Chad / Gordon / John et al.,

I'm still down & out. It took 7 weeks to get my parts: throttle cable, throttle pulley & gaskets (de-carbed the head). Got everything together following the Montesa Owner's manual very carefully. The bike is still over-taching.

Any of you guys got any ideas?

Here are the details:

Problem: The carburetor on my 2002 Montesa does not seem to be functioning properly.

The subject problem has been occurring for some time, thus, I completely disassembled the carb. & thoroughly cleaned it out with carb. cleaner. I replaced the throttle cable, also. None of this resolved the problem as indicated below.

Problem Description: If I tach up/throttle up approx. anything from 1/8 - 1/4 turn it takes a real long time (averages 30 secs. & more) to settle back down to idle, although even this scenario tends to be inconsistent (re: time to settle down to idle). If I tach up/throttle up anything more than ¼ turn (esp. >1/2 turn), the tach. stays up & does not return to idle at all.

In each of these scenarios I am 100% positive that the throttle returns/snaps back to its original position. You can see the very slight amount of slack in the throttle cable up at the throttle housing as a sanity check to confirm the throttle cable or needle is not sticking.

I made sure that the motor warmed up at least 15 minutes before I adjusted the Air Screw & the Idle screw after their original stock settings. After approx. 1 hr., I was not successful in arriving at the optimal combo. settings.

Questions / Potential alternative options:

1) Throw the bike off a 2,000’ cliff to see what will happen.

2) I am wondering if I took the bike to a Honda dealer (re: HRC engine) if they would be able to resolve this carb. problem or at least diagnose the problem. There are no Trials shops near where I live.

3) I could procure & replace specific sub-components that "may" be the culprits related to the subject problem:

-Air Screw
-Idle (Throttle Stop) Screw
-Float / Float Arm / Float Arm Pin / Float Valve Set
-Slow Jet 1
-Slow Jet 2
-Needle Jet
-By Starter Jet
-Main Jet

4) I guess #3 is included in a "Carb. Re-build Kit." What exactly is defined as a Rebuild Kit for a Montesa if it exists?

5) The major problem that I am facing is that I do not know exactly how to diagnose the specific problem at-hand or exactly what part(s) need to be replaced (if any?)

6) I’m wondering if I could ship the carb. to an authorized Montesa dealer for diagnosis & repair. Not sure if anyone has a test bench or equipment to do this.

7) The absolute worst-case scenario would be to order an entire carburetor & swap out the old carb. & my problem would then be resolved. Obviously this would be very expensive but probably would be a
successful resolution to the problem.

Any assistance or suggestions in selecting the best course of action would be greatly appreciated.

As can be imagined, I just want ride again...

Thanks,
Doug

sounds like an air leak in the bottem end. have you checked for this possibility?

Doug I remember how your bike ran the day we were at TNT and I did not consider an air leak !! As Chad pointed out the routing of the throtle cable is very important ! I would suggest you arrange to have one of Chad's mechanics check out the carb / Bike combination ,I am in the process of relocating and as such have no free time . Later I will be able to help ,I think you have a dirty pilot jet (running lean at the low throtle opening ) to clean a carb properly you need compressed air all the passages need to be perfectly clear !! Again I recommend having the bike checked out ( then all the factors can be addressed ) Trust me the cost will be well worth it !! Then we can get back to the fun part and ride again . Hope this helps,keep me posted !! cheers Gordon

Sounds like a possible air leak. When it's idling ok try spraying some carb cleaner around the intake manifold boot and see if rpm's change, if so you found the problem. If it's still an airleak and it's the right crank seal it should be pulling in trans fluid and smoking more than normal. If it's the left crank seal try removing the flywheel cover crank the bike and try to spray some carb cleaner behind the flywheel if that's the problem you should again hear an rpm change. Also spray around the head gasket and base gasket(again while the bike is running)
Hope this helps
Rick Caron

Genlemen,

I am definitely going to try spraying the carb cleaner around the intake boot & the other locations.

What really concerns me is I do recall getting some smoke on my last ride. Also, I noticed some gear oil on my bike stand yesterday. Rick - you might be onto the culprit, here. Maybe there is a crankcase seal leak somewhere. I'll keep hunting around.

Also, I'll tear down & clean the carb, again, if there is no response on the carb cleaner spray scenario. It may be the slow jet since it stalls out if left at idle for more than 10 seconds without touching the throttle & stays tached way up if tached over 1/4 turn.

Chad - Aiken is about 2+ hrs. away from Clover, SC. If all else fails, I'll bring the bike down.

Gordon - I keep thinking about Kings Mtn. esp. since I've driven by it several times. Hope this works out in the future. I was hiking up at Nanny Mtn. the other day but they don't want you riding up there even though I did see an ATV flying around.

Thanks everyone,
Doug