Royal Enfield Bullet 350 and 500 ignition timing degrees vs inches/mm BTDC discussed and compared.
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- เผยแพร่เมื่อ 22 มิ.ย. 2021
- This is the first time I have done this with the head off a Bullet engine. Hopefully this will demonstrate the relationship between piston travel versus crankshaft rotation in degrees, when checking and / or setting the ignition timing on these engines. The three sets of figures shown are straight from the Royal Enfield Redditch manual, so are as reliable as they can be.
People are sometimes concerned that using a TDC tool through the plug hole puts it at an angle and as a result, the recorded linear movement of the piston may not be accurate, so this was done with the dial gauge pointing straight down at the centre of the piston crown for greater accuracy.
Hi, paul, im a mechanic by profession, work on modern cars last 15yrs, very nice explaination , and very good informational video
My uncle gave me a 1992 bullet 350 dead condition , love this bike its a legend just like all those arround, love your content,im 35yrs old😂n bike 30,, im tuning mine back from its grave, watched your videos and figured out a lot of things, love oldschool engines 👌 simple and reliable
Thanking you for all those videos ..
Exactly on the spot the perfect demonstration using three measurement parameters with great accuracy. Measurements performed by people without much practice, not taking into account that the piston rises and falls a minimum in its course, this passage is not noticed with visual precision at the exact moment when the movement will be reversed, so having the steering wheel or any undercarriage on the box where it is possible to determine two marks when ascending and descending the piston, the mark found and centered between the other two will be the true TDC top dead center. Grateful for more this video involving techniques!
My head hurts but finally this is beginning to go in 😁 Keep up the education videos B.W., I need them!
Thanks a ton paul for doing this video
Sorry for my bad maths, I think I got it right this time.
Make a triangle with side 1 the crank offset(45mm)
Side 2 con rod length between centres(174.625mm)
Longest side is sides 1 and 2 minus the btdc
I'm now thinking that
5/16"=30.9°
7/16"=36.9°
1/2"=39.6°
Thanks again for the great videos
Love your tech videos Paul, thanks again...Irish mike..
Good knowledge
Show the workshop Manuel
Please make a video on point setting for bullet 350
Thanks 😊
Excellent. Your package left USPS today. It should be there by this time next week. Sure hope it gets there and everything fits. Thanks again for another great video.
Thanks very much Herman, I will let you know as soon as anything turns up!
Thanks! Som,ehow i managed to use a degree disc and still make mistakes.. No starting, only kicking back and spluttering. did it again with a stick from a brush with marks and it was okay..
There's a mathematical relationship between piston position and crank angle, but it's complex, lengthy, and approximate. See Bosch Automotive Handbook.
Paul, I turned up a bucket shaped spacer the correct thickness that would sit on the top of the piston and set the DTI to zero before I had a long reach DTI
Yet a famous RE dealer states to time the 500 at 32 degrees BTDC? I have even seen some quote 8.5mm BTDC which would be even more degrees? I think I will stick with your figures Paul!!
It seems an oversight that there was no sight hole with fixed TDC and timing marked incorporated into the design. BMW did it and it makes valves and timing a snack. The amount of trouble this omission gives Bullet owners is staggering. The amount of variance in determining TDC and then 8.5mm when the spark plug hole is not parallel to the bore...well it’s no wonder that every second Bullet runs badly. And there is no easy way of attaching a degree wheel without removing an engine cover and there is a cosine error using a normal dial gauge and plug adaptor. It is enough to convince a guy to install an electronic ignition and go through the whole timing process once.
It is easy to remove the oil feed quill and fit a timing disc into the end of the crank, using a suitable sized spindle running through it. TDC is not hard to find, but there are lots of people who mess with their Bullets who really shouldn't.
I have always timed my Bullet 65 using Hitchcock's data which is 32 degrees BTDC but they quote that as 8mm fully advanced? Might re set using 33 although it doesn't seem enough to bother about on a "cooking" engine like the Bullet? By the way Paul, what do you use to turn your points cam to full advance to check full advance timing whilst standing still? Thanks for all the fresh advice.
Thanks. I sometimes just use the ends of some pointy pliers to turn the cam against the springs when the engine is at the full advance firing position, to check if the points are just opening or not.
Thank you sir, Is that not 0.8 mm before TDC ?
Interesting vid Paul, just one question. You mention fully advanced so how do you go about obtaining this on both system mentioned in the manual please.
Hi David, basically, you have to lock any auto advance mechanism into the fully advanced position by various available means, ranging from special washers to fit between the end of the points cam and its retaining screw, to lock it up, to jamming bits of wood or card behind the bobweights of the auto advance unit itself. Manual advance magnetos and the like just need their ignition levers set to full advance.
@@paulhenshaw4514 Many thanks for the information and prompt reply Paul, looking forward to your next vid!!!
Hi Paul, when you said that your dial gauge was out of range for the 350 would it be within range if you put a 1mm feeler gauge between the pointer of your dial gauge and your piston crown? Sort of expand its range by an extra mm?
Thanks, I guess that could work, as long as that 1 mm was factored in, but the main problem is the gauge only records 10.6 mm from end to end of plunger movement.
@@paulhenshaw4514 Would it possibly work using a combination of feeler gauge sizes to compensate for the dial gauge's shortfall? BTW, I'm the newbee on the RE forum that asked about fork leg differences. LOL, as if it could be that easy swapping a fork leg!
