CRF Mods and Improvements

[blakegeee]

Can't say iv'e notice a lot of difference in performance, but it sounds a lot sweeter than it did before but not as loud as the aftermarket pipes.

Here is a video of some guy doing the same, i guess mine sounds like the middle sound byte...


[video=youtube_share;VI4EKf4Jr3c]http://youtu.be/VI4EKf4Jr3c[/video]

The muffler in the video is from the North American model and is not the same as ours as you probably noticed. Other than the spark arrestor and the fact that its bolted in, I don't know how much different they actually are though.

 

[Thump]

bsacbob, highly interesting operation, there shouldn't be anything left in that can?

Looks like all the walls and pipes plus the cat came out. But if it's empty and has no damping material it should be loud!

What size diameter end pipe did you install?

I rented a CRF250L in Phuket which had a similar operation, don't know exactly how much they took out, it had a 2" end pipe.



The sound was surprisingly good but a bit too loud for my taste. Maybe a 1,5" end pipe would be just right.

 

[Thump]

Here a couple of pics of my M with self-made luggage rack. I ride one-up and don't like the weight too far to the rear. Easy to install or take off.


Notice insulation material on the seat.

 

[bsacbob]

Thump, the rear bum hole is 1 1/2 inch pipe, the canister has been repacked with something, the same guy did my KLX and he packed it with a steel wool type material so i guess it's the same. It's obviously louder but not crazy loud, pops a bit going down the gears but i like that

He's done several others in Chiang Rai and no complaints so far.

Still waiting on the EJK box and then see how it goes.

Your bike looks great, have a look at taking off the rear light setup, you will be surprised how much it weighs !!

 

[Thump]

Did you take the rear lights off? If so, what did you replace them with and where did you hang the license plate? Pictures?

 

[CRF Rainbow]

from this shop in Cm - 100 metres from traffic lights past ping river on Narawat Road heading east
Bought these - a few different versions /options available. If going LED they also wanted to change the blinker can / relay???

 

[CRF Rainbow]

swapped the bash plate and got these handguards at same place

 

[bsacbob]

Co-ords For BNS Speed

N18.79471 E99.00162

 

[CRF Rainbow]

Nae at the Chiang Mai MX shop has been messing around making some aluminum panniers for the CRF, they don't look half bad.

Did bolt a set of these on and they as dodgy as. Hinge was sloppy, connections to frame was by hollow tube (would have preferred flat lugs with a hole since I have a rear rack fitted also), lid too tight and rubbed against boxes when closing, boxes sat at slightly different heights and also not square to brackets, 2 seperate keys, brackets stick out like cheese cutters when boxes removed. Luckily, hadn't paid for them so handed them back. Saw these Chase Harper throw overs for sale on this site and bought - are easily attached for when 2 up travelling or for when doing very long trips.

 

[CRF Rainbow]

more to come ...... rear rack and exhaust. Off to pick up modified OEM muffler now. Stay tuned.

 

[CRF Rainbow]

Road riding around 210km- 220km the light comes on, off-road variable with terrain around 170km -180km.

Has anyone measured the length of the forks between the 2 variants? If same, then me thinks the fuel gauge sender is at rear of tank because the light on my motard comes on at earlier k's (160-180) but still getting 32-35kms/litre.

 

[Thump]

Same here, the light starts flashing between 160 and 180 km, depending on how hard I rode. Usually I get between 3,3L and 3,5L per 100km. (3L/100km=33.33km/L)

If you fill the tank to the brim, 7,7L, and ride 200km using 3,5L/100km, you use 7L. According to the CRF manual there should be appr. 1,5L left when the light starts flashing, which would be at appr. 6,2L. The light should start flashing well before 200km.

At 220km my tank is empty!

