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1980 project mikuni rs 34 tuning
- rich67
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Injected : I have only bench syn the carbs , I did vac check they are all even but they have a large bounce even with the orifice installed in tubes . It has been a very long time since I degreed cams and I lost some notes . I found my cam card for the 410 cams and APE calls out for 107.5 intake and 108.5 exhaust for suggestion . according to APE its a Moderately Tight to moderate lobe separation reducing idle quality and Idle Vacuum is Reduced . I had spoken with Larry but can not find the email as to what he suggested . Idle is set to 1500 and bounces to 1700 then back to 1500. I am going to remove the valve cover and recheck . At the time I didnt have a the beat dial indicator so the might be off .
Dave : thanks for the vid that gives me some insight . That's nicest 1100 I have ever seen very nice work
What do you guys think about the cam card degree values ? I suspect they might be off. I will keep you guys posted
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Here is what I found for a timing card from the APE site :Hello, Everyone , First I want to say thanks to everyone who chimed in , I really appreciate all the helpful advice. I'v been away for a few days so just getting to them . Injected : I have only bench syn the carbs , I did vac check they are all even but they have a large bounce even with the orifice installed in tubes . It has been a very long time since I degreed cams and I lost some notes . I found my cam card for the 410 cams and APE calls out for 107.5 intake and 108.5 exhaust for suggestion . according to APE its a Moderately Tight to moderate lobe separation reducing idle quality and Idle Vacuum is Reduced . I had spoken with Larry but can not find the email as to what he suggested . Idle is set to 1500 and bounces to 1700 then back to 1500. I am going to remove the valve cover and recheck . At the time I didnt have a the beat dial indicator so the might be off . Dave : thanks for the vid that gives me some insight . That's nicest 1100 I have ever seen very nice work What do you guys think about the cam card degree values ? I suspect they might be off. I will keep you guys posted
www.aperaceparts.com/tech/camsk410.html
I think Larry would have suggested 108-110LC, making the most of his port job - It would run more like a race motor.
If your down towards the 105-106 settings they tend to run like a tractor, I don't think that's what your after just by looking at what else you got going on with the rest of your bike.
There is not a lot of duration in those cams so the vacuum loss is minimal. They are a hot street cam meant for street riding, they are a good cam for a mildly hopped up engine.
If your going to have the cam cover off check and record the valve lash before removing the cams just to make sure your still at .006" lash.
You have to remember that your engine is no longer stock, it will be a little rough at idle, you have increased all the aspects of your engine (bore, port/valve size, carb size, cam lift)
You have only so many adjustments you can make to optimize your tuning on this type of engine (carbureted air cooled)
Here is a video of my 650 street bike idling with big valve head and 280 duration cams set at 108LC.
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I am currently building a KZ1000 street engine just about a mirror image of yours.
1197 MTC 10.5:1, 37/31 KZ head ported to about 95CFM, .418" lift WebCam 280 duration cams (shim under), VM33 Smooth bore carbs.
I use a Color Tune to set my pilots then plug chops to set mains.
I make as many gaskets as I can from a master set from bulk roll Fel-Pro paper.
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I am a little confused by the "cam card" data! if the inlet opens at 18.5 BTDC and closes at 53.5 ABDC then the mid point would be 126 degrees ATDC but the LC figure is 107.5 degrees.
Is this the start of the "dwell" at full lift or is the profile asymmetric ??
Would like to understand better (I have dialled in "Piper" cams in cars previously but the timing data for these is quoted at the centre of the dwell so involves additional measurements to establish "start" and "end" of dwell and then establish the mid-point)
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This should explain the lobe centers :LC (lobe centres) is a term I'm not familiar with here in the UK. Am I right in assuming this is a timing figure for "full lift" (centre of the dwell on the tip of the lobe) ??
I am a little confused by the "cam card" data! if the inlet opens at 18.5 BTDC and closes at 53.5 ABDC then the mid point would be 126 degrees ATDC but the LC figure is 107.5 degrees.
Is this the start of the "dwell" at full lift or is the profile asymmetric ??
Would like to understand better (I have dialled in "Piper" cams in cars previously but the timing data for these is quoted at the centre of the dwell so involves additional measurements to establish "start" and "end" of dwell and then establish the mid-point)
store.schnitzracing.com/cam-lobe-centers-explained/
There is a calculation involved, need to put that school math to practice
Its probably on here in the archives somewhere, just easier to Google it.
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Here is the cam card i received when i bought the cams from APE , I agree keeping notes is essential I keep all mine in a file with all my invoices it a big help to remember 10 years later .
I have never seen a timing card with 1/2 degree increments on it, all of the ones I have been issued are to the nearest degree.
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Hi Rich, can you please confirm if there is an issue with your email ?Hi Rich67 - have tried emailing you ref a BOTM feature on this stunning KZ1000 but I am getting a bounce back saying there is an issue with your mailbox ?
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