rm 85 motor in a Raptor 125?

[exhausted]

Has anyone put an rm 85 motor in a Raptor 125 frame? I am in the process of doing it now ut wohld like to see some pics of engine placement if anyone else has done it successfully.
Main reason we are gonna try the raptor frame over the cobra or jb frame is that my son races his 4 stroke raptor and loves the chassis and the size. He feels too big on the smaller frames.
Anyone tried it?

[bigdaddy77]

I think there was one for sale in the classifieds. Haven't seen any in person but shouldn't be real hard to do. Does the raptor motor bolt through the swingarm pivot point or in front of it.

[exhausted]

I think there was one for sale in the classifieds. Haven't seen any in person but shouldn't be real hard to do. Does the raptor motor bolt through the swingarm pivot point or in front of it.

It bolts In front of it. Getting the motor to sit as far back as I want it is being a bit challenging. Where we have it right now has the drive sprocket further in front of the swinger pivot point than I want, but I think we are gonna try it like this anyway and see how it works. If I have to run a tensioner of some sort, so be it. The only other thing I was wondering is if there Is an easy way to e tend the kickstart out to get it to clear the frame of the quad?

[bigdaddy77]

On our Mod which is a CR motor in a Pitster frame. It has a roller under the swing arm pivot point. No other type of tensioner. As far as extending your kick starter I cut the part that goes on the motor shaft off and welded it to a short piece of 3/4" od 4130 chromoly tubing and then welded the kick starter to the other end. Also I cut a slit in the tubing to allow it to tighten down on the shaft better..

[trompen542]

we have done it, you can give me a call at the shop, 616-363-1215, and I will be glad to help you
kids on quads racing

[exhausted]

On our Mod which is a CR motor in a Pitster frame. It has a roller under the swing arm pivot point. No other type of tensioner. As far as extending your kick starter I cut the part that goes on the motor shaft off and welded it to a short piece of 3/4" od 4130 chromoly tubing and then welded the kick starter to the other end. Also I cut a slit in the tubing to allow it to tighten down on the shaft better..
Awesome. That was we were planning to do, but wanted to make sure there wasn't an easier way first.

we have done it, you can give me a call at the shop, 616-363-1215, and I will be glad to help you
kids on quads racing
Thanks. I will probably be giving you a call.

[exhausted]

Here is how ours is for now. We didn't get to try it out on any jumps yet, as something went wrong in the motor while I was breaking it in on the first gallon of gas.
Since the motor is further forward and lower than we wanted it to be, we added a roller where we wish the drive sprocket was, and a tensioner to keep the chain from going too slack when the suspension is unloaded. If it works, it's staying this way. lol if not, we will have to figure out some way to move the motor back.

http://i167.photobucket.com/albums/u126/perpetuallyscrewed/Mobile%20Uploads/20140209_133917_zpsqnkywliw.jpg (http://s167.photobucket.com/user/perpetuallyscrewed/media/Mobile%20Uploads/20140209_133917_zpsqnkywliw.jpg.html)

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[jlhughes750]

it IS possible to cut out the swing arm and mount it through the motor. we used a yz 85 and it worked well.

[exhausted]

it IS possible to cut out the swing arm and mount it through the motor. we used a yz 85 and it worked well.

Did you just notch the center out of the swing arm and run the bolt through the motor mount on the motor?

[Logan #34's Dad]

Did you just notch the center out of the swing arm and run the bolt through the motor mount on the motor?

I'm sure that's what you'd do. I'd check to see if the swingarm bolt is too big or to small to fit in the hole in the back of the RM 1st. Then carefully line up the sprockets and mark your swinger for the section to be cut out. Give yourself a lil extra clearance so you can shim it with a washer to the left or right.
I'd think that the further back the engine is the better it'd handle.
Is the Raptor without the engine pretty light? I remember the Raptor 250 we had was REAL heavy in the back to pickup.

Looking at your pictures and where the pipe is now, It looks like when you take the motor back to the swingarm bolt...the pipe should clear the frame..

[exhausted]

I'm sure that's what you'd do. I'd check to see if the swingarm bolt is too big or to small to fit in the hole in the back of the RM 1st. Then carefully line up the sprockets and mark your swinger for the section to be cut out. Give yourself a lil extra clearance so you can shim it with a washer to the left or right.
I'd think that the further back the engine is the better it'd handle.
Is the Raptor without the engine pretty light? I remember the Raptor 250 we had was REAL heavy in the back to pickup.

Looking at your pictures and where the pipe is now, It looks like when you take the motor back to the swingarm bolt...the pipe should clear the frame..
Ya, the swinger bolt with the sleeve that the bolt runs through is def too big for the hole on the engine. I think if this position doesnt work i can get it far enough back to get the pipe to clear without going into the swing arm. we actually added an inch to the pipe where it goes into the motor where it is too get it to go around the front of the frame. I will just have to cut down the factory rear motor mounts on the frame, which I was trying to avoid doing originally.
I've been watching some of Logans mod videos I believe, I cant wait for my son to get some time on his mod bike.

