Royal Enfield Bullet cylinder head porting to 'Asbo' specs discussed at Performance Classics.
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- Опубликовано: 10 фев 2025
- I had this cylinder head from a low mileage 500 Bullet going spare and thought I would do some tuning work on it, in case I might need it for a tuning job sometime, or possibly just to sell in a more desirable state than standard spec. I thought I would try filming and discussing various stages of the work, in case it might be of interest to some, so, not my best effort with the camera, but here it is anyway!
Fascinating work, all the more interesting that you walk us all through your thought process. Thanks for taking the time to put this all together for us! 🙂
Glad you enjoyed it!
super job that paul! its not just any old head now after
that skilled application of TLC its a work of asbo art👍
Thanks for posting! I have never seen a before and after view of porting work, only a picture of the end result. I was sceptical at the start but the change looks quite dramatic. Not something that I would ever feel even slightly tempted to try doing myself. Well done!
Paul,
Thank you very much for sharing the knowledge.
You are amazing
Thank you!
Nice 'how-to' video B.W. Ta for the close up shots. A few years ago this is something you and CC encouraged me to try on Delilah, I did but nowhere near as dramatically as you've done here though. I might give it another go when the head needs to come off again. Ta again for the education.
Fascinating and inspiring, not that I would try 👍👌👏
@paul henshaw can the same process be followed for a 350cc UCE head? If possible can you also make few videos on UCE performance mods. Thanks again for such wonderful videos
A long time ago there was a bulletmods yahoo group ..where we used to " tune" bullets ..some good work done ... Dan Holmes won the ama plate and a few runs at Bonneville ..we got short of 40 hp If I remember ... I still have the head and alloy barrel from that time ...hehehe now I'm happy with a standard 350 ...us oldies
The master at work!
Hello Paul . Just about to do my 350 head . I have the Hitch cock competition valve set to go in. Any advice before i go ahead please. . . . What size should i take the inlet out to?
It's got cams and 8 to 1 piston. Open pipe and filter.
Any advice i would be grateful Paul. Many thanks Simon
Hi Simon, I usually go to around 28 mm for the 350 heads.
@@paulhenshaw4514 lovely thanks Paul. . .
I can't get my valves out of the head any tips or tricks
How does porting effect gas mileage? Can I still get the same mileage at the factory level performance?
If anything, the fuel efficiency should improve and the engine would only use more fuel than a standard one when the extra power and performance is used.
@paulhenshaw4514 Great video Paul. I am going to port, polish an UCE 500 (classic 500) head very soon. Any suggestion what should be the inlet and exhaust port size should be kept at? I would be using a VM34 Mikuni carburettor jetted right
What are the seat and valve angles?
There looks to be a hole in the exhaust port between the guide boss and the seat. Is this an air injection port or part of the decompression setup, or something else?
Yep
It's for the decompressor
I remember doing my head, worked out fine in the end. But had a problem with the valves, I nearly managed to fit the inlet valve into exhaust or was it the other way!?
Makes you feel a real tosser when you realise the obvious. 🤪
Thank you for these videos, a great help. What is your take on removing the decompressor valve, machining out the entrance to allow a second plug and space to get a plug spanner on?
Hi John, I wouldn't bother, it will make no noticeable difference, as I found when I disconnected one of the twin plugs on our RE 500 racer, while on the dyno some years back.
Great video Paul. 👍 I assume you would have to rejet the carb to take full advantage of the new porting/gas flowing?
Hi Graham, a larger carb, jetted accordingly would be the best choice to get the most from such a head.
@@paulhenshaw4514 👍
They made the ports in the casting wide.
I made them wider.
Was that fairly rough finish typical for all years and sources of heads?
Yes, for Indian ones - and I have seen worse. The Redditch heads have much better porting.
The shroud behind the inlet valve is huge,I can’t wait to open mine up,I know it’s a pain but have you ever put a standard head on an as I, on the dyno to see what the losses actually are?
Hi David, I have only dyno tested any machines in their 'After' states of tune, but there would probably be a fair difference to the 'Before', I would think.
@@paulhenshaw4514 yes I do understand your not a big company and dyno time is very expensive,especially just to see,complete guess 3-4 bhp 🤷♂️
@@davidwilliamson9162 not unless you're changing the camshafts to match your new flow capabilities
With with a cam+port should give you 4-5 bhp easily (considering the stock 500 RE makes 27.5 bhp)
@@AmritGrewal31 yes Hitchcock do some uprated performance cams!