Treats 70cc kit not performing to full potential

Rourke Kendrick /

Hello everybody.

I have done all the research I could using the wonderful search function, but I am still stumped as to why my Puch Maxi E50 Is not accelerating and hitting a higher top speed.

My setup goes as following:

-1978 Puch Maxi E50

-treats 70cc piston port kit

-treats hi-hi head

-12mm bing bored to 14.3mm

-14mm intake

-High flow metal mesh filter

-2.22 atomizer and 70 jet

- mild case match (didn't want to cause a base leak)

-2mm base gasket and .2mm head gasket

-B7HS

-Timed to 18 degrees BTDC with a .018" point gap. I used a timing light.

-Boss Pipe

-Rebuild bottom end with super stuffy crank, new seals, bearings, and put back together with some aviation sealant.

-Stock clutch with kickstart springs and mlm clutch brace.

-17t front sprocket

I am aware that the Hi-hi head is not the best head, but I did not know this until after I ordered the kit. I have access to a milling machine that I could use to dial in the combustion chamber and squish, but I wanted to save that for last. After running at WOT for extended amounts of time, I am only getting just below 250F. My acceleration is pretty bad, but a little bit better after I modified the clutch with the kickstart springs, clutch brace, and went in 2 1/4 turns in from flush. My friend with a za50, velocity stack filter, and proma circuit is still killing me on acceleration. In terms of top speed, I am getting about 38 mph on flat. I get passed by my friend on his maxi e50 with the treats 50cc kit, hi head, velocity stack, boss pipe, and bing 14mm. I have put a lot of effort into this build and I am very committed to getting this moped tuned perfectly. I check for airleaks on the carb, intake, base gasket, head, spark plug threads and exhaust manifold, but found none. Should I expect more out of this build?

I can provide pictures, videos, additional info, or whatever you need.

Let me know what ya think!

Thanks,

Rourke

Re: Treats 70cc kit not performing to full potential

What jet is your friend running on his 50cc?

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

Mike Boyd Wrote:

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> What jet is your friend running on his 50cc?

He is running a 68.

Re: Treats 70cc kit not performing to full potential

I'm thinking you're running lean/ not properly tuned which is robbing your power. What's your rear sprocket?

Re: Treats 70cc kit not performing to full potential

Overpriced Parts /

250f head temps ?

Is that with a trail tech head temp gauge or somethin dumb like pointing a lazer temp gun at it ?

What gearing you running?

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

I know I am running a 17 in the front. I assume rear is stock, but I will double check to make sure the previous owner didn't change it.

As for jetting, I was running a 73 and I noticed it was running very rich, so I took off the air filter and it ran slightly better. After that I put a 71 in and reattached the air filter. I ended up having best luck with the 70 jet. This was before I decided to advance the timing from 14 BTDC, to 18 BTDC.

I was using a temp gauge that I use for breaking in my nitro rc cars. I have found it to be pretty accurate. I can't justify the trail tech since you cant replace the battery and many people have problems with them not lasting.(edited)

Re: Treats 70cc kit not performing to full potential

Overpriced Parts /

Rourke Kendrick Wrote:

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> I know I am running a 17 in the front. I assume

> rear is stock, but I will double check to make

> sure the previous owner didn't change it.

>

> As for jetting, I was running a 73 and I noticed

> it was running very rich, so I took off the air

> filter and it ran slightly better. After that I

> put a 71 in and reattached the air filter. I ended

> up having best luck with the 70 jet. This was

> before I decided to advance the timing from 14

> BTDC, to 18 BTDC.

>

> I was using a temp gauge that I use for breaking

> in my nitro rc cars. I have found it to be pretty

> accurate. I can't justify the trail tech since you

> cant replace the battery and many people have

> problems with them not lasting.

Knew it, no wonder why your temperatures are so low/way off,

the trail tech temperature gauge tells you the temperature when full throttle/full throttle runs, that's what counts the moment you back off throttle or use anything different it's changed. Your at least 160° off from using the trail tech temperature gauge @ wot.

