Need advice on my predator212 hemi build.

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Motoman

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So I have been working on a build for a customer of mine and have been having some issues with it any help and suggestions are very much appreciated

Let me start with some details.
First I live near Cleveland Ohio where the elevation is around 1000 feet or so.

The build:
-Predator 212 hemi
-Stock length billit rod
-Chargeing system from a Coleman ct 200u-ex
( had to have the crankshaft flywheel taper machined to work with the ct200u-ex flywheel and yes it has also been lapped)
- 4 degree timeing key (soon going to an 8 degree)
-.005 off the head (to clean up the gasket surface)
-Mikuni vm22 round slide carb kit with intake adapter size 15 pilot jet and 110 main jet
-.038 multi layer steel head gasket from cometic gasket(.009 head gasket has been ordered.)
-mod 2 camshaft
-intake valve lash .010
-exhaust valve lash .013
-18 lb valve springs
-stock piston
-aftermarket header with a spin on muffler from tractor supply co that the center baffle has been removed from (practically a straight pipe)
- 10w 30 oil
-mikuni pulse fuel pump pulse feed is in the valve cover
- ignition coil gap .030
-bp6es spark plug (i also have a bp7es, an autolight 3910x and its ngk equivalent
-93 octane pump gas

The issues with the build:
My first issue after I first put my engine together was it was very hard to start. Some times it would putter over but not actually catch almost like the decompression lever wasnt disengaging properly. I managed to get that issue sorted out and got it to where it will start first pull everytime and idle flawlessly. So I feel like it's safe to say that my idle is set good.

The issue I am having now is on the top end. Basically at full throttle it pulls good all the way up to a certain rpm (will measure what rpm once I get my tach from work). At that rpm it sputters in and out almost like it is too rich or to lean or it is starving for fuel. It acts almost like a rev limiter. If I close the throttle to 3/4 the issue stops but as soon as I bring it back to full throttle it acts up again.

At this point I don't feel like I am having a fuel issue. My spark plug reading is a nice tan to brown color even when I cut ignition when the issue is happening (plug chop).

I think my issue lies with ignition. I've ordered an 8 degree timeing key to advance my timeing some more. I also swapped out ignition coils from another Honda clone motor. Wich visually looks slightly larger (more windings?) than the predators stock coil. It is also very cold where I am at 28 degrees Fahrenheit wich I feel may be an issue as well.

If anyone has any insight of what I should check or if they have had similar issues i am all ears and open to any and all suggestions.
Also if anymore information is needed please don't hesitate to ask me for it.
 

Kartorbust

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I probably would have started with a Tillotson 212 with electric start. Those have a charging coil and balanced flywheel rated for what 10k rpm, or at least more than the standard Predator.
 

bob58o

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Since your measurements are not labeled with units I have to assume you are using inches. If your lash is also in inches, it is set wrong. Try 0.002-0.004”.
If the numbers you gave for lash are mm’s then it is much closer to being correct.

And I agree with Joe. That flywheel is not safe at the RPMs that cam is designed for.

Are you sure you got the correct 18lbs springs? Some will not work in a Hemi.
 

Motoman

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Unfortunately the customer didn't want a billit flywheel he doesn't plan on being at wot all the time and he understood the risk of the flywheel magnets coming apart. The valve springs are from nr racing that were advertised for working with the predator 212 hemi. Unfortunately arc doesn't make a flywheel that supports a chargeing system and he really wants his lights with out a buttery.

I will double check the valve clearances when I put the thinner head gasket on it and correct my measurements are in inches. Any other thoughts?

---------- Post added at 08:35 AM ---------- Previous post was at 08:33 AM ----------

I also agree on the tollitson electric start but he already had the predator at the time.

---------- Post added at 08:36 AM ---------- Previous post was at 08:35 AM ----------

Now is there another way of running a chargeing system on the predators with a billit flywheel?

---------- Post added at 09:11 AM ---------- Previous post was at 08:36 AM ----------

Also has anyone ever experienced ignition coil saturation causing a break up at higher rpm?
 

Kartorbust

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I'm curious if the electric start tillotson flywheel would fit? That might be the next best option. However I doubt they sell the flywheel by itself.
 

