Racing 2021

storm42

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Former chief scrutineer at CRMC was going over my bike and stopped for a while at the sharks fin, I was a little concerned until he looked at me and said 'that is so simple and straightforward...why can't they all do it like that!'

We don't do fancy!

But it was aluminium, so I have now replicated it in Nylon!

I don't recall getting pulled for anything at Gedinne! Belgium really isn't France...

I got pulled one time in France for not having a drain hole in the catch tray...so I made one...now you must not have a hole in your catch tray!
I found some scraps of alloy last night and welded them to the fin and reshaped it, it now has no gap but looks a bit Indian.:)

I don't mind the different rules between countries although it wouldn't hurt for all the governing bodies to look for good safety ideas and adopt them year on year, it is the race by race inconsistency that I struggle with.

Donington must be a bit hard on the bikes, I noticed the carbs had gone out of sync so popped the tank off to adjust them and found the right hand carb top just sat on the carb, it had come undone. My fault really as when I took the motor out the other week, I noticed the carbs had dropped slightly in the rubber manifolds so put a tie wrap round the frame and bell mouths to support them which seemed to work well. However the motor was going wooly at about 7000rpm but instantly cleaned up as I changed gear, this made me think the extra support was transmitting vibration to the carbs and causing the fuel to froth, I cut the tie wrap off for Sunday and the problem went away, another lesson learned.

The transmitted vibration must have been the reason for the top coming loose but it gets better. I use a small camera to set the carb sync and as I was going from carb to carb whilst holding the throttle slides at the top, I noticed the left carb needle was staying in the jet, the cir clip had come off and the needle had dropped, the clip was still there under the plate.

I cannot imagine that had been like that whilst racing but I had been saying that the bike didn't seem to be going as well as it usually does.

I had been talking to Moto55 and he had noticed that the Norman White prepared bikes had a sprung support under the carbs, I think I may try something similar. Mike, did you get any pictures?
 

SteveA

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I can't remember what carbs you have, but if Amals....fit Mikunis....I have had too many experiences with Amals dropping their needles....Chris will say....stick it in with bathroom sealer! Which in my experience is only a partial fix.

On a twin I have had one needle drop and been able to carry on with reduced power, so yes it was probably like that in your last race....but with a 500 single and a 38mm MkII....came in from one race with loss of top end...found a part blocked fuel tap and changed that, it ran fine with no load blipping to a few thousand rpm, if a bit smokey, until you pulled away to go to the holding area! Makes sense really....but 2 races lost!

I found some scraps of alloy last night and welded them to the fin and reshaped it, it now has no gap but looks a bit Indian.:)

I don't mind the different rules between countries although it wouldn't hurt for all the governing bodies to look for good safety ideas and adopt them year on year, it is the race by race inconsistency that I struggle with.

Donington must be a bit hard on the bikes, I noticed the carbs had gone out of sync so popped the tank off to adjust them and found the right hand carb top just sat on the carb, it had come undone. My fault really as when I took the motor out the other week, I noticed the carbs had dropped slightly in the rubber manifolds so put a tie wrap round the frame and bell mouths to support them which seemed to work well. However the motor was going wooly at about 7000rpm but instantly cleaned up as I changed gear, this made me think the extra support was transmitting vibration to the carbs and causing the fuel to froth, I cut the tie wrap off for Sunday and the problem went away, another lesson learned.

The transmitted vibration must have been the reason for the top coming loose but it gets better. I use a small camera to set the carb sync and as I was going from carb to carb whilst holding the throttle slides at the top, I noticed the left carb needle was staying in the jet, the cir clip had come off and the needle had dropped, the clip was still there under the plate.

I cannot imagine that had been like that whilst racing but I had been saying that the bike didn't seem to be going as well as it usually does.

I had been talking to Moto55 and he had noticed that the Norman White prepared bikes had a sprung support under the carbs, I think I may try something similar. Mike, did you get any pictures?
 