 

[CRF Rainbow]

Actually, closer to 3.
40/14=2.86

Hang on a minute -
OEM settings for dirt configuration are
40/14 = 2.857143 revolutions at front for every revolution of tyre
If changing front sprocket to a 13 tooth, then 40/13 = 3.076923 revolutions at front for every revolution of tyre
Therefore - the equivalent gearing for a 40/13 with a 14 tooth front sprocket at 3.076923 revolutions, then 14 x 3.076923 = would require a rear sprocket with 43.07692 teeth - an extra 3.07692 teeth and not 2.86 teeth.
In ratio terms - 14/13 = 1.076923 - or nearly 7.7% lower gearing.
Hope that clarifies.

 

[CRF Rainbow]

rear rack

Having ordered the OEM rack with the bike I've since found a rack in CM which has grip bars for the pillion.
It is slightly heavier as made from thicker gauge tube and sits a few more millimetres higher which makes looping straps so much easier.
Had mounted the 40 litre Coocase on the OEM originally and easily mounts on the alternative.

 

[CRF Rainbow]

Air box

Had a sticky inside there today and removed snorkel and mesh from air filter as many others have done.
Noticed the air filter was cleaner in the top 1/2 than the bottom 1/2 - maybe because snorkel drops 2-3 inches into the box.

Removing the snorkel changes the angle of air input from outside of box - it is vertically when removed whilst horizontal when fitted.
Cutting off most of the snorkel that is inside the box still allows air to access the airbox from the same angle as if the snorkel was still in place.

Am wondering if the the filter wont cop as much crap in it if the outside part of snorkel is retained in housing?
Q - Has anyone cut the snorkel off at just under where it enters the airbox, and if so, did you notice any difference in air quality /degredation build up on filter?

 

[CRF Rainbow]

To see - or not 2 see.

Changed original 35/35W yellowish headlight with this - a huge difference.

 

[CRF Rainbow]

Dave - does he have the rear brake pedal/ lever with a hinged end too?

Did bend the OEM brake pedal as a result from an off the other night and was (too) easily bent back to original position.
Mr. Motocross very handy being right next to Riders Corner.
They looked reasonably well made to me.
Doubt I'll be able to change foot brake lever with tool kit supplied so will wait till I get home for that 1.

 

[CRF Rainbow]

Exhaust mods.

After 1500k's on original exhaust bit the bullet and installed a full sports system copy.
Sounded nice and reasonably loud (like to let others around me aware of me on the road) and it seemed to have more power in mid to top end.
Fuel usage seemed similar.
There are 4 guards over the exhaust system - 1 near front and 3 at the rear.
In regards to the rear 3 - only 1 has been re-fitted (more could be possible, I'm sure) but the 1 fitted back on to date has 2 screw attachments and the plastic doesn't sit in exact same position in relation to the plastic above it - would need to modify or change the bracket supplied with system in order to do so . Decided to look into this further when back home with more tool options than the one supplied with the bike.
Update - the bracket has 2 holes to mount the muffler guard and they are slightly offcentre. by reversing bracket guard sits on a cleaner line with existing plastic.
By buying a few hose clamps, an OEM bracket and speed clip did manage to re-install the front guard and it looks 1/2 reasonable.

BUT THEN

Went for a ride on Australia Day.
Following Gnasher up the 118 I noticed he didn't change down from top for any of the hills and I needed to a few times.
Midway along the 1150 to Phrao we swapped bikes and I immediately noticed more lower end in his compared to mine - could even ride in a gear (Gnasher thought sometimes 2 gears) higher on his bike than mine.
When travelling the last few k's into Phrao (back on our own bikes with Gnasher following me) we both rolled on from 90kph and he easily kept up. My speedo topped out at 127 and his at 132.
The point was further proved when on the 1001 later in the day he overtook at approx 100kph after we gunned them out of a left hander.

FYI, Gnashers mods have been to remove snorkel, the metal grid off the air filter and a gut to the OEM muffler at a joint in Trat Wong Road Soi 3.
Another difference between the 2 bikes is 1 Gnashers is a dirk bike and mine a motard.
In relation to top end am yet to do the sums on gearing, rear sprocket, wheel diameter, tyre size differentials between the 2 but that's for another day.

