Need some advice with my first bike project - Custom 1974 Ironhead Sportster

Sutherland

Sutherland

Club Member
As you can see, the bike is an interesting thing, American Ironhorse Forks, Bendix carb but with a Linkert cleaner (from a 40s Knucklehead??), big old oil tank (also knucklehead?), aftermarket oil filter, non-stock rear mudguard with no brake light, no idea where half of it came from but it's a runner and I got it for 1300 bucks so why not have some fun. The plan is to tackle all the oil leaks and any mechanical problems first, buying good parts, doing it right, doing it once, but keeping the aesthetic cost to a minimum until it's roadworthy.

I've sorted the tank, cleaned and back to black. Got a speedo and tachometer systems and front mudguard but the front mudguard doesn't fit the forks, I guess spacers will have to do.

Need to find an air filter that'll fit, this is the only one I can find that has the same shape as the air cleaner: https://bit.ly/49OiXwC .

I need to decide what to do about the rear mudguard and break light, there's only one light on the rear light currently and the front brake doesn't activate it, the current mudguard is wrecked and doesn't seem to fit well. I was thinking of getting or making a custom or an old stock one. Any suggestions for a custom mudguard set up?

Not sure if it is worth keeping the oil cooler, cooler oil means better lubrication and longer lasting parts right? But is it necessary in the UK weather?

Planning to make and weld a dipstick to the cap but I will need to work out how much oil will be in the system with the oil cooler cooler and filter and bigger tank. I know the filter is aftermarket but I'm unsure of the oil cooler, no mention of it in the parts catalogue or service manual. On a stock bike, the low mark is 2 quarts, the high mark is 3 quarts. is this a big deal? Any idea how I should work this out?

The big thing is, I'm probably going to rewire the whole thing, the electrics do work but they're jerry-rigged, seems straight forward but I haven't done much electrical work before so might be challenging, any tricks much appreciated.

Finally, what is that thing that has snapped off the photos??

When I test rode it it wouldn't go into neutral, I hear that is a clutch adjustment issue. Also will need to adjust carb, youtube should help with that.

I have done a fair amount with old trucks and cars but assume I know nothing! I've never worked on a bike or a carburetted vehicle before so any knowledge will help.

Cheers!
IMG_4253.JPG
IMG_4690.JPG
IMG_4691.JPG
IMG_4259.JPG


IMG_4386.JPG


IMG_4713.JPG


IMG_4714.JPG


IMG_4715.JPG
 
Someone in here posted a basic loom diagram in here recently for one and a couple of the lads have done similar aged bikes up too recon they will be along in a bit 👍 seem to remember a 5 or 6 inch k+n available to fit what hanging brackets on the carb or filter ?
 
Is the bit that snapped off the bodge for the rear brake light?
Looks like you will have some fun with that, the wiring is pretty simple on the ironheads, so no panics on that score.
You will need to decide what you want from the bike first, then work out how to achieve that within your budget.
One thing you will need is a carb support bracket, when I got my first one I did not realise they should have one.
You look and feel like a right dick when the bloody thing falls off --- :rolleyes:
 
First thoughts are oil cooler, iron Sporties do run quite hot so yes for summer but will need a cover for autumn/winter, poorly adjusted primary chain can also affect finding neutral but even correct it is usual to practise snicking it in neutral before you stop and lastly ditch that rear tyre, especially in the wet.
 
I think the oil tank is an aftermarket one, the Knuckle one had it's filler centrally at the top, front of the tank. To see how much it holds fill it a pint or half litre at a time and mark up your stick as you go.

3 American Quarts is almost 5 imperial pints so extra oil in the filter and oil cooler is always good and the cooler will come into its own if we ever get a summer or you get stuck in traffic. I'd top up the oil before it got down to 2 Quarts ( 3.33 pints). The lower the oil the hotter it will run and the more oil it will use. There are no valve stem seals unless they have been fitted later. The Factory and various other people did supply oil coolers but without a name on it you're guessing.

The two fender rails which support the mudguard look to be from a Big Twin, the Sportster ones were shorter and straight. Loads of pictures on line. The mudguard could be from the Shovel Wide Glide or aftermarket along with the rear light.

The rear break light switch is mounted where the rear chainguard rear mounting bracket would have bolted to. The original would have been mounted to the swinging arm forward of the suspension unit and clamped round the rear brake rod as yours is but further forward.

When I adjust my clutch (1980 Sportster) I give it a bit less clearance at the chaincase and at the hand lever than the books say so as to get maximum lift to free it off and I can get neutral at a standstill.

The very best oil for the gearbox and clutch that I've found in 44 years is Spectro Heavy Duty Primary Chaincase Oil. The first time I put it in the change was better and better still after the second fill.

And on a lighter note if you happen to see Tim on here decrying our fine Sportster motorcycles it's only 'cause he's jealous;).
 