👍🏴
Paul, sorry to be a pain but I'm desperate. My coil is u/s but i do not know if I need a ballast or non ballost coil for it? It's a Bullet Sixty 5 iron barrel points ignition. I don't want to be out somewhere and have a bonfire between my legs!! Thanks.
Sorry, but I can't help, as I have never heard of this ballast and non ballast thing, maybe someone else who knows might care to comment?
@@paulhenshaw4514 No problem Paul, Keep putting out the great videos and i'll be happy!!
Doing my head in with metric clock used on a British Bike.
I've got an 1" travel Mercer clock looking for a good home, how can I get your address to send it to you from Bulgaria. I have other clocks to use. 1" is very handy for checking valve travel/lift.
Hi Hugh, thanks! - it doesn't worry me too much, but I see you are a member of my Performance Classics group, so I can message you details from there.
Forgot about Facebook, hardly use it these days. Will have a look later.
Sir i am from India can you provide me piston ring set for my bullet 500cc, as in India it is not available
Sorry, I do not sell parts.
Thanks again Paul, good advice as always, keeping numbskulls like me on track!!
My tiny brain has started wondering if it would be possible or accurate to make a piston stop to halt the piston at 8mm BTDC? Then when checking the timing you just need to find the compression stroke wind back the engine fit the tool, then when you wind it forward again it would stop at the 8mm mark every time? Just the thoughts of unhinged mind!!
8 mm might do for a 500, but it is more like 12 mm for a 350.
When I went to school, an inch was 25.4mm so surely a half inch is 12.7mm...... or has the EU changed things ?
Very observant - I was wondering when someone would spot that. I did state the conversion figures I gave were within a few thou, but thanks for your very precise figure, I am sure it will make a world of difference.
I've a 350 Indian bullet 2001 . My book says 0.8mm for the 350. . . I'm lost now jeez. What do you recomend. It's all standard
0.8 mm BTDC is for the retarded setting given for Indian 350 and 500 machines, but it is better to time them with the auto advance mechanism in the full advance position, which is often quoted as 8.8 mm for Indian 350 machines, but British 350 settings are more advanced than that, as seen in my video, while British 500's run a slightly later timing, as seen in my video. Somewhere along the line, the Indians transposed the British 500 settings to their 350's, if that makes any sense.
@@paulhenshaw4514 thanks for your reply Paul. Makes total sense thankyou. . . So set it up for Indian settings not British? Why the difference? Any reasons?
@@coco-te1op The British machines have higher compression ratios, sportier cams and bigger / better porting etc, so benefit from a little more ignition advance, I guess.
Do you have a video on how to set the advance unit up in the correct place? Thanks
@@coco-te1op Not yet sorry, but I will bear it in mind for the future.
The crankshaft gear has 20 teeth. 360 degrees divided by 20 teeth = 18 degrees/tooth. The camshaft gears have 40 teeth. 360 degrees divided by 40 = 9 degrees/tooth. if you back the crankshaft up 2 and 1/2 teeth, 5 teeth on the camshaft, you have 45 degrees BTDC. 2 teeth on the crankshaft, 4 teeth on the camshaft, gives you 36 degrees BTDC. My 350 seems to run best at the 36 degrees BTDC range = 2 teeth on crank = 4 teeth on cam.
You must remember, these specifications are for dynamic timing at 1/2 engine speed. At this speed the points cam's mechanical advance will have begun to affect ignition timing. This is why the old school rule of 8 mm BTDC for static timing, as measured through the spark plug hole, is a good rule of thumb to start. You can then fine tune the breaker points plate for best performance.
I am aware of all that. 1 tooth on the timing pinion = 1 tooth on the camshaft pinion = 18 degrees at the crank. The 'Old school rule of 8 mm BTDC' fully advanced applies to the 500 only, but seems to have crossed over to the 350 sometime after the Redditch manual was published. I think this is why many 350 Bullets seem a bit 'flat' in performance, combined with other things such as restrictive exhaust systems and so on. The correct full advance timing for the 350 is as stated in my video, at more like 11 - 12 mm BTDC.
What an absolutely fantastic & well illustrated video Paul.
I tried to follow this other Guy but without meaning to sound ungrateful i had a heck of a job understanding him but anyway he sets his at 0.8mm - 01/32in though but his is the Indian Variant. I never knew they was different? Are they?
8mm & 0.8 is a heck of a difference. I wonder if he means 8mm Paul?
When you set yours at 8mm or 11mm (if it's the 350cc model) is this where the points start to open or have i completely lost the plot?
Here is this other video. Not sure if YT will block it:
th-cam.com/video/Sasr_PHNk6Y/w-d-xo.html
So Enfield India quote 32deg 8.5
That is not quite what we see in my clip, but their measurements of piston travel might have been taken at an angle, through the plug hole, which could explain and make up the difference.
@@paulhenshaw4514 so.... the 8.5mm measured through the same angle as the spark plug hole IS 'somehow' correct???
..not that the 0,5mm will give any difference, i would expect a bigger difference because of the plug angle..
I would think the 8.5 mm through the plug hole at that angle could well equate to 32 degrees, but the 8 mm measured in my clip, directly over the centre of the piston crown gave 35 degrees and may well have appeared nearer 9 mm through the plug hole.
I set my Indian 350 up through the plug hole with Hitchcock’s special tool and it ran fine on their quoted figures but Joe I know how to do it correctly when when I get my next RE, Thanks Paul