JDR bike build

[koba]

Nah its when converting them over to CDI the backing plate will be sitting real far out and wont have any room to bolt flywheel onto the crank.

Im not worried about points its that the motor I have is SOOOO old its the old single piece head and I really wanted to keep that without ruining it as im gathering they are pretty rare to come across

True, ruining rare stuff is best avoided.

[Ivan]

True, ruining rare stuff is best avoided.

yeah even the bottom end is abit rare to be fucking around with,

So close yet so far away

[Henk]

Umm I thought the one piece / two piece head motors had the points at the top. All the 100cc versions I have in bits in the garage are like that. The only points at the bottom ones I've seen are the later model XL100s and XR100 motors, I am making the bold assumption that the 100 and 125 are very similar. Does it have two round plugs to cover the Valve adjuster thingies or one cover that covers the lot?

[Ivan]

Umm I thought the one piece / two piece head motors had the points at the top. All the 100cc versions I have in bits in the garage are like that. The only points at the bottom ones I've seen are the later model XL100s and XR100 motors, I am making the bold assumption that the 100 and 125 are very similar. Does it have two round plugs to cover the Valve adjuster thingies or one cover that covers the lot?

Nah your right the points are up the top on the camshaft, But the flywheel and stator are down bottom after taking the stator and flywheel off and lining up a pit bike stator and flywheel it wouldnt fit and then looking at it I dont think its going to work

[husaberg]

Because of the points? Or are did they sort a design fault out when they moved to CDI?

If you are worried about points, don't; they should be fine.

The advantage of more modern stuff would be fuck all to nothing, if the points are kept in good nick and well adjusted. The advantage newer-than-points systems is less maintenance which shouldn't be a problem on a race bike.

There may be an exception if you are revving it significantly higher than the points were designed for. I doubt it would be a problem before all that silly four stroke shit starts causing trouble.

The Honda 250 fours and the 250 6 ran to 18000 plus the 50s and the 125 even higher mainly always on points
on points the problem with the honda ignition set up is when the head cam tunnel wears the ignition wanders at revs not to mention the effect from the camchain.

[Hilleye]

The Honda 250 fours and the 250 6 ran to 18000 plus the 50s and the 125 even higher mainly always on points
on points the problem with the honda ignition set up is when the head cam tunnel wears the ignition wanders at revs not to mention the effect from the camchain.

To true, but the points cam on those engines were designed to prevent points float at very high revs. I'd say the points cam on the engine in question for this bike probably isn't.

[husaberg]

To true, but the points cam on those engines were designed to prevent points float at very high revs. I'd say the points cam on the engine in question for this bike probably isn't.

They also had a couple of springs and were gear driven as well.

Intersetingly the BSA and Triumph threes had a quill drive to stop the timing wandering from flex from the UHC. (OHV engine)
But the 250 4 and 250 6 had to fire a lot more cylinders as well a lot more often.
I think the 250/6 latter became the first engine to have a CDI setup ( I could be wrong though)
Even with more than one set of points.

The H100 motor you now had was originally raced on points and had no trouble running past 11000rpm which is EQ to 22000rpm for Ivans bike Food for thought.

I tried to run the CR80 ignition that you now also have with a XR200 CDI unit for fixed timing.
It ran quite well down low and at idle, but missed then cut out completely over about 6-7000rpm.
It took me a little to twig that it was because that would be 12-14000rpm on the std XR200 set with the trigger driven at 1/2 engine speed.


modified version of the RC148, the world's first 5-cylinder 125cc road racer won the 1966 Manufacturers' and Riders' Championships.

Engine Air-Cooled 4-st. Inline-5 DOHC 4-Valve Gear Train Displacement 124.42 cm3
Max.output over 34 PS / 20,500 rpm
Max.speed. over 210 km/h
Weight 85kg
Magneto Ignition
8-Speed Transmission

this link is well worth a read the 1960 honda six the engine contains materials alloys and surface treatments never seen before. Wholly shit what else is Honda Hiding!

