Manky Monkey Motors

I called in on Mr Dslam a few weeks ago, (he lives just a couple of miles down the road from me). He showed me this beastie, but swore me to secrecy until it's debut. A couple of days ago he sent me these snaps & wrote:

Top secret until July 8th when it gets revealed at the festival of 1000 bikes at Mallory where the owner will have first dibbs as the star turn opener in the demonstration sprint and I will ride it to close the sprint. He has asked me to pilot it from thereon. It's called "Impulse". A 998cc works Hillman Imp engine with a Shorrocks supercharger. We reckon on about 130bhp at the back wheel. If it stays in one piece I'll be riding it at the Brighton Speed trials in September which will be it's first competetive 1/4 mile outing since 1966, when it was last at the speed trials and competed at the Elvington world records meeting that year too. Loads of history and a good ten years ahead of the Japanese. I've nearly worn my lathe out making bits for it.
I'll endeavour to do a write up for the forum after Mallory. It's taken nearly 7 months to rebuild. Everything bar the crank was either bent, rusty, worn out or missing.
The things we do for a bit of fun!!

An update on the Imp. We found the guy who built it in the 60's yesterday and he is still in touch with the guy, Vic Phillips, who designed and rode it. We thought they were no longer with us. They're well into their 70's but hope to come to Mallory to see it run.
I'll do a write up in the near future with a history and the re build story.

Cool huh. Crazy, but cool.

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Beautiful.................

I remember seeing that race many years ago,
Very nice restoration well done.

ohh superb... maybe that's what I should use my NSU4 for... NOOOOO sorry nearly started another project there....

Outfit looks lovely but if thats supposed to be a brew in the mug YEUK!!!! :)

Thanks for all the positive comments and the mug of tea was very yeuk. Thats why it stayed there and went cold ;D.
I will add a write up of the restoration if anyones interested and perhaps some of its history.
I will be piloting it at the VMCC sprint at Wroughton nr Swindon on 19th August in preperation for its return to the Brighton Speed Trials after a 40 year absence.
I will try to get something up on here with some piccies in the next few days.

Well, here we go. The Impulse saga started for me some 15 - 20 years ago when I was round at my mate Paul's place in east London. "come out ere' and catch a load of this" said Paul.
I was taken to the garage where amongst other 2 & 3 wheeled contraptions lurked a fairly rusty beastie known as Impulse.
It was built in 1966 by Mickie Pierce who built bike frames for a living (more of him later) and ridden by Vic Phillips.
It did the rounds including the Brighton Speed Trials and various sprint events and also competed in the 1966 Elvington records meeting.
Vic & Mickie also built Impetus. A road race bike with a carburetted Imp sport engine. This was seen by someone at the Rootes Group who subsequently sponsored the bikes and provided a works 998 sport engine for Impulse.
Back to this January. Paul called me to say that he would succumb to the pressure I had applied over the last 2 decades and would I rebuild Impulse with a view to running it at Brighton once more. Game on said I ;D.
I went over to Paul's place with Mr oily bike and a trailer and picked up what can only be described as a bloody mess. The rolling chassis was complete ish but the old girl had suffered a flood, a leaking shed which filled the blower up and a fire which smoke damaged it.
A full strip ensued and the fuel tank (frame top tube) was drained of 20 year old fuel and water emulsion which had left so much crud in the tank even hot triclorethelene struggled to remove it.
Tank cleaned out as best I could I then pressure tested the tank. A small leak at the back and a gusher at the front where the fairing bracket had been bent. I decided that the only way to go would be to have the frame blasted so I could see what was going on with the tank and the rest of the joints. Got it back a few weeks later to be surprised by the lack of damage. One lightly cracked joint and the two fuel leaks brazed up then the frame went to powder coat. It only has a light dust of powder so any frame joint cracks can be detected before they become disastrous.
The rest of the chassis came next, 3 wheel rims and hubs dismantled and polished. New spokes and bearings. Plated fasteners and rebuilt. I did all the work except for the polishing. I hate polishing because of the mess it makes of the workshop,
Fork stanchions hard chromed and plated. Fork legs and bottom yoke powder coated. New bushes made and as the head races were obsolete, 'near enough' metric taper roller bearings sourced and thin wall bushes made to accommodate them. Brake shoes relined and hey presto a front end. I moved on to the transmission. The AMC/Norton gearbox was completely refurbished. All bushes and bearing fitted. The gears were surprisingly good. There is an extention piece between the gearbox and the clutch to get it in line with the engine flywheel which has been turned down for lightness and adapted to take a Norton crank sprocket. This was missing as was the adapter plate to mount the sprocket. This was remade and a Jawa speedway sprocket was used as many sizes are available if gearing changes are needed and are the right chain size. The tranny extention is a home made item and carries a double row bearing in a special carrier to support the now, very long output shaft. This was re-furbed and plated.
On to the motor. Took the bottom off to find the crank in perfect nick. It is truly a work of art. Hand polished and tufrided. Has an unusual bluey purple colour. Rods, pistons, bearings oil pump etc found to be in good nick too. So far so good. On to the head. These heads run Wills rings. They replace the head gasket. They are hollow steel rings filled with nitrogen under pressure and sit in a recess machined in the head and bear on the liners and are designed to cope with the high pressures generated in a blown engine. The head was shagged sadly but Paul being Paul had a spare. New Wills rings sourced together with the special water jacket gasket the head was on.
These motors have under bucket shims and I had real problems shimming it until we found that the buckets had worn barrel shaped and were rocking causing variable clearances. This was due to the mildly radical cam sweeping the buckets sideways whilst attempting to open the valves. This sorted the top was on. Engine fitted and the rest of the cycle parts re-furbed and in place the old bus was taking shape. Next was the blower and the SU carb. Easy enough. strip & rebuilt. New bearings and trunnions for the blower and a new needle and a rebuild for the carb. Job done. Sounds easy but this all took nearly 7 months and 350+ hours to do plus countless journeys sourcing parts and advice.
Cooling system re-furbed and a neat electric pump from the states fitted all that was left to do was the ignition system. Paul decided that the Scintilla Vertex magneto was the way to go. I bench tested it and it sparked. Sourced a new cap for it. Made up some leads, timed her up to 32 degrees and we have ourselves a bike. Woo hoo!!!.
Paul arranged for the paint on the fairing and the chair as this is not my forte. And a really nice job too.
In the next installment I will relay its first fire up and its maiden voyage at the festival.
Pictures below.............

