1977 reed kit questions.

so i got this kit. http://www.1977mopeds.com/product/50293/Puch-70cc-77-Reed-Kit/ the casting was straight for the most port, hard to do some clean-up on the transfers and on the exhaust port bridge. nothing more then a half an hour or so. when i put the cylinder on there with 1 base gasket, the top piston ring is visible through the exhaust port. i have to space this up with like 3.5-4mm to get piston fully clear of the exhaust port at BDC. this leaves some meat up top that fucks with my squishband, but i'll deal with that later.

but now as i'm getting closer to sealing it up and heatcycling and breaking it in i got some questions. this kit has a bridged exhaust, i think i should drill some holes in the piston to help cool this bridge. how do i do this?

it's gonna be going on an e50 with an unstuffed crankworks crank, with that pietcard 3055 and 2013 box combo pieced together from mopagan and treats, a 21mm phbg, boyesen dual stage reeds, braced 3 shoe with closed bell and a sidebleed weakends pipe. hoping for 55mph at 9250rpm 16x35 with uphill ability(110 pound rider).

will i have to do any other piston drilling to help cool the piston down or the rings? maybe some BBF tech? i need your opinions.

Re: 1977 reed kit questions.

Overpriced Parts /

17x40 gears should be good 16x36 the most needed with a needle crank A tuned clutch with thick springs is a must. 16-17 degrees timing a must for break in. maybe 1 more degree more advance after break in if running cool.

head temp gauge a must too.

Break in at normal speeds for 300 miles before long blasts

Re: 1977 reed kit questions.

Crankworks unstuffed has a rito rod and an INA bearing. Its either gonna be a braced kickstart spring 2 shoe with atf type f and a lightened bell and cover or braced paz spring 3 shoe with motul 10w30 and a closed bell both with lightened shoes. I got the temp gauge and a tach, no speedo, just a GPS when needed. After heat cycling am I good to start clutch tuning or wait?

I got a k-star, 14mm Bing 222 atomizer 74 jet (its cold), tecno circuit setup ripping with 17x36 gearing with a tuned 2 shoe pazzed and lightened clutch with a closed bell that's on my girlfriends bike now and its hitting like 52. She's light, like 110, but its good so far.

Re: 1977 reed kit questions.

Overpriced Parts /

110 lb/52mph I could see that

Re: 1977 reed kit questions.

Matt Mahloch -- MBM Customs /

I would like to put a 110 pound rider on my bike and see how fast it could go. My 210 lb self and 132 lb bike isn't the best combo for top speed.

Re: 1977 reed kit questions.

Yea tuning a light and fit maxi (thin spokes, light saga b4 tires, sealed bearings ) for a 110 pound rider is much more forgiving then on a heavy maxi with gazelles and wide spokes for a 170 pound rider. The same setup, except a 19 phbg got me to 48 at 18x40 on my heavy maxi.

Re: 1977 reed kit questions.

Overpriced Parts /

I'm 190lb with a 140+ lb magnum (mags, fenders, side covers, racks, hydro forks, gas, tool kit,)

My speed would gain by about 5mph if I weighed 110 lb

Re: 1977 reed kit questions.

Seems to rev to about the same rams from my bike with me to her bike with her. But me on her bike makes it struggle a bit, doesn't rev past 8k and is a bit sluggish though. Its gonna force me to get this 1977 reed kit together. Do I need to drill holes in the piston to cool the exhaust port bridge or nah? And I'm gonna be using a 70cc go-to comp head with a reworked squish. Its not revving too high so how much should I rework it? I'm thinking take the sharp edge off and bring it back maybe a 1/4 of the way but still keep semi high compression.

Re: 1977 reed kit questions.

Bump. Anyone?

Re: 1977 reed kit questions.

#CrazyWayne™ rocks. #CrazyWayne /

The EX port on that kit is a fucking joke, ive never seen a bridge EX-port that was round?

WTF

Re: 1977 reed kit questions.

