top speed of IP2?

[rjg30091982]

Hi All,what is the top speed of an IP2? mine will only do 95 on full throttle on a straight????it has the classic clock instead of the calibrated Jag clock but i checked the speedo against the measured half mile off the A38 in Plymouth and it read .5 on the speedo so i know it isnt a speedo fault!why is my bike so slow? the bike is rapid in acceleration in all gears but as soon as you hit 90-5 nothing?!?both my Commanders with hit 120 easy probably even more but at this speed the bike is so unstable it wants to throw me off so i never really push it on these two.any one else have this issue? my other IP2 i've never riden as it needs a rebuild.any thoughts?Russ

[Richard Negus]

Russ, Forgive my memory, but have I seen your slow IP2 anytime?I don't suppose it's one of those odd 'reverse-flow' conversions that make the engine last longer but strangle the air flow and reduce the power?How does it perform in the lower gears? Full throttle in 2nd or 3rd, does the rev limiter operate above 9,000?On standard'ish gearing, 90mph is around 6,000 rpm; does it go flat, sound harsh, mis-fire, or what?Is it reaching full throttle? Look at the l/h lever on the back of the engine and check it's touching the stop screw. There are some dodgy cables about that are dimensionally rubbish.What spark plugs are you running?What does the temperature gauge say? Stable, rising, falling?When it's stuck at 90, does it cough when you flick the kill switch off and on again?When it's stuck at 90, what does the tacho read?Have you checked the vacuum pipe and the fuel tap?I presume it re-starts well enough when hot?That's just the short list!Design top speed? At least 120 for a brave chap.Get some decent tyres on your Commanders! But tyre brand is a whole new discussion. My current preference is Avon RoadRider, 100/90 + 130/70; I'm about to try 110/80 + 130/70 on my fake Classic. That might be a step too far on such narrow rims, but an education and get it through the MOT.R.

[rjg30091982]

Hi Richard,i'm not sure what tyres are on my Commander but you put them on! i think they are BT45's which i had on my K1100 and they were fine on the K, the other commander i have is just as bad at those speeds, it seems to want to lift the front end and slap around in the wind!any way back to the IP2, no you havent seen either yet, the CITY of London bike i have C331EHM i believe we discussed about a year ago and you mentioned the reverse flow then because you had C334 in your W/S at the time, although until you rebuild it i guess we will not know for certain.the West mids bike is the one i am talking about but i dont think this one is reverse flow? C672GOJ is the number if that brings any memories back!any way back to the list, the tacho hits about 3000 rpm then drops to about 1000 which we discussed again when i had problems with my CDI on the P52 but i believe you said its normal for an IP2.in terms of running, there is no faults with this bike at all, it starts it runs, it doesnt really get hot and when it does it starts perfectly everytime, i've never had an issue with this bike apart from the electrics falling out of the dials occasionally!How does it perform in the lower gears? Full throttle in 2nd or 3rd, does the rev limiter operate above 9,000?IT DOES HIT THE LIMITER BUT AT WHAT REVS I DON'T KNOW THE REV COUNTER IS SHITE! BUT IT IS RAPID JUST LIKE THE COMMANDER IN ALL GEARSOn standard'ish gearing, 90mph is around 6,000 rpm; does it go flat, sound harsh, mis-fire, or what?IT DOES NOTHING, DOESNT COUGH, SPLUTTER ANYTHING MAKES NO WEIRD NOISES OR SOUNDS STARVED IT JUST DOESNT GO ANY FASTERIs it reaching full throttle? Look at the l/h lever on the back of the engine and check it's touching the stop screw. THIS MAKES SENSE BASED ON THE SYMPTONS, I WILL CHECK THIS TONIGHT OR IN THE AMThere are some dodgy cables about that are dimensionally rubbish.What spark plugs are you running?C8E SAME AS THE COMMANDER, I HAVE A STOCK OF ABOUT 50!!!!!What does the temperature gauge say? Stable, rising, falling?ITS 50 WHEN COLD AND NORMAL RUNNING ITS NORMALLY AROUND THE 100 MARK MAYBE JUST UNDER AROUND 90 AND NO MORE THAN 110 AROUND TOWN. SEEMS NORMAL TO ME.When it's stuck at 90, does it cough when you flick the kill switch off and on again?HAVENT TRIED BUT WILL CHECK THIS LATERWhen it's stuck at 90, what does the tacho read?ABOUT 1000 RPM HAHAHAHAHAHave you checked the vacuum pipe and the fuel tap?CHECKED FOR WHAT? THERE IS FUEL HERE PLENTY? SHALL I CLEAN THE PIPES?I presume it re-starts well enough when hot?NEVER BEEN AN ISSUE.PS I'm back to sea in 2 weeks shall i dig out the trailer or call David bate??? lolcheersRusspps the bike in question is below!