Me n a mate put together a few Impsa`s in the 70`s, A10 rolling chassis with the Imp lump in there. Went like s**t off a shovel and handled well too. Tried one with a Triumph T110 chassis but it didn`t work out so well. ;D ;D ;D ;D

They became really popular as an engine because of their lightness and modern design. Add a supercharger and you get really quick s**t!!

Andy, (Dslam), had some problems loading the photos, so these are they:

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Another

Teeny tiny piccie. Your shed's shrunk Andy.

and another

Bloody photo thingies are driving me nuts. Still trying though.

Maybe bigger this time ;)

OOO they are growing

Rear wheel hub

Rear brake assy prior to cleaning

Rear wheel built

Front wheel

Starting to take shape now

Chassis nearly complete and engine in

'Tis a thing o' beauty is that.

t' other side

Front sprocket and flywheel

A bit of a leap but the finished article

hats off to you, we bodge trikes together but this really is presision engineering, well done and god speed ;) ;)

In the next episode. We meet the guy who origonally built it and we get the first outing at Mallory complete with oil down and a hole burned in the boot. Nothing serious, just teething troubles.

Thanks Mr Bandit and Mr Manky.
I really don't see myself a particularly skilled engineer but live by the addage that if it looks right it probably is and if at first you don't succeed you ammer aint big enough ;D ;D ;D

Stunning  :)
Brings back lots of memories of the sixties / early seventies .
I had a 3 wheeler Bond 875 which was fitted with the Imp engine in the early seventies and , with the engine in the rear ,  the front end got very light at speed  ;D.
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That crank looks like a very well toughened article, nice to see such attention to detail. Lovely looking thing I must say.

Thanks Cabby,
Its nice to have my work appreciated. Everyone at the festival seemed pleased to see another historic drag/sprint bike resurrected.
Youtube link to see and hear it running;

http://www.youtube.com/watch?v=ZdOv_DBkvlY

Cool!
That's Mr Dslam in the blue sweatshirt by the way.
I've always wondered why race bikes have to be constantly revved like that. I can understand them being highly tuned & not having a steady tick-over, but wouldn't a constant rev be better for the engine? 