Motoman

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So I took it out again tonight a brisk 24 degrees it fired right up first pull, went for a wot RIP up and down the street and it still broke up on the top end got back did a plug reading and it showed lean so I raised the needle as far as I could raise it went for another RIP got back read it again still lean. Put the 114 jet I have in it put clip in center position and it read rich so I lowered the needle 2nd from top and it still broke up ontop. Gotta clean the plugs now to get a good plug reading now. I really am at my whits end with this thing...:mad2:

Again I still feel my issue is with timeing any thoughs? What rpm is the mod 2 cam designed to run at?
And has anyone ever had an issue with ignition coils breaking up on the top end but fine down low? Also the cam sheet with the mod 2 said billit flywheel must be used. Do you really need a billit flywheel with the mod 2?
I may try putting the predator cam back in it and see what difference it makes.
 

Motoman

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I started with a 130 main jet and a 12.5 pilot with a 12.5 pilot it was hard to start and a 130 main it was way to fat I've been re jetting threw this entire process. I have jet sized ranging from 100-140 for the mains like I said I've got my idle dialed in perfect.

Has anyone ever seen or used this ignition coil if so did you notice any gains or better
Consistency with spark?https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/292637472026
 

Motoman

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So yesterday my new head gasket and 8 degree timeing key arrived got it all installed last night but was unable to take it for a ride because it got too late and I didn't want to upset the neighbors. I'll post an update along with some photos of the build tonight when I get off of work. I have reset my valve lash to .003" in/ex per dyno cams recommendations for the mod 2 cam. Installed another new spark plug bp6es, and an tach /hr meter so I can see engine rpm it idles between 1300 and 1400 rpm and sounds healthy. Does anybody have any other suggestions on the build?

When it comes to manufactur bikes the big 4 I'm a professional at fixing them, Chinese clone motors I am still learning
 

65ShelbyClone

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So I took it out again tonight a brisk 24 degrees it fired right up first pull

With or without the choke?

Again I still feel my issue is with timeing any thoughs?

If the coil was causing a loss of timing advance, then it the power would flatten-out, not start breaking up.

How much plug gap are you using? Do you have another flywheel to try?
 

Motoman

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That's choke off. It's got a mikuni vm22 on it and the enrichiner or choke raises the idle rpm to around 2 k. I'm about to go mess around with it now
Want to do a few plug readings and will update a little later on tonight
 

Motoman

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Thought I would post some pictures of the machine I was able to get a few test rips in before the police arrived because of course people dont have anything better to do than complain. But it still breaks up around 5,000 rpm
With the 8 degree timeing key and a 0.010"head gasket . Im going to double check my valve clearances tomorrow morning. At 1/2 throttle it runs great and the wieredist thing is it revs out on the stand no problem

Any other thoughts as to what my issue could possibly be . I'm getting ready to say screw it and order a tollitson tct carb for this thing and try that out insted of the mikuni better yet just the 212 e start
 

Motoman

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Here are the photos
 

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Motoman

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i will double check my plug gap tomorrow i am almost debating to bite the bullet and order either a Tiliotson tct carb or a Tolliotson HL-334 wx carb kit from omb warehouse. BECAUSE I CANNOT FIGURE THIS THING OUT:censored::censored::mad2::mad2::mad2::2guns:
A high/low speed adjustable jet v.s having to swap jets every time would be nice too.

anyone have experience with the HL-334 wx carb?
 

Kaptain Krunch

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So I took it out again tonight a brisk 24 degrees it fired right up first pull, went for a wot RIP up and down the street and it still broke up on the top end got back did a plug reading and it showed lean so I raised the needle as far as I could raise it went for another RIP got back read it again still lean. Put the 114 jet I have in it put clip in center position and it read rich so I lowered the needle 2nd from top and it still broke up ontop. Gotta clean the plugs now to get a good plug reading now. I really am at my whits end with this thing...:mad2:
Just an fyi, the clip position does not effect wot. Only 1/4-3/4...
main jet does 3/4-full
pilot does idle-1/4 in conjuction with idle air or fuel screw
 

KartFab

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I still would go to a 130 main and see if it breaks up.

Makes me wonder if you have timing set to what the cam calls for. For all we know the Crank and flywheel have jetways in different locations.

Also, have you tried swapping coils?
 

Motoman

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I have tried swapping coils I'll put the 130 back in it and see what happens I'm going to take it out to an empty parking lot for tuneing today.

And do you mean keyway not jetway? I'm also thinking of putting the stock timeing key back In it and see if that helps.
 
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