Ironhead 75 Ironhead cafe racer reboot

[Iron Mike]

Take a closer look at your rear motor mount. In the pics it looks cracked. Could be just the pic.
Common area for cracking, near right side upper rear motor mount bolt.

[sifty]

Yeah small crack there. I noticed it and decided to ignore it for now. Will keep an eye on it...

[sifty]

Did a little tonight, replaced the clutch nuts with new nylocs (couldn't find the ones I'd bought so got some new ones) just snugged them up against the spacer tubes one at a time...


And fitted the primary cover after cleaning it up and fitting a new gasket, also cleaned up the threads on the clutch cable adjuster...


Gave the clutch a rudimentary squeeze, quite hard at the lever, I did use heavy duty big twin springs in the new clutch spring housing so that may be the difference? Plus there is no oil in it yet, it's not adjusted, and the clutch may need a few operations to loosen up, we'll see how things go...

[brucstoudt]

Originally Posted by sifty

Gave the clutch a rudimentary squeeze, quite hard at the lever, I did use heavy duty big twin springs in the new clutch spring housing so that may be the difference?

great deduction with the big twin springs.that was a mod used with the dry clutches from the 60's.i had 3 big twin springs in my dry clutch years ago.all 6 would be a bit much i believe.for the record i removed the 3 big twin springs in my clutch several years ago and replaced them with new oem XL springs.if i can keep my dry clutch dry i shouldn't need the big twin springs again.

[Ferrous Head]

Like everyone else I tried the 20% stiffer Barnett Springs. And discovered not only was the clutch pull a bear but it bent my worm arms.

Not sure if the later ramp version has that problem but the pull will be harder.

[sifty]

Had a busy couple of days, adjusted the clutch and it felt slightly better, but still not releasing completely, hopefully it'll shake loose with some oil in it and the engine running...?

Fitted the starter housing and was installing the angled oil tank bracket when the vented bolt snapped off, inside the case. Luckily was an easy extraction as it already had a hole drilled through it...


Debated fitting a solid bolt but it's not an easy thing to replace without pulling lots of gear off again, so decided to make one. Machined a nozzle out of brass...


And brazed it into a drilled bolt...




Fitted it and carried on, bit concerned that the solenoid bolts up on an angle...?


But decided to carry on, it was a stinking hot day so my apprentice (Jagger the border collie) found some shade for a snooze, while I got sunburnt...


Installed all new oil lines, fitted tank, battery tray, battery and connected starter wiring...


And oil was getting to the filter when I kicked it over, thought I was close to cranking it on the starter...


Except nothing happened, apart from a click from the starter relay...

[sifty]

Slept on it as I couldn't face pulling everything out again. This morning I confirmed the battery was fully charged, and tested the solenoid in place by connecting 12V directly to the pull in coil, still nothing, so (sigh) pulled everything out again...

Bench tested the solenoid and it was definitely working OK, both the pull-in and hold coils worked perfectly, better than the old one I tested beside it. I wondered if things were binding as it was on an angle, so tried it with the solenoid nut as a spacer, looked much better...


And it seemed to work better. I pulled the starter gear shaft out and ensured the thrust washer was in place, and re-installed everything, with thick washers as well as the spacer, it definitely looks better aligned...


I'd removed the primary cover and checked operation, a solid clunk as the gear moved in and out on the starter button, which was a relief. Unfortunately the starter motor didn't spin, it was getting power and spun ok on the bench so not sure what the issue is here, maybe something is binding...?

Carried on with other stuff to make some progress, fitted the chain to help spinning the engine when adjusting the valve clearances, and discovered the new sprocket cover hit it (couldn't even get cover on). Ground out a bit of material for clearance and fitted cover...


So getting there. The starter is a worry but everything works in isolation so must be solvable. also welded up the broken tank mount so another job ticked off. Still got carb to fit, ignition and valves to set, clutch to sort and general fettling, but feels like I'm getting closer...

[sifty]

Nothing much to report, just had other stuff happening. I did pop out to the shed to look at it and was dismayed to see it'd dropped all its oil all over the floor. A bit discouraging and bloody messy so I just ignored it for a while...


Wheeled it out today and cleaned up the floor, and tools, and everything else that had been rust-proofed. Checked my oil line connections, drain plugs and oil filter etc, nothing obvious so I assume it leaked out the clutch cover, which was a bit loose, a worry if so as it seems it's still collecting oil...


But a bigger worry is that the starter still isn't operating. The solenoid is banging in with a hearty clunk, but the motor does not spin. I know the starter works as it spins well on the bench, even tried connecting another battery in parallel but same result, so it's not a low voltage issue.
Tried measuring voltage at starter terminal but it goes to zero when trying to start, so measured current, it's drawing a decent 26A DC, so the motor is trying to run...


Can only guess it's mechanically binding somewhere? Kicker spins engine ok, so unsure where to look next. I'll open the primary cover next time I feel enthused enough to look at it...

[Ferrous Head]

the clutch cover, which was a bit loose,

Loose enough that the shaft going into the bearing in the primary cover might be binding?

[PoodlePunche]

sounds like a bad starter to me.
will spin on the bench, but not under load.

does it make any noise other than the clunk (I assume that's the bendix kicking out)? like a hum or buzzing?
would be worth having it tested