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PD: Primary Drive Alton Generator


erik

Well Known and Active Website User
VOC Member
How should I seal the gap betwenn the Primary drive and the alton Generator on a twin? regards Erik
 

timetraveller

Well Known and Active Website User
VOC Member
With the Walkernators, if oil is used in the primary drive, I provide a piece of soft 'rubber' round section material which has to be cut to length and the ends superglued together to make a large soft 'o'ring. If the bike is used with ATF in the primary drive then I provide a similar length of silicon rubber tubing which has to be cut to length and then have the ends glued together with clear silicon sealant. The reason for this is that the dynamo side of the casting can vary from having a cast in cone shape, a machined cone shape or a flat face. That means that I cannot provide a large 'o' ring that would suite everyone. If you cannot find what you want I could send you a small length of either type of material.
 

Dave61

Well Known and Active Website User
VOC Member
With the Walkernators, if oil is used in the primary drive, I provide a piece of soft 'rubber' round section material which has to be cut to length and the ends superglued together to make a large soft 'o'ring. If the bike is used with ATF in the primary drive then I provide a similar length of silicon rubber tubing which has to be cut to length and then have the ends glued together with clear silicon sealant. The reason for this is that the dynamo side of the casting can vary from having a cast in cone shape, a machined cone shape or a flat face. That means that I cannot provide a large 'o' ring that would suite everyone. If you cannot find what you want I could send you a small length of either type of material.
Hi Norman,
Just wanted to ask, isn't there a school of thought that the Primary breathes through the dynamo ?
Mine has the cast in cone shape & the soft rubber tube,(to suit engine oil), you sent me with the Walkernator doesn't take up the clearance so I was contemplating running without it sealed, am I being a total idiot ?
Cheers
Dave
 

Bill Thomas

Well Known and Active Website User
VOC Member
My ex l/ning, Has a ton of oil coming out the gap with a Macdouglator, Bruce sent me some special soft stuff that I still have to try. Cheers Bill.
 

timetraveller

Well Known and Active Website User
VOC Member
Hi Dave, my experience is that if one does not seal it then it blows oil out This is with the oil thrower etc all installed. There is another school of thought which is that there has to be a gap there to let the primary chain case breath. One of my bikes has a banjo connection on the oil filler cap on the primary cover so there is no pressure in there
 

erik

Well Known and Active Website User
VOC Member
what about using Silicone sealer and Drilling a small hole in a remote place where no oil is thrown to by the chain?
 

Gary Gittleson

Well Known and Active Website User
VOC Member
I've been running mine lately with just the oil thrower (on an Alton) and a bit less oil in the primary; just enough to cover the bottom run of the chain. Nothing seems to be coming out of there. I should add that I have a D, with the breather on one valve cover. I put that over the front intake valve, connected to a one-way valve and hose leading down to the bottom and out the back. The end of the hose is always dry. The previous owner had drilled and tapped the magneto inspection cover and placed a one-way hydraulic vale there with a little tube pointing downward. I left it because it seemed quaint. So I have two one-way breathers. I was also experiencing some oil blowing out of the oil tank cap. I made a diverter for the return but it didn't help. I assumed it was caused by pressure buildup in the tank. So I drilled and tapped the rear cylinder exhaust valve cap to accept a small brass pipe and connected that to a hose going the chain oiler outlet to allow the pressure to pass to the engine and be consumed by the one-way breathers. Whatever oil is also delivered over the valve drops down into the engine. This seems to have worked. My bike is a "D" Rapide, so the tank is on the side. Neither of the breather valve covers is visible without very careful inspection under the fuel tank and the hoses are tucked away pretty well.

After several thousand miles in this configuration, everything is quite dry. It does leave a spot of oil after resting for a few days, no bigger than an inch in diameter, coming from under the gearchange cover. I haven't tracked that one down yet. The valve lifter cable area is dry.
 

stu spalding

Well Known and Active Website User
VOC Member
The flange ET164 and oil thrower PD28 are there to provide a breather for the chaincase. If a lot of oil is being blown past the dynamo drive it means that there is something very wrong with the seal, whichever is used, on the primary side mains bearings. Trying to cure blowby using sealants or whatever usually results in an oily clutch when the chaincase becomes pressurised. The only cure is to address the problem at source and prevent the crankcase breathing through the main bearings. Cheers, Stu.
 

Dave61

Well Known and Active Website User
VOC Member
Hi Dave, my experience is that if one does not seal it then it blows oil out This is with the oil thrower etc all installed. There is another school of thought which is that there has to be a gap there to let the primary chain case breath. One of my bikes has a banjo connection on the oil filler cap on the primary cover so there is no pressure in there
Thanks for that Norman, I`ll have a rethink.
Cheers
Dave
 

Sakura

Well Known and Active Website User
VOC Member
To reduce slight oil mist around the dynamo, I made a breather in the inspection cap. I marked the flat at the top when the cap is tight. Removed the cap and drilled a 0.125" hole in the marked flat. Threaded the inside of the cap. Inserted a threaded ring first, then a very fine mesh, secured by another threaded ring. The mesh seems to stop most of the oil as a sort of baffle. When I check the chain tension I drain the cap of what little oil collects. Seems to work.
 