SteveA

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14.15 FOOTRESTS
1. The footrests for the rider must be placed not higher than 100mm above a line passing through the centre of the
wheels with a machine loaded and in front of a vertical line passing through the centre of the rear wheel.
2. They must be positioned to give easy access to any control pedals.
3. The ends of the footrests must be rounded with a solid spherical radius of not less than 8mm. Footrests may be of a
folding type but in this case must be fitted with a device which automatically allows them to return to the normal
position, the integral protection is to be provided at the end of the footrest which must have at least 8mm solid
spherical radius
#1 is fascinating, I am pretty sure I have never seen the footrest height measured!

But....100mm or 4"...above the centreline of a say 18" wheel and tyre, if you could ride a bike with footrests at that height, I doubt your legs would be long enough to actually put your foot on the ground!

I think most of us 'vintage' racers have resorted to 'lowering' footrests, mine are an inch lower on the same frame than they were 40 years ago!
 
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#1 is fascinating, I am pretty sure I have never seen the footrest height measured!

But....100mm or 4"...above the centreline of a say 18" wheel and tyre, if you could ride a bike with footrests at that height, I doubt your legs would be long enough to actually put your foot on the ground!

I think most of us 'vintage' racers have resorted to 'lowering' footrests, mine are an inch lower on the same frame than they were 40 years ago!

Mine are about 1" higher than the swing arm spindle, and further back. I could never ride with footrests as far forward or low as the spindle like some other Seeley riders manage. Mind you, mine is the "correct" height (low) compared to a lot of the more recent ones too
 

Fast Eddie

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Ralph, as you say, cable tying the carbs to the frame is going to undo some of the benefits of the rubber mounting.

You need some Hoover drive rings matey, wrap them around the carbs and cable tie to the frame = good support and still rubber isolated.
 

storm42

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I can't remember what carbs you have, but if Amals....fit Mikunis....I have had too many experiences with Amals dropping their needles....Chris will say....stick it in with bathroom sealer! Which in my experience is only a partial fix.

On a twin I have had one needle drop and been able to carry on with reduced power, so yes it was probably like that in your last race....but with a 500 single and a 38mm MkII....came in from one race with loss of top end...found a part blocked fuel tap and changed that, it ran fine with no load blipping to a few thousand rpm, if a bit smokey, until you pulled away to go to the holding area! Makes sense really....but 2 races lost!

Yes MKll Amals.

I have made up some manifolds to kick out the mikunis as they are wider than the MKlls and made up a couple of cables, I may need to make the tank sit a bit higher for clearance. Next job is a fuel line and run it up and talk to Allen's performance about jets.
 

storm42

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Ralph, as you say, cable tying the carbs to the frame is going to undo some of the benefits of the rubber mounting.

You need some Hoover drive rings matey, wrap them around the carbs and cable tie to the frame = good support and still rubber isolated.
That would be better than the tie wraps but not that practical on a Seeley frame, after talking to Mike, I may try to make some sort of damped under carb support.
 
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Hi Ralph
I run a large rubber strap cable tied to both sides of the frame looped under the belmouths.
Cant see when I will get out again but want to do Croft as I've always ridden badly there. Lol
 

SteveA

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Yes MKll Amals.

I have made up some manifolds to kick out the mikunis as they are wider than the MKlls and made up a couple of cables, I may need to make the tank sit a bit higher for clearance. Next job is a fuel line and run it up and talk to Allen's performance about jets.
I can check what is in the 36mms I am about to fit....again! But it will be close to:

Air 1.0
Pilot 25
Needle Jet 159-P4
Needle HD3
Main 200
Set float around 19mm
3.3 float needles/jets

Pretty sure the slide is 2.5, could be 3.0

You might want more pilot, 30 or 35, needle jet might come down to P2, HD2 needle might suit, main could run up to 220

Pretty much the same as I have used in 34mms....

This will get you in the ball park.

Where I can I use Steve at Motocarb, but Allens stock off the shelf cables to suit a twin pull throttle.

Don't forget the air jet...most people do...they come fitted with 2.0 which is OK for 2 strokes!

If you don't have it download the Victory Mikuni manual for Brit bikes.
 
