KR650F ?

Tofty · Post by **Tofty** » Thu May 31, 2007 9:42 pm

Hi I’m new to this forum,
At the moment I have a KR1 which I am in the middle of restoring and lightly modifying, as well as a second KR1 which I recently purchased initially for spare parts. I am now considering putting a different engine into the second bike as well as some alternative bodywork just to keep things interesting and as some of you have faced and beaten (or are still on the process of beating) many of the problems this type of project is going to run into I am interested in any suggestions or advice any of you may have.

I was thinking along the lines of a 4-stroke as I want the bike to be a bit more useable at gentler revs so I laid down a few constraints to help me choose:
-The new engine will need to be of similar weight to the KR’s otherwise the front forks and the swing arm and shock would need replacing (I get the impression that the frame can take a fair amount though) and I don’t really want to do that, I’d rather do a suspension upgrade on my first KR1.
-Of similar power and torque. Although if its got to be of similar weight a cant see much being more powerful than a race-bred 2-stroke but still...
-Compact and narrow enough for the cylinder or cylinders to fit within the frame as I don’t fancy widening the chassis as JanBros has done as it clearly requires more skill and energy than I have available.
-The engine needs to be available, affordable with spares and auxiliaries also available

The engine I have sort of decided on is….rather oddly the BMW F650’s Rotax 650cc single.
I always thought the early F650’s looked rather ugly, especially the tank so this might be a chance to liberate the engine to a better life. The engine produces about 55hp but 59Nm of torque, about 50% more than the KR so a decent amount of torque without being too much for the bike to handle, although I think I will strengthen the swing arm anyway. The weight of the beemer is almost 70kgs heavier than the KR but I don’t know have much of that is BMW’s over-engineering. I would “expect” this engine to fit needing only modified mounting points but I won’t really know that until I have the engine or even better some dimensioned drawings but that’s a touch optimistic. As the F650 has been around since 95 there must be a good few going cheap and as my dad owns a k1200rs I have become aware that the spares network is one of the best.
I have no real idea if this is a good idea or not but please let me know what you think. I will post some pictures of my first KR1 when I make a bit more progress over the summer.

Oh by the way does anyone know anything about Michelin M59‘s as this new bike has a new 140 on it, I have done some searching on the web but I don’t get a lot back, Michelin for one seem fairly tight lipped on the subject and I was hoping one of you may have come across them before.

mgtkr1 · Post by **mgtkr1** » Thu May 31, 2007 10:23 pm

not sure if the f650 is the same (but overbored) as the lump used in armstrong mod bikes but the rotax is very tunable up to 80hp i beleive! but as you want something more user freindly think high 60's wuld be quite easy. i recomend using a std kr1 s swingarm as it's stiffer, easily stiff enough for up to 80hp imho, so should cope with f650 power without breakin a sweat. i would be tempted to build a sos type machine with daytime mot and tuned to buggery rotax motor as the tuning parts are easily availible, in the future use dymags, spondon rad ohlins etc with rs250 bodywork(early 90's) to replicate the commonwealth h***a that paul lewis raced at daytona many moons ago. fug it, use a big kx, tuned to the back teeth, pipe under seat. ok starting to get carried away, seriously though what you suggested sounds the way to go, at least to start with. any pics of the other one?

mr_bungholeo · Post by **mr_bungholeo** » Thu May 31, 2007 11:23 pm

i'd recommend the f800...a very narrow parallel twin...if your gonna go the rotax way..

i'm a bmw mechanic....though they ar'nt that old so may cost a bit....

Tofty · Post by **Tofty** » Fri Jun 01, 2007 11:58 pm

Cheers for the responses guys, I think i'll start keeping at eye out for a cheap engine or semi complete f650 (i think the 800 isn't old enough). I hadn't really thought about any serious tuning but its nice to know the potential is there. As for the swing-arm i luckely have one that came with my first KR in a fairly tatty condition, good to know it can cope with the expected power.

I have a few pictures of my two KR1's

http://i194.photobucket.com/albums/z42/ ... 1180738270

My powder coated wheels with BT92's.

http://i194.photobucket.com/albums/z42/ ... 1180738445

My powder coated frame and swing-arm along with masses of spares and other junk.

http://i194.photobucket.com/albums/z42/ ... 1180738670

KR1 no 2 which i bought on ebay a week or so ago

http://i194.photobucket.com/albums/z42/ ... 1180738515

I have never seen a sprocket in worse condition. How can someone let it get like that?

http://i194.photobucket.com/albums/z42/ ... 1180737387

Same with the rear brake, less than 1 and a half mm width at the center.

rc46 · Post by **rc46** » Sat Jun 02, 2007 8:56 am

that sproket is so far gone... shit i bet its the original!!! Bloody helll, i did have a bad one but not like that!!! Fook...