Thoughts while riding - Whilst mine originally seemed a tad better in middle to top end maybe it really because the bottom end now a bit ordinary and difference between 2 is more noticable. Am noticing it more as I roll on the throttle it seems to find a power band.
Gnasher had also tried a different full system at 1 stage which is more suited to high speed tar hooning wheras his current set up he says is more user friendly on trips and different terrains.

Resultant Strategy -
Yesterday I visited this after market metal joint in Trat Wong Road Soi 3 with my OEM strapped on the back (no pics - go and see for yourself, is an eye-opener) and was advised to come back today to pick up the modified muffler (1000baht). When I visited this arvo I was told to come back in another 3 days time. We agreed on 2 but time will tell if it is ready then. 6 blokes in the workshop.
Later today - came back to unit and took snorkel off (see earlier post) and removed air filter metal grill.
Tomorrow - Go ride seeing how stage 3 (after mod 2) and compare.
In a few days - Go back to shop and have OEM system put back on bike along with with modifed muffler (hope they do exactly what they did to Gnashers) and I'll take for another ride and compare.
Will revert.

 

[Thump]

I realized that it would be a hassle to attach the rear guard to an aftermarket exhaust or slip-on (if it doesn't come with attachments).

Without it the subframe shows and it doesn't look right. Without the matte black part it doesn't look right, either.

Problem is that the guard attaches to the muffler, not to the subframe. So I decided to keep the stock muffler and cut it open.

 

[Thump]

In a few days - Go back to shop and have OEM system put back on bike along with with modifed muffler (hope they do exactly what they did to Gnashers) and I'll take for another ride and compare.

Do you know what exactly was done to Gnasher's muffler? Are there any photos? - I am interested since I'm in the middle of the operation.

 

[CRF Rainbow]

Do you know what exactly was done to Gnasher's muffler? Are there any photos? - I am interested since I'm in the middle of the operation.

Not exactly - only what he has told me. And I have no photos of the rear of his bike.
The metal shop where I took the muffler asked "You want us to do the same as we do to your friends", to which I said yes please.

 

[Thump]

I wonder if they only mess with the walls and pipes or if they install a perforated metal core and pack it with damping material.

 

[CRF Rainbow]

I wonder if they only mess with the walls and pipes or if they install a perforated metal core and pack it with damping material.

opened it up from both ends, gutted the inside, fitted new perforated metal, packed it with this (see pic) and sealed it back up.
Looks like fibreglass but doesn't feel like fibreglass and doesn't burn.
They warned me it would itch to the naked skin however it doesn't.
Showed it to 2 others today who support this thought.

 

[Thump]

That looks like my hairpiece! Just kidding, I still grow my own.

That's the way to go, gut it, weld in a core and stuff it with packing.

I left the catalyst in, it should cool it and keep the noise down.

Had a ss core done for only 300 baht! FMF muffler packing is on the way.

 

[bsacbob]

That looks like my hairpiece! Just kidding, I still grow my own.

That's the way to go, gut it, weld in a core and stuff it with packing.

I left the catalyst in, it should cool it and keep the noise down.

Had a ss core done for only 300 baht! FMF muffler packing is on the way.

View attachment 26105

Looks nice ,let us know how the end result turns out..

 

[Gnasher328]

They cut and burnt everything out, then installed a perforated tube surrounded by wadding.
Much quieter than the 'Yoshi' copies and difference in performance is staggering, made a bike that struggled into a real contender. Next comes the CBR throttle etc. But that's after I get Honda to address the dreaded 'rattle' under warranty.

 

[2wheels]

Having ridden Tim's bike I can say that it sounds good (and not too loud) and, more importantly, it hangs on to the higher gears much
better than an original bike.

However, I think I heard Ian referring to added back-pressure which may affect valves.

 

[2wheels]

Tim, that 'rattle' may be the cam chain.
Khun Lan at C&P Rental knows a lot about the issue.

 

[CRF Rainbow]

Having ridden Tim's bike I can say that it sounds good (and not too loud) and, more importantly, it hangs on to the higher gears much
better than an original bike.

However, I think I heard Ian referring to added back-pressure which may affect valves.

