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Messages - esometisse

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136
Identify these bikes! / Re: Royal Enfield found
« on: August 06, 2010, 09:52:18 PM »
It looks similar to a 1930 model DL of 500cc (frame, forks and gearbox), but not quite exactly the right engine for this.
Anyway, the saddle tank, hand shift and upright engine make it a 1928 to 1930 model, maybe a 1930 350cc C?
Come on you RE buffs out there and help this man out!
In any case it should be quite rare a model, so could be worth something to the RE enthusiast.

137
Japanese Bikes / Re: HONDA CB550K TUNING
« on: July 13, 2010, 10:09:43 PM »
erratic running is more likely a carb problem. Maybe you have an air leak at the flanges (cracks in the rubber)?

138
Japanese Bikes / Re: 1972 Honda CB250?
« on: July 13, 2010, 10:02:19 PM »
a 1972 CB 250 would be a "K" model. There are plenty of pics of these on the www. Some of the older Honda dealers still have parts for these models or you could try a specialist for the older models like Phil Denton:http://www.phildentonengineering.com/category.asp?catID=1

139
Japanese Bikes / Re: 82 honda 650 front brakes
« on: July 13, 2010, 09:54:17 PM »
problem is a stuck piston in the caliper ("wheel cylinder").
but don't work on the braking system yourself if you don't know what you are doing!

140
Japanese Bikes / Re: Honda 400/4 -> 750/4
« on: July 13, 2010, 09:51:19 PM »
complete rubbish!
no way will a 750 go in the 400/4 frame!

141
British Bikes / Re: What barrel and cylinder head is this form please?
« on: July 13, 2010, 09:39:38 PM »
certainely nothing British here!
this head is off a Ducati bevel single, although what capacity I can't say without knowing the bore size - 125, 175, 200, 250, 350 or 450cc variants were all similar. A Ducati specialist would know.

142
Identify these bikes! / Re: Honda Seeley
« on: June 24, 2010, 06:05:22 PM »
have a look at this:
http://classifieds.classic-motorrad.de/classifieds/detail.php?siteid=16226

143
Identify these bikes! / Re: Can anyone identify?
« on: April 17, 2010, 09:20:28 PM »
well these pics are very bad (why only the right side ;D?) but my guess is its a Sachs 98cc engine from around 1937 so this would make it a model 11AS

144
British Bikes / Re: HELP NEEDED
« on: January 29, 2010, 08:57:37 PM »
Hi Goldie,
the choice and timing of cams obviously is a question of what you have and what you want to do with it.
If I have understood you right you ordered a 2491 and got a 2444 cam.
The 2491 is the exhaust cam for 350 roadrace and clubmans and is the "hardest" cam you can fit for the exhaust, i.e. with the highest lift, longest duration and most advance.
The 2444 is indeed the equivalent to it for the inlet, meaning it has the same profile and gives the same lift and duration but not necessarily the same timing.
It is important that you use your "hard" exhaust cam with the 2442 inlet cam.
I suggest that you fit your new 2444 by just lining up the dot on it with the dot on the timing pinion and then use my method to establish the true lift peaks for both cams. This will give you an idea where you stand and if it is a usable cam combination.
What timing figures should you aim for? I am assuming you want to do fast road work or racing on your machine. If it is a 500 your inlet lift peak should be at around 100 to 102 degrees after TDC and your exhaust at 108 to 110 degrees before TDC. If it is a 350 you can use the same figures but to get the most of it both figures could be advanced a little as the 350 usually likes to be revved a little harder. So you could aim for 98/100 degrees ATDC for the inlet and 110/112 degrees BTDC for the exhaust.
This deviates a little from the figures given in any GoldStar publication and itīs just my personal opinion, but I have arrived at that opinion after racing a GoldStar for over a decade now in both 350 and 500 form.
There are a lot of cams out there and I have found that their timing marks are often way out so it is a good idea to check it out.
If you find that you cannot reach the desired timing figures to your satisfaction you have three choices: live with it or throw out the offending cam and try another one or (best way for the serious racer) fit a vernier adjustable cam!
Feel free to ask any further questions in this forum or contact me directly: esometisse@freenet.de

Cheers, Andy

PS: I indeed doīnt live in Cornwall but about 1000 miles from it, in southern Germany to be more exact.

