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ET: Engine (Twin) Kick Start Indexing Problem

G.L. Winter

Website User
VOC Member
My series B Rapide tends to jam from time to time at the initiation of the kick start down stroke. I fit a new kick start quadrant and ratchet pinion (G82 and G46AS) supplied by The Vincent Spares Company, but the problem persists. Does anyone have a suggestion? Thank you in advance for your kind help.
 

Bob P

Active Website User
VOC Member
No matter what you do to the first gear tooth on the quadrant, it will jam with a shape that is not pointy. As I showed in my posting above, I had reduced tooth height in several steps but no joy. I could still find situations when gears jammed top to top. The ONLY way to minimise a likely hood of jamming is to sharpen the first gear, filed or not, on the quadrant, to a pointy shape so in operation you will have to position its top EXACTLY to meet one pointy tooth top of the kickstart gear. Both components pointy you will be challenged to jam them as shown in my video clip above .
The MPH photo really only confirms the pointy shape idea, polishing any sloping areas may be nice but not essential. The real trick is to have the top point stoned smooth so it will rather slip in any direction than jam.
Please test your ideas on your bikes by carefully trying to find a position of jamming, the wider any face on gear tops is , the easier you will get a jam.
The kickstart gear has wide tooth tops which is design flaw really. This has to be corrected with next production, basically. But I will not tell them at Spares Co myself, seems they won´t listen to the people, matter of pride maybe.

Vic

Hello Vic
We are happy to listen to any problem or issue at the Spares Company, If we do not know of a problem we can't fix it.
Bob Patchett
 

oexing

Well Known and Active Website User
VOC Member
Hi Bob,
I was trying to address the shape of the kickstart gear teeth which to my liking does need a bit of correction: When you look at the photo below, the gear at the back is dremeled and diamond filed to more pointy tops whereas the front one is standard Spares Co . I believe a different type of gear cutting mill will improve the jamming effect. In this thread above you find my pictures and the video of BMW gears which clearly show a more pointy type of teeth for this reason. So for a future production an improved shape would be appreciated, the costs would be minimal, just a new cutter .
Another trouble maker comes to my mind , the ESA, and nobody at the Spares Co was even interested to look at my test set made from aluminium that I was offering to send for getting a finger feel for its caracteristics. Only comment was the Spares Co was not there to improve Vincents but simply provide original spares. So I am sorry for Vincenteers who will continue to break springs, break primary chains, smashing crank cases and expose all gears to high shock loads from non-working "shock absorbers" . I bet nobody ever had any troubles in the gear train when fitting belt drives - no ESA there. My point was, no ESA at all will be easier on your gears than this shock-inducing negation of an ESA.
Seems the club would require a peoples´ vote to get things done here.

Vic

26429


BMW type ESA modification :

26430


26431
 

Bob P

Active Website User
VOC Member
I have looked at our stock of kickstart gears and the land at the top of the teeth is about 0.5mm so is much better that the one's in your photo. I have noted your comment for when we reorder.
I will raise the ESA profile issue with the technical team as I am sure this issue has come up before.
We are happy to get some made, but would require drawings.
 

fogrider

Active Website User
VOC Member
I finally got 'round to relieving the trailing face of the first tooth on the quadrant. Same height, left it about 20thou wide on the tip. Transformed it. Gave the same info to a local friend with a Rapide also doing the jamming. He did the mod and is very happy too..
Should have made the effort long ago !
Regards all
 

MartynG

Well Known and Active Website User
VOC Member
I finally got 'round to relieving the trailing face of the first tooth on the quadrant. Same height, left it about 20thou wide on the tip. Transformed it. Gave the same info to a local friend with a Rapide also doing the jamming. He did the mod and is very happy too..
Should have made the effort long ago !
Regards all
Photos??
 

Bill Thomas

Well Known and Active Website User
VOC Member
Hello Foggy, If you have photos on your Computer, When you send something on here,
At the left lower corner, It says " Attach Files ", Click on that, And your photos should come up, Click on the photo you want to send and the number should show on the bottom line, Then press download.
If I have got it wrong ?, Somebody shout out please, It is a lot more easy now, The Forum lets you send bigger photos. Good Luck. bill.
 

Alyson

Website User
VOC Member
That seems to be the normal theory, but if you cut half the first tooth away, it misses, you might as well cut the whole tooth off !
I will do my 'add 25 thou ' mod this year, I'm sure the total wear on the small gear, the quadrant , the two shafts and the bushes, is what's behind the problem. If all dimensions were perfect, 'jamming' should not happen, the first tooth just touches and makes the second one fully engage.
Terry
Don't cut the first tooth completely off, the "half tooth" helps to engage without locking, if you cut it away the second tooth will take the brunt. BMW has this same set up on their /2 and /5 bikes so nothing new 'cept of course The Vincent did this much sooner. Alyson
 

oexing

Well Known and Active Website User
VOC Member
Please look at the previous page, there are more postings about the jamming. And no, a half tooth will not help much, I tried this first believing it would work. But I could easily find positions of quadrant / small gear orientations when tooth tops would jam, just try for yourself in small increments. The real trick is to grind the first tooth on quadrant to a pointy top, half tooth is allright as well when pointy . So then you´d have to be extra careful to get pointy tops to jam, unlikely with some grease on gears. Also watch the video clip, I had trouble to get gears to jam when all is pointy on small gears plus first of quadrant - and that was the exercise.

Vic
 

LoneStar

Well Known and Active Website User
VOC Member
Please look at the previous page, there are more postings about the jamming. And no, a half tooth will not help much, I tried this first believing it would work. But I could easily find positions of quadrant / small gear orientations when tooth tops would jam, just try for yourself in small increments. The real trick is to grind the first tooth on quadrant to a pointy top, half tooth is allright as well when pointy . So then you´d have to be extra careful to get pointy tops to jam, unlikely with some grease on gears. Also watch the video clip, I had trouble to get gears to jam when all is pointy on small gears plus first of quadrant - and that was the exercise.

Vic

I too fail to see the logic in the "half tooth" solution. To recap some points already made:

If it's short enough to not touch the tips of the teeth on the engaging gear, you've just moved the whole issue to the next quadrant tooth - no improvement.

If it can still contact the gear's tooth, it will jam whenever it happens to hit the tip of the gear tooth. A truncated quadrant tooth has a much wider flat surface than the tip of a normal one - so with greater area available for jamming, it seems likely to happen more often.

Having sharply-pointed profiles on all the teeth, on the other hand, makes perfect sense. Taken to the extreme, you'd have two knife-edges approaching each other. They could only jam if the edges aligned perfectly - very unlikely.
 
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