17 replies to this topic

[mcman56]

I’m still struggling to disassemble a C15. The distributor is stuck. Penetrating oil, light twisting with pliers and light tapping have had no affect. Could someone have pinned it in place or are the pins factory? Are there any recommendations? One picture shows the general condition of what I’m working with.

[nigelog]

Hi, can sympathise with you looks like your bike was run on honey as a lubricant, mine was more like carborunum treacle. There is a pin holding the shaft but care should be taken. Concentrate on freeing the clamp bracket which is situated at the top in the alcove first. Halfway down the tube holding the shaft there is a small 2BA grub screw which holds the bush in place which in turn holds the shaft from being driven up from below. If the head is bollixed drill it out as you have plenty of surrounding "meat" to re-drill and tap a larger replacement. When this is removed, with a soft metal bar tap the shaft up from the bottom, it can be accessed with sump plate and oil pump removed. Dont try twisting from the top as the metal used in the distributor housing has been oft described as "cheese" and will distort instantly. If after all this it is still stuck it is possible the worm gear cannot turn to allow the shaft to rise upwards. Youll have to remove the worm gear. When is finally comes apart and you can see how it was assembled first day you will wonder what all the stress was about.

Feel free to contact me with regard to rebuild as I am half way through a rebuild with one off replacement timing side needle bearing option and full bearing and bush rebuild. I could save you a lot of time and money and research as I have just been through it. 6 months now and only now starting the assembly stage. Rgds Nigel

Looking again at your top pic I have not seen what looks like that pin before. I take it it cannot be seen from inside the casing. If other instruction above does not loosen distributor it looks as if you may have to drill and use a stud remover to pull it out. I cant see why they would lock the timing so restrictively as you need minor adjustment even with electronic timing. That bottom of the pins in top pic might just be holding another bush in place fitted after factory. Best of luck with your efforts, but resist the temptation to belt the **** out of it as good replacement parts are expensive.

Edited by nigelog, 26 September 2008 - 04:58 PM.

[nigelog]

Hi, I have taken a few photos of the distributor set up on my bike and will post them up for you. I decided to record this rebuild to fill the time as I am assembling parts. Can be seen at

http://rebuildbsac15.blogspot.com/

Will post the pics up there later today. Ta Nigel

[nigelog]

This is the set up on my engine. No pin evident and I have shown the internal parts of the complete shaft assembled. Lower shaft held by grub screw that bites into bush at top of lower shaft. Distributor held by the clamp

[mcman56]

Thanks for posting that Blog. It will be a real help.

The pins were cut off or broken off screw threads. Someone must have put them in to prevent movement. The one in the distributor came out with an ez out but did not seem to do anything. The ez out broke off in the one in the cases. The big hammer method removed the distributor but did create a little damage. When I finally split the cases, it looked like there was dried mud in the crank area. Luckily the transmission and timing side parts look servicable.

Does someone sell an engine bolt/ screw kit? Most of mine are in poor shape.

I hear about converting from a bush on the timing side to a roller or needle bearing but do not see anything available on line. How is this done? Is it expensive?

[charlie prescott]

Hi Guy's

Hi MCM.
Try trialsbits.co.uk. for your screws and other C15 Bits Amanda is most helpfull.
I you have any more problems with the build, just post them on here ,and ia'm sure some of us will be able to help out.

Regard's Charlie.

[Vinnied]

Hi Nigel

Do you intend competing on your C15

we are trying to start a pre65 section in trials that are held in ireland, if you are iterested PM me


Vinnied

[nigelog]

Hi all, for anyone interested in rebuilding the C15 engine I have started a BLOG that will go step by step through the process. I am not an expert, and this is the first engine I have rebuilt since 1979, but I had a sound engineering background before changing tack to IT. Anyone is welcome to look and comment if needed as I am definately not the first to do this and their are problems which have already been solved by better minds.

Target date for completion is February 2009 - as I am still gathering the few elusive parts.
http://rebuildbsac15.blogspot.com/


Vinnie,

I scrambled in my youth and had the run of a farm on a 125 Bantam, but never tried trials although I followed it with interest. I would consider competition if there is a class for 46yr old complete novices. I had given up onthe idea of trials riding in Ireland (although 70% of the countryside would qualify as a course, including the roads). I found in my box of engine bits an 18 tooth primary drive gear with short primary chain to match and a 17 tooth gearbox sprocket. I was going to sell them but I think I'll hold on to them, I will gear for road with the 23 primary and 19 rear and keep the others as a "trials kit" in case anyone calls to Ireland.