[jlhughes750]

bore or drill the hole in the engine, that's what I did. cut out the swing arm, cut a piece out of the pivot tube and made some bushings. works good. Hes been racing and riding it almost a year. I was going to mount the engine in front of the swing arm but didn't like the sprocket to pivot bolt relation and wanted to have correct chain tension.

[exhausted]

bore or drill the hole in the engine, that's what I did. cut out the swing arm, cut a piece out of the pivot tube and made some bushings. works good. Hes been racing and riding it almost a year. I was going to mount the engine in front of the swing arm but didn't like the sprocket to pivot bolt relation and wanted to have correct chain tension.
Thanks for the insight. If this set up doesn't work, then I will probably try that.

[exhausted]

We got version 2.0 back together. I moved the motor back and up as far as I could without going into the swingarm. It still sits about 3/4" forward of where the stock motor drive sprocket does, but I think it will work. I also raised it a little more than stock since the stock configuration eats up the plastic Guide on the swinger pivot so bad. I had an fmf pipe made to fit the new position also. It turned out great, but it didnt leave me room to mount the bigger yfz 450 radiator on the frame, so I had to mount it up front. Its ugly up there, but I really dont have any other options without using a smaller radiator. We put about a gallon of gas through it in the yard last night and so far so good. Def gonna need some seat time for my son to get used to the 2 stroke.
Here is him riding it last night for about 30 seconds.

http://m.youtube.com/watch?v=ri5X9Gn7ppo

[exhausted]

http://i167.photobucket.com/albums/u126/perpetuallyscrewed/20140331_175325_zpssegdseeb.jpg (http://s167.photobucket.com/user/perpetuallyscrewed/media/20140331_175325_zpssegdseeb.jpg.html)

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[exhausted]

Got about 4 tanks of gas through it so far so good.

We also got to try out the Yamazuki for the first time here in the shifter class. Braden obviously wasn't comfortable on it yet, but at least it got broken in well and made it through the weekend.

https://www.youtube.com/watch?v=RJzBmRyVhiY

https://www.youtube.com/watch?v=DPGswo1b1Zk

http://i167.photobucket.com/albums/u126/perpetuallyscrewed/DSC00012_zps7b4f8881.jpg (http://s167.photobucket.com/user/perpetuallyscrewed/media/DSC00012_zps7b4f8881.jpg.html)

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[bigdaddy77]

Looking good. What did you use for radiator hose. Been wanting to reroute ours .

[exhausted]

Looking good. What did you use for radiator hose. Been wanting to reroute ours .
Thanks. Now that it has stayed together after 3 full days of riding, I can start going over everything to make sure nothing is coming loose or rubbing in a bad way. I also wanna try the vertical louvers in front of the radiator that Can Ams use, or something like them. I think Vertical would work better in a muddy race at keeping the mud off the radiator.

I just ordered Yellow and Blue silicone hoses from GPI on Ebay. One kit for an RM85 and one kit for a Banshee since they front mount their radiators, the kits come with longer hoses.

[bigdaddy77]

Thanks for the info. I was looking at some silicon hose that aren't p refabbed bends. Your suppose to be able to route them and make tight bends with them. We run a fluid dyne KX85 radiator with a CR85 motor in a pitster pro chassis . Seems to run plenty cool. The kx was the biggest bike radiator we could find.

[exhausted]

Thanks for the info. I was looking at some silicon hose that aren't p refabbed bends. Your suppose to be able to route them and make tight bends with them. We run a fluid dyne KX85 radiator with a CR85 motor in a pitster pro chassis . Seems to run plenty cool. The kx was the biggest bike radiator we could find.
It's pretty flexable, but def run the smallest diameter you can, as they bend tighter before they start collapsing.

[exhausted]

Anyone know off hand what throttle cable will work between the stock RM Keihin carb and the raptor thumb throttle? My son said he wants to go back to the thumb throttle now. lol

[exhausted]

Here is a video of it from last weekends D13 race. 2nd time racing it so he still has a ways to go getting the most out of it.

https://www.youtube.com/watch?v=8Cgkqk3EmtI

[bigdaddy77]

You can probably use a Blaster throttle cable . Thats what we run with a cr motor. You need to make sure that it the one that goes directly to the carb not that stupid thing yamaha runs on the side of the carb.

[exhausted]

You can probably use a Blaster throttle cable . Thats what we run with a cr motor. You need to make sure that it the one that goes directly to the carb not that stupid thing yamaha runs on the side of the carb.
Thanks man. Blaster cable worked perfect.