[rjg30091982]

Richard,here is a photo of the throttle i believe you are talking about, its not a great photo but at maximum revs here is the left hand mechanism.it doesnt foul against anything?am i looking at the right part?Russ

[Richard Negus]

[quote="rjg30091982"]Is it reaching full throttle? Look at the l/h lever on the back of the engine and check it's touching the stop screw. Follow the throttle cable down to where it attaches to the left hand throttle lever. If you then open the throttle fully, that lever should come to a stop against the head of an M5 cap screw in the rotor housing. If it's nowhere near, you're not getting full throttle; suspect the cable.ITS 50 WHEN COLD AND NORMAL RUNNING ITS NORMALLY AROUND THE 100 MARK MAYBE JUST UNDER AROUND 90 AND NO MORE THAN 110 AROUND TOWN. SEEMS NORMAL TO ME.That is cold for a normal engine; usually idicates around 150C and, if pushed hard, up to 180 -200C. Anything over 200-220 is time to stop and let it . The temp gauge senses from a thermocouple screwed in one of the rotor housings above the spark plug, but isn't connected to the bike's electrical circuit (except for the little lightey).CHECKED FOR WHAT? THERE IS FUEL HERE PLENTY? SHALL I CLEAN THE PIPES?Sorry! Check that the rubber fittings at each end of the pipe aren't perished and letting air in. This will restrict fuel flow.Connect the pipe to the tap and suck on the open end. With the fuel pipe removed, you should see a good flow of fuel. If not then either the vacuum diaphragm is perished or the fuel strainer blocked, either restricts fuel flow and loss of performance. R.

[bodgerbloke52]

Hello chaps from the Pacific NW.Re the excellent tyre choice advice from Richard. My experience with my Commander and IP2 is that both were originally lacking in the handling dept. Both were somewhat unstable at speed and suffered tank slappers between 40 and 50 mph unless handle bars had a hand on them. both were on Pirelli Phantoms. The Commander was much better by fitting Bridgstone BT45 F & R but head shakes were still present hands off. The complete cure was the fitment a Michelin radial 110/80 front and retaining the 120/90 B Stone on rear. The improvement from the radial was so pronounced I am tempted to go radial on the rear as well.The Plod bike is now on 100/80 110/90 BT45's, much more stable but head shakes hands off. Looks like I have to go radial front on this one as well. Every one and his dog says tyre types must never be mixed but I have found no one who can offer a reason. It was ex Norton tester of great experience Bob Rowley who kindly tipped me off on fitting a radial front to the rotaters.Roger

[rjg30091982]

Richard,i think i am getting confused, the throttle cable comes off the throttle then splits to two under the tank, one goes to the carbs centrally and the other on the L/H side to the oil pump? am i on the right track?which one am i checking?Roger, re the tyres in law you can fit radial and cross ply on bikes because the law says it is an offence (3 points and £60 fine) to fit a radial and cross ply on the SAME AXEL, so i take that to mean its ok on bikes?cheersRuss