In the same way, the seven main bearings are also different, ranging from 24mm in diameter at the center to 14mm for the outer pairs. The crankshaft itself runs on carriers bolted to the top crankcase half, which takes all the loads. Thus the bottom half can be made much lighter and flimsier from magnesium alloy.Similarly, the camshafts (each head has four, linked together in pairs) are barrel-shaped, concentrating their mass at the point of greatest flex, the center, and thus saving weight at their ends. But this in turn means the geometry of the valve gear varies from one cylinder to the next, with different cam profiles. The benefit is tiny, the resulting difficulties immense, yet at every turn Honda went to such obsessive lengths seemingly regardless of cost.

Yet even that was nothing compared to the engine parts. Most of these were made by JPX, a French company based near Le Mans, France, which specializes in aircraft and high-tech F1 car components. At JPX, the original engine was thoroughly photographed, then carefully stripped, and a detailed assembly handbook created. Every item was measured to the minutest accuracy and X-rayed, and had detailed three-dimensional drawings made--502 in all. Sophisticated hardness testing and metallurgical analysis was conducted on every piece, which revealed some interesting issues. Not a single engine bearing was a standard size, and some of the alloys and surface treatments used were quite unknown to modern science. Soichiro Honda, founder of the company, was also a gifted metallurgist.

The engine is riddled with galleries and tiny oilways, unseen by anything but X-ray, with some only 1mm apart. Sometimes two narrow oilways are combined, saving perhaps 0.5mm in width on a single, larger one. Cumulatively this allows the engine to be perhaps 3mm narrower than it might otherwise--yet another minute but worthwhile return on the work involved.

Read more: http://www.motorcyclistonline.com/fe...#ixzz1hpLB9Jvr

[Ivan]

ok so heres the dilemah if you can understand by the pictures what I mean I dont have much room and was wondering how I could bolt the inner rotor kit to this as theres no room



as this is the type of flywheel i should be running http://www.pacre.co.uk/Parts/185-200...RE-(70-71).jpg

[Henk]

Rick52 has had some luck with throwing away all the stock stuff and fitting a pit bike ignition. Admittedly he's using the newer XL100S motor and had to get a bit of work done to get the tapers to match.

[Henk]

Your other option would be to do what I have done with the XL100 motor in our second F5 bike which was to unplug the stator (Too lazy to take it out and it locates the oil seal on the cover) and run the standard points with a coil from supercheap total loss.

[Rick 52]

Hope this helps !

[Ivan]

bummer your stator and flywheel were dry wernt they? so they were sealed off were as myne isnt so I cant leave the cover off as all theoil will leak out


Henk Im actually consdering putting the points cam on the 200 head and running it points setup using the stator and all now I have 2 motors both identical tho and get one machined up to run the setup Rick has somehow

[Henk]

I bought the pit bike setup that Rick is running, it all got too hard so on sold it to him, I think the taper on the later motors is well different to the earlier ones since I couldn't see a way to make it work without adding material somewhere. Went total loss as a short term fix to get the thing on track. Took it to the track twice with one broken throttle cable and one flat battery (didn't charge it Saturday night between practice and racing) before we found the solution. Take out the XL motor and put in a CRF motor, the new engine is smaller, lighter, has an ignition system that doesn't require a battery and makes more and nicer power.
Main reason I went total loss to start with is I wanted to get away from the 6V battery and thirty year old charging system that came with the bike. Worked OK as far as it went but much prefer not having to charge batteries as I tend to be a bit disorganized on race weekends, especially at away meets.

One of the guys that turned up at buckets at one stage took some pics of my interim solution.

http://littleslugger.wordpress.com/page/2/

Not sure if that will get you to the page in question as the site is a bit odd but it's the XL motor in an FXR frame.


Edit: seems to work.

[Ivan]

what is actually stopping me from running the points stator and flywheel as the pulse coil is attached to the cam isnt it??? http://grimcyclesalvage.com/catalog/...3008_02_xl.jpg



So I wouldnt need to find a way of adding the pulse coil

[Henk]

Never bothered trying to get a CDI setup to work. Total loss I ran the points off the end of the cam, coil from supercheap and added a switch to prevent the battery getting drained and the coil getting fried, also threw in two LEDs, one for power on to make it obvious and one for a neutral light because the wife likes having them.