35HP Vanguard Mods?

[Hollywoodc]

Well I finally figured out my jetting range on this VM Mikuni!!!

I was too lean on the Pilot which caused it to hesitate on take off. Jumped up to a 60 from the 30 that I was originally playing with and WOW! That was the ticket!
Im gonna pick up a 45, 50, 55, and see which one feels and looks the best.
I have the Idle set at about 1200. I started with a .5 Air jet and then drilled it out a bit. Im still having some trouble getting the Pilot screw to show much of a difference after 2 turns out. It will slightly increase in RPM but after turning it out a few more times it doesn't really drop after the rise in RPM's. It will drop once I get down to about 1.5 turns from fully closed.
Im not really sure if I need the Air jet at all?

Gonna play with the Needle and Main to tweek it as close to perfect as I can, but all and all, I think Im ready to take it out and tune in the dirt soon!
I drilled out the Highest Jet I had which was a 520, the plug was still looking lean with the 520 at WOT.
I'd say Im close to a 600 Main by now. Plugs look a bit rich so Im gonna have to pick up some more mains between 520-600 to see which one feels best.

The Tach is working great and makes it a lot easier to understand whats going on with the tuning.
Next mod is gonna be the timing. I probably should have done that before tuning but I wasn't quite sure how to go about it and there isn't much info online on the process. I'll take Nubs insight and see if I can figure it out once I pull off the flywheel cover and see whats going on underneath.

Question:
Im maxing out the engine at WOT at about 4500 RPM, no pinging or irregular sounds from the engine, just feels like its reached it's.
Should I be getting more RPM's out of it or does that have to do with fine tuning the Main Jet to get a higher RPM out put?
Nubs, you said your 24HP was getting up to the 6500 RPM range, is that because you have an aftermarket CAM thats why its getting up in the higher RPM's?


Video of the Tach:

https://www.youtube.com/watch?v=SbC1MjkFi2Y

Clips rolling the buggy around the parking lot. Have to wait till everyone closes their shops in the evening before I can play around with the buggy and jetting, but it does sound pretty beefy! ;-)
Buggy1 - YouTube
Buggy2 - YouTube

[Hollywoodc]

I just wanted to say thanks for all your guys Insight and help. I hope somebody can take from this thread something that will help them on their builds.

I spent a lot of time trying to figure out the VM Carb and Jet range. There is no standard listings for this particular carb that I could find. But from the point I'm at now, the setup makes a huge difference on this engines performance compared to how it felt stock.
I still have the other 40mm VM that came. I'm thinking I'll keep the tuned bored out 40mm to 42mm for High desert higher speed runs, then I'll tune the 40mm VM and use that one for the Dunes.
Im thinking the 40mm will have a bit better lower end punch for Roosting in the dunes. :-)

[Hollywoodc]

My setup has an electric pump, is there a way to check the pumps pressure and how much pressure should it be pumping for a Mikuni setup?
I'm wondering if I was getting such a lean reading with the big jets because the pump wasn't filling the bowl fast enough. But I think I would have felt a hesitation in response once it hit the bottom of the bowl.

I did a compression check on both cylinders and front was showing 100-110 rear was showing 110. I hope that is adequate for these big block engines.

[Nubs]

A mikuni can be setup for up to 6psi, pulse fuel pumps run about 2.5/3
you can bottle feed it and see if it changes.

[Hollywoodc]

Bottle feed meaning gravity fed from a bottle, or electric pump to a larger sized bottle and then out to the carb?

What Compression pressure range be for the cylinders?

[Nubs]

Yep, gravity fed. there were different versions of heads over the yrs but 140ish with the carb wide open is right in there.

[Hollywoodc]

So I think I have it dialed in as Best as its gonna get.
I still notice some smoke coming from the exhaust when running hard in the upper RPMs, but the Plugs look like they're right about where they're suppose to be.
Is that a sign that I can lean it out some more or will the Timing advance help that?

[Nubs]

I would advance the timing first, runnin' stock pistons to lean will cause you problems at some point. fuel & plugs are cheap so I'd run er' rich.

[Hollywoodc]

Thanks Nubs. I pulled off the flywheel cover and plastic fins yesterday but I need to finish making the a flywheel remover to get the flywheel off. Hope I don't have any problems getting the flywheel off. I'll post pics of the process when done, there isn't much info on Image Search of the timing advance process.

After that, I I've read about advancing or retarding the stock Cam 1 tooth. Im just not sure which will be better for Duning, low end or Top end.

[Nubs]

The flywheel will pop right off, I'd just cut the key in 1/2 and that'll get ya a few degrees to start. I don't buy into that retardin' the cam deal, if your gonna bother to get to the cam just spend the money and buy one that been ground and dyno tested

[Hollywoodc]

Got it, Gonna contact Al Hodge and see what he has for the 35HP

Update:
Just got in touch with Al Hodge. He has the Cams, lifters and Billet Rods for a total of $300.
Sounds like a deal.

[Nubs]

Ya can't go wrong with that setup..

[Hollywoodc]

Pulled the Flywheel and Key.
Not sure how much of the key to shave down. I've read from up to 1/3-1/2 but that may have been just for the lower HP Vanguards.



How does the flywheel look like its in good shape?

[Hollywoodc]

Ok So I advanced the timing by half of the key which is about 8 degrees.
I also did some mods to the Primary Clutch. Closed the gap a bit between the primary sheaves, It had a 3/16" gap between brand new belt and sheave, so I modded it to bring it in which now has about 1/16" gap.

Car feels great on take off, It will pull all the way through until I run out of room in the parking lot.
Only thing I'm concerned about is, it feels like it takes longer to get through 3500 RPM range.
Its hard to explain and I don't feel like pulling it apart again to put it back to zero or try Retarding it to get the full affect.

What should the performance change feel like by advancing the timing?

[Nubs]

does it pull hard again after it gets passed 3,500? Sounds like it may just be the clutches not shifting when they need to be. once ya change one thing it sometimes moves or creates a another problem.