I think my reference to back pressure may have been about the size of the pipe when it comes out of the motor.
The larger pipe is liable to have less (and maybe not enough) back pressure and hence the OEM smaller diameter pipe may be better than what's on the larger one on the full system I bought.
Airbox mods done yesterday definitely made a difference on todays ride.
OEM outlet pipe and OEM modified muffler goes on tomorrow - Will revert.

 

[Thump]

Hi Gnasher - great pics! What about the cat? Did it come out, too? By looking at the length of the core, yes.

But I wonder how they got it out of there without cutting the conical part open close to the header/mounting point.

The boys in Phuket also went with a 2" endpipe outlet, but the bike was a bit too loud for my taste.

Any pics of the inside of the can?



The cat sits in the conical part to the right of the ruler.

 

[Gnasher328]

More silencer surgery pics.


They burnt out the thelarge end and cutting at the inlet released the cat then they welded it all back together. Same size, same fixings.

 

[Thump]

So it's practically a straight-through with a 2" core and damping material. With a 2" end pipe it must be loud!

I'm riding mine at the moment without walls/pipes but with the cat in and a 1.25" end pipe and it's a bit too loud for my taste.

No difference in performance, maybe the cat has to come out to give it some more flow.

 

[CRF Rainbow]

My muffler surgery and rehabilitation

Both surgeon and patient thought it was a successful operation.

Post-op ride saw an increase in both low end pick-up as well as a more even and continual pull through full rev range.
Being caught in too high a gear also not as much of an issue now than as was with full system sports setup.


Nurse Thip suggests going away for 3-4 days travelling the north east in cleaner air will aid recovery

 

[Gnasher328]

Great stuff CRF R'bow.
Thump, re noise, most of my bikes have loud pipes but I felt self concious and antisocial with the 'Yoshi'. The modded std pipe is much better, even Ron was happywith the noise. Don't mess about - gut it out!

 

[CRF Rainbow]

Decent rear brake - would like more bite.

Anyone else thinks there rear brake hasn't enough bite?

Anyone come across an alternate pad option solution?

 

[Thump]

Great stuff CRF R'bow.
Thump, re noise, most of my bikes have loud pipes but I felt self concious and antisocial with the 'Yoshi'. The modded std pipe is much better, even Ron was happy with the noise. Don't mess about - gut it out!

I've always messed with my exhausts but I like a deep, soft sound, and it should not be embarrassingly loud.

I rented a CRF250L with a gutted muffler and a 2" end-pipe which sounded alright in traffic, but when I returned to the bungalow resort after dark I coasted in because I didn't want to attract attention. Also on longer trips a loud exhaust gets on nerves even though most of the sound stays behind me.
But I changed my mind on the cat - I think it has to go because I read that without it the bike performs a tad better. I'm sure that thing slows the flow down! Also it's an easier job than welding in a containing wall for the core and the packing.
Maybe a 1.5" end pipe will do the trick.

 

[Gnasher328]

Did the rental have core and packing? Mine now sounds just right, like a real bike. Just take it to the place where I took mine, they know just what to do. Cost me 1kBht although I think CRF R'bow paid a bit more.

 

[Thump]

Well that would be quite a trip just to get the exhaust done!

Frankly I don't know what they did to the rental but they must have done the same as you did, everything out. I just wonder how long the fiberglass will hold up.

I got the core and heat-resistant FMF Racing muffler packing is on the way from the US; the local muffler shop does a decent job.

See the weld on the left in the pic with the ruler? I got on their case to make it clean!

Amazing what you can get done for a few hundred baht!

 

[bsacbob]

Been looking for some paddock ear's for the CRF, found these from Dirtshop Thailand http://www.dirtshopthailand.com/en_ProductsDetail.aspx?pid=1893

 

[CRF Rainbow]

So it's practically a straight-through with a 2" core and damping material. With a 2" end pipe it must be loud!

Is a 1.5" pipe both through the middle and bum hole.
Exhaust workshopshop/factory also built the muffler on the sports system but not the balance of the pipes - they tell me.