New build, New Problems

Im currently building a Frankenstein bike. Its a Sachs Eagle 1 frame, 505/1D bottom, Airsal 70cc kit, Dellorto SHA 15 (72 jet), and an MLM Intake. It's gonna be a top tank conversion... already built the seat and have a '73 Kawasaki tank. So before i strip the whole thing, deep clean, and paint, I wanted to put it all together and get it running because every time I paint before working out the functionality of the bike, i end up jacking up the paint and needing to change things. So its kind of a pile of junk all strapped together with zip ties at the moment ha - but it's enough to get it going and test some things out. Biggest problem is the wiring. I still don't have an exact diagram for the Eagle even though i found one titled "Eagle Wiring Diagram" but its not quite exact. This is a total birds nest, but i think i have it laced up pretty close to correct. So here we go. Kick it over and it starts up. Idles well surprisingly. The issue: it does not go over 5mph ha. Jumps off the line all quick then just hits a wall no matter how much throttle i give it. Im confused by this... Clutch? I just took the clutch apart and it looked good. It had a broken pad so i switched that out... Just not sure why or how that could be it... Maybe grounding issue? honestly couldnt tell you if this things grounded properly, did my best, but again its a total nest and things are out of order... ugh. Id be surprised if its the jetting cus its close enough to idle well... Carbs brand new so its not that.

Who's got some ideas?

Re: New build, New Problems

Is your timing good?

I've had that happen because of extreme over jetting and really fucked timing

Rough up the clutch pads and make sure it's all together OK

Re: New build, New Problems

♣Slew Foot♣ /

Decomp leak. But it's kitted. Piston not in right or too tall cutting off af...

Re: New build, New Problems

I remember setting the timing to stock... maybe I need to adjust that since the kit, or I jacked it up somehow. I couldnt do a plug chop or anything but i did check the plug to make sure it wasnt fouling or anything. It looked ok so i didnt think it was like a crazy over jet, but ill knock it down to a 68 n try that. Did not scuff up pads so im gonna try that. The decomp was spitting from the start. The little set screw that comes with the kit doesnt work at all so I put a bolt in there and sealed it up... but that little hole on the opposite side of the decomp is dripping. not sure what to do with that. I'll check the piston n make sure it's all good. Let ya know what happens! Thanks for the advice!

Re: New build, New Problems

♣Slew Foot♣ /

There's a m and I on the fly but it would be off due to the non angled head look up the mm difference to set the meter and use a depth gauge in the head.

Re: New build, New Problems

I knocked down the jet size to 68, im sure it was a bit rich, but that didnt really help. The timing is set to stock but i didnt take into account the non angled head so ill try that. It makes an almost clanging sound... Wish you could post video straight to this site without having to do like a youtube link.

Re: New build, New Problems

Just adjusted the timing... not effecting the issue somehow. sounds like the piston is just banging around in there. how would that happen? The piston obviously fits the cylinder, I slid it in there no problem with the rings correctly positioned, and the kit is made for the sachs...what am i missing... ?

Re: New build, New Problems

♣Slew Foot♣ /

D crank a piston bottom dead center or tdc the knock

The piston skirt is hung at bdc cut a notch there in the skirt so the Conrod don't knock.

Re: New build, New Problems

so im pretty terrified to cut up the skirt since the last time i did that...things went wrong. I really cannot afford to mess this up. So I posted a video of the sound. Scope it out n see what you think. if it still seems like the skirt is the issue...we'll need to talk details

Re: New build, New Problems

ewww. that sounds awful. sure the piston isnt smacking the head? did you measure the squish?

Re: New build, New Problems

Kit says its .8mm, but my readings are all over the place. I tried going in through the spark plug hole at an angle and it said anywhere from 1.25 to 2.25 depending on where i placed it on the wall. then i took the head off and laid a thick 3mm piece of solder in there and could not for the life of me kick the bike over to squish it. then i put a 1mm solder in there and it didnt even touch it. I really thought that may have been it cus its sounds kinda like its hitting or something... what are they issues you'll see if the squish is too large?

Re: New build, New Problems

If your on the cylinder wall with a 3mm piece if solder and its not touching when you crank it a few times then thats pretty bad.

You can always test compression with a tester, also post pictures of tdc and bdc so we can see if your ports are opening.

