine. Also don’t put too much in. Sounds like the clutch spring are weak.

        Update: I have got all the bugs work out of my motor! has been running good until this week when I broke a piston ring on main start.

         

         

         

         

         

        17 years of karting
        2009 NTK Yamaha heavy champion
        Yamaha
        Tag St.
        80cc shifter

      • #35908
        Broch Evans
        Participant

        Fred, do you know if your running the stock Honda clutch springs? If you are I would recommend running titanium spring, the Honda springs are an okay back up if any break but they’re often not stiff enough to overcome the forces at high speed.

    • #29396
      Dave Holstein
      Participant

      I use RedLine motorcycle trans lube with shockproof, makes shifting way smoother.

      I would recommend taking the clutch cover off and inspecting the clutch pack, the symptoms you describe doesn’t sound like fluid related to me…

    • #29401
      Gary Smith
      Participant

      Fred,

      Inspect the clutch pack, check for warpage of steel plates, no more than .15mm (.006 inch) and check for friction disc thickness 2.7mm min (.107 inch). If all your plates are within spec, take a wire brush to the surface of the friction discs to rough them up, it has worked for me when I had the same problem.

      Gary

      #55 Honda CR80

    • #32530
      Kyle Riedel
      Participant

      hey guys,much improvement since last update. i got a complete top rebuild after the ring went, had two races on it now and im up to speed with the leaders! i knocked 2 seconds off my problem laps at qual and another 2/10ths in the main, I finally got my tc4 pipe and will get to try it this weekend, but i still have a couple questions.

      i run a PWK28@

      air screw: 2 turns

      slow jet: 38-40

      main jet 138-140

      now i have 2 DIFFERENT pwk28 and Ive seen a 3rd and/or 4theach one has a variation to it. (i was told when i was putting my setup together that PWK was the best carb, yet everyone else runs the mikuni) can someone explain the pros/cons of the carbs and the different pwk28’s and provide a simpler tuning guide/scan the tuning guide from the cr80 manual as i have lost my mine.

       

      other issue: when i hit high enough RPM on the long straits i get what seems like a ignition “half ground out”, (the ignition quality suffers a little) am i overloading the coil? or could it be one of the pieces at the flywheel? this symptom has not seemed to be consistent. (that ive noticed)

      17 years of karting
      2009 NTK Yamaha heavy champion
      Yamaha
      Tag St.
      80cc shifter

    • #42901
      Derek Lodato
      Participant

      Anybody here have an RLV TC-4 or TC-8 with a STRAIGHT Stinger for sale?

    • #43079
      Harrison Potsworth
      Participant

      I’ve got a full 80cc setup for sale if anyone is interested:

      2011 CKR (CRG) Shifter kart with 80cc Honda NEW PICS

    • #19220
      Curt Smock
      Participant

      SOUTHERN INDIANA RACING ASSOCIATION runs this class as exhibition. I just got my son a Top Kart and a CR80 to run it next year. Lacking a lot of little parts. Motor Mount, carb, J-arm, pipe, fuel pump (same as clone?) Front drive gear with C clip. anyone have these or know where to look?

       

    • #22438
      Derek Lodato
      Participant

      For all of the 80/85 guys I have a question I have not found the answer to yet:

      Which pipe do you prefer and why?

      RLV TC4

      RLV TC8

      I will be running at a mid sized track. I’m looking for a good amount of bottom to get out of tight corners but I also want the mid and some high .. for straights and sweeping turns.

      I am from Florida so my main tracks are Anderson Race Park and Ocala Grand Prix

      Also, what brand and size silencer is best. I am looking at the Alden A3 and M4 but not sure size etc.

      Thanks everybody!

      Derek

    • #26643
      Kyle Riedel
      Participant

      I know about the 3rd gear. But that’s not what I’m looking at. Shark shifter has a 3rd gear set that another site says is only used on 82-99 models. Which until yesterday I believed to have a 2001. I talked to Honda direct and they were able to tell me its a ’97. What Honda told me is that “set” (m3/4,c3,c6) was “superseded” in 2000 to individual gears sold seperately with new numbers. As far as learned last year the gears are the same from around 96-+. With all the confusion I’ve run into trying to find gears I no longer know for sure. I’m hoping someone here can sound off with some knowledge and list all the changes through the years after it changed to water cooled.     My project has been rather testy. Started out with a motor that was way worn out on top. Replaced top end and limped through last year. While I gathered parts. I put an OEM eq. Wiseco crank. Namura piston and a replated cylinder on it this winter. but still had one plague after. going into 4th gear it would chatter and rev like it was going in and out of gear.

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

       

      17 years of karting
      2009 NTK Yamaha heavy champion
      Yamaha
      Tag St.
      80cc shifter

    • #26995
      Derek Lodato
      Participant

      If anybody is in the market for a Brand New CR85 Alden Built with break in time only please text me at 813-504-0192 or email to DLODATO7@yahoo.com

      $795 Shipped

      It comes with:

      Extra Cylinder Head

      Silencer (Mounts for Pipe and Silencer are included)

      3rd Gear Upgrade

      IGN Box

      Mikuni Pump Around Carb

       

      This ad  is already posted in Classifieds but it’s been a few weeks so it’s out of the spotlight

      Thanks,

      Derek

    • #27220
      Dave Holstein
      Participant

      What year were the Speed Concepts SPI ignition boxes discontinued?

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