Crm slow acceleration?

[Darrylmartin]

Hello! just bought my first crm 250 (mk2)... i do love it but im sure its ment to be faster on take off... its like riding a Dt125r? ... it has had a top end rebuild.. so im guessing its something to do with powervalve... only thinking this after reading alot on the forum.. what are your thoughts peeps?... i have had motorcross bikes in the past and this thing is nothing like a crosser... my brother has a kdx 200 which would beat my crm no probs... hes a vid i made https://youtu.be/O4-fZCmG7UE incase you are wondering the bike is in malta... im british and moved from the UK to malta (europe) last year... enjoy

[harveykrumpet]

Hmmm. I'm not really in a position to comment to much on the CRM. I've only managed a few short jaunts on gravel and I'm still not happy with the jetting.
I got the CRM off my father who now has a KDX200 SR. In his own words the KDX feels like it has a Briggs and Stratton carb on it. Not much going on, in other words. He's a bit miffed.
The other chook chaser in my shed is a DT 230 Lanza. A very different bike and as quick if not quicker than the CRM but the power delivery is very linear, no real step up when it comes on the pipe. The best way to gauge it's pace is how far your eyes pop out approaching a corner.
On my last squirt on the CRM if I used the throttle as you are in the video it would be getting the front end light unless I had my weight forward, hard to say from the vid but mine seems to pick up revs quicker and come on the pipe earlier. It is a bit fluffy off the bottom but I can only compare it to the DT. I briefly had a KDX250 SR with a fatty pipe which had bugger all bottom end but wheelied off the throttle in every gear when you got up it. Very much like a MX bike. And bloody scary.
My CRM is pretty sharp but not brutal.
Hopefully far more experienced owners than myself will pipe up. Heh heh.

[Darrylmartin]

Haha Thanks bud! My front wheel is certainly not going to lift of the ground very easy lol not unless I Rev it right up and dump the clutch! I could wheelie my dt125r easier than Crm..... I'm sure something is not right... It's just good for top speed and crap on take off

[Darrylmartin]

Also I took off front pipe to look at power valve flap... And it won't move..... Surely it's meant to..

[knackeredMk1]

Take the cover off the PV and watch it while the engine is running and you are moving the throttle so the engine goes from idle to revving. Watch if and how it moves.

Make a video if you want to put it on here?

[Darrylmartin]

Thanks for reply.. I took the cover over the power valve and revved it up and it's working fine.... Works just like the one on the YouTube vid... I don't get it.. Confused.... What else could it be.. I will do a vid also

Thanks

[fallenmikethebike]

Hi, I thought initially that was Xlendi on Ghawdex for the first few frames of the vid.
The engines revving out, it's a clean rev as well. What gearing is it running?
The balance shaft bearing has a familiar whir to it.
If possible check the compression it's making.
BUT, at the end of the day you need to compare your 20 year old TRAIL bike bike with similar mounts.
Mike

[knackeredMk1]

What gearing have you got? Teeth on the front and rear sprockets?

[harveykrumpet]

BUT, at the end of the day you need to compare your 20 year old TRAIL bike bike with similar mounts.
Mike

Nail. Head.
I wonder how many of the modern Katooms and valve bouncers will be still be loved in 20 years time.

Another thought. Check your air filter. Might be worth gauging the amount of spooge in your pipe, too.
I was using a cruddy air filter in the DT for quite awhile until I managed to source a new one from Japan. Hello! It was like a new bike.

[fallenmikethebike]

BUT, at the end of the day you need to compare your 20 year old TRAIL bike bike with similar mounts.
Mike

Nail. Head.
I wonder how many of the modern Katooms and valve bouncers will be still be loved in 20 years time.

Another thought. Check your air filter. Might be worth gauging the amount of spooge in your pipe, too.
I was using a cruddy air filter in the DT for quite awhile until I managed to source a new one from Japan. Hello! It was like a new bike.

+1, additionally 2T 's are adversely affected by a lack of maintenance to the following, plug, mixture, fuel age, fuel combustibility, oil type used, poor electrical system, in a way 4T are less prone too. Although simpler in design, the bits that do work, all need to work in harmony.
Mike

[Darrylmartin]

Morning all! i was running 13/45 teeth in that vid... and now im running 13/39 teeth... thats why i am scratching my head.. because in the vid its got 13/45 which should give me good acceleration?.... but there is just no power on take off?... and the air filter/sponge is not that old and crusty its in great condition........i have had a better look at the bike... and it has had a complete rebuild... i can see the nice green gasket still... so im really not sure whats going on...are they restricted ?

Thanks for the comments peeps

[Darrylmartin]

could it be that the flap is stuck on the exhaust port? although the power valve is working.... im just thinking the powervalve flap might be stuck? also i will do a compression test soon. and fallenmikethebike its not in Gozo... but very close hehe, https://youtu.be/z51cA0cLKgE

[Darrylmartin]

Kinda hoping my crm was going to be like this lol https://youtu.be/-UCpzAJ_ORs

[knackeredMk1]

Could be any number of things or combinations. Is the exhaust system clean? How's compression? What's the bore wear like? Correct carburation? Worn gear box/wheel bearings? Brakes aren't releasing completely? Wrong throttle activation? Knackered chain? ............. You're going to have the check everything.

[fallenmikethebike]

The definitive answer to the power being made would only come from a rolling road BHP test.
Up hill power wheelies should be a doddle, even on something underpowered, with a little technique.
You have some delving to do, are the carb jets right? is the needle in the right position, is the plug dirty?
The timing won't be out as it can't be altered. Can you get the compression tested?
I run 14/45 gearing on my MK3, and that will willingly lift the front end.
Check the pilot jet, and needle jet first for correctness and settings, no power from the off might indicate a lean bottom end mixture, or much to rich you see the problem
Mike