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KTM 65/85 F2 & Endurance Racer Build

21K views 31 replies 9 participants last post by  ryan konitzer 
#1 · (Edited)
Probably a little premature to start the "build" thread as there's not a lot of building going on just yet. A HUGE thanks to Mike (mg15 here) for making this come together, he's doing the frame work and has been a huge help already in trying to sort the exhaust and airbox fitment issues that are going to eventually need to be addressed. He got the wheels in my head turning on this thing as he's building one for himself for the OVRP 4-hour endurance series. I have been wanting to do a 65 for a long while for MD Minimoto and NJMiniGP, but the miniscule size kept me from it. This bike fixes all of that, 30 minutes sessions should be no problem on it.

The goal is to have it together and sorted by the 3/31 opening day at Sandy Hook. If all goes well and the motor is serviceable, that should be doable.

17" rims and spokes are on the way from RAD, and springs are on the way from Cannon Racecraft. I initially planned to go with 12s in the interest of making the bike as light as possible with the little motor in the heavier chassis, but they are out of 12x2.5 rims and will be for a long while it sounds like, so 17s it is.

The frame is still in New York being wrapped up. It should be welded up, media blasted and on the way down this week. I have a 65 motor coming that needs God knows what. I'm hoping it's not a basket case. Cases will be split the day it gets here so I can get whatever it's going to need on order. Brent at www.tdc2strokeperformance.com is going to get the cylinder for port work along with a couple of cylinder heads. He's going to set one head up aggressively for sprint races, and a milder, "safe" head for the endurance stuff. He's concerned about heat build-up in the 4-hour races, but he thinks with the dual radiators of the 85 chassis he can build a little more compression in to make a little more power and still have it live through the race. Will it be competitive against the 150 air-cooled 4-strokes? That is the big question.

The suspension is going to be sent down to Dave at FastBikeIndustries after the springs show up from Cannon.

Here's a 65 motor being mocked up in the 85 frame. It looks "silly" in there for sure. The width at the swingarm is exactly the same on both motors, and the rear lower motor mount lines up perfectly. The sprockets also line up perfectly. The upper mount did need to be moved and extended. The 65 motor uses 420 chain, the 85 sprockets are 428. Once I figure out the gearing Mike is going to turn down some rear sprockets so I can use the lighter, smaller 420 chain.


The frame after the mods and hit with some primer.


I sure do seem to have a thing for clapped-out 2004 Austrian Shitbuckets. This makes #3. I picked up the 85 "chassis donor" today. A little rough but not terrible.


I spent some time with it this afternoon with a bottle of Simple Green and a scrub brush, trying to get the mud and grime off enough to work on it. I'll tear it down this week to get a list together of what it needs.



That's it for now...much more to follow.
 
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#3 ·
Todd,
your donor 85 is looking a lot better now that it's clean.

...........maybe it would be more appropriate to thank me for being a "Huge" bad influence........
Yes...HUGE bad influence sounds about right! At least I talked myself out of the baby Marchesinis!
 
#6 ·
What a cute little motor in that frame...:lol:


Any plans for the blown 85 motor?
 
#8 ·
The frame got media blasted today and packed up for the trip down to VA. Mike and his people don't mess around, things get done with these guys.

The frame, new exhaust and the 65 motor should all be here in a couple days. I'm hoping to get the exhaust fitment sorted and get the new mounting tabs welded up this weekend.

 
#13 ·
Spent some quality time with the chassis donor today. All-in-all it's not too bad. The steering head, swingarm and wheel bearings are in good shape and usable. Nothing was stripped and/or broken.


The 85 motor needs some help. The cylinder and head are in good condition but the clutch basket is shot and it needs a crank rebuild. The piece of shrapnel in this pic was wedged behind the reeds. It's a piece of the connecting rod thrust bushing. This thing was literally seconds away from potentially damaging the cylinder and head. I'm glad I didn't start it even once. I have no idea what I'm going to do with this motor. I will split the cases and see if the transmission and all the other internal stuff is in good shape and go from there.


The frame and 65 motor should both be delivered tomorrow. I forsee a long night after work, opening the 65 up and assessing the damage (both to the motor and to the wallet).
 
#14 ·
I got a little more done over the weekend. The frame, motor and exhaust all showed up Friday.

Here's the frame wiped down and ready for primer. It was so nice dealing with a frame that had already been blasted. I just blew it out really good to get rid of the remaining blast media and dust, taped up the bolt holes and then wiped it down with some acetone.


The frame with several coats of etching primer. I still have to work on the exhaust mounts, so there will be a little more welding on the frame.


Test-fitting the engine to the 85 swingarm. Here comes the first snag.


Now...the motor is "supposed" to be the same width as the swingarm. Clearly it is not. Maybe it's "the same" up in New York...but down here in VA, we don't call this "the same"! (just ribbin' you a little, Mike) :D
Spacers should be no problem to fab for the gap.


Here's the 65 motor. I haven't opened it up (beyond pulling the cylinder and head) yet to see what's going on inside. The kid that I bought it from was told by his local shop that it needed a crank, clutch and a carb. We'll see. The plan is to pull it apart to get a parts list going, get the crank sent out for a rebuild, the cylinder and head to the motor guy for some work to broaden the powerband and to help the motor keep its cool during the long races, and get the transmission apart and the gears and shafts in the tumbler to be polished up.