Would my Ohlin reservoir shocks qualify as I like the extra height and bit of bounce??

Edited by nigelog, 21 October 2008 - 10:05 AM.

[nigelog]

C and D autos in Birmingham do an off the shelf needle roller for St£135. Or you can, if the parts are serviceable, buy the bearing K32 x 38 x 23 from consolidated bearings $15 and get the parts machined to fit new size. Will need two thrust washer machined though. Mine is in the machine shop at present and I will put up on blog when received. The reason I went the consolidated route is that European bearing width stops at 20-21mm and I thought I would rather have 2mm more bearing surface than thrust washer. Rgds

[mcman56]

That is an interesting idea. I pulled the specification on the needle bearing. On my engine, it looks like the oil pumps from the cases, through the bushing and into the crankshaft to feed the big end bearing. How do you get oil flow though the outer wall of the needle bearing? What material do you use for the thrust beraings?

[Vinnied]

nigelog, on Oct 21 2008, 10:53 AM, said:

Would my Ohlin reservoir shocks qualify as I like the extra height and bit of bounce??

I dont think so nigel


Vinnie

[nigelog]

Hi mcman, both the bronze bush outer casing and the crankshaft sleeve are re-used. Machined to the 38mm and 32mm respectively it only needs the sleeve to be shortened to suit the two thrust washers. I have used 2 x 1mm circular saw blades (machined to size) that were lying around for the washers as they appeared to be a nice tensile steel.

The sleeve would have to be machined shorter from both ends to keep the internal oilway track central over the feed hole in the crank.

The oil feed to the bearing will still come through the holes and the external oilway track in the outer bush housing.

I have while waiting for the bearing to come back from the machine shop spent a bit of time overhauling the non return valve and the pressure relief valve as I dont want to have to strip this again.

I'll post a pic of the finished item when I get it. The parts that went for machining can be seen on the blog site mentioned earlier on the thread.

C&D will send a two part flyer with photographs and an explanation if you ring them. They are very helpful and their kit is supplied with new outer and sleeve components, needle roller and washers all ready to go. I had time on my hands and an uncle with a machine shop so I took the family favour route. (I gave him an engine for his go-kart so he's all right about the work)

I would be very interested though if anyone knows the dimensions of the C&D supplied needle roller, its not specified on the flyer.
Ta Nigel

[mcman56]

The picture on your blog explains quite a bit. I thought the needle bearing came with an outer race. I can do lathe and mill type machining but these inner and outer races must be hard so grinding would be required. Is the original steel outer piece of the bronze bush hard or is a whole new one required?

Looking at the Rubert book, if you stick with a bushing, you should just replace the bronze piece. However, I have been looking on line and the bronze piece does not seem to be available separately.

[nigelog]

I searched for weeks and could not find a Vandervell replacement bush so I gave up. There are complete units available but 2 things put me off.

1 pattern part quality varies dramatically, some bushes I have bought are fine, some need reaming which adds to the cost. Seeing that all shafts seem to be 2thou under a stock bar size I would have thought it easy enough to provide a useable tolerance without reaming, I know this can be handy at times if your shaft has worn undersize, but I have just found it awkward.

2 the replacement bush whether bush only or bush and outer would have to line reamed once in situ through the 2 assembled cases. Probably very easy back in the 60's when everyone was geared up for this but I did not even bother investigating that one.

The outer and sleeve are hardened but it is possible to machine and hone rather than cylindrical grinding. If mine gives up in the first year I'll know if that is true or not but I have asked the advice of a bespoke manufacturer here in Ireland and they agree.

If it all go's wrong All I have lost is $50 and a bit of time and I can go back and buy the C&D product which does not require line reaming

Ta nigel

[mcman56]

It looks like the crank journal is actually 25 mm. Does this mean I could just use one of their complete bearings with inner and outer race? Like their NKI-25/20 or NA-5905 (25 42 23)? The case would have to be machined to match the OD but it would avoid having to machine hardened parts. I guess it would still need thrust washers. Are they really needed for thrust or more to limit oil flow out the side of the bearing?