Oldguy said:
Is the bit that snapped off the bodge for the rear brake light?
Looks like you will have some fun with that, the wiring is pretty simple on the ironheads, so no panics on that score.
You will need to decide what you want from the bike first, then work out how to achieve that within your budget.
One thing you will need is a carb support bracket, when I got my first one I did not realise they should have one.
You look and feel like a right dick when the bloody thing falls off --- :rolleyes:
Click to expand...
I'll see if I can find a bracket that will fit. Cheers.
 
Ron said:
I think the oil tank is an aftermarket one, the Knuckle one had it's filler centrally at the top, front of the tank. To see how much it holds fill it a pint or half litre at a time and mark up your stick as you go.

3 American Quarts is almost 5 imperial pints so extra oil in the filter and oil cooler is always good and the cooler will come into its own if we ever get a summer or you get stuck in traffic. I'd top up the oil before it got down to 2 Quarts ( 3.33 pints). The lower the oil the hotter it will run and the more oil it will use. There are no valve stem seals unless they have been fitted later. The Factory and various other people did supply oil coolers but without a name on it you're guessing.

The two fender rails which support the mudguard look to be from a Big Twin, the Sportster ones were shorter and straight. Loads of pictures on line. The mudguard could be from the Shovel Wide Glide or aftermarket along with the rear light.

The rear break light switch is mounted where the rear chainguard rear mounting bracket would have bolted to. The original would have been mounted to the swinging arm forward of the suspension unit and clamped round the rear brake rod as yours is but further forward.

When I adjust my clutch (1980 Sportster) I give it a bit less clearance at the chaincase and at the hand lever than the books say so as to get maximum lift to free it off and I can get neutral at a standstill.

The very best oil for the gearbox and clutch that I've found in 44 years is Spectro Heavy Duty Primary Chaincase Oil. The first time I put it in the change was better and better still after the second fill.

And on a lighter note if you happen to see Tim on here decrying our fine Sportster motorcycles it's only 'cause he's jealous;).
Click to expand...
Cheers Ron, very helpful knowledge. I'm confused about what you're saying for making my dipstick. It says in the manual 2 quarts is the minimum and 3 the maximum, so with the aftermarket oil filter and oil cooler, will that be the same? (if I prime the filter). Or should I add a half quart to each value to accommodate the extra oil capacity or something? Also, I'm assuming I should do this on a level surface (due to tank shape) and after it has been ran a little and cooled?
 
Paul P. said:
First thoughts are oil cooler, iron Sporties do run quite hot so yes for summer but will need a cover for autumn/winter, poorly adjusted primary chain can also affect finding neutral but even correct it is usual to practise snicking it in neutral before you stop and lastly ditch that rear tyre, especially in the wet.
Click to expand...
Okay, so it can run too cool?? What kind of outdoor temperatures would I want to use the cover in?
 
I'd say keep it on for very short journeys anyway but as a rule of thumb cover on in weather that you have to wear your thicker bike gear. On the bike in my avatar on seventies helmet protest runs into London my thighs would be cooking like on a rotisseri and neutral said "goodbye, I'm off!". By the way, any advice from Ron is good...but don't tell him I said so.
 
Congrats on a smoking deal. You will certainly end up spending a grand or three on it, but you will learn lots.

I would ditch the oil cooler. Just my view. I'm in Australia, and I removed one that came with my Shovelhead. Just one more thing to go wrong, and certainly not necessary in the UK, unless you are a London commuter, which would be kinda mad on that bike right now.

Get an Ironhead parts manual AND a service manual. Try to get some genuine bits where they are critical .. gearbox, engine, etc.

Others here will know the best parts sources in the UK. Good luck!
 
Because it's not a standard Sportster oil tank the only way to check the capacity is to fill it with something, measuring as you go. It's easier to have the dipstick marked for when the bike is on the sidestand as this way it's easier to check where ever you are with out trying to hold the bike upright at the same time. Fill it on the side stand but keep standing the bike up to check it's not going to flood out the first time you do it.

Several marks on the dip stick are useful as a guide for running a lower oil level (warms up quicker) if you are going to run in the winter.

With the filler on the right hand side there will probably be a big difference between the oil level with bike upright and on its sidestand. On my 1980 bike there is a difference of two and a half pints between full on the side stand and full upright. This has the filler on the right hand side. If you are planning long runs in the summer the more oil in the bike the better. Different Sportsters over the years have had different sized oil tanks with 1979/80 and 81 being the largest with 4 American quarts ( 6.6 imperial pints).

The oil pumps up to around 1975 can let oil pass through when parked which builds up in the sump. Some of this will pump back and some will blow out the engine breather over your floor. This is why the bike needs to run a bit before checking the oil level.

I don't think you will be able to prime your filter at the angle it's mounted at. Look at the oil change instructions in the manual for bleeding some oil through to prevent an airlock after a oil change.

