CV-Tech to Comet 780

[raydhd]

Again I found more speed from using the thicker cross section Dayco XTX over the lesser HPX unit as again it rides higher in the primary clutch. I am running the Dayco XTX2264 which measures 42.83 X 1.27 ". P.S I moved my engine as far back in my cart to allow more space in front of the engine to do my lay down S/G to use the front oil fill port with my magnetic dip stick.

[kellett5261]

Originally Posted by raydhd

Again I found more speed from using the thicker cross section Dayco XTX over the lesser HPX unit as again it rides higher in the primary clutch. I am running the Dayco XTX2264 which measures 42.83 X 1.27 "

Duly noted, ill have to get a longer belt because my oil cooler & filter are on the back side of the engine and are a mother f*cker to get off now without making a huge mess & that's running a 47" belt. I'm thinking of trying maybe a 48 and see where that gets me after I figure our my issue now.

[raydhd]

One other thought here. At first I was brazing my muffler on to my exhaust header. As I was moving the engine back I would cut more off the header and rebraze it. After some issues with the muffler/header connection I really reinforced this area with welded gusset plates. One of the disadvantages of my 1 piece exhaust system. Just keep your exhaust system in mind with moving the engine around.

[kellett5261]

Originally Posted by raydhd

One other thought here. At first I was brazing my muffler on to my exhaust header. As I was moving the engine back I would cut more off the header and rebraze it. After some issues with the muffler/header connection I really reinforced this area with welded gusset plates. One of the disadvantages of my 1 piece exhaust system. Just keep your exhaust system in mind with moving the engine around.

I am running the header/muffler set up from VC for now, the muffler is slowly getting louder and louder. one day after I have the time i'd like to make a new one with a tractor muffler or something to make the drone ago away.

[kellett5261]

So last night I messed mostly with finishing my new back seat install, however I did my best to watch the clutch with the RPMs with the engagement and I am roughly around 1750-1850 before I start to move.

I cant remember exactly with the CV but I wanna say that one was more like 2200 rpms if not more. I also took a pic of the belt at high rpms, there about 1/4" ish from the top of the belt to the the top of the 780 clutch, see attached

[kellett5261]

Has anyone had random this issue after being up to speed and cruising with a big block and the rear end starts jerking ? It only seems to do it after the engines warm and it’s almost like the feeling like the shift cable is jumping in and out of gear into neutral. If that makes sense

I keep trying to adjust it tighter and looser using the linkage at the shifter but it only does it randomly. Any suggestions?

[kellett5261]

So I think I found my issue with my "loosing" my top end speed. I haven't physically measured the clutch yet but after days of research online the CV 06 clutch is 7 1/4" tall and my 780 clone is only 7". I wouldn't think a 1/4" would kick me down 8 mph but maybe, can anyone confirm my theory?

has anyone ever pulled apart a CV clutch and messed with the weights and springs? or is there any aftermarket /alternatives when running this set up? the 780 even a though its a clone takes off so smooth but all i hear is that **** motor because I am running higher rpms than with the CV. Im not even sure how the CV comes apart? I'd assume i could use a piece of 3/4" all thread on a bench vise and try to take it apart?

[sho305]

You can change the springs/weights and make it shift faster to kill rpm, but the top shift rpm is another thing. Quarter inch should not change it that much but you are not at the top either. Normally you can push the belt down 1.5 inch at rest between the clutches. Also see if its a 1 3/16 or 1.25 clutch. I could not run a 1.25 belt on my 94c it would drag at idle. Even the 1 3/16 I had to get a longer scrambler belt for it compared to my stock clutch, without moving the engine as it was already about hitting the shifter on trans.

If you have a stock type spring in the secondary you can loosen that some, less preload will make it shift more at part throttle and about the same WOT. Stock springs have the tang on end and you wind it up to preload it. You can also use a marker to put a line in the clutch and see where the belt has been.

The 780 is a salisbury type clutch it has 3 little springs. Most comet style have one big spring in the center. So you can't really compare them spring wise they work differently.

[slonomo]

Originally Posted by kellett5261

So I think I found my issue with my "loosing" my top end speed. I haven't physically measured the clutch yet but after days of research online the CV 06 clutch is 7 1/4" tall and my 780 clone is only 7". I wouldn't think a 1/4" would kick me down 8 mph but maybe, can anyone confirm my theory?

Early in this thread I suggested a size difference between the two, but I've never owned a CV Tech clutch so I didn't know for sure. If your 780 is .25" smaller, that's a 3.5% reduction in gear on the primary drive. Also, if the CV Tech has more "shift out", meaning the belt rides higher in the pulleys, then it will have more "overdrive" than the 780, hard to compare unless you had a video of both. Both of those factors could absolutely account for 8mph loss of max speed.

One thing you could do is use black sharpie and draw some lines up the faces of each clutch, run them, and compare how much of the lines get rubbed off. Not sure how well this will work due to the belt length and the secondary full shift out position, all comes into play.

Speaking of belt tension, your adjustment of the belt could also account for some speed. I've played around with belt tension vs. engagement feel vs. top end speed and it can vary quite a bit based on how much slack you have setup on the belt. Without some kind of measuring device we rely on "feel" when adjusting our drive belts. This is also a factor.

[Dave in VA]

The CV Tech 06 was the clutch that CCP used with their big block kits when I got mine in 2012. I never had to do anything with it. Performance was great from the get go. 40+ mph with the 23hp Vanguard and 23's...