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Discussion Starter #1
Ok, so the rubber idler gears tend to be an issue, in digging around, I found metal ones for the cl 350's ext available. and apparently the CT70 ones are interchangeable 9 or a least usable) but still rubber. does anybody have a line on metal, toothed idler gears for the groms? preferably on a proper bearing?

or does any body know if CL350 ones will work? found these on ebay, look promising.
 

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Its on a bronze bushing, right? (looks like it, at least) I dont see any issue using that, as the CB350 reved higher than the grom does.
Although, at 115$ for the pair, i wouldnt be running out to buy them just as a test.

Id personally prefer to stay in the nylon department, as it is self lubricating, but with oil right there, I could see the use of metal idlers.
I think nd4spd said that the CRF70 used nylon/delrin/some other plastic rollers, and ive been meaning to get some, when mine go bad. I suspect one has, because after my rebuild, running at 8k+ was quieter than before, but now, the noise is back again. (strangely enough, it quiets down after 10k or so)
 

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Discussion Starter #3
nope the 350 ones are on a needle bearing. nylon is not self lubricating BTW, unless its designated as such. heat and chemicals break down the rubber wheels, the added tension just makes it worse.
 

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dont remember ever seeing a crf70 using a nylon / non rubber rollers. I think i was referencing the fact they (crf50/70) use a very similar cam chain tensioner setup, and that they make manual cam chain tensioners for them that could possibly be used for the grom setup.

My valve train is NOISY, but thats due to the cam, finbro springs, and i think most of all, the nylon button (bolt) that floats on the top of the tensioner rod, it all kinds clacks together at idle, but when running its fine.
 

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Maybe a handy dandy machinist type fellow with a nice lathe could turn a high durometer skateboard wheel to fit with some abec 7's or something?
 

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FinBro just released an upgraded cam chain roller. Unsure of it's composition (looks like nylon), but I imagine it is likely a beefier OEM sourced part
Around $50 plus for them verus

Bikebandit OEM replacement
3: ARM COMP,CAM CHAI 3154732 14500-K26-900 1 Ships within 3 to 4 business days $20.38 $19.16

Hollisterpowerhouse
003 ARM 14500-K26-900 001 $20.38
 

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FinBro just released an upgraded cam chain roller. Unsure of it's composition (looks like nylon), but I imagine it is likely a beefier OEM sourced part
It's a xr/crf50/ct70 (and I'm sure it fits a few others) idler wheel. Toothed rubber.
 

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Around $50 plus for them verus

Bikebandit OEM replacement
3: ARM COMP,CAM CHAI 3154732 14500-K26-900 1 Ships within 3 to 4 business days $20.38 $19.16

Hollisterpowerhouse
003 ARM 14500-K26-900 001 $20.38
Cisco,

Once you start ripping on your four valve engine and shredding the wheel on that cheap arm in less than 500 miles, it will get annoying quick. They are cheap but you have to pull the LH cover and flywheel every time to replace it. I just changed oil after the crawl- surprise surprise, rubber bits everywhere. I just put a new arm in before the crawl. I shred wheels in 250 miles or so if I'm riding hard. The arm is $20, wheel is $15 maybe? Biggest thing is getting the pressed on wheel mount off and then TIG welding it back on from the backside without introducing too much heat.
 

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Ok, so the rubber idler gears tend to be an issue, in digging around, I found metal ones for the cl 350's ext available. and apparently the CT70 ones are interchangeable 9 or a least usable) but still rubber. does anybody have a line on metal, toothed idler gears for the groms? preferably on a proper bearing?

or does any body know if CL350 ones will work? found these on ebay, look promising.
I tried to find what size the cl's cam chain was- no joy. If it is the same pitch length it should work. I think a tensioner slider setup could work- just find a suitable bike, hack up the slider assembly and mount it onto a modified arm to ride on the slack side of the chain.
 

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Im going to have my engine apart this week/coming days (smoked the engine today, not sure if i melted the piston, or blew the head gasket), so im going to take the time to find some better wheels, whether it be delrin, or metal.
 

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The only way to solve this cam idler issue is to change the whole unit to a slider unit, like its made in daytona anima and yx140/150/160 engines. They are the same family horizontal single honda engines like on the grom, they are showing 20-28hp easily on 12k rpm and there are no any issues with that setup. I don't know why any of the parts supplier still didn't make a special cylinder with this kind of tensioner mechanism on it. May be the stud pattern is too narrow on the grom to make it fit (but Api Thailand is making these cylinders already but they are 140cc only). May be thats why Kitaco released their 2V kit, not a higher-revving 4V kit knowing this idler issue.
 

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Discussion Starter #18 (Edited)
Honesty, a bearinged wheel would last the longest. hm. might have to do some research

edit: ordered a metal wheel. I bit the bullet, will report back. $70 gamble but IF it eliminates that turd rubber idler, we are golden.
 

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Honesty, a bearinged wheel would last the longest. hm. might have to do some research

edit: ordered a metal wheel. I bit the bullet, will report back. $70 gamble but IF it eliminates that turd rubber idler, we are golden.

PLEASE do report back!!! If its an easy slide off the old wheel on the arm n slide it on 70 bucks is worth it.
 
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