Roadster/Interstate/Thruxton R tank (2020)

Sounds crisp Glen !

Thanks, yes it's guick to rev up.
I must get the tach mounted.
And a rear brake of some type!

Love your starter rollers Glen, I am thinking about making one for my workshop, great when things all come together and that first start up, its looking good.

Ashley

Thanks Ashley.
Progress from here will be slow. There is about 15 lbs to be added to the bike to make it roadworthy. Coincidentally, I've gained about 15lbs of Covid weight over the last year.
I'm going to add parts to the bike as the Covid weight comes off. That way the ever important power to weight ratio will be maintained.
LCR Ken has helped that by giving me titanium bolts to replace the steel bolts in the rear sprocket. There are more bolts to replace with titanium, but I'll need to lose body weight to keep the power to weight ratio sharp.

Glen

Well, if you are starting with Ti bolts, you can get there with the COVID weight by having a ponder on the loo before getting on the scale.

worntorn said:

Thanks Ashley.
Progress from here will be slow. There is about 15 lbs to be added to the bike to make it roadworthy. Coincidentally, I've gained about 15lbs of Covid weight over the last year.
I'm going to add parts to the bike as the Covid weight comes off. That way the ever important power to weight ratio will be maintained.
LCR Ken has helped that by giving me titanium bolts to replace the steel bolts in the rear sprocket. There are more bolts to replace with titanium, but I'll need to lose body weight to keep the power to weight ratio sharp.

Glen

Click to expand...

Glen as we get older its a lot harder to get the weight down, so good luck with that one, its taken me 3 years to get my weight back down but seem to be losing it in the legs, arms and of course my bottom, but the gut is still the same lol, gone from 115kg and now down to 88kgs just by eating better and of course less and drinking less beer helps, sugar is our worst enemy and have cut it out of my life but so many things we eat has hidden sugar, but the best thing I am now wearing my old Levi jeans I out grew 35 years ago and other clothes I have put away all them years ago.

Ashley

The low speed misfiring was a carb problem. Rather than spend more time fiddling with these unknown carbs, I decided to borrow the carbs from the nice running MK3.
Now I have a nice running 920 and a non-running MK3!
I ran the bike down the road a few miles and observed the following-
It needs bar risers. My aging back was screaming after just a few miles.
The plan is to copy the Thruxton R layout for the rider. Right now with the low bars and the temp footpegs, it's miles off those ergonomics.
The power level is great but not terrifying like the 1360 Vincent.
I would guess that it will approach the acceleration times of the Thruxton R, at least up to 60 or 70 mph. After that HP wins, weight isn't so important.
Anyway it has more than ample power. I haven't tried the higher RPM range and won't until after breakin. The midrange pull is a lot of fun. It really makes you hang on.

I set the gearing about he same as my Mk3, about 4.6 to 1 overall. It could stand to be higher. Part of that is the current rpm limitation. The other part is the very healthy power to weight ratio. Im going to go up a tooth and see if that increases the fun.
I tried it though some tight corners and it felt fantastic. Very little effort is needed to flip it back and forth.
I see why Ludwig enjoys his lightweight Commando in the mountains.

So it seems like a possible keeper, time will tell. After riding it I got quite enthused and ordered another parts order to finish things off a bit, RGM kickstarter etc. Speaking of which, the rings seated quickly, it now requires 3rd gear for roller starting. Second worked before, but now it stops the rollers dead in second.
Hope I can kickstart this thing!

Glen

You may end up like Nigel, and need a lump of an e-leg, which would defeat the purpose wouldn't it?

Yes, really hate to bolt that much weight on after all the effort.
I may have to readjust my own weight loss program slightly to leave just enough ballast for the kickstart... this I can do!

Here it is with functioning but not dialed in carbs-

gortnipper said:

You may end up like Nigel, and need a lump of an e-leg, which would defeat the purpose wouldn't it?

Click to expand...

Glen is more sensible than to go for 11.1 compression ratio unlike some idiots

And he’s used to kick starting a 1360cc Vincent !

I think he’ll be orright.

Fast Eddie said:

Glen is more sensible than to go for 11.1 compression ratio unlike some idiots

And he’s used to kick starting a 1360cc Vincent !

I think he’ll be orright.

Click to expand...

He also claims to have a better ballast to compression ratio.

Fast Eddie said:

Glen is more sensible than to go for 11.1 compression ratio unlike some idiots

And he’s used to kick starting a 1360cc Vincent !

I think he’ll be orright.

Click to expand...

As long as he doesn't have a sneaky daughter videoing any difficulties he may have - eh?

9.5 to 1 Cr, so not so high, however stock cam won't be helpful.
Would 9.5 to one with stock cam be similar to 10 to one with a big cam on kickover?

Glen

9.5:1 with a 312a and a long RGM lever kicks over fine most of the time for me.

You can tell though when you have done something stupid, like forget to turn the key on. After few kicks it isn't as easy. And I am not a small guy, 6'1" 210lbs.

Is that a 920 size? If so that is reassuring.
And isn't the 312a a wee bit bigger on duration than the stock profile? If so that bleeds off some compression.

Glen

No, just a +40 bore.

The 312A with 4 inch radius lifters has duration numbers slightly longer a stock cam with considerably more lift and a little more overlap than the stock cam.

Afraid I'm in for a bit more of a tussle then.

RGM kickstart should arrive next week.

Glen

Start doing your squats!

The RGM kickstart arrived, what a beautifully made item that is.
At 2 lbs 4 oz it's not going to bend or break and is still the lightest method of built-in starting available for this beast.
I can start it OK but it must be squeezed through compression or backed up to compression first. Then, with an all-in effort, it kicks through every time.
Just randomly kicking it over results in a dead stop for the foot about 1 time in three.
The foot stops hard but the body continues downward until the knee gets everything stopped. A couple of those and the knee is very unhappy!
So it will require taking the extra bit of time to get the engine positioned correctly for starting every time. Also, it will be important to tune it for easy starting, as much as possible.

Hopefully the engine won't develop any more compression, that would not be good.
I'm also glad that these are conventional gapped piston rings. It is reasonably easy to slowly squeeze just through compression to get the engine in the correct position for the big leap.

I can see why Nigel opted for the e-start on his 11 to one , gapless ring 920.

Glen