You can drill holes if you want, just assemble the kit and piston on the motor then mark the top of the piston where the bridge is. Drill 2 or 3 holes down the bottom of the piston in that area and make sure to chamfer the edges.

On the exhaust port spacing problem:

Don't space the cylinder up any more than 1mm. You'll end up with extremely high port timings and a nearly useless kit on an e50.

Re: 1977 reed kit questions.

#CrazyWayne™ rocks. #CrazyWayne /

That kit wont last if the ring cant dip below the EX-port for oiling.

Re: 1977 reed kit questions.

yeah i'm with wayne on this one. that exh port doesn't make any sense. what is the distance from the top of the cylinder to the bottom of the port? if it is more than the 43mm stroke of the puch, that is a serious flaw.

if it were me, i'd definitely put some oiling holes in the piston, i also dont like how shallow the bridge is.

it will be interesting to see how these run.

Re: 1977 reed kit questions.

#CrazyWayne™ rocks. #CrazyWayne /

SEND IT BACK TO F FREDDY AKA 77 etc...........

(edited)

Re: 1977 reed kit questions.

Here is how far I got on it so far been to busy doing other things.

I match it with a transfer in the cylinder.

Then, I chop the reed stops. (edited)

Picture 099 (Medium).jpg
Picture (Medium).jpg

Re: 1977 reed kit questions.

I have a old stock gasket that is 2mm thick and green like money.. planned on using this on my za50 w/ some rebuilt clutches. Maybe someone can make us some lazer cut/clone gaskets but 2mm thick?

Ya, I would drill oilers in the piston for the bridge and put some on the sides of the transfers. The casting and liner coating is really nice.

Re: 1977 reed kit questions.

If I had to guess it's about 47mm from the top of the cylinder to the bottom of the exhaust port. K stars are like this too, but not so severe.

Re: 1977 reed kit questions.

#CrazyWayne™ rocks. #CrazyWayne /

So i just talked with a nether builder and Ya this kit is all wacko!

From the top of the cylinder to the bottom of EX-port is 46.25mm most E-50 & ZA-Kits are 43.1mm, that's 3.15mm of wacko BS.

And top of cylinder to base is 68.02mm on the 77 kit, E-50 & ZA's 67.50mm, so it's 0.52mm taller than a stock cylinder.

Not even going to wast time on posting the other port's, that EX-port kill's it.

It will take a shitton of work to get this kit to work on a E-50 or ZA-50.

Look's to me like you got a new in box door stopper.

Good luck with your kit.

Re: 1977 reed kit questions.

What are the exhaust and blowdown numbers Wayne?

Re: 1977 reed kit questions.

Wayne countersink me a head 1.5mm with an o-ring that'll be good for 9500 rpms. Pleeeeeease. That should fix the problem right? I hope 77 wouldn't sell shit like thooooo

Re: 1977 reed kit questions.

Post a port map.

Re: 1977 reed kit questions.

I'll snag one on Saturday, my shits at my parents so i can't get one tonight. If I recall correctly the ex timing seemed to be at around 170-175 just measuring how big the ex port was from the bottom of the port to the top of the port, and blow down didn't seem too crazy either. I dunno why I couldn't just make a base spacer or motoseal 4 1mm gaskets together (when torqued down its about 3.25mm thick) and countersink a head 1.5mm or so though. If blow down is straight, which it should be, is that illogical?

Re: 1977 reed kit questions.

#CrazyWayne™ rocks. #CrazyWayne /

I need to have the cylinder & piston on this kit in my hands, it's so fu--ing out of spec, "" 3.15mm "" changes everything!!!

For 98% of the builders on MA it's just a door stopper.

Remember junk + junk = junk

Re: 1977 reed kit questions.

A Boy Named Britchez ... /

The athena ajh leaves a couple mm of piston meat in the ex port at bdc too with a single 1mm-ish base gasket. Still hits high 40's no probs right outta the box. I'd assume thats what this kit was copied directly from?

Re: 1977 reed kit questions.

Do not run 3mm of base gaskets.

25.5mm= 172.5*.

