Probably ruined my new 78 Pinto, but in what way...?

Hey guys.

I haven't been to these forums in almost 10 years. I gave up the hobby for a while, but I just moved to sacramento and I needed an easy, reliable (ha!) way to get around, saw the bike on Craigslist, and bit the bullet - bought a 78 JC penny pinto II, and had the poor thing running like a dream for about a day.

When I went to pick it up, I filled it up with two quarts of premix on the spot. It ran great, idled great, thing looked fine, price seemed reasonable. I bought it, drove it to my brother's house about 6 miles away, hung out for the night, then set out in the morning to drive the 13 or so miles back to downtown Sacramento. I started to run out of gas on the way back - or maybe I just thought I was, maybe it was just stalling for a different reason, but - I figured, I remember how to do this, I'll just gas up and get back on the road. So I pull into the gas station, grab some oil, and then quickly google what octane gas I should use in the bike. First result says Premium, I barely skim through it, figure I'm fine. I fill the thing up with a gallon of premium, toss a couple of capfulls of oil into the tank, shake it up a bit, and get back on the road.

Obviously I made it like, 15 more minutes down the road - and that was probably only because It was burning through the rest of the premix - before the bike gave up the ghost. It was right when the thing was starting to run it's fastest too, it was going about 45 - so I imagine the thing was heating up pretty good thanks to the premium fuel, on top of being starved of oil.

Thing is, I'm not sure what happened. I thought I seized the engine at first, but, having pedaled it back to my brother's garage and poked at the thing, it seems like piston's moving perfectly, and from a cursory thumb check, the engine seems to have ok compression. I haven't pulled the whole thing apart yet, because I'm real rusty when it comes to this stuff, but having heard what a fucked up engine sounds like on one of these, compared to what I'm seeing - I think it's still OK.

So then I started to think maybe I was lucky enough with the amount of premix I had and the amount of oil I mixed that the thing wasn't running dry, and that wasn't my issue, maybe it was an electrical issue. So I checked, the spark plug was rusted all to hell but I replaced it and checked the electical and it all seems A'OK. It's sparking fine, and I don't think the timing suddenly got fucked up while I was driving it so fast, but I don't know.

The carburetor seems clean and functional, too - though it looks like the one I had on my old Garelli, and not at all like the one on any others I've seen online for this bike.

Also the thing's got no air filter at all - just a bit of stocking over the hole. But that's how my old one was too, if I recall, and that wasn't much of a problem.

so, I figured maybe the premium fuel just overheated it, and it blew a gasket on the engine from getting too hot and now all I'm getting is because I've got low compression? but it should still be turning over occasionally, if that were the case, right? the lights will flicker on when I pedal like a madman but the thing just doesn't even begin to fire up.

I don't know, this thing was regularly maintained by it's previous owner - it was mint and great and I just feel like such a fool having been so cavalier with it right after I got it. I haven't messed with one of these things in so long, and while it's been fun to take it apart and poke at it a bit this evening, It was perfect yesterday and now it's another project bike. I don't think I've done too much damage, I'm sure I can fix whatever issue this is OK, but.... I'm gonna need some help. Any advice?

thanks!

Re: Probably ruined my new 78 Pinto, but in what way...?

Take 20 mins to take off head/cylinder, check bore, piston, rings, and post pics. Inspect head, base, exhaust, intake gaskets to see if any blew out or were leaking. Before you do that though, take carb off intake, note if it is on there nice and snug before you do so, and remove float bowl, check to see if jet is clear. What is the setup and what size jet is in there? If you were doing a true 45 then it is likely piped and/or kitted, and should be upjetted accordingly. Timing could be an issue as well.

Just make sure you are carefully inspecting everything upon disassembly, it will tell you what happened if you keep an eye out for the evidence of what caused it to die.

Order all new top end gaskets and temp gauge at the very least, and if you’re lucky, the cylinder, piston, rings, are unscathed and all you have to do is a quick top end rebuild.

Re: Probably ruined my new 78 Pinto, but in what way...?

You say it was maintained by the previous owner, but you also say the spark plug was rusted to hell. That could be your answer. Clean the carb, poke fishing line in the jet holes to give it a good going over. Service and set timing. Head off to check cylinder and piston/rings. Check gaskets while there. I take it you've got fuel flowing from the tank?