Is your throttle slide opening all the way? did you change out the crank seals? instead of going down on jetting id go up, you can test by choking the carb a bit and then try to rev up the motor. Timing first though( wanna say sachs are timed stock something crazy advanced, you might wanna triple check this) then compression, fix decomp, change seals, brakes, lube bearings, etc etc etc then paint.

Re: New build, New Problems

> pat splat Wrote:

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

> Timing first

> though( wanna say sachs are timed stock something crazy advanced, you

> might wanna triple check this)

Totally true, the mark on my 504 was at 21* btdc

Lapping the flywheel and putting it on without the keyway helps a lot in the department

Re: New build, New Problems

Oh what i meant was, when i put the 3mm solder in there, it was too tight to squish it. Like it just stopped when it hit the solder... couldnt turn the engine over. I think it's around 1.5...maybe? Which should be too large, but wouldnt that mean id have poor compression? cus this thing definitely has some strong compression. I guess im saying i cant get an accurate reading like the videos ive seen on it.

Throttle slide is good, carbs new and so is the cable. did not change crank seals... I think the 72 jet is the highest i currently have, so id have to order some new ones to check that. The timing... Sachs timing some how does not compute for me.. I have it set to stock. Really do not know what this thing wants for timing. No idea if im just burning it up trying to get it to work for me cus it feels like im shooting in the dark with it..and maybe im trying to solve this problem by messing with the timing when its actually fine. I just cannot figure out this noise. I swear it sounds like its coming from the near the flywheel...but that could actually be the crank seals... something busted in there and maybe the crankshaft is just jumping around in there. I'll send some photos tomorrow though. thanks for the advice!

Re: New build, New Problems

That noise would have me tearing the motor down to find what was making it .

Just like building anything : Start at the bottom and work up .

No sense building a great roof on a base of mud .

Insure good bearings and seals , as without these there can be no proper transfer of fuel .

Compression is next , as with out that there can be no boom .

Then , set timing .

Last comes carburation .

Re: New build, New Problems

Ok, I opened her up. Other than some seals looking rough and this needing an obvious cleaning, I am not seeing a reason for the noise. Im buying a seal and bearing set on Treats... just worried that im going to put it all back together and have the same issue. Posting a bunch of photos... please let me know if anyone seeings anything amiss here that im not seeing myself. The front sprocket is welded on. I did not do this haha. I made a separate post about that before, but yeah, wont be able to change that seal...like ever.

IMG_4740.jpeg
IMG_4742.jpeg
IMG_4743.jpeg

Re: New build, New Problems

more photos

IMG_4744.jpeg
IMG_4745.jpeg
IMG_4734.jpeg

Re: New build, New Problems

Not sure if anyone is still checking this...but now that i have the engine disassembled, I am trying to figure out the clicking/knocking sound. Looking at the piston. These videos are of skirt and ports...there is no gasket on the head. Is there where things should be sitting/lining up?

Re: New build, New Problems

Uhhh your piston looks to be upside down... arrow should be pointing towards the exhaust port. That would be a huge reason why you couldn’t get above 5mph

Re: New build, New Problems

Ha, this is just a test. It was on the right way when it was actually assembled. just looking at spacing right now. Good eye tho! (edited)

Re: New build, New Problems

♣Slew Foot♣ /

Did you hear that slight tap about 3° bdc that's the Conrod arm tapping against the piston skirt at bdc on the exhaust side I think...

I had an a cyl. And a d crank it had just about a pencil width notch in the skirt about 1.5mm in depth arched.

PO was a dirt track guy who rigged it.

Re: New build, New Problems

♣Slew Foot♣ /

I will check the pile I got to see which side was notched.

Re: New build, New Problems

Thanks Slew Foot, that'd be great! I also noticed it sort of snugging up at a couple points. nothing i cant easily push through, but how freely should this thing rotate? should there be no resistance at all?

Re: New build, New Problems

For starters that crank is probably shot. Your bearings and seals are junk too.

When you see the rusty water line on the crankshaft, it usually means it's toast. The kits are all designed for D cranks so you're best bet is to replace it with a new aftermarket D crank

Re: New build, New Problems

I already ordered the seals and bearings, they're on their way. Unfortunately, i will not be able to afford a new $200 crank... just gonna have to clean this one up the best i can. my budget is just maxed out as is...

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account