How Hot Runs A Beta3 270?

[eugenevd]

Hi trialistas!

I've recently finished taking apart and rebuilding a '05 Rev3 270 I got my hands on.

I went out today for the 2nd time after that (woot! loving it! ), and when I got home (rode home, 3rd/4th gear low/medium revs) I noticed how hot the bike was. The pipe is extremely hot, then the engine, the frame and fuel tank area was warm, so the silencer and even the swingarm!

Is that normal ??

(It has new coolant topped up. The fan comes on. The bike runs fine once warmed up, no issue to report. No coolant came out the overflow, ie no boiling that I know of.)

The only thing I can think of is: the bike had water pump area corrosion that I fixed up, so I'm wondering if the impeller is spinning; how would I be able to check that?

Thanks

Eugene

[shercoben12]

Check your carb is not too lean as this may cause it to run hot

[shercoben12]

Take the pump cover off and kick the bike over while turned off and see if the impeller is turning

[eugenevd]

If I lay the bike on it's side before taking off the water pump cover, will I be able to not lose all the coolant?

[shercoben12]

Not too familiar with betas so I don't know. Someone will though

[eugenevd]

Pulled the spark plug:

Before the rebuild the spark plug gave me the impression of an almost too rich carb. I didnt change anything ito the carb settings; could it maybe be that a different cylinder gasket thickness would cause this change, or the ones around the intake valves?

I didnt actually check to get the same ones, just new ones...

Edited February 8, 2013 by eugenevd

[b40rt]

Timing can also affect engine temp, worth checking.

[eugenevd]

I retract what I said in my prev. post re. the spark plug color! That was light choc brown; for up to 1/4 throttle.

I had the bike on it's side and was able to pull the water pump cover with minimal coolant loss. Moving the kickstarter shows that the impeller does turn; first thought: how effective is that impeller!?

Then, I pulled off the carb and cleaned it thoroughly. I didnt get the impression that anything was blocked or worn.

I did the carb tab and tangs adjustment as per Billy Traynor's notes found elsewhere on this site.

I then continued jetting the carb.

Turning the air screw has little effect; ie, there isn't a peak anywhere, just a slow general raise of revs as I continue to screw out. This I understand indicates that I need a smaller pilot jet. Regardless, setting the air screw at about 2.5 turns out and doing a 1/8 throttle opening ride and engine kill reveals a decent looking spark plug color.

Onto the needle which had the clip in the top position. Did a 1/2 throttle run and chop. Didn't feel like the bike was running funny. Had to wait for the bike to cool down, but not too much. Spark plug white.

So then I dropped the clip two positions (into the middle position). Did a 1/2 throttle run and chop, bike felt like it was running sligtly less clean. This time the bike was much hotter, silencer too hot to touch, mostly everything else. Spark plug STILL white.

I took the airbox off and had a look at the boot between it and the carb, no obvious cracks.

Soooo, drop the clip two more positions and call it a day. Will test it in the afternoon after being a spectator at a local event...

With all the needle clip changes I started to wonder how important is it to have a good seal where the throttle cable joins the carb?

Edit:

Carb:

?2.5 ehm, I think this was the float valve

27.5 Pilot

140 Main Jet

2.0 Slide

5C23 Needle

Temp here: 20-30'C (summer)

Altitude: +- 1440m

RE: TIMING

I read up on the timing thing; it seems that if advanced, one would find higher temps andkickbacks on the kickstarter. I don't have the kickbacks, but I do have the temps. Or am I just pedantic?

I've searched around for a guide/howto on checking /adjusting the timing, but found none, any help? (I've never done such a job)

Edited February 9, 2013 by eugenevd