[bodgerbloke52]

No tyre mix laws over here in the land of the free of any sort but loads of free advice and old wives tales saying it should not be done. Bob Rowley while stating his preference did point out that his findings could not be adopted for production because the law in Uk does not allow it. Intersting point you make about the "same axle" verbiage. There are examples of bikes here having mixed type tyres from new.From my experience, a radial front on my rotaters works very well indeed.Roger

[Richard Negus]

i think i am getting confused, the throttle cable comes off the throttle then splits to two under the tank, one goes to the carbs centrally and the other on the L/H side to the oil pump? am i on the right track?Check the one that you can see move the throttle spindles. The other cable that moves at the same time goes into the gearbox cover to operate the oil pump.Roger, re the tyres in law you can fit radial and cross ply on bikes because the law says it is an offence (3 points and £60 fine) to fit a radial and cross ply on the SAME AXEL, so i take that to mean its ok on bikes?I believe, in UK law, you can only use tyres of the same type on a motorcycle ie two crossplies or two radials. A mix of radial+crossply, whether front or rear, is not acceptable. I'll try and find the relevant bit of Construction & Use to confirm.R.

[Richard Negus]

Construction & Use, 1986, Para 26. Ain't Google wonderful!

img058.jpg

It seems to infer that you can use a radial on the rear with a cross-ply on the front.

[rjg30091982]

Hi Richard,i can see that cable going to the carbs but nothing seems to be restricting it? there is an adjustment screw on each side but its not fouling anything?re the tyres, i can remember back to the early 2000's when i first joined the Police, one of the few things i remember about traffic law was cross and radial ply were not allowed on the same axel but you could mix front and rear etc. that being said in all my years on the beat i never once saw a cross ply on a car!!!!!! seems to always come up in Sgt's exams as well!clearly all that training back then has paid off here! loli tried to take it out today but it was far to windy to get the bike up to speed i was blown all over the place!

[bodgerbloke52]

RMost interesting chapter and verse re tyre mixing. I go back to my original conundrum, WHY IS MIXING CONSTRUCTION NOT ALLOWED? WHAT IS THE TECHNICAL REASON FOR SUCH STRICTURES??All a bit moot over here as we have no restrictions but it makes me consider more seriously matching the front radial with a rear, just a bit nervous of messing up the excellent results I have.R

[rjg30091982]

I was never told a "scientific" reason but i believe the behaviour of the tyres fitted this way can lead to an increase in losing control of the vehicle. The only other explanation i got was "because the Government knows best"!! i think this was also "i don't know just shut up and stop asking me!"Russ

[Malc]

Tyres, Radials and crossplies cannot be mixed on the same axle on cars because the flex of the sidewall is different and so alters the tyre's footprint. This can alter the handling of the car and make it dangerous.The sidewalls on crossplies have cords at 90 degrees as the name implies but these plies tend to try and tear apart so causing heat build up and failure.The next improvement was to use 'Bias' belted tyres, these have the plies put at approx 30 and 45 degrees to the centerline of the tyre. Derbyshire police ran the early Michelin bias belted rears on the IP2. Again as with cars, could only be used on the rear.The true radial was a bit later appearing for motorcycles than cars because of the amount of sidewall flex affecting handling. Although providing a bigger footprint than crossplies and Biased belted, some would provide extra grip and then suddenly let go.The aspect ratio (height of tyre as a percentage of its width) was then reduced so the more flexible sidewalls were reduced in height.A true radial though, in its pure form with its plys at 90degrees to the centerline is too flexible to be steered hence the need for a re inforcincing ply running in the circumference only under the tread. The advantages are the radial will run cooler as the sidewall carcass fibres do not interfere with each other. The tread pattern is held more rigid so reducing 'squirm' and increasing tyre life. Thats why a modern radial with less tread depth will outlast a crossply with a much greater tread depth.Now just to confuse things a little, some modern front radials are using a ply not set at 90 degrees to the centerline but at varying degrees which the manufacturers keep a guarded secret as this can improve the 'feel' of the steering and some racing radials have a belt at 23 degrees.My two track bikes (which are both for sale along with some othe rotaries) run different tyres. One runs 18inch dunlop crossply race tyres and the other runs dunlop 17 inch radials. This makes the bikes handling feel completely different.Most riders who have ridden both bikes prefer the crossplies as there is more feel as the tread pattern deforms and moves about but the radials last longer.With reference to another thread about top speed of the IP2, on a police course I had approx 125mph out of one. The track bikes pull approx 145 mph with a measured 92 bhp at the rear wheel from one with the other being quicker on track but not measured on a dyno. The slower one pulled an 11.7 standing quarter (setting off in second gear) which is quicker than my Zx7rSo one of these lovely bikes could be yours if your not careful! (Including the Kawasaki)Malc