Re: Probably ruined my new 78 Pinto, but in what way...?

Premium fuel did nothing to contribute to the issue you're having. Premium fuel doesn't burn hotter, it has a higher resistance to pre-ignition (which is useful in high compression performance ignitions). The reason most mopeds recommend regular fuel is that they don't have a high enough compression to require high octane fuel. Do a compression test.

Re: Probably ruined my new 78 Pinto, but in what way...?

Jack Rutherford /

They generally run their fastest when they are running out of gas. Even though you just got gas, I bet your gas tank is rusty and something blocked the fuel flow at petcock or somewhere else down the line to the carb.

Re: Probably ruined my new 78 Pinto, but in what way...?

Try to condense things man, I look at a wall of text and just move on.

Re: Probably ruined my new 78 Pinto, but in what way...?

> DPC Ryan Wrote:

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

> Try to condense things man, I look at a wall of text and just move on.

I dunno man, I like a good back story sometimes when the poster makes the effort for punctuation and grammar.

I agree with some of these other responses:

Check fuel flow from petcock and venting from gas cap. Sounds sort of like a fuel starvation problem. That or the main jet got clogged with rust or sediment from the tank. Remove the carb for cleaning and check the fuel in the float bowl for signs of rust or dirt.

If you don't trust the gas that's in there just drain the whole tank and replace with premix. If you drain in a clear container you'll be able to get a sense if the fuel has a lot of rust particulate in it. Is there an inline fuel filter? Add one if not. High octane should not be a problem.

Best bet would be to pop off the top end for inspection and to replace all the gaskets for peace of mind. But if you don't have time/tools then at least run the usual air leak tests to rule those out as well.

Good luck!

Re: Probably ruined my new 78 Pinto, but in what way...?

Maybe if all the above fuel/carb stuff checks out try cleaning points or a fresh condenser?

One of my old bikes would take a dump at running temp. Ran great then got warm and soon sounded like it was wheezing out the carb and backfiring then quit. 15min cool down and it would start up again easily, warm up and crap out. Just needed a new condenser.

Good luck!

Re: Probably ruined my new 78 Pinto, but in what way...?

Connor Winter /

> DPC Ryan Wrote:

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

> Try to condense things man, I look at a wall of text and just move on.

> DPC Ryan Wrote:

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

> Try to condense things man, I look at a wall of text and just move on.

Hahahaha it’s a paragraph, it takes a minute to read. He gave good info instead of saying “ my ped died and I’m not sure why, help!” so why act like he’s causing an inconvenience? Help him out or don’t post(:

- throw an air filter back on, same thing happened to me,sold to me without an air filter and my dumbass didn’t notice cause I️ was a goon, I agree with what the others are replying with too( no need for me to state what they said again). Good luck man!

Re: Probably ruined my new 78 Pinto, but in what way...?

first post in 8 years, w/b.

Diagnostics, rather then blindly tearing apart something and introducing more issues, i'm glad you didn't "dig in and pull the whole thing apart"

you mentioned low compression, subjective? it's not uncommon to overheat the piston and damage the sealing of the rings, couple approaches to verify this.

compression tester, because of issues with small displacement motors, either comparing to baseline numbers using the same tester under the same conditions, or comparing to a known good motor are the only useful results.

eg, with this tester, example, your listed TFR has 70#, the puch 50#, inconclusive. (automotive testers give notoriously low results)

pull the exhaust off and look up at the piston while turning the motor, make sure the rings are loose in the grooves.

fuel starvation, remove the carb, take off the float bowl, if you don't tip the carb, look what's accumulated in the bottom of the bowl for fuel health, clean accordingly.

let the gas run into a container, decent trickle? at 45 mph, it takes hours to burn a tank of gas so not much flow is needed.

besides compression and fuel (you said good spark) an air leak will prevent fuel from being drawn into the motor, example a crank seal popping out. add a dribble of gas to the plug hole, install a good, dry plug, and with fuel shut off, try to start.

exhaust off, as the gas could run right out of the motor if the exhaust port is open, try a couple times and check the plug for any color / carbon for signs of burning.

trying to start indicates an airleak or carburation problem.