The broken bit is the electrical part (sender unit?) of the oil pressure switch. there should be at least one wire coming from it. Do you have a oil pressure warning light?
 
Ahhh I didn't realise Harley's have dry sumps. Is this that what I'm missing: the tank is supposed to be as full as it can be without overflowing when the oil is hot and that's where you mark your top mark?? Meaning the extra oil in the larger aftermarket tank won't cause a problem?

I also didn't drain the oil when I shipped it from Houston and barely any at all came out the tank so I guess there's a load in the sump - and another problem to diagnose (just a new check valve?)

re- the oil pressure switch - I can't find a dash replacement anywhere for the oil pressure light and whatever else goes on there. I was considering making my own speedometer and tachometer mounts and buying one of these gauge adapters for the oil pressure: https://www.ebay.co.uk/itm/315244959834 . Are these any good?

Also, what I meant about the valve seal job was that I read that you can get a kit for retrofitting valve seals in order to stop the engine burning so much oil. Looking in the exhaust ports you can see a huge amount of carbon build up, I'm considering getting it terracleaned but I'd be worried about causing blowby when the piston rings are cleaned haha. What do you guys think about terracleaning a 50 year engine??
 
Last edited:
Before you buy any goodies, I suggest you check the compression on each cylinder, just to see if there are any issues.
Like some "ladies" I used to know, they looked ok, but you just didn't know where they'd been --
The engines are not hard to take apart (other than the crank) so check big ends if you take the barrels off.
Generally if oil returns to the tank, you have enough oil pressure ---
 
Oldguy said:
Before you buy any goodies, I suggest you check the compression on each cylinder, just to see if there are any issues.
Like some "ladies" I used to know, they looked ok, but you just didn't know where they'd been --
The engines are not hard to take apart (other than the crank) so check big ends if you take the barrels off.
Generally if oil returns to the tank, you have enough oil pressure ---
Click to expand...
"Can of worms" comes to mind
 
I can see why you were concerned about having the correct amount of oil when you thought the bike has a wet sump but it is definitely a dry sump motor.

I think as much oil in the tank as will fit without spilling with the bike upright is the way to go Also make sure the oil level does not cover where the oil returns to the tank and there may be a breather there as well if the tank was made for a Big Twin.

My standard oil tank dip stick has "fill" and "full" marks. So far (95,000 miles) it has never sumped( typed while clutching a large piece of wood) so for topping up and after oil changes I fill to the "full" mark with it cold and fill the oil filter before fitting it. This is done on the sidestand, if I then stand the bike up the oil is right on the verge of spilling. There's never been a problem with the oil expanding from heat and leaking even if I do a 200 mile run just after filling the oil tank.

You will have to work out what works for your tank as you go.

As far as I know the oil leaks into the sump through the oil pump which does have a check valve but many have done this from brand new so a new check valve (ball and spring) probably wont help. There are some other reasons as well. It's well explained on the "Sportsterpedia" web site along with a shed load of other stuff.

A oil pressure light is a must have item, a pressure gauge can scare the pants off you when it drop to zero in hot running. What all Harleys need is a flow gauge just so you know oil is moving round ( I've never found one alas). The Sportster has a full roller bearing bottom end and does not need the high pressure a shell type crank needs. This is also covered on "Sportsterpedia".

The 1970 to 1978 bikes are shown as having a minimum 3-7 psi at idle, a maximum of 15psi at 60 mph in top gear and 4-15psi in normal riding. I don't know if there is a pressure gauge that will read clearly at these low pressures.

Sutherland said:
Also, what I meant about the valve seal job was that I read that you can get a kit for retrofitting valve seals in order to stop the engine burning so much oil. Looking in the exhaust ports you can see a huge amount of carbon build up, I'm considering getting it terracleaned but I'd be worried about causing blowby when the piston rings are cleaned haha. What do you guys think about terracleaning a 50 year engine??
Click to expand...

I've never heard of terracleaning, what does it do.

You could try running it round for a bit to see how it behaves before pulling bits apart and if you go for valve stem seals there would be no need to disturb the barrels and rings if only the heads are coming off.

Good Luck.
 
Ahaha, I have a block to clutch in my garage too. I might well need some luck for this one. Interesting read on sportsterpedia. Sounds like I'll have to wait to find out if it is sit sumping before I make my dipstick because by the time it's filled, warmed and cooled, some of that might be in the sump, offsetting my reading. And I see that the XL Forum people say the gauge would be useless unless it's a 0-15PSI one.

Terracleaning is carbon cleaning the inside of the engine, they hook up your vehicle to a machine that does a load of stuff but the important bit is using aliphatic only fuel, ultra high grade, this basically turns all the carbon to gas due to opposite electrical charges. Just briefly reading about it now, doesn't seem damaging.

https://www.terraclean.co.uk/how-terraclean-works.php
 
You must log in or register to reply here.
Back
Top