[Wayne]

Hi AllOn cleaning fule lines its a good idea, at the MGP evrything was ok until the mountain mile at sutaind full throttle all of a suden speed droped of, part throttle for a few minuits back to full as cleard breafly then droped off, now would not reve above 6000, repetet part closing throttle, full reves for about two minuits then back 6000, ran allthe way back to the just pased the grand stand at 5000 ok then engine dead. No fule getting to the fule filter. puled pipe of at the fule filter and stuck in in the mouth and blew somthing cleard bike then ok. Also note turning on reserve made no differance neither did opening the tank filler.Regards wayne

[rjg30091982]

Hi Malc,That sounds a little more detailed to what my training sgt told me! Makes sense though cheers!Richard,Back to the issue at hand, 90 twice once was 4k rpm the second 5k so maybe 6k as you suggested is right but my tacho moves all over the place.Turning the kill switch at 90 causes constant back fires.Re the cable I cannot see anywhere were it could foul so I'm guessing I'm looking at something different to what you suggested?CheersRuss

[Malc]

Russ,I only know this because in the mid-eighties I was having time out for teacher training at college and so the force asked if I would do a half day on the traffic patrol course specifically to cover motor-cycle issues.At least the lads on the college courses behaved!

[johnbirchjar]

It may sound obviuos but I suppose you have checked the inline fuel filter for the dreaded "Ethanol Melt"? With engine temps; as low as you say it sounds like your temp; guage is about as accurate as your tacco!! (this is an IP2 we are talking about?,not a Commander?) J.B.

[rjg30091982]

Hi JB,yeah its an IP2, both my commanders will easily get up to speed, the ethanol hasnt affected this IP2 the fuel filter seems fine and there is no jelly inside etc, i always run them out of fuel before i go to sea in any case.I think the temp sensor must be shagged somehow, it looks to be screwed into one of the plugs.having played around with the bike the last few days i think it may be the final gear and lower compression from what Richard Negus suggested because it seems capable in 3rd and 4th but in 5th it won't increase in speed but will maintain what you hit in 4th. also its been pretty windy down here in.... err Germany for me to be getting these speeds.cheers to all

[bodgerbloke52]

My ex MOD IP2 engine is no where as sharp as my Commander. Both are geared about the same 3700 revs at 60mph. The IP2 on that gearing will top out at about 100 in fifth while the Commander will keep on trucking well past that. Top speed aside, for the wide open spaces over here the Commander could do with gearing up a touch, the IP2 is about right in that it drones along at 80 nicely.Tempararure reading on the air cooled is 150c, the wet one is 90ish. However, the air cooled reading drops at idle while tother goes higher. The fan is inadequate for the job. I would suggest that you check your temp sender/gauge with a infra red temp gun. Shoot at the sender and its surroundings.Roger in the Pacific NW.

[Interpol2471]

In test conditions at the weekend from the 30th bash my IP2 was hitting 110 mph quite nicely thank you but that was as brave as I got 7500+ rpm was looming....