Temps are based on trail tech nothing else, if you do not get one you are going to soft seize if you didn't already (could be why your slow)

I got trail tech gauges over 5 years on original batteries.

I get near 48 near 50mph with great take off on similar setups/builds so you should be at least 45mph so you way off.

Ya timing needs to be lower/depends on your max rpm, 18° BTDC is good for 7,500 rpm, after that it's hot/seize city.

See dyno Graph

image.jpeg

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

Thanks Ken I appreciate the info. Ill pick up a trail tech as soon as I can afford it. I really don't think I have soft seized since it has been this slow from the start. The last time I took off the cylinder, I inspected everything and I did not see any deformities. Are signs of soft seizing visible to the eye? How would you recommend move forward?

Thanks

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

I have double checked, and my rear sprocket is a 45t. That makes my ratio 17:45.

Re: Treats 70cc kit not performing to full potential

What's your squish at? I see you used base gasket spacers but didn't mention decking your jug to compensate for it.

Re: Treats 70cc kit not performing to full potential

Overbored Bing carbs have a tendancy to run RICH so that would be a reason to 4-stroke and not rev to higher RPMs and have lower temps too...Try a leaner atomizer like 2.17 or just buy a new carb...

Re: Treats 70cc kit not performing to full potential

Read my other reply

Re: Treats 70cc kit not performing to full potential

Jack Rutherford /

Hell, post a video of the thing running.

You can get a trail tech temp gauge only for $39. Are you thinking of the Vapor for $100+?

Re: Treats 70cc kit not performing to full potential

Add an 82 jet

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

If I can afford a vapor, then I will grab one. I can probably afford one later this month for my birthday. I notice that on flat conditions I hit 39 or 40, but if I blast down a hill, I can get to about 43mph and hold the speed on flats. When I hold a higher speed after a hill it sounds like I am 4 stroking. I am at sea level by the way.

Here is a link to a playlist of videos of it running.

https://www.youtube.com/playlist?list=PLKo_XVZ-iXPP3CJn3mNAHu9z6ybwSBPyG

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

Ethan Brady Wrote:

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> Add an 82 jet

An 82 sounds really high, Ken roff suggested 71-73 and travis tutorial runs a 68 for this type of setup. But if you are confident in this I will give it a go. Do people usually upjet after advancing timing?

Re: Treats 70cc kit not performing to full potential

Overpriced Parts /

Rourke Kendrick Wrote:

-------------------------------------------------------

> Ethan Brady Wrote:

> --------------------------------------------------

> -----

> > Add an 82 jet

>

> An 82 sounds really high, Ken roff suggested 71-73

> and travis tutorial runs a 68 for this type of

> setup. But if you are confident in this I will

> give it a go. Do people usually upjet after

> advancing timing?

Never advance it, lower it to specs

A bored out carburetor many times gives poor results it's best to use a real 14mm Bing carburetor

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

Ken Roff Wrote:

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> Never advance it, lower it to specs

> A bored out carburetor many times gives poor

> results it's best to use a real 14mm Bing

> carburetor

I am very confident with the job I did with my carb, but I can borrow my friends bing 14mm to see if it is the root of the problem. I will clean my points, re gap it to .018, and dremel my stator if I need to. Ill shoot for 15.5- 17 degrees. What rpm should I read the timing at because I have found that it jumps around a little at varying rpms?

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

Steve Miller-

I will go ahead and check squish in my auto shop class tomorrow. I will also check compression and take pictures of my case match, and cylinder/piston.

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

I checked my squish, and in the process I realized that I had two head gaskets instead of just one. So after removing one head gasket, my compression went from 150 up to 160 psi. My squish came out to be 2.565mm. I didn't want to remove my cylinder all the way, because I did not have enough time. So here are the best pictures I could get.

20160510_094734.jpg
20160510_094816.jpg
20160510_094828.jpg

Re: Treats 70cc kit not performing to full potential

Shouldn't squish be lower than that? Like half that?