Because the supercharger is dumping so much mixture into the chambers at low revs you need to rev it regularly to clear the unburned fuel. You can see in the video it looks really rich but at full chat its clean. The smoke goes slightly blue as the blower has an oil feed which ends up being burned. Bearing in mind the engine is tuned for flat out power only. The blower is running at 25lbs of boost at max revs which leaves it at about 10 at high tickover revs. The motor cannot cope with that much fuel at such low revs and we run the risk of severe bore wash (the fuel washes the oil off of the bores and the rings wear very fast indeed) or worse, the blower gets droplets of fuel laying in it. BOOM!!
What is interesting is that after less than a minute of running the blower is encased in ice where the fuel is vaporised and acts as a refridgerant on the body. The slow run back to the paddock gives it time to thaw out. I remember some years ago riding Ron Mays' (Sadly no longer with us) blown Triumph which the blower used to be fully encased in a 6mm block of ice after each run. A bit worrysome at first but the carb had an unsulator block between it and the inlet manifold so it would only ice the carb if you ran it in temps below 10 degrees. That was scarry!
 We were attempting to get some rapid heat into the motor as well to ensure we had measured the water jacket gasket correctly and that there were no leaks.
A constant tickover on race bikes is possible but on bikes such as these the cam is designed to open the inlet valves really fast to allow as much charge into the motor as possible and to take advantage of the pressure in the plenum chamber.
Imagine this, Take a breath and blow out through your mouth, easy and not remotely agressive. Now take a breath and blow your cheeks out (the ones on your face!!) whilst maintaining pressure open your mouth. You get a lungfull out in half the time. Also there is no overlap between the time the exhaust valve is closing and the inlet valve is opening. In a naturally aspirated engine this overlap helps scavenge the exhaust gasses out and the shock wave in the exhaust helps the fuel in. With a blower this simply blows fuel down the exhaust and wastes pressure.
So, having dealt with all that I think that tickover is unessesary ;D

I think I understand!
Impressive mechanicking Andy.

I just added a bit more ;D

O.K, now I've given up trying to understand.  :P

yep understood,,

Gets a bit complex very quickly doesn't it? :)

It gets really stupid when trying to work out airflow/air fuel ratio's/plenum chamber size/carb throat diameter. Does my head in as well but I have to go there soon as my new build is about to start.
An old school blown pre unit triumph drag bike. I am scratch building the frame as well. I think I might start a new thread for that one.

Next episode;....................

Arrived at Mallory on Friday amidst tropical rainfall. The fear was the whole weekend would be cancelled. The paddock was awash with rivulets running everywhere.
Set up camp and got the bikes out. The Imp, My Triumph Sprinter and my Triumph road bike which is a total bitsa (most of my stuff is). A 1951 tiger 100 rigid with a generater engine.
By 6pm the rain had stopped and the track begun to dry. Off to the beer tent then. The rest of the evening was a bit vague ;D
Saturday dawned. Big breakfast in the paddock cafe (best brekkie ever) and off on scrutineering duties.
Ran the road bike in two sessions on Saturday. That was fun. Don't often get the chance to give it the beans on the road.
Lets move on to Sunday as Saturday night is a bit of a blurr. All I remember is laughing so much it hurt.
Paul, the owner, had told me that Mickie pierce and Vic Phillips, contrary to popular belief, are both alive and kicking, in their mid 70's and living in the south east. Near me. Paul had invited both and got passes to them. Unfortunatly for us, Vic had to go to Thailand with his new bride!!!! but Mickie was really keen to attend. He duly arrived and after introductions were made we checked out the bike. I could see in his face that he had been transported back 40 years. A sight that will stay with me for a very long time.
Mickie came up to me, put his arm over my shoulder and wispered "you done a bloody good job of that boy"!
Compliment indeed. It made the last 7 months so worth while. Paul was on top of the world getting his bike back in tip top shape and having the approval of Mickie was the cherry on the cake.
We ran the bike up in the pit garages as you can see in the earlier link and everones faces lit up. She is loud and revs like a modern jap 4. A whiff of throttle and the revs have peaked. Brilliant.
Paul had the honour of first dibbs (it is his after all) and we took it onto the straight and fired her up. I could see in Pauls face that he was going to give it the biggun even though I has said please take it easy as it hasn't moved under it's own steam for 20 years. I was concerned also as the oil pressure was dropping. You can see me and Paul in the video looking at the oil pressure guage on the lh side. We suspect the bypass valve or the guage but you have to believe what the guage is telling you until you prove otherwise.
Paul got on board and asked me to engage gear as his foot is a bit knackered after too many years grasstracking and speedway riding. I made the snap decision to put the bike in second but unbenown to me he had pushed into second so I had put it into 3rd.
The flag dropped and Paul pulled away. Even though it was in third it started to pick up speed and by the 100 foot the revs were climbing fast. It is not usual to do a shakedown run in front of 20 000 people but hey.
As paul came back into the paddock I got onto my Sprinter and did a couple of runs. I wasn't aware tht he had had a couple of dramas. Apart from the 3rd gear thing he had his left foot near the exhaust outlet which promptly burned through the toe and burned his foot. He said he was really pi**edat this because it wasn't his sock changing month and that it was the only decent foot he has left! Also, there is a plug which blocks an oil take off at the back of the block which we will use to pressure feed the blower in due course. Said plug blew out, I know not why, and covered paul with oil down his right side.
A burned foot and oil soaked leather the test was declared a success. ;D
We rolled the bike into the display tent for the rest of the afternoon where we decided on the plan of action for it's next shakedown meeting. A full quarter at Wroughton.
Watch this space!!!
The photo's are Me and Paul on the main straight at Mallory. I am the one with no hair, and Mickie on Impulse time travelling some 40 years.

