Need Advice: CR500 Project - Year of Motor Choice

G FORCE · Post by **G FORCE** » March 13th, 2011, 11:59 am

Hello all,

Great forum with lots of info. Glad I found it.

Anyway, I have a '98 CR250 with a blown engine that I sourced for the conversion. I originally wanted to follow the Gen 1 write up for the conversion and go with a '92+ CR500 engine and order the mount kit and all that stuff. I recently found a local '86 CR500 bike for sale for $750. Would this be a worthwhile option for the conversion or should I wait for a newer motor?

I know the earlier CR500 engines are rated a bit higher and more on/off switches. I was thinking of taming it down with a heavy flywheel weight. My main question is would this require different engine mounts than the '92+ motors? Anything else I should be aware of before taking on the conversion with this donor bike?

Thank you for any input,

Gabe

87CR500Rider · Post by **87CR500Rider** » March 13th, 2011, 12:15 pm

Info is all over this site on this. You'll have to bore the bushings the swingarm bolt passes through and redo the the water pump hose routing from the pump to the cylinder. Chances are the water pump is rotted and if it's not, it will be. For ease, the later engines are the way to go although I prefer the 87' engine and went with that. The mounts are the same.

G FORCE · Post by **G FORCE** » March 13th, 2011, 12:31 pm

Thanks. I've been searching but couldn't find exactly the info I was looking for.

So aside from the swingarm bushings and hose routing that's about it? Budget is kind of an issue and I'm looking at least $1500 for a newer model donor bike so at half the price, this one is a decent option?

supermotoflunkie · Post by **supermotoflunkie** » March 15th, 2011, 7:32 am

I'm not trying to be a Dick here (sorry if I am) but why find a nasty motor and tone it down? Might as well rebuild the 250 motor....?

G FORCE · Post by **G FORCE** » March 15th, 2011, 7:39 am

Not at all! I appreciate all the info I can get.

Well, the 250 engine is completely lunched. It's going to cost me about $800 - $900 to source a good used one or source new parts. This '86 donor bike is the cheaper option (and cooler option!). I've just been reading a lot of mixed info on earlier motors and wanted to make sure this was a good option.

I'm going to add a flywheel weight to whichever 500 engine I end up getting either way in order to make it easier to ride and get more of the power down.

Post by **AlisoBob** » March 15th, 2011, 7:42 am

G FORCE wrote: I'm going to add a flywheel weight to whichever 500 engine I end up getting either way

G FORCE · Post by **G FORCE** » March 15th, 2011, 7:45 am

AlisoBob wrote:

Have I been reading misinformation about a flywheel weight? Isn't it supposed to smooth out power delivery and get more power to the ground?

supermotoflunkie · Post by **supermotoflunkie** » March 15th, 2011, 7:52 am

G FORCE wrote:
AlisoBob wrote:
Have I been reading misinformation about a flywheel weight? Isn't it supposed to smooth out power delivery and get more power to the ground?

You are correct. Thats what flywheel weights do.

The 500 is the Cooler option. Just don't slow it down is what I'm saying.....

Post by **AlisoBob** » March 15th, 2011, 7:54 am

Its suposed to take the fun out of riding a 500.

Flywheel weight equals:

No flywheel weight equals:

Get it ?

G FORCE · Post by **G FORCE** » March 15th, 2011, 8:01 am

LMAO. Nice use of visual aids!

Fair enough. I'll give it a shot without it and see how it goes.

Nodge · Post by **Nodge** » March 15th, 2011, 4:51 pm

In my opinion, 86 was the best motor......... I'd be all over an 86 for 750 bucks.

nmdesertrider · Post by **nmdesertrider** » March 15th, 2011, 5:35 pm

IMHO flywheel screws up the handling too

Nodge · Post by **Nodge** » March 15th, 2011, 7:24 pm

nmdesertrider wrote:IMHO flywheel screws up the handling too

Yep. [shatner] "Bike.....will...not...turn!!!" [/shatner][/img]

Post by **MojoScojo** » March 15th, 2011, 7:29 pm

Nodge wrote:
nmdesertrider wrote:IMHO flywheel screws up the handling too
Yep. [shatner] "Bike.....will...not...LEAN!!!" [/shatner]

Fixed.

You can still turn them. You just have to do it with the back brake.

G FORCE · Post by **G FORCE** » March 16th, 2011, 1:07 pm

Glad there is another fan of the '86! I think it's a pretty good deal. I probably could find a newer donor for about $500 if I waited but these bikes don't pop up too often around here. $750 seems pretty cheap anyway! Would the roller be worth any money after I canabalize it for the engine, cdi and carb? Be nice to recoup a little cash.

Interesting info about the turning/leaning issue. That hadn't even crossed my mind.

Post by **AlisoBob** » March 16th, 2011, 1:51 pm

Most everyone here is a '86 fan.....

100hp honda · Post by **100hp honda** » March 16th, 2011, 1:53 pm

never seen a good running '85 for $750. if its worn out, youll be into it as much as buying a nice newer model. i would read up on all the bullshit that comes along with the older engines. nothing wrong with the old ones but its hard not to look towards something newer.

http://www.youtube.com/user/500bigbore · Post by **Roostius_Maximus** » March 16th, 2011, 2:00 pm

i've got a sweet 86 motor in a '88 chassis too. Its alot of fun, but it'll lay a hurtin on ya.

G FORCE · Post by **G FORCE** » March 16th, 2011, 2:01 pm

That's a clean bike there!

I guess the one good thing is that it is a running bike and I can ride it and check it out first. He says he went through it and did a top end 3 years ago and it hasn't been ridden much since. You're very right though, it could end up costing more than a $1500 newer donor bike if something is amiss.

100hp honda · Post by **100hp honda** » March 16th, 2011, 5:47 pm

if the bike your looking at is half as nice as the one in the picture it would be a shame to chop it up. those years had great significance. the later years had far less importance and are a dime a dozen.

dannygraves · Post by **dannygraves** » March 16th, 2011, 7:26 pm

honestly, I loved my '86 powered dunes bike, but found my newer bikes with '90s motors ran better and were much more trail friendly and even faster by being more controlable, plus the conversion is much easier. I prefer the '93+ motors, wide ratio with all the newer stuff. If you'r buildi ng a drag bike, then go for the '86, if you are building a trail or MX bike get s '90s motor.

G FORCE · Post by **G FORCE** » March 17th, 2011, 9:57 am

Maybe the bike would be a good spare bike for $750 as is, considering it runs and all. I suppose I could be patient and wait for a newer donor but will inevitably pay double or more. There is also a clean '06/'99 AF for sale locally for $4k that is tempting!

Danny, thanks for your opinion. I will be using it for trail/sand dune riding. What you say makes sense about using a bike with more controllable power so I'll see what comes up as far as other options.

pstoffers · Post by **pstoffers** » March 17th, 2011, 10:40 am

I love my 86 motor....

hoofarted · Post by **hoofarted** » March 17th, 2011, 11:19 am

dannygraves wrote:honestly, I loved my '86 powered dunes bike...

ya back when you had a "real mans bike" - u poser.

dannygraves · Post by **dannygraves** » March 17th, 2011, 5:51 pm

LMAO, bring your 500 to vegas this weekend and come riding with us...

BannedCR500Riders.com

Need Advice: CR500 Project - Year of Motor Choice

Need Advice: CR500 Project - Year of Motor Choice