[ElekVins]

Hi,

I recently mounted a magneto on my 67 shovel and went for my first long ride last week for the Linkert Attacks (France reunion of Old Iron motors).
The morning before leaving I had to clean my carb because no gas was coming to the cylinders. After that it started fine.
The bike idle very well, and revs very good too.
Then, while on the road at high speed, maybe at 3500 or 4000 rpm, I have breaks in the acceleration, with noisy "Bang!" from the motor usually 3 or 4, and then the bike runs again very well for 1 or 2 miles, and again several Bang!
I also noticed that my chrome exhaust changed colors and turned purple, especially near the end of it...

Does it sound like a carb or ignition problem to you guys?
What direction would you look first?

Vins

 

[ElekVins]

Sounds like an intake leak.

Ok, thanks, I'll look in that direction first.

That what it sounds like ....A leak or super lean carb mix...

If you pull the spark plugs and look at the porcelain....
How white is it...???

What do you mean by: "super lean carb mix" ?

ok, I will take off my plugs and tell you how they look

Elekvins!

Please bubble-test your manifold as discussed at http://virtualindian.11techleaktest.html.

When the manifold proves air-tight, we can go on to other concerns.

Good luck!

...Cotten

Thank you Cotten, but the link doesn't seem to work anymore....

 

[ElekVins]

^^^^^^^^^^^^^^^^^^^^^^
link works, thanks

 

[ElekVins]

Another way to detect a leak is at idle spray some carb cleaner around the intake seals....If you notice a diff. in the rpm of the motor...Got a leak.

The first test bein' a little difficult right now for me since I don't have the appropriate tools, I'll try this other test first...

What should I expect while sprayin' around the intake seals (if I have a leak) ?
Increase or decrease of the rpm?

 

[ElekVins]

ok
don't know yet for the plugs, worked all day, could step into the garage (it's midnight here...), hopefully tomorrow

 

[ElekVins]

I think you guys nailed it once again !
First of all I went looking for a carburetor cleaner in the auto store, it was for sale in the "performance section" of the shop at 29,90€.

I thought "fuck that it's expensive!"
So I left the store and went to a store for garden where they sell chainsaws and Land mower.... exact same spray, same size, same brand, etc: 11,90€ !!! Bang
Funny
So anyway, I've got a leak at the front cylinder admission pipe, the rpm drop when I spray at idle, and if I spray a lot, I even managed to shut off the engine


What do you guys recommend ?

 

[ElekVins]

Yep, thank you, that's my dancing shoes: Dr Marten's 10 holes

I'd love to have the money for an S&S instead of that japanese stuff... maybe some day...

I did put new seals about 1000 miles ago, so I assume they are ok, do they happen to move or something? I'll take the whole thing appart tomorrow, was in a hurry today.

the brace that hold the pipes has this screw and it seems a little weak, maybe this is fucked up, cause I couldn't tighten it stronger...

 

[ElekVins]

"I did put new seals about 1000 miles ago, so I assume they are ok, do they happen to move or something? I'll take the whole thing appart tomorrow, was in a hurry today".

Head alignment possibly?

Jerry
Rhode Island

Do you mean my head aren't in line ?!?!!??
Or just the admission pipe that could be twisted?

 

[ElekVins]

^^^^^^^^^^^^^^^^^^
Thanks, I see more clearly, what's the angle on that ruler, between both admission port?
Those clamps seems great, probably more efficient indeed than mine !
Gotta upgrade i guess...

 

[ElekVins]

30⁰ , are you certain? looks like 90⁰ to me

Hmmm... seems to me 90° is on the other side of the ruler....
So 30° seems ok....

 

[ElekVins]

Right on the 60° !
Yes we still have this guillotine, the blade is just a little rusted from not been used for about 2 century, should be perfect cut ...
Yes I have a bracket to hold my carb.
New seals ordered...
I'll let you know how it goes when installed

 

[ElekVins]

I dismantled my admission pipe (67 shovel) and have a question regarding the seals, are the rubber seals mounted on my bike regular ones or are they wrong?

 

[ElekVins]

Well...

They was New Once.......A long time ago...???

How do you check if they are still useable?

Why are they round? wouldn't they be more efficient if they were square?

 

[ElekVins]

Will the later style oem 27062-78 fit? Would that be an inprovment?
Why is that for 1978 to 1985? What's the difference with mine (1967)?

and what about this kit?

Is that the kit Dragstews mentioned in post #21 ?

 

[ElekVins]

Not sure to understand what is "stroker .200 taller cylinders" but I don't think mine are...

Don't think you have a stroker.....Those rings take up the space between the head ports when taller jugs are being used....
Being the jugs are on a 45 degree plane from one another, when tall jugs are installed, the head ports move away from each other....Hence the need to fill the gaps..or a longer intake ( admission pipe )

If I understand everything well, the best way to go for me would be to get
VT No: 35-0411 in addition of VT No: 35-0409...?
Is that correct?

Vins

Yes that's the ticket....^^
As said before about the gap.....IF....you have very much of a gap with the conversion rings, you could use one of the stroker rings to get a more perfect fit.....

Well.... Poo

Looks like I screwed up your post somewhat. (Ain't the first time I've done this....But I am getting a little better at it..)....
Please hit the edit box and re post your photos and comments....
Thanks...Jesse

 

[ElekVins]

So I installed these clamps

but I still have the same problem. (maybe I installed them wrong ? seeing my skills, it's possible !)

I figured I could post a video of my problem, maybe it'll explain my problem better and someone here will know what's goin' on

The sound isn't great, but in this video my problem appears at second 16, second 29 and second 36, you can see little cough from the carb and hear it if you pay attention. (in reality the sound is way more hearable)

 

[ElekVins]

I think i have a Keihin carb. Is it the same thing as a bendix for the jets?



To be honest I'm not impressed with these clamps, but maybe I didn't install them properly. When I spray the cleaning stuff near the admission it still turns off the engine. Should it be totally sealed or is it normal for it to let air pass thru when you spray right on the clamp?
I first install them with one adapter ring on each side, then 2 (one on the pipe, one on the cylinder) but it didn't change a thing. Should I put three on each side? (there is 6 or 8 of them in the pack)

PS: Yes Jesse, I puted those dancing shoes specially for you in the vid

 

[ElekVins]

if its popin out carb your runin lean, popin out exhaust your runin rich foulin plugs check plugs

My pipe turned blue from the head to the silencer around the same time the problem appeared, does that mean anything according to this ?

 

[ElekVins]

Does it get worse the longer you ride?

Not really, when I did the video, engine was still cold, it was started since 1 mn or 2 only.
It happens also when the engine is hot.
Doesn't make a real difference in fact.

Are you thinkin' about the valves?

 

[ElekVins]

Also the air cleaner could be a bit restrictive...causing a rich mixture...
Might want to service the foam element...

Just changed the foam (previous one was burned by the back fire of the carb)