Forum

[Phil Ashbrook]

After finding silver metal flakes in my Samrat type alloy rocker bearing cap ( the exhaust one ), I flushed out all oil ways in the timing housing cover and crankcase including sump pick up oil way and mesh filter , new filter will be fitted .
I will do a engine test run of 50 miles and pull the rocker cap for the truth of the state of the big end .
If it's going I must think about the future of my crank .
I want to fit a long stroke crank with an E15 roller bearing and a forged rod so to match my 535cc forged piston . My crankcases are from a 1995 Export 500 classic .
The catalogue does not state if the 612 crank can have these things , I want our hosts to build it and send it .
I know with this combo that I cant break it when I fit the hi-flow oil pump . I think in fact it would last many years more than the STD big end .

[Norm]

Phil, don't be so sure, I was listening to a longstroke crank the other night and I don't like what I was hearing at idle, soon as it lifted of idle it was fine. I guess time will tell

[John Turner]

Phil,
The conrod and the bigend on the 612 crank are different to the conrod and roller bigend offered for the standard crank. The bigend is vastly improved especially in the diameter where it fits in to the flywheels, a common weak point on with the standard flywheels.
JT

[Colin F]

Don't think it can be done Phil.The standard 612 crank that is sold on this site has a special shortened
rod,shorter than the 500 rod infact.So i don't think the forged rod would do the job.It's either the racing
612 crank you want or a specially made up matching rod.
cheers
colin

[Norm]

Hi Colin,
I'm not sure that Phil knows what he is on about but the longstroke crank will bolt straight in as you know so I'm not sure what he want Mr H to do apart from put it in a box and post it

[Phil Ashbrook]

Norm , I dont know the specs of the 612 crank as in the big end bearing and rod , if there are indeed 2 versions of it as race or road then I would want a E15 roller bearing and forged rod .
If this is not possible then it's the race 500 crank with forged steel rod and the massive roller big end thats bigger than the E15 .
Norm , what did you not like about the 612 crank at idle , any info would be good as at $2,200 ( not including postage )is a lot of money and I want to get the best with no short cuts on reliability with power . I imagine that the main bearings will suffer more when stroking an engine...but how much more ?

[devon john]

this is what i intend to do to my bike, so as you spending this type of money i need to know its going to be the right way??
ownes of these conv engines it would be good to here from you??

john

[Norm]

Phil, I have put 3 longstroke cranks in bikes in the last couple of years and what I think is the best performer is the 570, using the Hitchcocks +40 high comp piston. The 2 612's have both been fitted with the Ace piston and we have had a lot of trouble with the oil rings. We had one pulled down last week and the conrod has suffered badly from heat for some reason and this motor is the one with a bad sounding noise at idle and this motor has done about 15,000ks. Problem is this bike has been shipped to Nepal so fingers crossed it can make it back so we can pull it down and have another look. Apart from that they are a brilliant bit of kit and I see no reason why the mains would suffer anymore than with the standard setup. The Speed Dog Racing 612 copped a real hammering and only failed because the Indian pump spindle failed and took everything with it. It should have been fitted with an H spindle for those conditions and I only twigged that when they were complaining that the spindle had failed. It was easy when I asked if the worm nut was a bonded one because the H one isn't bonded. That was when the jaw hit the floor

[Phil Ashbrook]

Norm , it looks like I need to get our hosts oil pump spindle to match my bonded seal worm for peace of mind , when I get the 612 crank with a E15 roller bearing ( I hope ) your heat effected rod sounds bad , I thought it might be forged alloy and this was part of my original questions on 612 rod specs .
When the high pressure pump is fitted do people drill the timing cover oilways bigger so as not to load the spindle even more ?
Devon John , my top end tuning specs so far are the 535cc Accralite/Omega forged piston , high lift sports cams , ported head , 32mm Amal concentric carb , bronze valve guides , competition valve spings , larger nitride valves , alloy rocker set , and spring collars ,race type cam followers and guides ,adjustable cam spindles , skimmed head and barrel ( 60 thou ) 1mm solid copper head gasket , twin plug /twin coil , free flow exhaust 2 oil filter magnets and digital electronic ignition , 18 tooth sprocket , close ratio gear box ...any wonder my big end is going after 13 years !
With a 612 crank it will pump 40bhp and stage 1 will be complete .
Then comes the 20 tooth sprocket, belt drive clutch and crank mounted ignition unit which is my stage 2 ( will use solar pannels to recharge the battery during the day ).
Stage 3 is the 1 1/2 inch Fury head with GP3 carb and remote float , alloy barrel which should pump 45bhp without the race cams , by this time I will have been living on a diet of rice for 3 years to pay for it !

[Phil Ashbrook]

I forgot to mention that my 32mm Amal concentric carb is a MK 2 , they are so much better than the mark 1 as the body is not prone to distortion or heat transfer and I have the full alcohol kit so I can run E85 fuel if I want to .