Re: Probably ruined my new 78 Pinto, but in what way...?

pull the petcock out of the tank and clean the filter off.

Then order the tool from treats to pull the Bosch flywheel off also get a new set of Bosch points and a condenser you will probably end up discovering that you have rust Pits on the cam lobe of the flywheel this will wear down the cam follower on the points there for the points will close up retarding the timing which works good for high RPM combine that with a weak condenser heating up and failing and you get your problem fuck the grammar you're just getting this information in one long sentence

Get some white grease for brakes lithium grease is what it is make sure you put a little fat on the cam lobe that makes the points open and make sure that if you have rust pitting and it's on part of the cam lobe that happens while the points are opening your flywheel is a paperweight and you will need a new one set the points at 16th AO and time it at about 18 degrees and you will be fine fuck you can 18 degrees is fine he's running a stock carb don't listen to Ken he's full of shit so you want your points to open 1.4 mm that's how far the pistol be from Top Dead Center you can just stick a piece of cigarette paper between the points and when you get to that point they should just slide out that'll put you read about 18 degrees you should also post a picture of this bike that you got somebody on here probably knows the history of it or what problems that had that the previous owner dumped it on you for chances are it's going to need crank seals and another thing that'll make the bike hard to run and start is too large of a spark plug gap you want to get that puppy down below 0.020" but not smaller than 0.019"

And when you pull the petcock out of the fuel tank the little plastic screen will unscrew or pull off when you have that removed you'll see a little tube sticking up in there that's for the reserved portion of the fuel tank I suggest cutting it in half and add a 30 degree angle the newer gas with alcohol in it has a different tension in the liquid and it creates a resistance to flow that is greater so make sure that your fuel line hasn't shrunk because if you do run out of fuel you'll find that you may have to actually blow into the gas tank to get the flow started once you have a connection of fuel with no air bubbles the fuel will flow find another thing that happens quite often is the fuel cap gets rest that tends to block the fuel cap the bike will run fine when you first take off but the outside of the tank cools off and creates a light vacuum within the tank then the fuel stops flowing in the bike quits running so you want to make sure that the fuel cap is vanting many folks will take and drill a small 16th hole through the side of the cap to the underside not to the top to be sure that it is venting properly I also suggest you get an air filter of some sort can will jump in here and tell you to get the blah blah blah metal screen filter yeah that's okay it works but anything on there that will stop the rocks and sand and bullshit that the chain and rear tire is going to be throwing into the carburetor because if that happens you're going to end up with score lines in your cylinder and low compression anyway be sure you post some pictures of the bullshit and I would also take a small stick and put a little rag on it with a zip tie over the end and rub it around the bottom of your tank and see how much rest and shit there actually is you may find that you're going to need to clean your fuel tank if you don't the rest will break loose and you will be doing the rinse and repeat bulshit of everything and replacing your fuel filter repeatedly that is if you actually have a fuel filter in line to the carburetor and a big indication that you have rust in the fuel system is the fact that the porcelain on your spark plug was Rusty that's not a good sign the other thing that could be causing this is water got into the engine because the dipshit had it out in the rain last so if you end up pulling your cylinder off and you notice that there is rust on the crankshaft itself then your bearings are pretty much fucked so you might as well just order a new crankshaft from treats get the stiffy whatever crank new bearings new seals and be sure to get a INA rod bearing for it because the one that comes with that crankshaft ain't the best.

And when you put the cylinder back on make sure that you slowly tighten the bolts in a Criss-Cross X fashion bring it up one pound at a time and stopping at 7 foot pounds if you go past that and stretch the studs well will just call you a dumbass so be prepared to get flamed here and there but I think I gave you enough information that you can do this without having to repeatedly wipe your ass so good luck get the shit you need get the thing running and maybe you'll have something Dependable to ride maybe you'll just be one of those poor SOB's they can't get the fucking cap back on the toothpaste tube I don't know what your skill-set is but good luck have fun

Charlie

Re: Probably ruined my new 78 Pinto, but in what way...?

0.023" to 0.019" on the plug gap.

1.3 mm to 1.4 mm on the timing that should put you between 16 and 18 degrees Max BTDC

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