Tec Camshaft + Big Bore too much compression to kick over

[JebGrep]

Hi forum members!
My mechanics are working on installing the big bore kit in my 2018 carby himalayan right now, theyve come back to me with the work done saying the engine wont kick over. They've eliminated other variables and are saying that there is too much compression post install for the starter system. A TEC camshaft was already installed and broken in last year, which does not include the decompressor function of the factory camshaft.

Has anyone else installed the kit with the TEC camshaft in their system? I feel like this is one of the two more popular combinations so I'm surprised to find there isn't much on this issue online already. Which makes me wonder if there isn't something else going on. Firsts thing first tho, has anyone here installed both these components succesfully without further modification?

 

[Dool]

What Compression is being recorded?
Being a Carby model there is a trick to checking the compression.
What condition is the battery?
Stock cables are barely adequate.

 

[sam2019]

Carby model, you lucky bastard! no hassle with maps and ECUs

I do have our HT-b cam in 1 of my carby and one of my BS6 (ECU) 477 and these cams also do not have a decomp.
I do have startup "problems" regularly - meaning I usually need 2 attempts - depending on the piston position. If the piston is near top then the voltmeter will show of a fraction of a second 5 volts because the starter tries to overcome the compression alone and that never works. as soon as I give the piston some travel room to top dead center it will always start. Dool and others suggested that a better cable from the battery to the starter can overcome this problem. Me being lazy I live with the 2-startup approach. Sometimes I have to move the bike slighlty in gear to move the piston but mostly it will start by itself on second attempt. On the 500cc which has a higher compression that is not the case and starting that bike became a headache so I had to give it the newer HT-C cam which has a decompressor (but less power gains, due to the decomp and also due to a slightly different torque distribution curve).

hope that helps.

and yes, what is you compression in PSI?

 

[sam2019]

Has anyone else installed the kit with the TEC camshaft in their system? I feel like this is one of the two more popular combinations so I'm surprised to find there isn't much on this issue online already.

The reason there are no more TEC / BB combos here is basically that our HT-b turned out to be better than the TEC so ppl changed over. There where a few in the early days but TEC also for a while was not available if I remember correctly. And of late they started to smear the competition which may not have helped with their reputation.

 

[sam2019]

before I forget: you should change both jets, 125 to 130 and the pilot 1 up too. and Dool recommands to "slim" the needle a bit as well, which worked good for my 500 (which has a 135 main jet and is now a rocket!)

 

[sam2019]

also this was discussed here from message 15 onward

HT-b cam - improved version

16. November 2021, 22:43 Dool introduced the new HT-b version of our cam. There was some confusion (in the dyno-charts thread) because he failed to make it clear that this indeed is a different cam he is now testing (on his second "stock" Hima). The result seems much better than the TEC and we...

forum.himalayan-tools.com

 

[Dool]

Buy the HT-C with decompressor

 

[JebGrep]

Buy the HT-C with decompressor

Hmmm not a bad idea, mechanics are justifiably anxious to get this one out the door though after two months waiting for parts :s

I can't see an HT-C for sale on the site however? Just the HT-B?

 

[JebGrep]

before I forget: you should change both jets, 125 to 130 and the pilot 1 up too. and Dool recommands to "slim" the needle a bit as well, which worked good for my 500 (which has a 135 main jet and is now a rocket!)

I provided two larger sizes of main and pilot jets, I will pass on your advice about slimming the needle thanks

 

[JebGrep]

What Compression is being recorded?
Being a Carby model there is a trick to checking the compression.
What condition is the battery?
Stock cables are barely adequate.

So replace the stock cables? Whats the situation there, the cables gauges are too thin to carry the load? I can probably do that myself once I have the bike back. The battery was new 6 months ago and they have said its basically done, they have tested with a brand new battery and its still not kicking over, hence their focus on investigating compression issues.

I'll call the mechanics tomorrow to ask what PSI they are getting and report back.

 

[Dool]

So replace the stock cables? Whats the situation there, the cables gauges are too thin to carry the load? I can probably do that myself once I have the bike back. The battery was new 6 months ago and they have said its basically done, they have tested with a brand new battery and its still not kicking over, hence their focus on investigating compression issues.

I'll call the mechanics tomorrow to ask what PSI they are getting and report back.

Look around, there have been reports of starting issues, some seem to be related to switches like the Clutch.
Rock back in high gear first and give the starter a good run up, then try starting.
Might get better with time.

 

[Old Man Himmie]

So replace the stock cables? Whats the situation there, the cables gauges are too thin to carry the load? I can probably do that myself once I have the bike back. The battery was new 6 months ago and they have said its basically done, they have tested with a brand new battery and its still not kicking over, hence their focus on investigating compression issues.

I'll call the mechanics tomorrow to ask what PSI they are getting and report back.

I replaced the stock cables with heavier gage cable and also the stock solenoid just because the cable ends are epoxied in. I haven’t had any issues whatsoever with turning over since. There’s too much voltage drop with the OEM starter cables. Both ground and feed cables.

Post in thread 'Starter motor improvement'
https://forum.himalayan-tools.com/threads/starter-motor-improvement.299/post-1742

 

[bcrist]

Hi forum members!
My mechanics are working on installing the big bore kit in my 2018 carby himalayan right now, theyve come back to me with the work done saying the engine wont kick over. They've eliminated other variables and are saying that there is too much compression post install for the starter system. A TEC camshaft was already installed and broken in last year, which does not include the decompressor function of the factory camshaft.

Has anyone else installed the kit with the TEC camshaft in their system? I feel like this is one of the two more popular combinations so I'm surprised to find there isn't much on this issue online already. Which makes me wonder if there isn't something else going on. Firsts thing first tho, has anyone here installed both these components succesfully without further modification?

I had the TEC camshaft installed with the 477 kit, eliminated the clutch and kickstand switches, and the engine started pretty much the same as when it was stock. Since then I have added the red box ecu, Delevic exhaust, foam air filter and a fresh battery. Still starts fine. Mine is a ‘21, though, so maybe there were some changes made to the starting system between ‘18 and ‘21? Doesn’t seem like the addition of fuel injection on my bike should affect the engine cranking ability. I do keep the battery attached to a charger when I’m not riding.