MartynG

Well Known and Active Website User
VOC Member
what about using Silicone sealer and Drilling a small hole in a remote place where no oil is thrown to by the chain?
think ahead. Silicon is also a very strong adhesive - so think about how you would go about removing things some time after the silicon sealant has cured!
 

stu spalding

Well Known and Active Website User
VOC Member
Speaking of main bearing oil seals, it's a wonder that nobody has come up with an oil seal set up to replace the standard ET19/ET77 scroll items. It looks easy on paper. Just a thought. Cheers, Stu.
 

Dave61

Well Known and Active Website User
VOC Member
think ahead. Silicon is also a very strong adhesive - so think about how you would go about removing things some time after the silicon sealant has cured!
I think Simon ( Vin998) said he put oil on one side of the joint, let it cure then dismantled to trim up the Silicone & clean the oiled face & you'd end up with a reusable gasket.
Cheers
Dave
 

Garth Robinson

Well Known and Active Website User
VOC Member
Speaking of main bearing oil seals, it's a wonder that nobody has come up with an oil seal set up to replace the standard ET19/ET77 scroll items. It looks easy on paper. Just a thought. Cheers, Stu.
I've been using those for many years.Terry Prince used to sell them,they are easy enough to make,the seal is the same as the one in the gearbox cover plate and the inner is dimensionally the same as the scroll. I have also had oil free clutches for the same number of years.Main bearing wear has not been a problem in any of the bikes fitted with them.
 

oexing

Well Known and Active Website User
VOC Member
Great discussions again, so I came to some more ideas : Using the dynamo for venting the primary case cannot be a serious proposition, so instead I chose to drill from there into the gearbox dip stick adapter, not a long way to do. So I expect to get any air out the gearbox dip stick cap and no oil leaks from there. Also no risk for washing or rain water to get into there. Some caps are vented some not so, at least in my old stock. So I did some Dremel grooving the thread for easier air venting, no hole on top.
As to dynamos, I do not like the Alton gearbox solution for offsetting the rotor drive. You have to care for lubrication in there . Instead I found some permanent magnet dc and three phase ac motors at small size so they can be fitted in this place after some minor milling the engine case for concentric motors with 68 mm o.d. . I will have a big magneto for ignition so all generated current will go into lighting only.
The dynamos - ahh, dc/ac motors got new longer front plates for twin sealed ball bearings on 8mm shafts for reinforcing this place. Sealing will be an o-ring machined in the motor front plate, no silicone or some such.
I did some power tests today with an electric hand drill and got these readings, revs corrected to crankshaft speeds, 1.25 lower than the dynamo sprocket:

The round dc perm mag. motor 68 mm o.d. performance was :
bulb 6 V 35 W : 6V at 1260 rpm
" 12 V 45 W 13.5 V at 2040 rpm
" quartz 12 V 60 W 12.6 V at 2020 rpm
" quartz 12 V 100 W 10.6 V at 1950 rpm
I could not get higher revs and voltage with the 100 W quartz because the hand drill did not pull it . So I guess at 2300 rpm I will get min. 12 100 W , but don´t really need that.

The square three phase ac motor and its three phase rectifier had these numbers:
6 V 35 W bulb 6V at 1160 rpm
12 V 35 W bulb 14 V at 2070 rpm
12 V 45 W bulb 13 V at 2030 rpm
12 V 60 W quartz 12.4 V at 2030 rpm
12 V 100 W quartz 11,4 V at 1950 rpm
again, slowed down by the drill at 100 Watt load.
So both motors are quite close in performance and show a very smooth pull with 8 or 9 poles. I do not have numbers to compare with the Alton but I believe they will satisfy me completely, no more night driving for me anyway. I got the motors from Aliexpress at € 40.- to 60.- each.

Vic
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stu spalding

Well Known and Active Website User
VOC Member
I've been using those for many years.Terry Prince used to sell them,they are easy enough to make,the seal is the same as the one in the gearbox cover plate and the inner is dimensionally the same as the scroll. I have also had oil free clutches for the same number of years.Main bearing wear has not been a problem in any of the bikes fitted with them.
Thanks Garth, I didn't realise they existed, they certainly seem like the obvious answer to the problem. Cheers Stu.
 

bmetcalf

Well Known and Active Website User
VOC Member
Vic. what are those circled capscrews for, cam spindle boss support?

Vic Primary.jpg
 

danno

Well Known and Active Website User
Non-VOC Member
Have been reading this post with interest as I’ll be fitting an Alton alternator soon.
May encounter the same issues so this will help.
 

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