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storm42

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Hi Ralph
I run a large rubber strap cable tied to both sides of the frame looped under the belmouths.
Cant see when I will get out again but want to do Croft as I've always ridden badly there. Lol
Funny isn't it, I built the bike in 2017 i think and never had any support for the carbs, but because I noticed they had dropped a tad, I now have a problem. I may just not bother and just keep an eye on them.:)
 

storm42

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I can check what is in the 36mms I am about to fit....again! But it will be close to:

Air 1.0
Pilot 25
Needle Jet 159-P4
Needle HD3
Main 200
Set float around 19mm
3.3 float needles/jets

Pretty sure the slide is 2.5, could be 3.0

You might want more pilot, 30 or 35, needle jet might come down to P2, HD2 needle might suit, main could run up to 220

Pretty much the same as I have used in 34mms....

This will get you in the ball park.

Where I can I use Steve at Motocarb, but Allens stock off the shelf cables to suit a twin pull throttle.

Don't forget the air jet...most people do...they come fitted with 2.0 which is OK for 2 strokes!

If you don't have it download the Victory Mikuni manual for Brit bikes.

Thanks Steve, I had a word with Allen's and he said to start with main jet similar to the Amals and they have 260s in, I have put 270s in the mikunis because the 260s I have have a considerably different flow rate. I have ordered a couple of 1.0 air jets.

My pilots are 30s and my needles are 6DH3, the slides are 2.5.

I am just going to run them in practice and see what happens. I will be taking the Amals with me though.
 

SteveA

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Thanks Steve, I had a word with Allen's and he said to start with main jet similar to the Amals and they have 260s in, I have put 270s in the mikunis because the 260s I have have a considerably different flow rate. I have ordered a couple of 1.0 air jets.

My pilots are 30s and my needles are 6DH3, the slides are 2.5.

I am just going to run them in practice and see what happens. I will be taking the Amals with me though.
First time I ran on the dyno I had fitted 240s, very rich went straight to 220s which was fine for a fresh motor, but too much for a bedded in one. I also had a bigger needle jet, we only came down one size on that, but I would say over the years each step weaker has been better.

Make sure you have steps down to 210 with you, or I shall just say....I told you so! ;)

Remember, someone who sells you bits will never deliberately feed you a week setting, much safer to have you go rich than come back saying you had a melt down!

Also, you will be impacted by your manifold and flow/gas speed, the Mikuni should get a better flow, if it does it will work with a smaller jet. But no two bikes will be exactly the same, very few cylinders are really the same!

Been in the workshop, head now ready to fit when I get the bottom end built up...getting closer...
 

SteveA

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First time I ran on the dyno I had fitted 240s, very rich went straight to 220s which was fine for a fresh motor, but too much for a bedded in one. I also had a bigger needle jet, we only came down one size on that, but I would say over the years each step weaker has been better.

Make sure you have steps down to 210 with you, or I shall just say....I told you so! ;)

Remember, someone who sells you bits will never deliberately feed you a week setting, much safer to have you go rich than come back saying you had a melt down!

Also, you will be impacted by your manifold and flow/gas speed, the Mikuni should get a better flow, if it does it will work with a smaller jet. But no two bikes will be exactly the same, very few cylinders are really the same!

Been in the workshop, head now ready to fit when I get the bottom end built up...getting closer...
Oh, and I will offer the opinion that a lot of people end up with a bigger main jet than they need because they are still running a 2.0 air jet!
 

storm42

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Thanks Steve, I ran it up yesterday and it fired instantly, no choke, I reckon I could bump it now. With the Amals, it needed choke from cold, they could be turned off almost straight away but It would turn over for a long time before it fired if I didn't use them.

When it started with the Mikunis it settled down to a 1500rpm tick over immediately, I blipped it a couple of times and then lowered the tick over, It was stable and even, and settled straight back down after blipping. It seems to rev quicker, I hit the rev limiter once and the motor feels smoother, so far I am impressed.

I bought 2 sets of 12 Mikuni jets off that there internet, of course they are not real ones but they were cheap. And because I know cheap often doesn't = good, I ran some flow tests on them using the rig that I used to test the fuel viscosity. I took each pair of jets and ran the same 200ml of fuel through each one and timed them to make sure they were the same.

