Added a Cobra to the stable.. HELP !!! :)

[TeamNeilson]

Hi All

We bought our son a cobra chassis at Loretta's this year with the intent of putting in a shifter motor for him.

I initially planned a 'father/son' build of an RM85 slash Cobra as I really, really REALLY want to be away from CVT for good...


I think i've bitten off more than I can chew and would love to talk to someone who's done this transplant and if they have the parts I need I would likely just buy what I need right from them and make my mouthful a little (a lot) more manageable.


I'm in the process of securing an RM85 bike to pull the motor from.. I want to keep it stock. I'm worried about the engine mounts and pipe.. Does someone make motor mounts for this or can provide a template? What about a pipe? surely the dirt bike pipe doesn't fit up, is there a suitable alternative? I've read about the trackside pipes but i'm fairly certain that's complete overkill right now.. Is there an alternative? Heck... if someone has an RM85 motor they want to ship me I'm listening :)

Lastly, I understand that I have to shave down the swingarm where the rear motor mount is.. Can someone tell me how much I need to mill off to get the sprockets lined up?


Any advice from the experts would be GREATLY appreciated.. It's breaking my heart to watch my son spectate while all of his friends are out on their trusty steeds.




oh, for those that know us.. the DRR is dead and has been retired... We had to pull out of our last race and have given up on the rest of the season.. He's heartbroken to say the least, but there is a glimmer of hope with the cobra chassis sitting in the garage (he sat on it for more than 2 hours today)....


thanks again all...

[doonanracing]

A good person to talk to is John from Heath Racing. I know Wileys does make mounts for some mods like a KX65 or a CR80 and that is another good resource to contact.

[jandjracing]

Call Greg @ Trackside performance. He is the original person to build a pipe for your combo, and the only one I know of. His work is top notch and you will eventually get one anyhow, might as well be now. I think he has motor mounts that you need also.

[BradLoomis]

http://www.exriders.com/vbb/showthread.php?s=&threadid=442880

CR85 install

[gistmarrs]

I've got three mods right now. Two YZ85's and a rm85. I could part with one of the YZ motors, mounts and pipe. Let me know if you are interested.

By the way, I didn't do anything to the swingarm to make it fit. I needed a few washers on the right side to take up a bit of gap and drill out the pivot on the motor and that is it.

Every Cobra that I have seen around here (California) has been modded with RM, YZ, or CR motors. They are really reliable, light, and fast.

Let me know if you need anything like pictures, dimensions, etc.

[TRI-Z3]

we have 2 cobra's with rm 85's I have about a dozen spare motor mounts cut out and drilled in steel pay the shiping and a set is yours. on the exhaust I do build and mod up mine but have seen some folks use the 70 cobra pipe with little change to the head pipe. it may not be the peak power but would be great for a start. i have a spare 70 shifter pipe for short $ give me a call 1 413 237 5396. Eric , would be happy to help ya out. cause it sure was nice for me having Brandon Tittle walk me through our first one!

[TeamNeilson]

Hi All.

Thanks so VERY much for all the replies. I did secure a good running 2003 RM85 late, late last night.

Tri-Z3, i'll give you a call today to talk shipping and motor mounting, if that's ok.

I'll check on Trackside for pipes if they've got something that bolts in, otherwise if you guys know what modifications are needed to the stock 70 pipe I can ask my welder if he's comfortable tackling something like that

I'm not much of a fabricator, so bolt in and go is my preferred path.. But i'm working towards it.

I was told that taking a piece off of the swingarm to fit the motor was the preferred method so that the motors could be purchased and slipped in without modification, but it doesn't seem like anyone has gone that route when I read around here. Is there an issue i'm not aware of or haven't been told?

Lastly I do want to talk gusseting, but i'll tackle that over the winter I think. I just want him out riding for now, learning the clutch and gears and getting back to having some fun. Hopefully someone has a good gusset tutorial handy that I can throw to my welder hahaha

I also looked at the CR85 install pictures and that actually inspired me to continue with this project. I'm still pretty worried but it seems you guys in this section are as passionate about their bikes and kids as I am, so I know I'll be ok.


Thanks again, I'll likely be back again soon with updates :)

[Ryko racing]

gusset it now. the added performance will continuously crack the frame.

corner gusset all corners around engine mounts, run a tube across front shock tower mounting tube and all corners under subframe. we never broke one all last year after gusseting and addind motowoz shocks
we ran a cr

[TeamNeilson]

Would you be able to shoot some pics my way of the gusset points?

I can then take it all over to the welder and have him add it in for me..


You are likely right though.. he's probably going to pound this thing even when he figures out the first few gears.

[DoubleDad]

Listen to Ryko, gusset it now. If you use a cobra pipe, you will need an head pipe to RM exhaust port adapter. Cut a section of the head pipe out the thickness of the adapter to take out the added length, then reweld back together.
Use the stock swingarm as is, drilling out the pivot hole in the motor case is all that is needed.

[Ryko racing]

ck your pm

[TeamNeilson]

I'll give you a shout tonight after work.

Thanks :)

[thequadfather+2]

Yes Loretta's must be the mini quad flea market....I also purchased a Cobra. Looked at several while I was there, talked to Horton about the one he had left, my cash offer wasnt quiet enough. Anyway, I settled for a 70ss that needs some work. I have 2 CVT's and actually enjoy them, one 90cc with a Malossi motor, pipe, ect....

We bought the 70ss to build and convert our youngest rider (7) over to it. I think he may ride better on this quad than his DRR.

I live about a mile from Brandon Tittle and have already been to his house for tech support, I told him we would be visiting frequently. he gave me a short list of things to do, begining with tearing it down completely so we can look it over good and powder coat and gusset the frame before we start building it.

[Ryko racing]

You will love them, we raced them for 3 yrs and felt that they were way less hassle than our cvt quads. Personal preference i guess.

Tittles, Heaths, Wiley mods will all set you straight.

I cant believe the deals that people were giving at Lorettas.

Good luck.

I think Horton sold all 3 of his at Lorettas.

I know Brett Musicks COBRA mod and Supermini are available.
(they are about the best running Cobras i have seen)

I f interested shoot me a pm and i will forward it to C D.

[TeamNeilson]

I'm thinking my son will love his too.

He's already got as much seat time on this as his other bike and there isn't even a motor in it yet! He just sits on it and practices pulling in the clutch and fake shifting the gears.


I'm hoping the hassle is far less... i'm fairly certain the hassle will be less than what i've faced as i'm far more comfy with the dirt bike motors than the scooters.


Ryko I got really immersed in the other motor last night and one thing led to another and voila it was 4am... I plan on pulling the chassis completely apart nut for nut over the next few days and will set up a time to call that i can actually be sitting with a bare frame.

[Ryko racing]

no problem