Jump to content

My WR450 25 pound trim off...


Recommended Posts

I'm on a quest to make my WR450 as light as possible for tight woods use.

I've mentioned this a couple times in threads and now I'm getting PMs about it.

I promised to write it up. I haven't had time to and I'm off riding again this week. I'll get to it, with pictures and more numbers, but for now, here is what I have done.

Removals

Done: Starter: 1.63 lbs

Done: Starter idler gears: 1.05 lbs

Done: Tank mount bracket: 0.39 pounds with the 4 bolts <-- needs reinforcement though

Done: Starter switch and harness to right side rad mount 0.11 lbs

Done: Boil off vent hose, tank to under bike, 0.15 lbs

Done: Head light assembly 1.45 pounds

Done: Reflectors: 0.72 pounds

Done: Trip computer assembly: 0.88 pounds

Done: Battery: 4.60 pounds

Done: Snorkel: 0.52 pounds, with screws

Done: Starter relay, cables, isolator rubber, other relays, etc. 0.88 pounds.

Done: Boil off bottle and connector hose: 0.52 pounds

Done: Battery tray, boil off bottle fender plastic, ECM rubber isolator: 0.44 pounds

Done: Breather reduction off starter port. 0.13 pounds gross, about 0.12 pounds net

Done: Throttle body harness holder. 0.06 pounds

Done: Front brake line bracket 0.13 pounds

Done: Skid plate rubber block 0.11 pounds

Done: Aluminum rear sprocket 1 pound net. stock 1.78 pounds - new 0.78 pounds

Done: Starter clutch and gear. 1.45 pounds, lighter flywheel and less gyroscopic mass as well.

Done: Handlebar ends trimmed off. 0.06 pounds

Done: kickstand 1.16 pounds

Total 17.43 pounds.

260 lbs stock, dry - 17.43 removed = 242.57 pounds, dry.

I have made a couple small additions that are not in the list.

This list is by no means complete or comprehensive, but it gives people an idea of what I've been up to. Best of all, most of these removals are very inexpensive to do.

I have another 6 to 10 pounds of weight reduction planned. Thus far its been very easy to remove weight from this bike. Yamaha builds things very robustly.

The most contentious removal will probably be the starter. Frankly, I don't see the need for it and being a new (returning) rider, I've been stuck in some very tight spaces with my bike since I got it a bit over a month ago. For those not aware, the WR450 starts excellently with the kick starter. Once the throttle is adjusted, 1 kick does it even when its hot to the point of boiling over. And it doesn't flood when you stall it or tip it over either.

Its interesting to watch Graham Jarvis vids... he almost always appears to use the kick starter on his TE300, even though it has electric start.

FYI, I'm weighing everything with a Berkely (15 lb?) digital fish scale. You need to have something like this before you tackle a project like this.

Edit. Correction. I'm using a Rapala scale, not a Berkley.

http://www.rapala.com/Digital-Scales/Digital%20Scales,default,pd.html?start=11&cgid=rapala-toolsAndMore-scales

I hope this helps someone.

Edited by MidlifeCrisisGuy
  • Like 5
Link to comment
Share on other sites

I've been thinking about reducing the weight of my bike as well, but then remembered that the extra 20 pounds sitting around my midsection is part of the problem.  If I can lower my weight 20 lbs not only will I ride lighter... but maybe live longer to ride.

 

Now, if burning fat was as easy as removing a starter...

  • Like 4
Link to comment
Share on other sites

I've been thinking about reducing the weight of my bike as well, but then remembered that the extra 20 pounds sitting around my midsection is part of the problem.  If I can lower my weight 20 lbs not only will I ride lighter... but maybe live longer to ride.

 

Now, if burning fat was as easy as removing a starter...

I lost 4 pounds myself since I got my WR. Its much easier to be motivated to work out when you have a reason to, ie riding. Nothing like being totally spent after a fast section to realize that one needs to improve one's fitness. I won't need new springs on my WR and all the work of changing them if I manage to lose 20 pounds or so.

But its not about the weight of the rider/bike combo per se. Its more about making the bike more responsive and flickable.

Link to comment
Share on other sites

When you put a decent skid plate, radiator guards and bark busters all that weight goes right back on.

The stock skid plate weighs 0.99 pounds with the rubber damper piece and 0.88 pounds without it. It has withstood the test of time thus far. It needs a piece of foam to stop mud build up. One could always opt for a (quick releasing) carbon fiber model to save some weight.

I haven't needed rad guards yet. The stock louvers weigh 0.30 pounds each, which will offset some of the weight when I do add them.

I'm using the Moose Racing handguard bars without any plastic. They weigh 0.48 pounds each, plus a bit for a custom mount I built.

This stuff does add weight to the bike, but its better adding weight to a lightened bike than a heavy stock bike. A stock 2012+ WR450F weighs 260 pounds without fuel. If one isn't careful with accessory selection, it would weigh 270 pounds dry with accessories. I dislike bikes that heavy.

Link to comment
Share on other sites

In another post you mentioned it would be cheaper to lose the weight off the WR vs setting the YZ for trail etc. Are you making your comparison to the older 08-09' YZ's or the newer FI ones? I'm asking because I'm interested to see what you end up with in weight at the end. You have (going to) basically strip everything off the WR down to that of being a YZ with a wide ratio tranny and a shorter wheel base (250f frame)? The only other differences I can think of is Rear wheel size, suspension valving and some sort of pipe/spark arrestor?

