860 Kit

[dogshome]

My 650 has always ran like a 1980s 250 2 stroke. Except less noisy, no power band and better MPG! Apart from those things, she is light and easy to handle, not particularly fast and needs a gear change on hills. Similar performance (in a different way) to my old RD.

The engine is completely different to my friends R80. He describes it as deceptively fast. The 650 is nothing like that, more revs=more go, but rolling on and suddenly doing 90 is never going to happen.

So it's in. I found the upside down head gasket and dodgy pushrod rubber. The quality of the alloy and fasteners is nothing like my old RD, 39 years and 63,000 miles and the bores, rods and big ends are like new.

Some soft carbon buildup and totally dry exhaust ports. Perfect.

Just got to fix the exhaust and a test run is in order.

[dogshome]

I can see the much discussed squish band is not perfect, but the design is clever and they squeeze in 2 more cooling fins.

I never achieved perfect squish on any of my bikes and ultimately performance is a combination of things.

Quality is excellent, although clearance on the back of RH cylinder to crankcase is only 8 thou. I thought I might have to Dremel some off, but it was OK.

My experiences with bike carbs is that the jetting matches the bore size and engine type (2 stroke or 4). Unless the engine is doing a lot of revs with modern cams, then the setup for one engine on a 32mm carb is pretty close to another, whatever the capacity.

I do know what rich and lean mixtures feel like, but insights into possible jetting changes are welcome. I have standard type  exhausts, standard paper air filter and absolutely no plans to change those things.

[mrclubike]

After you assemble it turn the motor over by hand and make sure it does not lock up
I cant remember exactly but I think some R65 blocks foul the piston skirt or something to that  affect and need to be trimmed

[dogshome]

First rule of comedy!  8-)

In gear and slowly by hand, plugs out. Then did on starter with plugs out and laid on head, then did with plugs in. All good, but new rings, assembly oil and bigger cylinders = hard time for battery.

I've rebuilt a few overhead cam engines and am always wary about that first rotation. Wasn't expecting any issue with this pushrod engine, just force of habit. My XT500 became about 560 and I put a huge Amal carb and a slightly modified speedway cam in it. I had to grind the rocker covers out and trim the tappet adjuster tops to get the big valves and lift inside. It changed the bike from soft into a bit of an animal. 

I seem to remember having to cut something out of the top of the case as well due to the forged piston shape - which wasn't Yamaha. Can't remember, it was in the 80s.

Just getting grinder to the totally rusted cross pipes now....

[dogshome]

It runs. Hooting down with rain and I've been messing with the exhaust for a couple of hours. I bought some Keihan standard style stainless mufflers second hand for £60 and they are very quiet compared to the chrome ones that were on the bike.

So she sounds a lot slower 

[dogshome]

We have unwanted interest!

Her big brother is happy sleeping.....

[Tony Smith]

If you think it is good now, just wAit till it is run in.

[dogshome]

If it EVER STOPS RAINING!!!!! Tomorrow looks good. 

[dogshome]

It doesn't feel like it will need much running in. Already idles after 30 miles and a couple of deliberate stops and warm restarts. Less vibration and feels very turbine-like.

Keeping the revs between 2500 and 4500 and stopping after a few miles to cool. I've found with various engines that keeping the revs up, load light and stopping for a rest now and then is the best way. Iron bores and cheap pattern pistons take a while. These little forged beauties and plated 'liners' are not going to take long at all.

I am looking for 7th and 8th gear though. On my usual routes, even being aware of keeping light load, I did't think about changing down on the regular inclines. It all feels much more together. I didn't weight the pistons, are they lighter than the standard ones?

Is it worth E900? Same as it cost at the vet when one of my dogs got a very nasty infection, same to get my car through it's MOT a couple of years ago, same to help my daughter out now and again. Less than council tax council tax. Orders of magnitude less than a new BMW. A good holiday? Not really. Is it coming off and the 650 stuff going back on? NO CHANCE! 
 

[dogshome]

Going on a bit now, sorry!

RD250 plastic swing arm bearings. BMW Taper rollers.
RD250 Cheese crankcase screws. BMW Proper hard hex and cap fasteners.
RD250 Pretty poor castings and flaky paint. BMW Different alloy altogether and will last probably 1,000 years.
RD250 Very unreliable 2T injection and not long lasting (apart from the crank which was bulletproof). BMW Bulletproof all over.
RD250 Lively and tune-able engine (if you have time with a die grinder, which I did). R65 Lawn mower engine. R86 I'll let you know, but signs are good!

[mrclubike]

The 860 pistons are heavier
But I cant remember how much it was

Without a side car you definitely want  a taller final drive 

[dogshome]

I should have checked the insurance first!!! 
5p per additional cc for the year.

Siebenrock confirmed standard jets all good with an unlikely incremental main jet increase. According to Haynes, mine should have one of the larger types already.

[BPT]

I would never encourage anyone to flout the rules    , and I do know that some countries can be quite strict, but I am curious  - the insurance company will know that the cc's have increased? Does this have something  to do with your (from what I've heard....) more rigorous inspection process?

[dogshome]

If it had been an 800 or 900 upgrade, it would have been the same. It took a little longer because of the odd size, but we are talking 30+ year old bike with at best 50HP going to possibly 65. So the £10 yearly cost to me is very reasonable.

You could simply fit it and not tell anyone. However, if something really expensive happens then a simple count of cooling fins would identify the change. I doubt they would bother for written off bike and a bumper smash, if there was a fatality and multiple pile ups caused by me, then they might have a look.

If I were 30 yrs younger, the bike was a Hiabusa and I'd fitted a home brew turbo with nitrous, the premium might have been a little more.

I imagine there might be lots of undeclared mods, our bike inspection process is quite basic because it would be expensive and make no difference to accidents. A hot cam or performance exhaust is unlikely to affect the chances of SUV muppet pulling out on you.

Bike gets nicked, undeclared expensive mods? Still low risk to insurance company.

It's all down to risk and money. Which is the same as any government or corporate business model. Same in engineering.

I should charge a consultancy fee for this insight 

[dogshome]

She gets a wriggle on in 4th and 5th now. Front lifts up and hang on. I can't change gear quick enough at 4500 rpm. Happy at 75/80MPH indicated (70 then). Acceleration from that speed in top gear is very positive. Acceleration in second or third is lively, definitely in tuned RD400 territory now.

Pickup is clean, but I am trying to avoid any low speed lugging. Consequently I am looking like a novice at every stop junction. Stop, go, GO!, NO! go, Go!!!. Kangaroo fuel.

Actually becoming aware of power in the back wheel in corners now. Never an issue as 650. Unlikely to smoke the back wheel or become a problem in rain (we are talking maybe 65BHP instead of optimistic 50) and I feel has similar performance to my car at speed now. Saab 9-5 remapped 1.9 Diesel. Don't laugh, the Fiat engine with 9-5 petrol intercooler and swirl valves removed is easily 400NM.