Spark plug insulator around electrode broke off in the motor

[TGM_OFFROAD]

Originally Posted by Zman

I do not know what heads you have and if they have been modified. My point is that squish is independent of compression ratio.

I would assume that a stock unmodifed head should be fine for 100 octane fuel. I have been on this site for many years we have come across some factory built bikes that were machined differently than others and some bikes that were shipped with different parts.



Your detonation situation seems out of the ordinary so I would assume nothing.

It is really odd, it had done it with my stock gp head, rk tek head set for pump gas and the s3 low compression and high compression head. It passes a pressure test with flying colors so no air leaks. My only other thought is timing which would have to be a cdi issue on this model. Hopefully I can get a new one tomorrow or wed.

[gasgasman]

What is the number on the spark plug?

Heat range may be wrong for your bike.

[TGM_OFFROAD]

Originally Posted by gasgasman

What is the number on the spark plug?

Heat range may be wrong for your bike.

Br8eg as the manual specifies

[Doc Brown]

Originally Posted by TGM_OFFROAD

It is really odd, it had done it with my stock gp head, rk tek head set for pump gas and the s3 low compression and high compression head. It passes a pressure test with flying colors so no air leaks. My only other thought is timing which would have to be a cdi issue on this model. Hopefully I can get a new one tomorrow or wed.

Considering it does it with all the head inserts you mention I doubt the problem is compression ratio. If it would be close to the technical limit then pinging would stop or at least be reduced by using 100 octane or race gas.

I agree that trying another/updated CDI could solve the problem. The BR8EG is the more expensive brother of the BR8ES and both are cooler than what other brands, like KTM, use in their 300's. I think it has nothing to do with the spark plugs...

[TGM_OFFROAD]

So I did get 3 new to me cdis to use, the first one I tried at home seems to be easier starting and the bike sounds different so I am optimistic but won't know for sure until I get out on the trail.

[Zman]

That sounds promising!

[Doc Brown]

Yep, sounds good. My dealer said the purpose of the CDI update on my GP 300 was easier starting.

When I bought my first and later my second 2019 EC I asked him about the update but he said it is not necessary on the 2019's. Unfortunately I do not know why.

As the 2019 does not have the Hydria Ignition System anymore I assume that the 2019 CDI is different.

[Zman]

I did some research with different CDIs on my GG300. The bigger engine did not "like" the smaller bike 125 and 200 CDIs. It would flame out at very low rpm, it was difficult to start and it was prone to detonation. Maybe your bike came with the wrong CDI, the CDI failed or that CDI was build with the wrong parts.

[TGM_OFFROAD]

Originally Posted by Zman

I did some research with different CDIs on my GG300. The bigger engine did not "like" the smaller bike 125 and 200 CDIs. It would flame out at very low rpm, it was difficult to start and it was prone to detonation. Maybe your bike came with the wrong CDI, the CDI failed or that CDI was build with the wrong parts.

I have tried to research the cdi that came with the bike, but there is limited info out there that I could find and the part numbers are confusing.

The p/n on the cdi that was in the bike is ee51100ct-clk-1 but all the info I found shows ee51100ct-clb-1 as the stock cdi.

Detonation was definetly and issue and it did also seem to flame out from time to time but being my first 300 and coming off of a flame out king YZ450 I thought it might just be normal.

I am hoping to take the bike out tomorrow for a real ride but everything is day to day right now with all the lock downs in place due to COVID19

[TGM_OFFROAD]

So I switched over the cdi with the stock jetting and wow what a difference. The power picks up from the bottom with little to no hesitation and pulls all the way through. Zero pinging or detonation. Pulled a longish hill climb wide open amd got to the top and the idle dropped right down where it should be. The bike sounds completely different and feels like I thought a 300 would. I am finding out that prior to this my bike was extremely under powered especially in the low end. I lugging in 3rd and 4th gear in placed where prior to this I would need second or even first. I will get a video up soon but damn I am excited. This was a long expensive journey but I am soooo happy with this bike now and just want to get back out and ride. Its too bad the timing is horrible with the covid 19 pandemic and riding areas getting shut down till this is over.