I can match you on the disc thou, LOL i just threw away a set of fronts that where paper thin

so bad the disc had a 2mm lip! LOL

like your frame and wheels NICE!

JanBros · Post by **JanBros** » Sun Jun 03, 2007 10:28 pm

*as for wheight : even an aircooled 125 will outclass the KR-engine, so fotget about that

* as for BHP : that's why I didn't use a sigle 4-stroke : unless some real tuning (which ain't good for life-expectancy, and requires a lot off maintenance) you'll never be able to get the performance off a KR-engine. unless it's for a trackbike, than it doesn't really mather

* on my project, I didn't have to widening the chassis (even I wouldn't try to do that), but yes, a lot off work needs to be done.

col · Post by **col** » Sun Jun 03, 2007 10:55 pm

does the fact that the final drive chain on the F650 is on the r/h side?
surely that'll make it awkward if your planning to keep the kr swingarm??

Tofty · Post by **Tofty** » Sun Jun 03, 2007 11:28 pm

'Damn you beat me to it' (edit)

I just realised something, after downloading an f650 manual and glancing at it, that makes this project a much more complicated prospect than i thought it might be; drive leaves the f650 engine on the opposite side to the KR. This is not the end of the world but it means swapping the drive train and rear braking system over. Problems include: finding a new rear brake and making a new brake carrier, the rear wheel could just be rotated round hopefully as it looks symetrical but the valve will then be in a more exposed position, the swingarm will need to be heavily modified with the shock linkage mount moved from the bottom to the top of the swing-arm so it can fit up-side-down with the widening arm on the chain side, custom chain guards and hose clips will need to be made and positioned. This is all work i had not forseen and wont look forward to as it makes those modified parts useless for my other KR. I think the search is back on for an alternative engine.

The idea for this bike is not to be an improvement on the KR in terms of performance in any way but to just be different and interesting, to be honest if the finished bike works at all i will be suprised.

col · Post by **col** » Mon Jun 04, 2007 12:21 am

how about a h***a dominator motor?
not great power but it'll fit.
maybe even a crf450 jobbie, might be a bit high maint though

Red Devil 777 · Post by **Red Devil 777** » Mon Jun 04, 2007 7:17 am

Or how about different back end? RS125 swing arm, they run the chain that side and are always pretty cheap as there isn't too much demand for them because of this.

Tofty · Post by **Tofty** » Mon Jun 04, 2007 3:26 pm

As one of the major factors of this project is cost limitation, i think a better suited single is the way to go and the KLR650 appears to be cheap and available since its been around since 87. Not the perfect engine but it has potential.

col · Post by **col** » Mon Jun 04, 2007 4:03 pm

early klr's had problems with oil feed to the top end.
dont know if this was the 600 or 650 version

Tofty · Post by **Tofty** » Mon Jun 04, 2007 8:30 pm

The KLR650 info on wikipedia gives a list of the changes that occured to the model over the years, and to the engine there are a good few. From 97 onwards no engine changes seem to have been made so hopefully these engines are fairly reliable.

Although if i got an earlier one and it was still working after 30,000+ miles i suppose it means that that particular engine doesnt suffer from the oil feed problem as it would have gone pop long ago if it did.

JanBros · Post by **JanBros** » Mon Jun 04, 2007 9:22 pm

col wrote:early klr's had problems with oil feed to the top end.
dont know if this was the 600 or 650 version

If my memory is correct, on the early had to come in to change the headgasket. in those days I knew somebody who had one when they came out, and I don't remember anything about oil-feeding-problems.

but then again, I might be wrong, 'cause I only knew him in my "Cliff-period" from the pub

Bikemike · Post by **Bikemike** » Tue Jun 05, 2007 10:44 am

JanBros wrote: but then again, I might be wrong, 'cause I only knew him in my "Cliff-period" from the pub

Cliff, your reputation has spread to the continent

If our members from Usa and Down under used "Cliffed" as a euphemism for being merry you could have worldwide acclaim

Mike