Re: Treats 70cc kit not performing to full potential

Overpriced Parts /

Rourke Kendrick Wrote:

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> I checked my squish, and in the process I realized

> that I had two head gaskets instead of just one.

> So after removing one head gasket, my compression

> went from 150 up to 160 psi. My squish came out to

> be 2.565mm. I didn't want to remove my cylinder

> all the way, because I did not have enough time.

> So here are the best pictures I could get.

Why are you showing the base not head gaskets!

Do you know the difference? And every time are you you remove the head you should change the head gasket and you should change the base gasket if you remove the cylinder like you're doing now it's OK to have a big squish it's a moped not a track bike.

I got 64cc Polini kitted bikes that have 2+mm of squish and they go 55-60 with small carbs and cheep pipes.

I don't think you understand! you're supposed to space up the base to get the ports full open with the piston at bottom dead center then you set the head squish with a different thickness of head gasket, decking the cylinder, milling the head whatever,

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

Ken,

I should have been more clear. I was showing the base of the engine because yesterday I posted "I will go ahead and check squish in my auto shop class tomorrow. I will also check compression and take pictures of my case match, and cylinder/piston."

According to Fred's guide, "Metal head gaskets can be reused over and over as long as you didn't damage them by bending them badly" That is why I am reusing my head gasket.

I forgot my extra base gasket at home, so instead I reused the base gasket, and checked to make sure there were no air leaks after.

I am aware that you are supposed to space the base gasket so the exhaust port opens fully, you get full power, and don't overheat your ring. Thats why I am running a 2mm gasket, and checked to make sure it clears the port.

According to a thread that I found from 2012 called "kstar full potential", user "flagrant" says that the Estoril pipes likes about 175 psi of compression and boss pipes like little bit more than that. Once school ends ,which will be in a little over a month, I start a full time job. I then can use the 10% of my pay check that I don't put towards college, into buying nicer moped parts like an Esoril and nicer carb. Perhaps I will buy a VM20 and a weekends intake. So for now I would like to utilize the 1 1/2 hours of autoshop I have everyday in school to tune my moped to the best of my ability using the awesome tools I wont have access to over the summer. I have read up on squish tuning and modding the Hi-hi head to more of a hemi shape that matches the piston. Crazy Wayne gave these guidelines "Hi HI compression 70cc head mods with 3mm's of the squash band border cut back, set your squash band no smaller then 1.1mm/0.043", to a max of 1.8mm/0.071"

With 6mm's of the squash band border cut back, set your squash band no smaller then 0.81mm/0.032", to a max of 1.65mm/0.065". "

Is it possible that my Boss pipe could be clogged? I have ran my moped rich for many many miles because I was told that my bing was a 14mm, so I never down jetted more than what people recommended in fear of seizing. I only very recently realized that it was a 12mm, so I went ahead and bored it out. Am I right in thinking that running rich would clog a pipe faster than running a good tune?

Thanks,

Rourke

Re: Treats 70cc kit not performing to full potential

Overpriced Parts /

Get/run a real 14mm Bing

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

Ken Roff Wrote:

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> Get/run a real 14mm Bing

I will try to do so as soon as possible. What range of jets would you recommend?

Re: Treats 70cc kit not performing to full potential

Rourke Kendrick /

Just tried the 14mm and it did not run differently. Any other input?

Re: Treats 70cc kit not performing to full potential

Jet, atomizer, filter, slide , n intake on your setup on bing 14? Timing checked that to make sure its spot on?

Re: Treats 70cc kit not performing to full potential

I'm having this exact issue. Did you ever find a resolution? Going to check my squish this weekend.

Re: Treats 70cc kit not performing to full potential

Richard Eberline /

That's the cleanest engine I seen in a long time. You have a air leak somewhere.

Re: Treats 70cc kit not performing to full potential

Dirty30 Dillon /

Jesus christ, stop opening your engine up while it's covered in sand.

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