22.5mm= 188.5*

Changes the kit to a super high rpm nearly unuseable kit.

Re: 1977 reed kit questions.

Hmm. I'd like to send it but I feel like it would be a burden. I've dealt with shit like this on a 50cc 77 kit (they all have spacing issues, the 50 racey is 3.2mm short with any puch piston, this reed valve and the 70cc cheapo pp looks like it needs 1.6mm of base gaskets and a k-star head with a head gasket for proper squish. ) that 50cc kit had to be spaced 3.2mm up but then the head spaced out fine with a headgasket on a regular comp head. Proper squish would be about 1-1.4mm on the 70cc reed kit right? I'd have to countersink it like 2mm to get around that and ofcourse an o-ring groove. I think I'll get it milled down and then fuck with the squish myself.

Graham what did you mean by a shallow bridge?

Ed, I got mb5 boyesen dual stages, no reed stop for me.

If the bridge isn't garbage I'd eventually want this thing with huge ex ports, big enough for a big pipe to take care of and make this the lil gila killer I think it could be.

If it is garbage I might just file it out of the cylinder. Then its pretty much just a stupidly spaced Athena, right?

Re: 1977 reed kit questions.

No with the kit adjusted the 3.2mm it was 170-174ish. I just measured how long ex duration would be if the whole ex port was used and used that out of a full 43mm strokes timing duration. I measured how long the port was an subtracted it from 43, I don't remember the size but I'll get a map Saturday and shed some more light.

Re: 1977 reed kit questions.

#CrazyWayne™ rocks. #CrazyWayne /

Jake P Wrote:

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

> Do not run 3mm of base gaskets.

> 25.5mm= 172.5*.

> 22.5mm= 188.5*

>

> Changes the kit to a super high rpm nearly

> unuseable kit.

The top of cylinder to base is 68.02mm on the 77 kit, E-50 & ZA's 67.50mm, so it's 0.52mm taller than a stock cylinder.

25.5mm = 172.5deg +3.15mm i= 28.65mm on the 77kit from the top of the cylinder deck.

22.5mm = 188.5deg +3.15mm = 25.65mm on the 77kit from the top of the cylinder deck.

So how far is top of the EX-port from the top of the cylinder deck?

Re: 1977 reed kit questions.

#CrazyWayne™ rocks. #CrazyWayne /

Millimeters Degrees

21.5 === 193.7 +3.15mm on the 77kit from the top of the cylinder deck.

22.0 === 191.1 +3.15mm on the 77kit from the top of the cylinder deck.

22.5 === 188.5 +3.15mm on the 77kit from the top of the cylinder deck.

23.0 === 185.9 +3.15mm on the 77kit from the top of the cylinder deck.

23.5 === 183.2 +3.15mm on the 77kit from the top of the cylinder deck.

24.0 === 180.6 +3.15mm on the 77kit from the top of the cylinder deck.

24.5 === 177.9 +3.15mm on the 77kit from the top of the cylinder deck.

25.0 === 175.2 +3.15mm on the 77kit from the top of the cylinder deck.

25.5 === 172.5 +3.15mm on the 77kit from the top of the cylinder deck.

26.0 === 169.8 +3.15mm on the 77kit from the top of the cylinder deck.

26.5 === 167 +3.15mm on the 77kit from the top of the cylinder deck.

27.0 === 164.3 +3.15mm on the 77kit from the top of the cylinder deck.

27.5 === 161.5

28.0 === 158.6

28.5 === 155.8

32.0 === 134.7

32.5 === 131.4

33.0 === 128.2

33.5 === 124.8

34.0 === 121.4

34.5 === 117.9

35.0 === 114.3

35.5 === 110.5 (edited)

Re: 1977 reed kit questions.

I'll take a picture and get a portmap Saturday, or maybe tomorrow if the snow is not too bad. Either way the weak-ends sidebleed has a super long tuned length, I think like 32-33in, and a pietcard 2013 can't rev past 10k. It won't rev too far anyways and the pipe doesn't over rev at all, not even down hills. Hits around 5 and pulls hard though.

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