Fabulous!  ;D

"The paddock was awash with rivulets running everywhere".

-those rivulets are buggers aren't they. Should've left 'em at home with a rivulet sitter.

I knew I should have taken my rivulet gun ;D

Lovely bit of engineering and a great story as well :)

Cheers Nabsim.
I had a good time building the bike and was a real pleasure seeing Pauls face when it was done and Mickies face was a picture too. I guess its just nice to do something big, worthwhile and for no personal gain at least once in your life.

Well said that man!

As a shakedown for the Brighton Speed Trials on Sat 8th September, Paul's supercharged Imp-powered Impulse about to be given the beans by Dslam at the VMCC Sprint at Wroughton last weekend.

Looks fantastic!
Hi Tony, not heard from you in a while mate.  ;)

I cant believe Ive only just seen this thread! All  I got to say is WOW! what a bit of engineering!..hats off to dslam! There were a couple of guys in Leyton e london in my yoof ,that used to run a bike and sidecar racer. Had a Thames 15 cwt van as support vehicle I think.

Blimey!!
Thanks Rod. I just see myself as a 'garagista' as the Italians say. Jack of all and master of none. I was amazed by the response this bike recieved both on here and at the couple of events we have attended. It's nice that quite a few of the sprinters and drag bikes from the 60's and 70's are coming out of the woodwork and the nostalgia drag/sprint scene is resurgent once more. Hooray coz it means I will have more to race against with both the Imp and my trusty Triumph (see avitar)
Cheers
Andy.

Finally you're back in fashion mate!

shame about me hair though!! ;D

It's the racing look -sleek & aerodynamic.  ;)

Trouble is it's the only bit of me that's sleek and aerodynamic :'(

You'll just have to polish all the bits of you that are exposed to the elements when youre racing!

This is giving me the "urge" to get my 1935 MOV Velocette sprinter out of the boxes its been in for more years than I can think of,bit like 'Lord Charles' :P and screw it together again.........mmmm, now there's a thought....

I think it's great to see these back up and doing what they were intended to. Are there enough of you with stuff like this to start a Manky Formula? :)

 :D Old stuff is cool!  8)

does old is cool extend to people as well

 :P

I hope so. ;D

I am nearly frozen .
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Hi all,
If anyone is in the Brighton area tommorrow (Sat 8th) don't forget the Brighton Speed Trials are on and the Imp will be in action with yours trully aboard so come and say hello and watch some really interesting cars and bikes doing their thing.
Forecast is good too.
Hope to see you there ;)

I'm working  :(
I'd love to see that in action. Lots of piccies please Andy -& good luck!

I have plans for my spare HWT M100 Panther part's to be built into a racer of some kind, maybe sprinting or flying mile.. not sure yet  ??? :-\

Found this piccie so thought would add it.

Going back a little, here's Impulse completed and ready to load into the van (fairing removed for transportation), with its first shakedown not far away.

A beautiful machine Tony.

That really is a nice piece of Brit. "hengeneerin'" Tony  and it looks "right" as well, in the manner and style that Brit. sprinters should look!!Alfie Hagon and George Brown I am sure would have agreed....... ;D ;D ;D ;D ;D ;D

i take it a biiiiiiiiiiiiig smile every time you go out on that what a thing of beauty
sorry missed this
thanks

Just for clarity, Impulse belongs to guy I know by the name of Paul, the restoration work was done by his good mate and fellow Monkey, Dslam.

I was watching the resto from first viewing of the rusty bits, throughout it's progression, as I've known Dslam since we were both at school.

Paul did the first shakedown at the 2012 VMCC Festival 1000 Bikes at Mallory Park marking its public outing for something like a couple of decades (?), then Dslam did further shakedown runs at a VMCC Sprint at Wroughton, ready for the 2012 Brighton Speed Trials.

VMCC - Vintage Motorcycle Club