And some of the new parts have started showing up.
 
#16 ·
Oh no...the ******* paint booth has yet to be unveiled. That comes a little later on.
The was just a quick and dirty "get some primer on it before the surface rust sets in" thing.
HERE is the ******* paint booth!


I'm working on the team. The only person that seems genuinely excited about it is my buddy Terry, but I'm not sure the bike will survive him over the course of a 4-hour race...he crashes too damned much.
Here's an example of some of his handy work on my 105. :headshake


For some reason I was thinking you weren't big into the endurance stuff. You know, you're always welcome on the team (and of course Mark, too)...plus with you on board the chances of winning go way up!
 
#17 ·
That is a sweet setup. Earl Scheib (remember them - paint any car for $99.00?) would be proud. I might be the only one old enough to remember.

I did three of the endurance races year before last. I'd be happy to ride and contribute in the form of tires, entry fee, whatever....
 
#18 ·
I remember Earl Scheib! Hey, it did the trick..the paint job turned out clean and I kept the overspray down (my main concern was overspray on the neighbors' vehicles). Plus it was free.

That sounds like a plan. I've never done one so it will be nice having you onboard for the experience and pointers.

Of course it all depends on how the bike runs and rides. That little 65 may be a miserable thing to try and go fast on for 30 minutes at a time.
 
#19 ·
Didn't do much with the bike over the last week, I split the cases on the 65 last weekend and pretty much found a basket case. It needs a new crank, clutch basket and inner hub, several transmission gears, countershaft, kickstarter and shifter spindles, and the cylinder has been sleeved and needs to be sent out to have the ports chamfered (there is no chamfer to speak of at all) and the sleeve to cylinder mismatched fixed. I was a little disappointed/frustrated after opening it up.

Several blasted gears.



Crank nose where it drives the water pump is starting to round off.


Big time port mismatch and zero chamfer on the edges.


Picked up a used eBay transmission. It looks to be in great shape. I broke it down to inspect the gears and dogs and to run it through the tumbler.



I'll tumble everything for a couple of days. The pieces will come out with an almost polished look to them.


A bunch of parts showed up this week.

Cannon Racecraft did a custom set of .46 fork springs (the heaviest they stock is .38) that are 1" shorter than stock. The suspension is all boxed up and will be sent down to F.B.I. this week.


The 17" rims and spokes.


Some of the other random stuff. Catch cans, crank bearings for the 65 and my 105, carbs for the 65 and 105.


I spent some time mocking up the exhaust to see what it was going to take to make it all fit. The 65 silencer definitely won't work, but it looks like an 85 one will.


Now the next major hurdle is making the 85 swingarm bolt work through the 65 motor and making a spacer for the motor to swingarm gap.
 
#20 ·
Maybe I over looked it, but why are you going with the 65 as oppose to the 85? Looks cool either way. Interesting to say the least!
 
#21 ·
The bike is being built to run the 4-hour endurance races with NJMiniGP and OVRP. Both organizations have 65cc 2-stroke/ 150cc air-cooled 4-stroke displacement limits. I'm doing the swap because 65 bikes are just so small, the 85 chassis will be much more comfortable to ride.
 
#25 ·
Yup, ground English walnut shells from Petsmart or Petco. It's lizard/reptile bedding. I added some liquid metal polish from the auto parts store. I can't remember the name offhand.

I experimented with ground corn cob and Nu-Finish car polish on the transmission I did before this one, it didn't work nearly as well as the walnut shells.

This batch ran for about 36 hours.
 
#26 ·
Just got an e-mail from the crank guy (www.cookseycrank.com) that the 65 crank is ready. It is a brand new crank but he trues them up regardless. The pics and videos are typical of what you get from him. If any of you 2-stroke guys need crank or even engine rebuilds, Andrew's customer service and attention to detail are hard to beat.

Video:


 
#27 · (Edited)
Damn, that's pretty much awesome. Very rare you see customer service like that, especially on a what? $1xx dollar crank. Or was that one different? I'll def be buying from him just off that video. Unless he only works with KTM engines. I'm going to rebuild my spare 85 engine :D
 
#28 ·
Exactly, that is an off-the-shelf, nothing special Hot Rods crank. He works on pretty much all 2-strokes I think (and some 4-stroke stuff).

New o.e. CR85 cranks are only about $100. I think I'd go that route when you rebuild it. For piece of mind you could send it out to have it checked/ trued. I'm not sure what he charges for that but I bet it's <$20 or so.
 
#30 ·
are you using 17 x 2.5 for the front and 17 x 3.5 for the rear?
where did you order them from? (and spoke kit as well)

Thanks

(I'm toying with the idea of taking a 2005 KTM 85sx and converting to a supermoto)
Yes, they are 17x2.5 and 17x3.5 Excels. I ordered them from www.radmfg.com, they had the rims and spokes in stock. Cam at mmracing.biz or ksrwheels.net will both also take care of you. You can't go wrong with any of the three really.
 
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