Link to comment
Share on other sites

In another post you mentioned it would be cheaper to lose the weight off the WR vs setting the YZ for trail etc. Are you making your comparison to the older 08-09' YZ's or the newer FI ones?

Well, here's the thing... after owning my FI WR450, I'll never own a carbureted dirt bike again. So that rules out the 08-09 (06-09) YZs. And I don't care for the newer YZs for trail use.

I think the WR450 engine package is an absolute gem. Its highly under rated because of the bike its in. The stock WR is simply too heavy to get the attention that the European 350s do, for example. But the WR450 engine starts extremely well, runs crisp from the basement to redline, its extremely torquey, responsive, smooth, etc. I'll go out on a limb and say that a tuned WR450 engine (muffler, cams ?, competition box and GYTR tuner) is the best woods engine you can get.

And in a stroke of brilliance, Yamaha stuffed it into the YZ250F chassis. Unfortunately, they then overbuilt absolutely everything else on the bike, making it a very heavy, clumsy overall package.

 

I'm asking because I'm interested to see what you end up with in weight at the end.

That depends on how much money and time you want to spend. Basically, I suspect the weight difference between the WR450 engine and the YZ250F engine is about 10 pounds, after the starter is removed and a few other things are taken care of. The limit of lightening a WR450 is the dry weight of a YZ250F plus the engine difference (10 pounds) plus whatever off road equipment you need to add to the bike.

 

You have (going to) basically strip everything off the WR down to that of being a YZ with a wide ratio tranny and a shorter wheel base (250f frame)? The only other differences I can think of is Rear wheel size, suspension valving and some sort of pipe/spark arrestor?

Engine tuning and the FI system is the other big difference. You'd get FI on the '10 to present bikes, but I doubt you can tune them to be as great as the WR450 is. But I'm not an expert either.

The way I look at it is with the WR450 you get the excellent YZ250F chassis and the excellent WR450F engine, both of which are nearly unbeatable. All you need to do is strip off all the other junk that has been thrown onto the bike that hides its true potential.

Edited by MidlifeCrisisGuy
  • Like 1
Link to comment
Share on other sites

Might look at running a YZ tank. They are smaller, and so probably lighter.

The WR450F tank is on the verge of being too small for long rides as it is. The YZ tank would make that worse.

FYI, the 06-09 YZ450F tanks might fit, but they don't have a built in fuel pump. The '10-present YZ450F tanks probably won't fit because the air filter is in front of the engine on those years. The YZ250F has never been fuel injected, so those tanks won't work either.

Link to comment
Share on other sites

Update.

My FMF Powercore Ti muffler with the quiet insert arrived on Friday. I installed it. It was a perfect fit.

I don't have the exact weight savings figured out, but its a bit over 2 pounds, bringing the total weight reduction on the bike to nearly 20 pounds.

I installed my hand guards. Total weight added was 1.2 pounds. I built some simple custom mounts that worked out quite well.

By my calculations, the dry weight is right around 241 pounds, down from 260 stock.

I had the bike on the trail today and all I can say is WOW ! I don't know which change did what as I lightened the flywheel, removed 5 pounds from the bike, installed the new muffler and slightly changed the gearing since the last time I rode it.

All I can say is that the package has really come together. The engine is way more powerful/torquey and responsive and it handles a lot better. Its still outside the YZ250F realm, but I'm not done yet either. Gone is that top heavy "big thumper" feel. It still has a thumper feel, but it feels lighter and more responsive. The front wheel is way lighter when you want it to be and yet the rider has outstanding throttle control. There isn't a dead spot in the powerband from idle to redline. I think the engine is incredible and I'm still running the stock competition ECM tune.

All this just makes me want to lop another 10 pounds off the bike.

FYI, the Powercore muffler with insert isn't much if any louder than the stock muffler.

FYI, the stock flywheel without the starter componentry weighs 1.5 pounds. The starter componentry on the flywheel weighs 1.45 pounds, but not all of it rotates with the flywheel. Nevertheless, I have to think I reduced the rotating mass of the flywheel by 25% or so. In spite of this, I did not find the engine to be any less smooth or tractable. In fact, unless my senses are playing tricks on me, I found it to be smoother at low RPMs. I also think it kick starts easier. Again, it may be my mind playing tricks on me.

FYI, I'm now running 12/51 gearing. I think this is perfect for tight woods use. I say this because even in the most gnarly situations the engine isnt running at an idle. This allows it to have way better throttle response when blipping to lift the front wheel in these situations. Of course this gearing limits top end speed, but I'm rarely in 5th gear as it is.

The other thing this gearing does is move 1st, 2nd and 3rd closer together, which is great for tight trails. Between the gearing change and the widened powerband and increased torque due to the FMF muffler, one always has a gear whereby you can lift the front wheel instantly. This really helps on trails littered with logs. It makes the bike so much easier to ride in technical situations.

Edited by MidlifeCrisisGuy
Link to comment
Share on other sites

One more thing. Most of the changes I made were nearly free and done with simple hand tools in my spare time.

The FMF muffler of course wasn't free, but I needed a different muffler to replace the very restrictive stock exhaust and the Ti option wasn't that much more than the regular aftermarket muffler anyway.

Furthermore, everything I have done to my bike so far is reversible. Ie, I could put it back to stock if I wanted to sell it. I might make more dramatic changes in the future.

BTW, the weight listings on the FMF site were incorrect for my muffler. And there are potentially other, lighter FMF options. I'll discuss this later if there is interest.

Edited by MidlifeCrisisGuy
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

×
×
  • Create New...