Oh dear, anyone thinking of buying the cheap jet bundles off E-bay, don't bother, unless you are prepared to test them all. Also you will need a real Mikuni jet as a base line because the numbers on the copy jets don't flow the same as a Mikuni numbered jet.

I have a real 300 Mikuni jet and that flowed 1m 43s 82ms the copy 300s were amongst the worst for flow jet to jet, one was 1m 36s 9ms and the other was 1m 33s 27ms. The nearest copy jet to the real one was one of the 260s.

As it happens Steve, the pairs of jets 220, 230, 240 are all fairly close to each other as pairs, all within a second for the 200ml. I will fit the 240s and do the practice to get an idea of where to go, the 1.0 air jets have just landed so I will fit those as well. I will only have a 10 minute practice, so if it isn't right and I don't get it right first time then the first race will be compromised, but as I haven't been to Castle Combe before jetting will only be a small part of poor performance:)
 
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Thanks Steve, I ran it up yesterday and it fired instantly, no choke, I reckon I could bump it now. With the Amals, it needed choke from cold, they could turned off almost straight away but It would turn over for a long time before it fired if I didn't use them.

When it started with the Mikunis it settled down to a 1500rpm tick over immediately, I blipped it a couple of times and then lowered the tick over, It was stable and even, and settled straight back down after blipping. It seems to rev quicker, I hit the rev limiter once and the motor feels smoother, so far I am impressed.

I bought 2 sets of 12 Mikuni jets off that there internet, of course they are not real ones but they were cheap. And because I know cheap often doesn't = good, I ran some flow test on them using the rig that I used to test the fuel viscosity. I took each pair of jets and ran the same 200ml of fuel through each one and timed them to make sure they were the same.

Oh dear, anyone thinking of buying the cheap jet bundles off E-bay, don't bother, unless you are prepared to test them all. Also you will need a real Mikuni jet as a base line because the numbers on the copy jets don't flow the same as a Mikuni numbered jet.

I have a real 300 Mikuni jet and that flowed 1m 43s 82ms the copy 300s were amongst the worst for flow jet to jet, one was 1m 36s 9ms and the other was 1m 33s 27ms. The nearest copy jet to the real one was one of the 260s.

As it happens Steve, the pairs of jets 220, 230, 240 are all fairly close to each other as pairs, all within a second for the 200ml. I will fit the 240s and do the practice to get an idea of where to go, the 1.0 air jets have just landed so I will fit those as well. I will only have a 10 minute practice, so if it isn't right and I don't get it right first time then the first race will be compromised, but as I haven't been to Castle Combe before jetting will only be a small part of poor performance:)
Were they EBC ??
 

storm42

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Castle combe is the race location for this weekends racing. And it is pissing down. :mad:

I have just been out for the practice session and i feel a wet track isn't the best way to learn a new circuit.

The bike seems to be running OK with the new carbs and one of the other advantages of the Mikunis is I can hold the revs at a constant 3700rpm for noise testing, this was not possible with the Amals. 102 db was the result.

It is a very fast track with a proper mickey mouse chicane which I am sure will be a bottle neck on the first lap, but we will see.
 

Fast Eddie

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Rain, a new track and new carbs… great combo here Ralph, good luck !

What size Miks you running, 36mm ?

How did you handle the fact the ports are too close together ?
 

baz

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Castle combe is the race location for this weekends racing. And it is pissing down. :mad:

I have just been out for the practice session and i feel a wet track isn't the best way to learn a new circuit.

The bike seems to be running OK with the new carbs and one of the other advantages of the Mikunis is I can hold the revs at a constant 3700rpm for noise testing, this was not possible with the Amals. 102 db was the result.

It is a very fast track with a proper mickey mouse chicane which I am sure will be a bottle neck on the first lap, but we will see.
Best of British
 
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Funny isn't it, I built the bike in 2017 i think and never had any support for the carbs, but because I noticed they had dropped a tad, I now have a problem. I may just not bother and just keep an eye on them.:)
I was fretting about carb support with my Seeley build, but an Irish Road Racing champion I know has never had the carbs supported on his bikes, based on advice from Steve Maney.
 
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