145
British Bikes / Re: HELP NEEDED
« on: January 29, 2010, 03:26:52 PM »
here goes part three:

3.Setting the cam timing

Many cam manufacturers give setting instructions as you have gotten for yours, i.e. degree figures for opening and closing points. Although this surely is the most exact method to define cam timing I find it extremely impractical. I prefer to set the cams according to their lift peak point. A cam with a symmetrical lift profile -as yours presumably is- has its peak exactly between the opening/closing points, in your case at (180+95+50)/2-50=112,5 degrees BTDC, which in my opinion is extremely advanced! This cam should work in conjunction with an equally advanced inlet cam or you will have too little overlap and your engine will not rev too gladly!
But back to work: rotate the engine from its TDC backwards until your pointer marks 112,5 degrees BTDC on the timing disc. This is the position in which the new exhaust cam has its peak i.e. the tappet has travelled farthest up. If your old exhaust cam is still installed, the tappet foot should sit on the cam peak - at least approximately because your old cam will have other timing figures.
In this position, however, you cannot change the cams because the full valve spring load is on them. So you turn the crank one full rotation until it again sits at 112,5 degrees BTDC. Now the exhaust valve is fully closed and you can take out the old cam and put in the new one; put it in as exactly as you can so that the tappet foot sits squarely in the middle of the cams bottom circle. Leave all the other gears in place, just move the exhaust cam in and out on its spindle. Now turn the crank again one full rotation. The exhaust pushrod should be up again at its maximum. Now set your dial gauge on top of the exhaust pushrod and turn the crank around a little to both sides. The dial gauge should read equal figures on both sides of the peak. Take measurements at about 30 degrees both sides from the peak. Are they the same at 142,5 BTDC as at 82,5 BTDC? Congratulations, you are done! But usually you dont hit it first time. If the measurements are not the same then you have to establish your true peak. Lets say your peak lift is 9,65mm and you have equal lift figures of 9,05mm at 140 BTDC and 82 BTDC. Then your true lift peak is at (140+82)/2=111 degrees BTDC. Leave well alone! You wonīt get any nearer! Remember that you can only change the timing of your cam by by engaging its drive gear one tooth apart! And with the cam wheels having 36 teeth one tooth apart means your cam timing will be moved out by 20 degrees crank angle!
So with a non-vernier cam the worst you can be out is 10 degrees crank angle.

Hope this will help a bit. This is the method I have found to work easiest but I am sure there are a lot of people out there who have useful hints to add.
Cheers and good luck
Andy   

146
British Bikes / Re: HELP NEEDED
« on: January 29, 2010, 03:21:08 PM »
Hi Goldie,
to own a timing disc is in itself a good thing, but its just the very first step in your task.

1. Preparation
You will need to fabricate something to attach your timing disc to the crank, preferably at the drive side of your engine.
Make a pointer out of a piece of wire, attach it to any fixed point of the bike and bend it so that it is pointing to the markings on the disc.
You need something to measure valve (or in case of the GoldStar tappet) lift. This should usually be a dial gauge with 1/100mm scale. On an assembled GoldStar engine you have no other choice than to remove the little inspection cover on the rocker box and measure the tappet lift at the top of the push rods. If head and barrel are removed you take the tappet lift measurement directly at the tappets, of course. In any case you will have to fabricate something to attach your dial gauge to the engine so that it is still adjustable but firmly held. There is still one "special tool" to be made and that is a piston stop: take an old spark plug, file off the earth electrode, knock out the center electrode and ceramic insulator and weld a 6mm or 8mm nut to the lower part where the electrodes used to be. Screw a short bolt of the appropriate length and diameter through the plug sleeve so that it protrudes some 10 to 20mm over the newly welded on nut.

2.Finding TDC

Take out the plug of your engine. Peer into the combustion chamber and slowly rotate the engine by hand until you see the piston move to the top. You should be able to establish a rough TDC by this method to within +-2degrees of crank angle. Make sure you have compression stroke by feeling the tappets or pushrods. It should be possible to rotate both of them freely. If not, you have the overlap TDC and have to turn the crank one full rotation. If you are now satisfied with your rough TDC, attach your timing disc to the crank and set the pointer to the TDC marking. Now rotate the crank some 40 degrees forward and screw your piston stop into the spark plug hole. Make sure it goes all the way in and doesnt hit the piston crown before it is fully seated. If it does, you just back out the inner bolt a little until it fits. Now rotate the crank slowly backwards. Does it hit the stop somewhere between 40 to 20 degrees after TDC? Fine! If it does not, adjust the inner bolt of the piston stop until you are satisfied. So lets say now the piston hits the stop at 36 degrees after TDC. If you now rotate the crank forward until the piston nears the stop from the other side it should hit it at approximately at the same marking before TDC - if you did a good job establishing rough TDC, that is! Lets say the other piston stop is situated at 30 degrees before TDC than your "true" TDC regarding the actual setup is at (36-30)/2=3degrees after TDC. You correct the setup by bending the wire so that it points now to (36+30)/2=33 degrees BTDC. Rotate the crank backwards and it will hit the other stop at exactly 33 degrees ATDC! No? Correct accordingly until you are satisfied that both stops read the same figure! You have now established true TDC and can remove your piston stop.

Part three to come in the next posting.....this gets too long
Cheers Andy

147
British Bikes / Re: Help required on exhaust type.
« on: January 09, 2010, 02:06:25 PM »
Hi,
Armours of Bournemouth do an extensive range of exhaust pipes for British motorcycles.
Find a pdf catalogue on http://homepage.mac.com/armours/.Public/MasterCatalogue.pdf. Should be part number HDTR3S.
And there is a system just like you require on ebay at the moment: item number 360206294618!
The silencer should be available from any better sorted Triumph classic parts dealer in the UK.
Hope this helps!
Cheers, Andy

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